E L E C R A F T K 1 T R A N S C E I V E R
BAND
DISPLAY
MENU
E L E C R A F T
RIT/XIT
TX
RX
K 1 T R A N S C E I V E R
EDIT
+
AF GAIN
RIT
-
+
XIT
O W N E R’S M A N U A L
ATTEN
WPM
FILTER
WPM
ATTEN
MSG
TUNE
+
1
-
2
E
LECRAFT K1
Multiband
CW Transceiver
Owner’s Manual
Revision I, April 15, 2011
Copyright
2011 Elecraft, LLC
All Rights Reserved
Elecraft www.elecraft.com P.O. Box 69 Aptos, CA 95001-0069 (831) 763-4211 Fax: (831) 763-4218
2 ELECRAFT
Table of Contents
1. INTRODUCTION....................................................................................................................................................................................3
2. SPECIFICATIONS................................................................................................................................................................................ 5
3. PREPARATION FOR ASSEMBLY....................................................................................................................................................6
4. FILTER BOARD..................................................................................................................................................................................11
5. FRONT PANEL BOARD....................................................................................................................................................................17
6. RF BOARD, PART I ........................................................................................................................................................................... 25
7. ALIGNMENT AND TEST, PART I...................................................................................................................................................... 36
8. RF BOARD, PART II..........................................................................................................................................................................42
9. ALIGNMENT AND TEST, PART II.....................................................................................................................................................46
10. FINAL ASSEMBLY............................................................................................................................................................................48
11. OPERATION.......................................................................................................................................................................................50
12. CIRCUIT DETAILS............................................................................................................................................................................. 58
PARTS LIST .............................................................................................................................................................................APPENDIX A
SCHEMATIC .............................................................................................................................................................................APPENDIX B
BLOCK DIAGRAM..................................................................................................................................................................APPENDIX C
PHOTOGRAPHS.....................................................................................................................................................................APPENDIX D
TROUBLESHOOTING............................................................................................................................................................APPENDIX E
PARTS PLACEMENT DRAWINGS.......................................................................................................................................APPENDIX F
QUICK REFERENCE..............................................................................................................................................................APPENDIX G
ELECRAFT 3
1. Introduction
The K1 is a versatile, low-power CW transceiver that covers two
or four builder-selected HF bands. It provides 5 watts or more of
power output; excellent receiver sensitivity and selectivity; and
many useful operating features, including instant band selection,
receive and transmit incremental tuning (RIT/XIT), digital
display, configuration menu, and multiple crystal filter
bandwidths.
With receive-mode current drain of about 55 mA, built-in keyer,
and a stable, low-frequency VFO, the K1 is ideal for portable
operation. It's also one of the smallest multi-band HF transceivers
available–smaller than many single-band rigs. And, when used with
the optional wide-range tilt stand (KTS1), the K1 is truly trail-
friendly. The tilt stand comes with long arms for ground-mounting
(see below), as well as shorter arms for desk-top use.
Like our all-band K2 transceiver, the K1 uses modular construction,
allowing it to adapt to your operating needs. The Filter board covers
either two (KFL1-2) or four (KFL1-4) bands, and a different Filter
board can be swapped in at any time. There are two plug-in options,
including a noise blanker (KNB1) and automatic antenna tuner
(KAT1). There's also an internal AA-cell battery option (KBT1).
These options can be installed easily at any time.
The K1's modular assembly will also appeal to first-time builders.
The kit requires almost no point-to-point wiring, unlike earlier
designs that used wiring harnesses. The K1 even provides its own
built-in test equipment, including battery voltage monitor,
wattmeter, and frequency counter. The manual provides complete
troubleshooting and signal tracing procedures, and you’ll find further
support on our website, www.elecraft.com.
We’d like to thank you for choosing the K1 transceiver, and hope it
meets your expectations for operation both at home and in the field.
Wayne Burdick, N6KR
Eric Swartz, WA6HHQ
4 ELECRAFT
Customer Service Information
Technical Assistance
If you have difficulty with kit construction, operation, or
troubleshooting, we’re here to help. You may be able to save time by
first consulting our web site, www.elecraft.com
question on the Elecraft e-mail forum, elecraft@qth.net
Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time
(weekdays only) at 831-763-4211. You can also send e-mail to
support@elecraft.com
. Please use e-mail, rather than call, when
possible since this gives us a written record of the details of your
problem.
Repair Service
If necessary, you may return your completed kit to us for repair.
Contact Elecraft before mailing your kit to obtain the repair
shipping address, as well as information on repair fees. (Kits that
have been soldered using acid core solder, water-soluble flux solder,
or other corrosive or conductive fluxes or solvents cannot be
accepted for repair–see Warranty.)
The following information should be provided to expedite repair:
your name, address, and phone number; your e-mail address (if
applicable); and a complete description of the problem.
Shipping: First, seal the unit in a plastic bag to protect the finish
from dust and abrasion. Use a sturdy packing carton with 3" or more
of foam or shredded paper on all sides. Seal the package with
reinforced tape. (Neither Elecraft nor the carrier will accept liability
for damage due to improper packaging.) Cover the "to" address label
with clear tape.
, or by posting your
.
Elecraft’s 1-Year Limited Warranty
This warranty is effectiv e as o f th e d ate of fi rst consum er purchase (or i f
shipped from factory, date product is shipped to customer). It covers both our
kits and fully assembled products. For kits, before requesting warranty service,
you should complete the assem bly, careful ly fol lowing all instructions in the
manual.
Who is covered: This warranty covers the original owner of the Elecraft
product as disclosed to Elecraft at the time of order. Elecraft products
transferred by the purchaser to a third party, either by sale, gift or other
method, who is not disclosed to Elecraft at the time of original order, are not
covered by this warranty. If the Elecraft product is being bought indirectly for a
third party, the third party's name and address must be provided to Elecraft at
time of order to insure warranty coverage.
What is covered: During the first year after date of purchase, Elecraft will
replace defective or missing parts free of charge (post-paid). We will also
correct any malfunction to kits or assembled units caused by defective parts
and materials. Purchaser pays inbound shipping to Elecraft for warranty repair,
Elecraft will pay shipping to return the repaired equipment to you by UPS
ground service or equivalent to the continental USA and Canada. Alaska,
Hawaii and outside U.S. and Canada actual return shipping cost paid by owner.
What is not covered: This warranty does not cover correction of kit assembly
errors. It also does not cover misalignment; repair of damage caused by misuse,
negligence, or bui lder m odifications; or any performance malfunctions
involving non-Elecraft accessory equipment. The use of acid-core solder,
water-soluble flux solder, or any corrosi ve or conductive flux or solvent will
void this warranty in its entirety. Also not covered is reimbursement for loss of
use, inconvenience, customer assembly or al ignment t ime, or cost of
unauthorized service.
Limitation of incidental or consequential damages: This warranty does not
extend to non-Elecraft equipment or com ponents used i n conjunction with our
products. Any such repair or replacem ent is the responsibility of the custom er.
Elecraft will n ot be liable for any special, indirect, incidental or consequential
damages, including but not limited to any loss of business or profits.
ELECRAFT 5
2. Specifications
Measurements were made using a 14-V supply and 50-ohm load.
General
Size (H x W x D)
Weight 1.4 lbs. (0.6 kg), excluding options
Supply voltage 8.5 to 15 VDC
Current drain
Bands covered (MHz) 3.5, 7.0, 10.1, 14.0, 18.05, 21.0
Frequency control Electronically-tuned 3 MHz VFO;
VFO drift < 200 Hz per hour after 5-minute
Cabinet 2.2 x 5.2 x 5.6" (5.6 x 13 x 14 cm)
Overall 2.4 x 5.2 x 7.1" (6 x 13 x 18 cm)
Receive 55 mA typ. (no signal)
Transmit 700-900 mA typ. (5 W, 14 VDC)
(2 or 4 selected bands per module)
approx. 80 or 150 kHz range,
selected during assembly
warm-up at 25° C
Transmitter
Power output 0-5 watts or higher; spurious and
harmonic content -40 dB @ 5 W
Load tolerance 2:1 or better SWR recommended;
will survive high-SWR operation
Sidetone pitch 400-800 Hz in 10 Hz steps
Internal keyer 8-50 WPM; Iambic modes A and B;
2 message buffers; auto-repeat
Receiver
Sensitivity Approx. 0.2 µV for 10 dB (S+N)/N
I.F. 4.915 MHz, single conversion
Selectivity 4-pole variable-bandwidth crystal
filter, approx. 200-800 Hz
Audio output 1 watt (peak) into 8-ohm load
RIT/XIT range Approx. +/- 3 kHz
Display 3-digit LCD w/bargraph modes
1
The RIT/XIT range can be easily modified; see page 55.
1
Int. speaker 8 ohms, high-efficiency
Headphones 8 ohms or higher; stereo plug
or ext. speaker (mono optional--see page 31,
second assembly step)
6 ELECRAFT
3. Preparation for Assembly
Overview of the K1
The K1 uses modular design for ease of assembly and
troubleshooting. The chassis is made up of five pieces (Figure 3-1),
any of which can be removed individually. The RF power amplifier
transistor uses the right side panel as a heat sink, so there is no
separate heat sink element. Each side panel includes a 10-32
threaded PEM nut as a mounting point for the KTS1 tilt stand.
Side
Panel
Top Cover
Front
Panel
Bottom
Cover
(Right side panel
not shown)
There are three printed circuit boards (PCBs), as shown in
Figure 3-2: Front Panel board, Filter board, and RF board. These
boards plug in together with no wiring, as explained in the next
section. K1 options, such as the KNB1 noise blanker, also plug in
directly. Appendix D shows photographs of each completed PC
board assembly.
Filter
Front
RF
Panel
Figure 3-2
Figure 3-1
ELECRAFT 7
Board-to-board Connectors
The circuit boards in the K1 plug in together using board-to-board connectors, which eliminates nearly all hand wiring. Gold-plated contacts
are used on these connectors for reliability and corrosion resistance.
Figure 3-3 shows a side view of the PC boards and board-to-board connectors. As can be seen in the drawing, the Front Panel board has a
connector J1 which mates with right-angle connector P1 on the RF board. The Filter board has three connectors, P1, P2 and P3, which mate
with J6, J7 and J8 on the RF board.
These multi-pin connectors are difficult to remove once soldered in place. Refer to Figure 3-3 during assembly to make sure
you have each connector placed correctly before soldering. If you install a multi-pin connector incorrectly, clip all of the pins at
the body of the device first, remove all of the pins individually, and call us to request a new connector. You may damage pads
and traces by trying to remove such components intact.
Front Panel
Filter Board
J1
P1,P2
J6,J7
1
Figure 3-3
RF Board
3
8
K1-2 (2-band version) and K1-4 (4-band version)
This manual covers all aspects of assembly for the two-band K1 (model K1-2). If you purchased a four-band K1 (model K1-4), you'll use the
KFL1-4 assembly manual during assembly and alignment of the Filter board. You'll find instructions specific to the 4-band module at all
appropriate places in this Owner's manual.
8 ELECRAFT
Unpacking and Inventory
Handling Integrated Circuits and Transistors
This kit uses integrated circuits (ICs) and transistors that
can be damaged by electrostatic discharge (ESD). Problems
caused by ESD can often be difficult to troubleshoot. To
avoid this:
Leave parts in their anti-static packaging until you install them
Use an anti-static mat on your work bench
Use a soldering iron with a grounded tip
Ground yourself using a wrist strap with 1-Mohm series resistor
At minimum, touch an unpainted, grounded metal surface
before handling ESD-sensitive components
Inventory
We recommend that you do a complete inventory, using the parts
lists in Appendix A. Start with the K1 Packing Box Parts list,
which details the items you should find when you first open the
box. Additional parts lists are provided for components used in each
subassembly. Component photographs are provided in most cases.
Identifying Resistors and RF Chokes
Resistor and RF choke values and color bands are provided in the
text. However, it's helpful to familiarize yourself with the color
code. The color-code chart, Figure 3-4, shows how to read the four
color bands on 5% resistors. For example, a 1,500 ohm (1.5 k) 5%
resistor has color bands BROWN, GREEN, RED and GOLD.
1% resistors are similar, but use five bands: three significant digits, a
multiplier, and tolerance. The first four bands on a 1.5 k, 1%
resistor are BROWN, GREEN, BLACK, BROWN. The multiplier
value is 1 rather than 2 in the this case because of the third
significant digit. 1% resistors have color bands that are sometimes
hard to distinguish clearly; use an ohmmeter to identify them.
The markings on RF chokes reflect their value in microhenries
(µH), using two significant digits and a multiplier. Example: a choke
with color bands RED, VIOLET, BLACK has value of 27 µH.
Color Code
Tolerance
(gold = 5%,
silver = 10%)
Multiplier
Second Digit
First Digit
Color MultiplierDigit
Black 0 x 1
Brown 1 x 10
Red 2
Orange x 1K
3
Yellow 4 x 10K
Green 5 x 100K
Blue 6 x 1M
Violet 7
Gray 8
White 9
Silver -- x .01
Gold -- x 0.1
Figure 3-4
x 100
ELECRAFT 9
Identifying Capacitors
Small-value fixed capacitors are usually marked with one, two, or
three digits and no decimal point. If one or two digits are used, that
is the value in picofarads (pF). If there are three digits, the third
digit is a multiplier. For example, a capacitor marked "151" would
be 150 pF (15 with a multiplier of 10
33 pF, and "102" would be 1000 pF (or .001 µF). Exceptions are
described specifically in the text and parts list.
Fixed capacitors with values of 1000 pF or higher often use a
decimal point in the value, such as .001, .047, or 2.2. This is the
value in microfarads (µF). (1 µF is equal to 1,000,000 pF.)
1
). Similarly, "330" would be
Tools
The following specialized tools are supplied with the K1:
.050" (1.3 mm) and 5/64" (2 mm) Allen wrenches
Double-ended plastic alignment tool
In addition to the tools supplied, you will need these standard tools:
Temperature-controlled soldering iron, 700-800°F (370-430°C)
Fine-point soldering iron tip, approx. .05" (spade type)
Small-diameter, IC-grade solder (see Solder Recommendations)
Desoldering tools (wick, solder-sucker, etc.)
Needle-nose pliers
Small-point diagonal cutters, preferably flush-cutting
Small Phillips and flat-blade screwdrivers
DMM (digital multimeter; do not use an analog VOM)
Magnifying glass
Soldering and Desoldering
Use adequate ventilation when soldering, and avoid
inhaling smoke or fumes. Always wash your hands after
handling solder, as lead residue is highly toxic.
Solder Recommendations
We recommend small-diameter (.02 to .04") rosin-core solder,
similar to Kester type 44. Solder with 2% silver is used by some
builders and will work equally well. If you use a minimum of solder,
there will be no need to clean PC boards. The use of acid-core
solder, water-soluble flux solder, or any corrosive or conductive flux
or solvent is likely to damage components and/or PC boards.
Soldering
When applying solder, use the minimum amount required to
surround the component lead and make good contact with its
printed-circuit pad. You don't need a "fillet" (build-up) of solder.
To provide a good connection, the solder must flow onto both the
component lead and its PC board pad. To ensure that both will be
heated at the same time, the tip of the iron should contact both the
component lead and the PC board pad before solder is applied.
Solder joints should be clean and shiny. If a joint appears dull or has
fine cracks, it is probably cold. Cold solder joints should be cleaned
and re-soldered. First, use solder wick (desoldering braid) to remove
the old solder. Then apply fresh solder. If you have many cold
solder joints, it probably indicates that your soldering iron
temperature is too low, or that the tip or solder itself is defective.
We strongly recommend that you use a conductive wrist strap and
anti-static mat during assembly. These items are available at very
low cost from Jameco, Mouser, and other electronics suppliers.
New soldering iron tips must be tinned before they’re used. Allow
the iron to warm up completely, then apply solder and allow it to
coat the entire tip. After a few minutes, wipe off the excess solder.
Use a sponge for wiping the iron tip, and clean the sponge often.
10 ELECRAFT
Desoldering
The printed circuit boards used in the kit are double-sided, meaning
that they have circuitry on both sides. The component mounting
holes are plated-through to complete electrical connections
between the two sides.
Removing components from double-sided boards can be difficult,
since you must get all of the solder back out of the hole before a
lead can be removed. To do this, you'll need solder wick
(desoldering braid) and/or a vacuum desoldering tool. It also takes
some practice. A number of suggestions are provided below.
The best strategy for avoiding de-soldering is to place all
components properly the first time. Double-check values
and orientations, and avoid damaging parts via ESD.
When removing components:
Don't pull a lead or pin out of a hole unless the solder has been
removed, or you are applying heat. Otherwise, you can literally
pull out the plating on the plated-through hole.
Limit soldering iron contact to a few seconds at a time.
Use small-size solder-wick, about 0.1" or 2.5 mm wide. Use the
wick on both the top and bottom pads when possible. This
helps get all of the solder out of the hole.
If you use a vacuum desoldering tool (solder sucker), use a large
unit. Small solder suckers are not very effective.
The safest way to remove ICs and other components with more
than 3 leads is to clip all of the pins at the body of the device
first, then remove all of the pins individually. You may damage
pads and traces by trying to remove such components intact.
Invest in a PC board vice with a heavy base if possible. This
makes parts removal easier because it frees up both hands.
Assembly Notes
Each step in the assembly process is accompanied by a check-box:
This symbol is used to alert you to important information:
i
Do not skip any steps. You may adversely affect both the
performance and appearance of the kit by using the wrong
assembly order.
Components
Sometimes we refer to components by their PC board and reference
designator. For example, "FP-Q1" refers to transistor Q1 on the
Front Panel board.
A few components in the kit are mounted on the bottom of PC
boards. Component outline symbols are provided on the
appropriate side of the board, so it will always be clear which side a
particular component goes on. Bottom-mounted parts are also
identified on the schematics by this symbol:
Photographs
If in doubt about a particular repair, ask for advice from Elecraft or
from someone else with PCB repair experience.
Before beginning assembly, you should review the photographs in
Appendix D to get an idea of what the completed PC boards look
like. You'll also find front and back views of each PC board in the
Parts Placement Drawings, Appendix F.
ELECRAFT 11
4. Filter Board
This section applies only to the two-band K1 Filter board. If
you have a four-band K1, refer to the assembly instructions
in the KFL1-4 manual.
The Filter board determines the K1's bands of operation.
A photograph of the completed board appears in Appendix D.
Open the bag of components labeled KFL-2 and
sort the parts into groups. Identify components using the
photographs in the Filter board parts list in Appendix A.
Locate the Filter printed circuit board (PCB), labeled "K1
FIL2" on one side.
With the top side of the PC board facing you (notch at the
lower right), locate the position of resistor R1, along the front
edge. The label "R1" appears just left of the resistor’s outline.
Install a 100-ohm, 5% resistor (brown-black-brown) at R1,
with its first color band (brown) toward the left. Make sure it is
seated flat on the board, then bend the leads outward at about a 45degree angle to hold it in place.
Solder R1 on the bottom of the board. Trim the leads as close
as possible to the solder joints.
i
Components may be soldered one at a time or in groups.
Leads can be trimmed either before or after soldering.
Install an 18-pin IC socket at U1, with the notched end of the
socket oriented towards the "K1 FIL2" label. Bend two leads of the
socket outward slightly to hold it in place while soldering. (U1 itself
will be installed in a later step.)
i
In the following steps you'll install three relays (K1-K3).
Relay pins must not be bent, even after placement on the PC board,
as this may cause unreliable mechanical operation.
Place relays K1-K3 on the top side of the board. One end of
each relay has a heavy line printed across the top to indicate the
pin 1 end. This end must be matched with the same end of the
relay’s PC board outline. Do not solder the relays yet.
When all three relays have been placed on the board, lay a flat
object such as a book or piece of cardboard on top of the relays to
keep them in place, then flip the board over.
Solder only two pins (at opposite corners) on each relay, using
a minimum amount of solder. Limit soldering time to 2 or 3
seconds per pin. Do not bend or trim the leads.
Turn the board back over and verify that all of the relays are
in the correct orientation and are seated flat on the board. To
check the orientation, refer to the Filter board drawing in
Appendix F, at the bottom of the page.
Solder all of the remaining relay pins. Do not bend or trim the
leads.
12 ELECRAFT
Install the capacitors listed below. The list shows the
capacitance value, followed by the labeling (in parentheses). After
installing each capacitor, bend the leads outward at about a 45degree angle to hold it in place until it is soldered and trimmed.
__ C29, .001 (102) __ C30, .001 (102) __ C27, .047 (473)
Place a bookmark at this page, and another at the
Per-Band Components table in Appendix A.
Locate the two bags of per-band components, which are
labeled by band, e.g. "40m" or "K1B40" (40 meters).
Under Reference Designators in the Per-Band Components
table, there are Band 1 and Band 2 columns. Fill in the blanks at
the top with your two bands (e.g., "40" and "20"). The lowerfrequency band should be designated as Band 1.
Using strips of paper, or labels with a light adhesive such as
“post-its,” temporarily cover the band 2 reference designators
column. Similarly, cover all of the components columns except the
column associated with band 1. This is a very important step
that will eliminate possible confusion during assembly.
Open the bag of components for band 1 only, setting the
band 2 components aside for now.
At this point you’ll need to choose whether to set up the VFO
for 80-kHz or 150-kHz coverage (approx.). The smaller range
covers the most-used portion of every band, provides smoother
tuning, and is strongly recommended if you plan to upgrade to the
four-band module (KFL1-4), which has narrower band-pass filters.
Record your VFO range selection here for reference:
___ 80 kHz ___ 150 kHz
Note: Two different crystals are supplied for 30 meters,
corresponding to two different lower band edges. Which one to use
depends on your selected VFO range (see below). In the following
steps you’ll select one of the two crystals when applicable.
Band VFO Range Crystal Band Edge
30 Meters
If band 1 is 30 meters, select the appropriate crystal using the
table above. Save the other crystal for possible future use.
Install the band 1 crystal at X1 on the filter board (to the right
of X2), bending the leads to hold it in place. Make sure the crystal is
seated correctly, then solder. Use a minimum amount of solder to
avoid a short under the can.
80 kHz 18.100 10.100
150 kHz 18.000 10.000
i
The leads on small capacitors may be pre-formed so that
the capacitor sits slightly above the board when inserted; this will
not affect performance. The leads are also somewhat fragile.
Install the capacitors for band 1, using the reference
designators and values from the appropriate columns in the parts
list. For example, if band 1 is 40 meters, install 390-pF capacitors
at C1 and C5, then 330 pF capacitors at C2 and C4, etc. Double-
check each capacitor value as it is installed. Do not solder yet.
Solder all of the band 1 capacitors.
Move the strips of paper or labels that you used earlier so that
they cover the band 1 reference designators column, and all of the
components columns except the column associated with band 2.
Open the components bag for band 2. Install the band 2
capacitors, using the reference designators and values from the
appropriate columns as before. (Example: if band 2 is 20 meters,
you'll install 180-pF capacitors at C6 and C10, etc.)
Locate the band 2 crystal and verify that it is the correct
frequency. If band 2 is 30 meters, select one of the two crystals
supplied (see table above). Install it at X2 and solder.
ELECRAFT 13
Cut two 3/4" (19 mm) bare wires (use component leads).
Referring to Figure 4-1, insert bare wires into the grounding
holes provided near X1 and X2. Fold each wire over the top of the
crystal and solder it on top. Keep soldering time below 5 seconds at
a time; if it takes longer, your iron may not be hot enough, or your
iron tip may not be making good contact with the crystal can.
Solder and trim the wires on the bottom of the board.
2
Figure 4-1
Install the ceramic resonator, Z1, to the right of U1. (The
ceramic resonator looks like a capacitor with three pins, and can be
oriented in either direction.) Limit soldering time to 2 or 3 seconds
on each pin to avoid altering the oscillation frequency.
Locate the eight 1-µH slug-tuned inductors, and make sure
they are all have a red stripe or are labeled "T1050".
Install the inductors at L1 through L8, pressing each one down
as far as it will go. They have five pins, plus ground tabs, and can
only be installed on the board one way. Solder the inductors.
1
At the left and right ends of the board you’ll find two short
jumper locations, each labeled with a ground symbol (
component leads to make 3/4" (19 mm) U-shaped wires for each
jumper (Figure 4-2). Solder the jumpers on the bottom of the board,
with the top of the U-shape approx. 1/4" (6 mm) above the board.
). Use
op side
Figure 4-2
Identifying Toroid Cores
Several toroidal inductors are used in the K1, including four on the
Filter board. It is important to use the correct type of core. This
can be determined from the color and size.
The cores used on the Filter board are type T37-6. The T identifies
an iron-powder core. The number following the T specifies the
outside diameter in hundredths of an inch, in this case 0.37 inches
(9.4 mm). The suffix (-6) refers to a specific mix of iron powder,
which uses a particular color, in this case yellow.
Later in assembly you'll encounter ferrite cores, for example type
FT50-43. In this part number, FT identifies the core as ferrite, and
50 is the size (0.50", 12.5 mm). The suffix (-43) identifies the type
of ferrite used, although all ferrite cores are dark gray in color. All
ferrite cores used in the K1 are of the -43 type.
14 ELECRAFT
i
In the following steps you’ll install toroidal inductors L9L12 (type T37-6 cores). They must be wound as indicated in the
instructions, or the transceiver will not operate correctly. Use only
the number of turns specified. It is not necessary to attempt to
precisely match the inductances specified in the parts list.
Find the component outline for L9 on the Filter board.
Compare this component outline to Figure 4-3, which shows two
views of a typical toroidal inductor. L9 will be mounted vertically
as shown at the right side of the drawing, with one wire exiting at
the core’s upper left, and the other at the lower right. There are
pads on the PC board in these two locations.
Using the Per-Band Components parts table (Band 1),
determine the number of turns and wire length for L9 and L10.
To wind L9, cut the specified length of #26 red enamel-coated
wire, then "sew" the long end of the wire through the core. Each
pass through the core counts as one turn. The finished winding
should look similar to Figure 4-3, but with the number of turns
indicated in the parts list. Figure 4-3 shows 14 turns.
Verify that the turns of L9 are not bunched together. They
should be evenly spaced, and should occupy about 80-90% of the
core.
Stripping Toroid Leads
The enamel wire supplied with the kit can be heat-stripped. One
way to do this is to place a small amount of solder (a "blob") on the
end of your soldering iron, then insert the wire into the hot solder.
If the iron is hot enough, you should see the insulation vaporize
after 3 to 6 seconds. Another possibility is to burn the insulation
off by heating it with a small butane lighter for a few seconds, then
use fine-grain sandpaper to remove the enamel residue. Avoid
scraping insulation off with a razor blade, as this may nick the wire.
Strip the leads of L9, as explained above. You should remove
the enamel from the leads up to about 1/8" (3 mm) from the core
(Figure 4-3).
Tin L9's leads. The solder should appear clean and shiny. If it
looks dull or is not adhering very well to the bare lead, there is
probably some insulation remaining. Remove it as described above.
Install L9 vertically as shown by its component outline. Pull
the leads taut on the bottom of the board.
Remove insulation
Figure 4-3
Solder the leads of L9. When soldering, make sure that the
solder binds well to the leads. If the lead appears to be an "island" in
a small pool of solder, chances are it is not making good contact.
Wind and install L10 in the same manner as L9, using the
same number of turns. Install L10 vertically, to the right of L9.
Wind and install L11 and L12. Use the Per-Band Components
table (Band 2) to look up the wire length and number of turns.
i
Do not use adhesives or fixatives of any kind to secure L9L12 to the PC board. They will be adequately held to the board by
their leads alone.
ELECRAFT 15
i
The connectors to be installed in the following steps
must be positioned correctly to avoid intermittent or
unreliable operation.
information on page 7.
yet. Figure 4-4 shows P1 as viewed from the left end of the Filter
board. The plastic part of the connector must be on the bottom
side of the board, with the long end of the pins pointed down. The
short pins are inserted into the board.
Before attempting to install multi-pin connectors, review the
Install an 8-pin male connector (plug) at P1, but do not solder
P1
Figure 4-4
Solder just one of the middle pins of P1, on the top side.
Note: multi-pin connectors have plastic bodies that can melt if too
much heat is applied, causing the pins to be mis-positioned. Limit
soldering time for each pin to 2 to 3 seconds.
Examine the placement of P1 closely. If it is tilted or is not
flat against the board, re-heat the solder while pressing down on the
connector.
Cut a 1" (25 mm) length of insulated hookup wire. Strip about
1/8" (3 mm) of insulation off of each end.
Install this wire between pins 2 and 10 of J2, in the upper righthand corner of the board (Figure 4-5). The pins on J2 are counted
from left to right and top to bottom as shown.
1 2
2
109
Figure 4-5
i
Before handling U1 in the next step, touch an unpainted,
grounded metal surface.
Straighten the leads of U1 (PIC16C620) as shown in Figure
4-6. The two rows of pins must be straight and parallel to each
other to establish the proper pin spacing. To straighten the pins,
rest one entire row of pins against a hard, flat surface. Press down
gently on the other row of pins and rock the IC forward to bend the
pins into position as shown below.
Flared
Straight
Once P1 is in the right position, solder the remaining pins. Do
not trim the leads.
Install P2 and P3 in the same manner as P1. Before soldering,
verify that each connector is flat against the board and not tilted.
Figure 4-6
16 ELECRAFT
Insert U1 into its socket, with the notched or dimpled end of the
IC aligned with the notched end of the PC board outline. Figure 4-7
shows an 8-pin IC; U1 is similar but has 18 pins.) Press U1 down into
the socket as far as it will go.
Notch
Pin 1
Dimple
Pin 1
Figure 4-7
Note: IC pins are counted by going around the IC counter-clockwise
from pin 1.
Examine U1 closely. If any pins are bent, remove the IC and
straighten them. (To remove U1 from its socket, pry it up gently on
each end using a small flat-blade screwdriver.)
Locate the blank white area near U1. This area is provided for
labeling the Filter board with the two bands covered (e.g. "40, 20").
Use an indelible marker, dry transfers, or an adhesive label.
Uninstalled Components
All component locations on the Filter board should now be filled
except J1 and J2, which are provided for the automatic antenna tuner
(KAT1). The KAT1 option should be installed only after the basic K1
kit has been completed and tested. At that time, the jumper you
installed between pins 2 and 10 of J2 will be removed. If you’re
building a 2-band Filter board that includes 80 meters, you’ll have a
10 µF electrolytic capacitor left over at this point. This will be
installed on the RF board at C78 in a later step.
Visual Inspection
Using the parts placement drawings in Appendix F, re-check the
orientation of the relays (K1, K2, K3) and U1.
i
About 90% of all problems with kits are caused by poorlysoldered component leads. Such problems can be avoided by doing a
careful inspection of the board, preferably with a magnifying glass.
solder bridges, and unsoldered components.
Examine the bottom of the PC board closely for cold solder joints,
Resistance Checks
Make the measurements listed below, touching the meter's (+)
and (-) leads to the indicated points. Measurements at relay K3 must
be made on the bottom side. Relay pins are numbered like ICs, with
pin 1 identified by its round pad. The Filter board schematic (in
Appendix B) may help you troubleshoot any incorrect readings.
i
The symbol > means greater than, and < means less than.
Your DMM may indicate infinite resistance (all digits flashing) for
readings that are listed as "> 100 k." (Do not use an analog VOM.)
Test Points (+, -) Resistance
U1 pin 6, U1 pin 7 230-270 ohms
U1 pin 6, U1 pin 8 230-270 ohms
U1 pin 6, U1 pin 12 230-270 ohms
U1 pin 13, P2 pin 6 90-110 ohms
P1 pin 1, P1 pin 3 > 100 k
P1 pin 2, P1 pin 3 > 100 k
P1 pin 3, P1 pin 4 > 100 k
P1 pin 3, P1 pin 6 > 100 k
P2 pin 1, P2 pin 2 > 100 k
P2 pin 7, P2 pin 8 > 100 k
K3 pin 2, K3 pin 9 < 5 ohms
K3 pin 4, K3 pin 7 < 5 ohms
ELECRAFT 17
5. Front Panel Board
The liquid-crystal display (LCD), switches, and other controls are
located on the Front Panel board, as well as the microcontroller.
See Appendix D for photos of the completed assembly.
Open the bag labeled FRONT PANEL and sort the parts into
groups. Observe anti-static precautions with ICs and transistors.
Locate the front panel PC board, which is labeled "K1 FP"
along one edge. In the steps that follow, we will refer to the side
with the switches and LCD (S1-S6 and DS1) as the top side.
Place the board in front of you with the bottom side up.
Locate the component outline for J1, below the large hole.
Install a 20-pin female connector (receptacle) at J1 as shown
in Figure 5-1. Do not solder yet.
Solder one pin of J1 on the top side, near the middle of the
connector. If J1 is not seated flat against the PC board or is tilted,
re-heat the solder and press down on the connector.
Once you're sure that J1 is correctly installed, solder the
remaining pins. Do not use an excessive amount of solder.
Locate the Switch Spacing Tool (made of PC board
material).
Position push-button switch S1 on the top side of the board as
shown in Figure 5-2, using the switch spacing tool to set the switch
height. Make sure all four legs of the switch are centered in their
holes, then gently push the switch until it is resting flush against the
switch-spacing tool. (Caution: switch pins are fragile.) Do not
solder yet.
Top side
(with LCD)
S1
Bottom
side
J1
Figure 5-2
Figure 5-1
18 ELECRAFT
If the socket does not appear to be seated flat on the PC
Top of
board
board, reheat these two pins while pressing on the socket. If the
leads of C4 hit the socket, trim them closer to the board.
1/16”
Solder the remaining pins of U1. (U1 itself will be installed in
the socket in a later step.)
Install and solder the following components. When soldering
Figure 5-3
components near the push-button switches, be careful not to touch
the switches with the soldering iron.
Figure 5-3 shows a side view of a switch that is properly mounted
(spacing tool not shown). The leads of the switches will just be
visible on the bottom of the board. Proper switch height is
important for maintaining an even appearance.
Once S1 is seated correctly, solder the leads on the bottom side
of the board. Leave the spacing tool in place while soldering.
Install S3, once again using the switch spacing tool to adjust
the switch height. When soldering S3, be careful not to contact the
plastic body of J1 with the soldering iron.
Install switches S2, S4, S5, and S6 using the same technique.
Note: Switch caps will be installed later.
Install these parts on the top side of the board. Solder them on
the bottom side, using a minimum of solder.
__ R8, 22 (RED-RED-BLK) __ C4, .047 µF (473)
Trim the leads of R8 and C4 as close to the board as possible
so that they won't interfere with the 40-pin IC socket (next step).
Install the 40-pin IC socket at U1, on the bottom side of the
board. The board is labeled "SOCKET" at this location. Orient the
socket's notched end to the left (the pin 1 end). To hold the socket
in place, bend pins 1 and 21 outward slightly; these two pins are
diagonally opposite. Solder only these two pins.
Top side:
__ R4 and __ R5, 10 k (BRN-BLK-ORG)
__ R11, 100 k (BRN-BLK-YEL)
Bottom side:
__ R6, 12.7 k, 1% (BRN-RED-VIO-RED)
__ R7, 3.92 k, 1% (ORG-WHT-RED-BRN)
__ R9, __ R10, and __ R19, 100 k (BRN-BLK-YEL)
__ R13, 470 (YEL-VIO-BRN)
__ R12, 2.7 k (RED-VIO-RED)
__ R14 and __ R15, 1 k (BRN-BLK-RED)
__ R16, 2.7 k (RED-VIO-RED)
__ C5 and __ C6, .01 µF (103)
Install capacitors C1 and C2 (82 pF), near U1.
Locate resistor network RP1. ("RP" means "resistor pack,"
another name for resistor networks.) One end of RP1 has a band or dot,
indicating pin 1. RP1 should be labeled 77083102, 83C102, or
8A3102G. If the labeling differs, verify the resistance. You should
measure about 1.0 k between each pair of adjacent pins.
Install RP1 on the bottom side of the board. The end with a
dot or bar should be oriented towards pin 1 of the PCB outline.
When soldering RP1, keep the iron tip away from S4 and S5.
Install and solder the two 82-µH RF chokes, RFC1 and RFC2
(GRAY-RED-BLK).
ELECRAFT 19
i
Before handling ICs and transistors in the following steps,
touch an unpainted, grounded metal surface.
Locate transistor Q1 (type 2N4124), which has a small, 3-lead
TO-92 package. Q1 and other TO-92 devices may have either of
the two shapes shown in Figure 5-4. The right-hand illustration
shows a "modified TO-92" package, which may be labeled on either
the front or back side. The large flat side of each device will be
aligned with the flat side of its component outline.
Figure 5-4
Install Q1 on the bottom side of the board, to the right of the
large hole. Align Q1 as shown above. The transistor should be
mounted about 1/8" (3 mm) above the board; don’t force it down
too far or you may break the leads. Bend the leads outward slightly
to hold Q1 in place, then solder and trim the leads.
Locate U4, a 78L06 voltage regulator, which has a TO-92
package similar to Q1. Install U4 below the large hole.
i
Touch an unpainted, grounded metal surface before
handling the 2N7000 transistor in the next two steps.
Locate the component outline for Q2 (2N7000) on the top
side of the board near the rectangular hole. Q2's outline has the
three pins side-by-side, not in a triangular pattern. Pre-form the
leads of Q2 to match this hole pattern, so that it can be mounted
very close to the PC board with little excess lead length.
Install Q2. Make sure the top of Q2's body is no more
than 0.25" (6 mm) above the board when seated. Solder Q2.
Install the 8-pin ICs, U2 (MAX518), U3 (24LC04), and U5
(LM358) on the bottom side. Orient the notched or dimpled end of
each IC with the notched end of its component outline (see Figure
4-7). Bend two leads outward slightly on the opposite side of the
board to hold the devices in place, but do not solder yet.
Turn to Appendix F (parts placement drawings) to verify that
you have the ICs installed in the proper locations, then solder.
Limit soldering time to 2 to 3 seconds on each lead.
On the top side of the board at the left end you’ll find a short
jumper location, labeled with a ground symbol (
(19 mm) U-shaped wire here, as you did earlier on the Filter board.
i
The potentiometers to be installed in the next step can be
damaged if you push on their plastic shafts. When seating a
potentiometer, press down only on the metal frame.
). Install a 3/4"
Install the two 10-k potentiometers at R2 and R3 (on the top
side of the board). They must be pressed downward until the metal
frame is fully contacting the PC board on both sides. Do not use
excessive heat when soldering.
20 ELECRAFT
e
Open the bag labeled MISCELLANEOUS and empty the
contents into a shallow box or pan. This will prevent loss of any of
the small hardware while allowing you to locate items as needed.
i
Five sizes of 4-40 screws are used. All are black anodized
except the 1/4" and 3/8" pan heads (see Figure 5-5). The length of
flat-head screw is measured from the top of the head.
Top Sid
Pan-head, 1/4” (6 mm)
Figure 5-6
Pan-head, 3/8” (9.5 mm)
Pan-head, 3/16” (4.8 mm)
Flat-head, 3/16” (4.8 mm)
Flat-head, 5/16” (8 mm)
Figure 5-5
Identify all of the 4-40 screws and sort them into groups.
Install a 3/16" (4.8 mm) diameter x 1/4" (6.4 mm) long round
standoff on the top of the board (Figure 5-6). The hole for this
standoff is just below the large hole. Use two #4 split lock washers
and a 1/4" (6 mm) pan-head screw (not black anodized) as shown.
Insert the lock washers between the standoff and PC board.
Install crystal X1, near C1 and C2 on the bottom of the board.
To the right of X1 you'll find a ground pad for the crystal can.
Use a discarded component lead to make the grounding wire, as
shown in Figure 4-1 (page 13).
Locate LEDs D1 and D2, which are identical in size but have
different-colored bodies. D1 has a clear diffuse body, while D2 has a
yellow tint. Near the point where the leads exit the body, you'll find
a flat side in the plastic, which identifies the cathode lead.
Install D1 (clear diffuse body) on the top side of the board,
with its flat side aligned with the flat side of the component
outline. (This is the side nearest the square pad.) Position D1 about
1/16" (1.5 mm) above the board. You can use the switch-spacing
tool, a toothpick, or short length of insulated hookup wire to
maintain the proper spacing while soldering.
Verify the orientation of D1's flat side, then solder.
Install and solder D2 using the same method.
ELECRAFT 21
Inspect the solder side of U1's socket on the top side of the board.
Make sure all pins are soldered, with no cold solder joints.
Using a DMM, check every pair of adjacent pads on U1 on the
top side of the board (pins 1-20 and 21-40). The resistance between
pads should be over 1000 ohms (1 k) in all cases, and may read infinite
on your DMM (often indicated by a flashing display).
i
Before handling U1 in the next step, touch an unpainted,
grounded metal surface.
i
Caution: the LCD (DS1) and its pins are fragile.
Remove the LCD from its packing materials, being careful not to
bend the pins. As shown in Figure 5-8, the pin 1 end of the LCD glass
has a very slight bump, along with a break in the black border. This
end will be oriented towards the pin 1 end of DS1's component
outline.
24
13
Straighten the pins of the microcontroller, U1. You can hold the
IC body at the ends as you re-form each row of pins.
Insert U1 into its socket, with the notched end oriented towards
the pin 1 end of the component outline.
Look at both rows of pins on U1 closely. If any pins are bent,
carefully remove the IC by prying at both ends using a small flat-blade
screwdriver. Straighten the pins using long-nose pliers.
NOTE:
install it into your K1 now, refer to the instructions for adding the
backlight, then go directly to Visual Inspection on the next page.
x 1/2 square and 3/16" thick (12 x 12 x 5 mm). Remove the adhesive
backing from one side and position the spacer as shown in Figure 5-7.
It must be mounted flat against the PC board, centered between the
two rows of pins on U1's socket.
If you purchased the K1 LCD Backlight Kit and are going to
Locate the black neoprene LCD spacer (MISC. bag), which is 1/2
Spacer
Bump
DS1
112
Figure 5-8
Remove the adhesive backing from top side of the LCD spacer.
Install the LCD at DS1, oriented as shown above. Make sure that
all 24 pins are inserted into their holes, then press down gently on the
LCD to secure it to the LCD spacer's adhesive surface. The LCD pins
may not extend all the way through the holes. The surface of the LCD
must be parallel to the PC board.
Once the LCD is positioned correctly, solder all pins.
Figure 5-7
22 ELECRAFT
Visual Inspection
Using the parts placement drawings in Appendix F, re-check
the orientation of the LEDs (D1 and D2), LCD (DS1), and all ICs.
Examine both sides of the PC board closely for solder bridges,
cold solder joints, or unsoldered components.
Resistance Checks
Set both potentiometers to their mid-points.
The resistance measurements shown below can all be made
from the top side of the board. The (-) lead of your DMM should be
connected to the ground jumper (
Test Points (+) Resistance
DS1 (LCD) pins 1-24 > 100 k
J1 pin 6 > 100 k
J1 pin 7 > 100 k
J1 pin 8 > 100 k
J1 pin 10 90-200 k
J1 pin 12 > 100 k
J1 pin 15 < 50 k
J1 pin 16 15-18 k
J1 pin 19 > 100 k
) at the left side of the board.
ype 1 Type 2
CCW
CW
Attach the prepared wires to the three lugs Each wire should be
wrapped around its lug, leaving the other end free. (Do not solder
yet.)
R1’s plastic body can be damaged if you apply too much heat
to the lugs. Solder the three lugs, limiting soldering time to about
two seconds each.
Insert R1 through the large round hole in the Front Panel
board, rotating it into approximately the position indicated above.
Make sure that none of the lugs are touching the PC board.
S
3
1 2 3 R1
Figure 5-9
2 1
1 2 3 R1
Front Panel Final Assembly
Cut three 1.25" (32 mm) lengths of hookup wire. Remove 1/4"
(6 mm) of insulation from both ends of each wire.
Locate the 10-turn potentiometer, R1. Look closely at
Figure 5-9, which shows the positions of the three lugs. The lugs
may be labeled 1, 2, and 3, or S, CW, and CCW. 10-turn
potentiometer labeling can be confusing, so use the drawing to
identify the lugs. Your potentiometer may be either of the two
types shown.
Near the large hole in the board, you'll find three pads for R1's
leads (labeled 1, 2, and 3). Referring to Figure 5-9, insert the
potentiometer's wires into their corresponding holes. Do not
solder yet.
i
Caution: If the leads of R1 are not connected to the
correct pads, the potentiometer is very likely to be damaged.
Re-check the connections, then solder R1's leads on the top
side of the board. Avoid touching nearby parts with the iron.
ELECRAFT 23
Install caps on switches S1 through S6. S3's cap is square, while
the others are rectangular, as shown in Figure 5-10. The caps are
installed by pressing them onto the switch plungers.
Figure 5-10
i
The LCD's glass surface is protected by a very thin,
nearly invisible piece of protective film. In the following
step, be very careful to remove only the thin film, not the
LCD's glass top. Do not use any type of metallic tool.
Hold the Front Panel PC board assembly under a strong light so
that you can see the surface of the LCD glass clearly. Using a
fingernail, rub one corner of the LCD's glass top to loosen the
protective film, then peel it off.
Locate the front panel chassis piece. Place it on a soft cloth
to protect the finish and labeling.
Some holes in the front panel are masked on the inside surface
during painting. If masking tape (usually green in color) is still
present, you'll need to remove it. To remove masking tape:
After removing any masking tape, turn the front panel face
up, with the Elecraft logo at the top.
Position the clear plastic LCD bezel over the large LCD
opening, then secure it with four 2-56 screws (stainless steel) as
shown in Figure 5-11. Tighten the 2-56 screws only the amount
needed to hold the bezel to the front panel. Over-tightening may
crack the bezel or strip the threaded holes in the panel.
2-56 Screw (4)
LCD Bezel
Figure 5-11
Remove all hardware from the shaft of the 10-turn
potentiometer (R1). It will be re-attached in a later step.
Locate the 0.75" (19 mm) diameter nylon washer. Place this
washer over R1's threaded bushing.
Use a blunt instrument such as a ball-point pen to push on the
tape through a hole until the tape begins to lift away.
Peel the tape off, using a sharp tool if necessary. Be careful not
to scratch the outer surface of the panel.
24 ELECRAFT
Insert the Front Panel PC board assembly into the front panel
(Figure 5-12). The push-button switch caps should protrude slightly.
Figure 5-12
The 1/4" (6.4 mm) standoff on the PC board should now be
visible through the countersunk panel hole just below R1. Secure the
panel to the standoff with a 3/16" (4.8 mm) flat-head screw.
i
Caution: The 10-turn potentiometer may have a
plastic bushing. In the following step, do not over-tighten
the nut or you may strip the threads.
Use the nut and lock washer supplied with R1 to secure it to
the front panel. It should be just tight enough to keep R1 from
rotating.
i
The Allen wrenches are located in a small bag with the
MISCELLANEOUS items. These wrenches may have been oiled
during manufacturing. Remove the wrenches and wipe off the oil, if
any, then discard the bag.
Use the larger Allen wrench (5/64" [2 mm]) to tighten the two
set screws on the large knob.
Set the AF GAIN and RIT/XIT potentiometers to midway in
their rotation, and place a small knob on each. Do not push down
hard on the knobs, as this may damage the potentiometers.
Tighten each knob's two set screws using the smaller Allen
wrench (.050" [1.3 mm]). Align the pointers per panel labeling.
i
At this point in the assembly, the push-button switches
may not all protrude an equal distance. The switch height will
become equalized once the front panel assembly is mated to the RF
board in a later step.
i
When you rotate the VFO knob, you may hear a faint
sound produced by the wiper of the 10-turn potentiometer as it
moves across its resistance element. This is normal.
Uninstalled Components
All component locations should now be filled.
Place the large knob on R1's shaft. Push the knob on until it
just touches the bushing. If the knob does not spin freely, move it
out slightly. If the shaft or knob appears to be tilted, the large
nylon washer may not be positioned correctly (behind the panel).
ELECRAFT 25
6. RF Board, Part I
In Part I, the VFO (variable-frequency oscillator) and receiver
sections will be assembled.
Open the bag labeled RF and sort the components into groups.
Observe anti-static precautions when handling transistors and ICs.
J8
T-R Switch
and Transmitter
J6
VFO
AF Amp
J7
Receiver
Locate the RF board and orient it as shown in Figure 6-1. This
illustration shows the major areas of the board. Receiver and VFO
circuits occupy the front half; transmitter and T-R switch stages use
the rear half. The Filter board plugs into J6, J7, and J8.
Turn the board over. (Figure 6-2 shows the bottom side.)
Four 2-D fasteners will be attached to the RF board at the indicated
locations to secure it to the chassis panels.
-D Fastener
Figure 6-1
Figure 6-2
26 ELECRAFT
Locate a 2-D fastener and hold it vertically (Figure 6-3a).
Looking at a side with two holes, note that the holes are offset
from the center. The PC board outlines for the 2-D fasteners have
a matching offset, which will aid in installing them in the next step.
i
In the steps that follow you’ll install the connectors that
mate with the Filter and Front Panel boards. These connectors
must be installed properly to ensure reliable mechanical connection.
They are difficult to remove once installed, so follow all
instructions carefully. Review Figure 3-3 before proceeding.
Install an 8-pin female connector at J6, on the top side of the
RF board. It must be flush with the board and not tilted (Figure 6-4).
Solder just one pin near the center of J6.
Holes offset
from center
J6
(a)
Figure 6-3
Install 2-D fasteners at the four locations indicated in Figure
6-2, on the bottom of the RF board. Secure each fastener from the
top side of the board with 3/16" (4.8 mm) pan-head screws and #4
split lock washers (Figure 6-3b).
Make sure that the 2-D fasteners line up with the edges of the
PC board and do not hang over. If they hang over or do not match
their component outlines, they are installed backwards.
Install relay K1, near the center of the board. Make sure the
pin 1 end (with the heavy line) is oriented as indicated by K1’s
component outline. Do not bend or trim the relay leads.
(b)
Figure 6-4
If J6 does not appear to be completely flush with the board, or
it is tilted, re-heat the soldered pin and press down. Do not solder
the remaining pins yet.
Install J7 and J8 in the same manner as J6, soldering just one
pin in each case.
The Filter board can now be used to check for proper
installation of the three 8-pin connectors. Place the Filter board
above the connectors (do not plug it in). Verify that all pins of P1,
2, and 3 on the Filter board align with the corresponding holes of
J6, 7 and 8 on the RF board.
Remove the Filter board. Solder all remaining pins of J6, 7,
and 8 on the bottom of the RF board.
ELECRAFT 27
Position 20-pin male right-angle connector P1 on the bottom
of the RF board (Figure 6-5), but do not solder yet. Review Figure
3-3 for correct placement. The short ends of the bent pins are
inserted into the holes, and the long ends are parallel to the board.
Top of board
Front edge
P1
Figure 6-5
Solder just the two end pins of P1.
Make sure that the front-panel assembly can be plugged into
P1 as shown in Figure 3-3. Then unplug the front panel assembly.
Look closely at P1 to make sure that its plastic support is
pressed down as far as it will go, and that the pins are parallel to the
board. If not, re-heat the soldered ends while pressing it into place.
Once it is seated properly, solder the remaining pins.
i
In the steps that follow, you'll be installing larger groups of
components. When working from a long list, install all of the items
on one line before moving on to the next. Arrows (⇒) appear in
the list to remind you of this order. In general, assembly proceeds
from left to right across the board.
Install the resistors listed below. R23 is at the left-front edge.
__ R23, 1.5 Ω (BRN-GRN-GOLD) ⇒ __ R7, 680 (BLUE_GRAY-BRN)
__ R21, 2.7 k (RED-VIO-RED) __ R13, 2.2 M (RED-RED-GRN)
__ R2, 100 k (BRN-BLK-YEL) __ R16, 75 (VIO-GRN-BLK)
__ R17, 120 (BRN-RED-BRN) __ R18, 75 (VIO-GRN-BLK)
__ R14, 2.7 k (RED-VIO-RED) __ R1, 1.8 k (BRN-GRAY-RED)
These resistors start on the left edge of the board near J6:
__ R19, 39 k (ORG-WHT-ORG) ⇒ __ R20, 20 k (RED-BLK-ORG)
__ R9, 2.7 k (RED-VIO-RED) __ R26, 1.8 k (BRN-GRAY-RED)
__ R34, 100 k (BRN-BLK_YEL) (at the back-right edge near J8)
The following capacitors are all of the disc or monolithic
type. Start with C26, which is on the left edge close to J6.
Note: C65 (22 pF) may be labeled "220J" (see top of page 9).
__ C26, 39 (39) ⇒ __ C27, 39 (39) ⇒ __ C42, 220 (221)
__ C41, .047 (473) __ C30, .047 (473) __ C40, .01 (103)
__ C25, .01 (103) __ C7, 39 (39) __ C4, .01 (103)
__ C6, .01 (103) __ C69, 220 (221) __ C72, .01 (103)
__ C18, .01 (103) __ C74, .01 (103) __ C73, 0.1 (104)
__ C64, .01 (103) __ C68, 0.1 (104) __ C17, .01 (103)
__ C32, .047 (473)
__ C70, 0.1 (104) __ C71, 0.1 (104) __ C23, .01 (103)
__ C75, .01 (103) __ C63, 330 (331) __ C65, 22 (22, 220J)
__ C61, .047 (473) __ C24, .047 (473) __ C19, .001 (102)
__ C66, .01 (103) __ C21, .01 (103) __ C22, .001 (102)
__ C39, 220 (221) __ C37, .01 (103) __ C38, 220 (221)
__ C36, .01 (103) __ C34, 0.1 (104)
__ C28 and __ C29, .001 (102) (back-left corner of the board)
__ C49 and __ C48, .01 (103) (back-right corner)
__ C45, .01 (103) (near J4, which is on the back edge)
Note: All components mounted in the T-R switch and transmitter
areas must be kept as low-profile as possible since the Filter board
will be plugged in directly above.
1200-pF polystyrene capacitor C11 (labeled “1200J”) has
axial leads, like a resistor. Note: the kit also includes a 120 pF
polystyrene ("120J"). Install C11 in the VFO area of the board,
near J6. Limit soldering time to 2-3 seconds.
28 ELECRAFT
Install the resistor networks listed below, checking the part
numbers carefully before installation. Orient the black dot or bar on
each network towards pin 1 of its component outline.
__ RP3, 47 k, 10 pins (10A3473G, 103C104, or 770103473)
__ RP1, 100 k, 8 pins (8A3104G, 83C104, or 77083104)
__ RP2, 100 k, 8 pins (8A3104G, 83C104, or 77083104)
__ RP6, 27 k, 6 pins (6A3273G, 63C273, 4306R-102 LF273 or 77063273)
__ RP4, 3.9 k, 6 pins (6A3392G, 63C392, 94163392P or 77063392)
__ RP5, 3.9 k, 6 pins (6A3392G, 63C392, 4163392 or 77063392)
Install a 33-µH RF choke (ORG-ORG-BLK) at RFC1, near the
front edge of the board. (Orange bands may appear to be brown.)
Install a 100-µH RF choke (BRN-BLK-BRN) at RFC4, in the
transmit area of the board.
The ceramic trimmer capacitors (C13 and C20) have one side
that is flattened. This side must be oriented towards the flattened
side of the component outline. Install C20 near the front edge of
the board, and C13 in the back-left corner.
Sort the diodes into groups for identification purposes. You
should have two types of small glass-bodied diodes: 1N5711, and
1N4148. The 1N4753 zener diode may also be glass, and is larger.
If necessary, use a magnifying glass to read the labels.
i
Diodes with long axial leads (such as the types mentioned
above) must be installed with the banded end (cathode) oriented
towards the banded end of their component outlines. If a diode has
more than one band, the widest band indicates the cathode end.
Install 1N4148 diodes at D17 and D1, observing the proper
orientation as explained above. Do not solder yet. D17 and D1 are
both near RP2, in the VFO area.
Install 1N5711 diodes at D2 and D15, but do not solder yet. D2
is in the VFO area. D15 is in the back-right corner near J8.
Identify the two types of black, axial-lead diodes: 1N4007 and
SB530. The 1N4007 is the smaller of the two.
Install the SB530 diode at D16, near the back edge of the
board.
Install 1N4007 diodes at D11 and D10, to the left of D16.
Install a 1N4007 diode at D5, near J7.
The varactor diodes have a small plastic package, like a TO-92
transistor, but with only two leads. Sort the varactor diodes into
two types: MV209 (quantity 1) and 1SV149 or V149SL (quantity 4).
Install the varactor diodes listed below. The flat side of each
diode must match the flat side of its PC board outline. Bend the
leads slightly on the bottom to hold the diodes in place.
__ D4, MV209 (in the VFO area)
Note: The 1SV149 diodes may have a third lead in the center, cut off near the
body. Mount them slightly above the board to avoid letting this lead short
the two pads together.
__ D3, 1SV149 (in the VFO area)
__ D6, __ D7, __ D8, 1SV149 (right-front corner)
i
TO-92 package may have either of the package types
shown in Figure 5-4 (page 19). Orient the large flat side of the
package with the flat side of the component outline. Verify the
part numbers using a magnifying glass if necessary.
Install the TO-92 package transistors listed below, starting with
Q9 in the VFO area. Observe anti-static precautions.
__ Q9, 2N3906 ⇒ __ Q8, J309 ⇒ __ Q11, J309
__ Q10, 2N7000 __ Q2, MPSA14 __ Q1, 2N7000
__ Q3, 2N4124
Re-check the orientation of the diodes, then solder.
ELECRAFT 29
i
Transistor Q4 (ZVN4424) is labeled on the back (the side
with smaller area), which is different from most TO-92 devices.
The labeled side of Q4 must face the power switch, S1.
Install Q4 (ZVN4424A) in the back-right corner near S1.
Install U6 (78L06) near the left edge of the VFO area.
Install the 8-pin ICs listed below. Orient the notched or
dimpled end of each IC with the notched end of its component
outline (see Figure 4-7). Make sure the part numbers on the ICs
match the numbers on the component outlines.
__ U4, LM380N-8 (do not confuse with U3--check part numbers carefully)
__ U3, LM386N-1
__ U2, __ U7, and __ U1, SA602AN (alternates: NE602, SA612, NE612)
Install the following components on the bottom of the board,
soldering them on the top side. Note: R3 is easier to solder on the
bottom. In this case, pre-trim the leads to the correct length.
__ R3, 8.25 k, 1% (GRAY-RED-GRN-BRN) (see note above)
__ R15, 10 ohms, 5% (BRN-BLK-BLK)
__ R5 and __ R6, 2.7 k (RED-VIO-RED)
__ R27, 1.8 k (BRN-GRY-RED)
__ D12, 1N4007 (black body)
__ RFC6 and __ RFC7, 100 µH (BRN-BLK-BRN)
__ C5, 3300 pF polystyrene (3300J)
__ C12, 1200 pF polystyrene (1200J)
Install C8 (82 pF) on the bottom of the board, near P1.
Before soldering, fold it down against the board, towards the back.
On the top and bottom sides of the board near J7 you’ll find
short jumpers (
Locate the DC power switch, S1. Install S1 near the back of
the board, with the plunger facing the back edge. Make sure S1 is
pressed firmly onto the board, and that it is not tilted.
). Install U-shaped wires at both locations.
Push the black keycap onto S1’s plunger until it snaps.
Install the DC input jack, J4, at the back edge. The 3 leads on
the jack must be lined up with the slot-shaped holes in the
component outline. If the holes are a tight fit, press firmly until
the connector snaps into position, flat against the board.
Visual Inspection
Verify correct orientation (banded end) of each diode installed
so far, using the parts placement drawing (Appendix F).
Examine both sides of the PC board closely for solder bridges,
cold solder joints, or unsoldered components.
Resistance Checks
Make the resistance checks listed below, with your DMM's (-)
lead connected to the ground jumper (
measurements on P1 (the 20-pin right-angle connector) should be
taken from the bottom side of the board.
Test Points (+) Resistance
P1 pin 6 > 100 k
P1 pin 7 > 100 k
P1 pin 8 > 100 k
P1 pin 12 > 10 k
P1 pin 14 > 100 k
P1 pin 15 > 100 ohms
P1 pin 16 > 1 k
P1 pin 17 > 1 k
U3 pin 3 < 200 k
U3 pin 5 > 10 k
U4 pin 3 > 50 k
U4 pin 6 > 10 k
U4 pin 7 > 1 k
) near J7. The
30 ELECRAFT
i
board outlines are circular. The (+) lead must be installed in the hole
marked with a "+" symbol. The (+) lead is usually longer than the (–)
lead, and the (–) lead is identified by a black stripe (Figure 6-6).
Electrolytic capacitors are mounted vertically, so their PC
+
-
Figure 6-6
Install the electrolytic capacitors listed below. They must be
seated as close to the PC board as possible to avoid interfering with
option modules that you may install later. Note: The 10-µF capacitors
are of the low-profile type, so they may be smaller than the 2.2-µF
capacitors.
__ C33, __ C59, and __ C35, 10 µF (see note above)
__ C54, __ C31, and __ C67, 2.2 µF
__ C9, __ C10, and __ C53, 220 µF
8-volt regulator U5 (LM2930T-8) is a TO-220 package device
with 3 leads (see photo in parts list). Mount U5 vertically at the back
edge of the PC board (Figure 6-7). Only the wide part of the leads
should be above the board. The hole in the tab of U5 will not be used
for mounting, so positioning is not critical.
Locate the component outline for RFC8, on the bottom of the RF
board in the transmitter area. Install a short wire jumper at RFC8,
formed from a component lead or solid hookup wire.
Note: an RF choke may be supplied with the 80-meter band kit (2band Filter board only) for use at RFC8. This RF choke can be
installed at any time, and will have no effect on K1 alignment or
testing on any band. Its function is to improve stability on 80 meters
when the K1 is used with poorly-matched loads or an ATU.
DC Voltage Checks
Set power switch S1 to its OFF position, with the plunger out
(extended toward the back).
Connect a 12 to 14-V DC power supply or battery to J4. If your
power source does not already have a plug that mates with J4, use the
supplied mating plug and prepare a suitable power cable. The center
lead of the plug is positive (+).
Turn on S1. If you see or smell smoke, or a component feels
hot to the touch, disconnect the power source immediately. Locate
the source of trouble before proceeding.
Using your DMM's DC voltage setting, make the DC voltage
checks listed below. The (-) lead of your DMM should be connected to
one of the ground jumpers.
Figure 6-7
i
Be careful not to short adjacent pins of ICs with the DMM
probe (use only a fine-point probe).
Test Point (+) DC Voltage
P1 pin 15 5.8-6.2
P1 pin 16 (supply - 0.3 V)
U3 pin 5 3.8-4.2
U3 pin 6 7.6-8.7
31 ELECRAFT
Turn the K1 off and disconnect the power supply.
Install the headphone jack, J2, on the small board extension near
the front-left corner. The pins on J2 are not very long, so they will be
nearly flush with the bottom of the board. Solder the pin closest to the
front edge first (ground), then verify that the jack is seated flat on its
plastic nubs before soldering the other pins.
Mono Headphones: If you plan to use only a mono plug at J2, cut the
trace marked "cut = mono" on the bottom of the board, under J2.
(You'll lose the sound on one side of stereo headphones.)
Install the key jack, J3, at the back-left corner. Before soldering,
make sure that the jack is aligned with its PC board outline.
Install the antenna jack, J5 (BNC), in the back-right corner.
Solder one of the large ground mounting pins first. If J5 then appears
to be tilted or twisted, reheat this ground pin while pushing J5 down
onto the board. Once it is seated properly, solder the remaining pins.
The internal speaker connector, P2, is a 2-pin connector with a
locking tab. Orient P2 as shown by its PC board outline, near the
front-right corner of the board, with the locking tab facing the front.
P2 must be seated flat against the board before soldering.
Install crystal X5, near the front edge of the board. Make sure it
is flat against the board and not tilted before soldering. (The leads can
be bent to hold it in place.)
Install R39 (1.8 k, BRN-GRAY-RED) on the bottom of the board
near crystal X6.
In the back right corner of the board near the antenna jack (J5),
install P3, a 3-pin male connector. The long end of P3's pins face up.
Install the two-pin shorting jumper across pins 1 and 2 of P3 (the
two terminals closest to J5).
On the bottom of the board, install R4 (5.6 k, GRN-BLUE-RED).
Locate the miniature slide switch, S2. Install S2 on the bottom of
the board, with the switch pressed down onto the board as far as it will
go. (If it isn't pressed all the way down, the actuator might hit the
bottom panel.) Limit soldering time on each of S2's pins to 2 seconds
to avoid melting the plastic body.
Set S2's actuator to the "OPER" (operate) position.
Locate the component outline for RF choke RFC9, on the bottom
of the board between the pins of relay K1. Flush-trim the four pins of
K1 closest to RFC9.
Form the leads of RFC9 (15 µH, BRN-GRN-BLK) to fit between
the indicated pads. Install RFC9 and position its leads so that they
don't contact any adjacent pads of K1. Solder and trim RFC9's leads
from the top side of the board.
Install X6 near the back-left corner.
Install X1-X4 at the front-right corner.
Ground the cases of all six crystals, using the near-by ground
pads. Use discarded component leads as before. Limit soldering time
to 4-5 seconds to avoid overheating the crystals.
32 ELECRAFT
Locate the dark gray (ferrite) toroid cores. You should have
four smaller cores (type FT37-43) and one larger core (FT50-43).
The three inductors to be wound in the following steps, L2, T1, and
T2, all use the smaller ferrite cores.
i
Review the toroid winding and lead preparation instructions
if necessary (page 14).
Wind L2 using 16 turns of red enamel wire (11 inches, 28 cm).
L2 should appear similar to Figure 4-3, on page 14 (the figure
shows 14 turns rather than 16). Recall that each pass of the wire
through the core counts as one turn.
Prepare L2's leads as before (page 14). Remove the insulation
to within about 1/8" (3 mm) of the core, then tin the leads.
Install L2 vertically, at the back edge of the RF board between
the on-off switch (S1) and the antenna jack (J5).
i
T1 is a toroidal transformer, with two numbered windings.
These numbers are printed next to each pad on the PC board. T1's
windings are 1-2 and 3-4
T1 is wound on an FT37-43 ferrite core (dark gray) and has
windings similar to those shown in Figure 6-8a. Wind the 3-4
winding first, using 20 turns of red enamel wire (13", 33 cm). This
winding should occupy 80 to 90% of the core. Note: the drawing
shows only 14 turns.
Wind the 1-2 winding on top of the 3-4 winding, using 4 turns
of green enamel wire (6", 16 cm). These turns should be wound
tightly, and will overlap the turns of the first winding. (The drawing
shows the turns interleaved, for clarity, but this is not required.)
Strip and tin all four of T1's leads carefully.
.
Install T1 flat against the board, between U1 and U2. Insert
the leads into its numbered holes as shown by the component
outline. Pull the leads taut on the bottom, then solder and trim.
1, GRN
2, GRN
(a) T1
T2 is wound on the same core type as T1. Start with the
3–4 winding, which uses 20 turns of red enamel wire (13", 33 cm).
The 1-2 winding uses 5 turns of green enamel wire (6", 16 cm).
Strip and tin T2's leads.
Install T2 flat against the board, to the right of U2. Pull the
leads taut, then solder.
Using your DMM, check for continuity between the pads of
L2. If the DMM doesn't indicate a short (< 5 ohms), you may not
have fully removed the insulation from one or both leads. Since the
insulation can be heat-stripped, you can usually improve the
electrical connection by re-heating each lead for 4 to 5 seconds.
Similarly, check T1’s two windings (1-2 and 3-4) for
continuity. Then check T2's windings.
3, RED
4, RED
Figure 6-8
4, RED
3, RED
(b) T2
2, GRN
1, GRN
i
Toroidal inductor L1 (VFO) will not be installed until the
VFO is aligned in Alignment and Test Part I (page 36).
ELECRAFT 33
On the top side of the RF board, locate the hole identified as
(A) in Figure 6-9. (The label "S1" appears near the hole.)
(B)
(B)
(A)
J6
i
When working with the side panels in the following steps,
place a soft cloth on your work surface to protect the paint. (A
clean anti-static mat will also suffice.)
Locate the two side panels and arrange them as shown in
Figure 6-10, with the inside surfaces facing up. The right side can be
identified by the presence of an extra hole as shown. The
illustration also shows where 2-D fasteners will be installed, as well
as the areas which were masked during painting.
Left side, inside surface
2-D Fastener
Masked area
Figure 6-9
Install a 7/16" (11 mm) hex male-female standoff on the top
of the board at location (A) as shown. Use an internal-tooth lock
washer and 4-40 nut on the bottom. Do not over-tighten the
hardware; the standoff threads can be easily stripped.
Install 7/16" (11 mm) hex male-female standoffs at the two
locations identified as (B) in Figure 6-9, replacing the existing
3/16" pan-head screws. Do not use any lock washers.
Temporarily place the Filter board assembly on top of the
three standoffs just installed. If the standoffs are in the correct
positions, they will be visible through their holes in the Filter board.
Right side, inside surface
Extra hole
Figure 6-10
Remove any masking tape from the panels using the same
technique described on page 23, taking care not to scratch the outer
surfaces.
34 ELECRAFT
p
i
Flat-head screws are more easily damaged than pan-
heads. Do not use excessive force when tightening them.
Attach two 2-D fasteners to each side panel at the locations
indicated in Figure 6-10. (Make sure that the holes are countersunk;
if not, you may be working with the wrong side of the panel.)
Use one 3/16" (4.8 mm) flat-head screw to hold each 2-D fastener
to the side panel (Figure 6-11). The two unused holes on each
fastener must be offset away from the side panel as shown.
Attach the side panels to the RF board using two 3/16" (4.8
mm) flat-head screws per side panel. The side panels are attached
using the 2-D fasteners that are already in place on the RF board.
Figure 6-12 shows the approximate location of the two screws used
to secure the right side panel.
Holes offset
away from
anel
Figure 6-12
Figure 6-11
ELECRAFT 35
With the assembly upside-down or resting on one side, plug the
front panel assembly into the RF board (Figure 6-13). Connector J1
on the bottom of the front panel PC board mates with P1 on the
bottom of the RF board (indicated by an arrow below).
i
The switches should now be accessible, and the headphone
jack should be even with the front panel. Also, the LEDs above the
VFO knob should be visible. If any of these controls are not
properly situated, you may not have the Front Panel fully plugged
into the RF board.
Note: The coaxial jumper to be installed in the following steps is
referred to as W1 in the RF board parts list.
Cut a 2.6" (67 mm) length of RG-174 coax cable. Using a
sharp tool, remove about 3/8" (9 mm) of the coax jacket from
each end. Be careful not to nick the braid.
Figure 6-14
Separate the braid (shield) from the center conductor at both
ends (Figure 6-14). Clip off about half the strands of the braid close
to the jacket, then twist the remaining braid into a fine bundle.
Remove a small amount of insulation from the center
conductor. Use long-nose pliers to hold the center conductor while
stripping it, or you may pull it out of the coax jacket.
Figure 6-13
Secure the front panel to the side panels and RF board using two
flat-head and two pan-head 3/16" (4.8 mm) screws. Flat-head
screws are used on the top, and pan-head on the bottom. You may
need to adjust the 2-D fasteners slightly, then re-tighten all
hardware.
On the bottom of the RF board you'll find the component
outlines for two 2-pin connectors, J9 and J10. Install the coax cable
on the bottom of the board between these two points. The center
conductor should be inserted into pin 1 of each connector (square
pad), and the braid into pin 2 (round pad). Do not solder yet.
Make sure that the coax braid is not touching any adjacent
pads at either end, and that the coax is not covering the nearby
screw mounting hole. Solder the coax (on the bottom side of the
board). Trim the leads on the top side if there is excess lead length.
36 ELECRAFT
7. Alignment and Test, Part I
In this section you’ll become familiar with K1 operation, while
testing control circuits and aligning the VFO and receiver.
The Tap/Hold Rule
Each of the push-button switches on the front panel has two
functions, one activated by a TAP (short press) and the other
activated by a HOLD (long press, about 1/2 second). The upper
label on each switch shows the TAP function (white lettering), and
the lower label shows the HOLD function (yellow lettering). To
highlight this in the text, we use two different typographical styles
to identify switches:
T A P and H O L D .
Initial Tests
i
If any test or alignment step fails, refer to the
Troubleshooting section (Appendix E).
To improve the visibility of the LCD during testing, you
should prop up the front edge with a non-conductive object (small
box, book, etc.). Note: Do not attach the KTS1 tilt stand at this
time. With the bottom cover removed, it could cause a short.
Set AF GAIN fully counter-clockwise (minimum volume).
Make sure the K1 is turned OFF (power switch S1 out).
Plug your power supply or battery into J4 on the rear panel.
LED Test
i
When you turn the K1 on the next step, watch for the
LED test. You should see the ATTN (yellow) LED turn on briefly,
followed by the RIT/XIT dual-color LED (green, then orange).
Turn on power to the K1. If you see or smell smoke, or a
component feels hot to the touch, disconnect the power
source immediately. Locate the source of trouble before
proceeding.
If you did not see the LED test, refer to Troubleshooting.
LCD and Error Codes
You should now see E 2 7 on the LCD. This is an error code
which occurs when the K1 self-test finds that the Filter board is not
plugged in. (Error codes are listed and described in the
Troubleshooting tables.)
i
If the LCD is blank, it may indicate that one or more
switches are closed. Check for shorts on all switch lines.
Tap any switch to clear the error code. You should then see
E 4 2 , which indicates that the self-test found the VFO signal
missing. This is correct, since the VFO inductor, RF-L1, has not yet
been installed. (When the VFO is functioning normally, you'll see
the operating frequency displayed.)
ELECRAFT 37
Sidetone Generator and Audio Amplifier
Plug in a pair of stereo headphones, and rotate the AF GAIN
control clockwise to about 9 or 10 o’clock.
Tap M E N U . The first menu entry will be displayed: O U T
(transmit power output). Tap
W P M + to select the next menu
entry, S T L (sidetone volume). (Lower-case "t" is used.)
The Sidetone can be activated by editing the S T L menu
parameter. Hold
sidetone. You can then use
level, from 0 -3 1 . Select a comfortable level, then tap
E D I T to show the parameter and turn on the
W P M + and W P M - to vary the sidetone
M E N U to
turn off the sidetone and return to the S T L display.
Note: S T L is used to set the sidetone volume level in relation to
normal received audio. However, the AF GAIN control sets the
overall headphone or speaker volume.
Select the sidetone pitch menu entry (STP) using by tapping
W P M + . Hold E D I T to turn on the sidetone and edit the pitch
parameter. The pitch can be varied from 4 0 0 to 8 0 0 Hz using
W P M + and W P M - . Select the desired pitch, then tap M E N U to end
parameter edit and return to S T P .
Keyer
Note: If you don’t have a keyer paddle, you can still test the DOT
and DASH lines by using test clips to touch them to ground.
Plug a keyer paddle into the key jack (J3). The plug must be
stereo (2 circuit). A stereo plug is supplied with the kit.
Tap M E N U and locate the I N P menu entry (CW input device
selection). Hold
(hand key or external keyer). Use
P D n or P D r (paddle normal, or paddle reverse). Then tap
E D I T to see the parameter, which defaults to H n d
W P M + and W P M - to select either
M E N U
twice to return to the VFO display.
Select the keyer speed using W P M + and W P M - . If you tap
these switches quickly, the speed will jump 2 WPM at a time.
While listening with headphones, test the keyer paddle to
verify that both dot and dash are working.
If you use a dual-lever keyer paddle, you may wish to use the
menu’s I A B entry to select iambic mode A or B (page 55).
Relays (Filter Board and Attenuator)
Tap M E N U again to return to the normal display (in this case
E 4 2 because of the missing VFO signal).
Voltmeter
On power-up, the LCD shows the operating frequency, with
100-Hz resolution. Holding
Holding
D I S P L A Y again selects voltmeter mode. You should see
D I S P L A Y once selects S-meter mode.
B A T flash briefly on the LCD, then your approximate power
supply or battery voltage, which will continue to flash slowly.
Return to the operating frequency display by holding
D I S P L A Y again. You should see E 4 2 , as explained previously.
Turn off the K1.
Plug in the Filter board assembly. The connectors on the Filter
board must be fully inserted into J6, 7 and 8 on the RF board.
Turn the K1 on. The LCD should show E 4 2 . You may also
hear one or more relays switching.
Tap B A N D twice (quickly) to change to the next band. Tap
B A N D two or more times quickly to return to 7 . 0 MHz.
Test the attenuator relay and the yellow LED by holding
A T T N . Hold A T T N again to turn the attenuator off.
38 ELECRAFT
VFO Alignment
Turn the K1 off and disconnect the power supply.
Two different capacitors are supplied for setting the
approximate VFO range: C2 (68 pF disc) and C2A (120 pF
polystyrene). 68 pF provides a range of about 80 kHz; 120-pF
provides a range of about 150 kHz. Other values can also be used
(builder-supplied).
Based on your VFO range selection (page 12), install the
appropriate capacitor at C2. Save the other for possible future use.
If you use the 68-pF disc cap, pre-form the leads to match the pad
spacing for C2.
Wind L1 on a T50-6 toroid core (yellow, 1/2" [12 mm]
diameter). Use 24 inches (61 cm) of red enamel wire. Wind 33
turns on L1, leaving the two leads about 1/2" (12 mm) long.
Adjust the turns of L1 so that they are fairly evenly spaced
and occupy about 90% of the core.
Strip and tin the leads of L1 to within 1/8" (3 mm) of the
core. (Review toroid lead preparation instructions, page 14.)
Secure L1 loosely to the PC board as indicated by its
component outline, near J6. As shown in Figure 7-1, use two nylon
washers, a 1/2" (12 mm) nylon screw, and nylon 4-40 nut.
VFO Range Test
Tap M E N U and locate C A L . To enable the operating
frequency calibration display (O P F ), hold
E D I T . The 100-Hz digit
should be flashing. (If you see E 4 2 , the VFO is not functioning.)
To see the VFO frequency, you’ll use CAL’s other display
mode, O S C . To select this, hold
D I S P L A Y . You’ll see O S C ,
followed by the VFO frequency in MHz (1 digit), then kHz (3
digits). For example, 3.012 MHz would be shown as 3 , then 0 1 2 .
Make sure that the VFO frequency goes up as the VFO knob is
rotated counter-clockwise. If not, see Troubleshooting.
Rotate the VFO knob fully clockwise until it stops, then note
the frequency: __________ kHz. Rotate it counter-clockwise until
it stops and note the frequency: __________ kHz. Subtract the
low reading from the high reading to obtain the VFO range:
_________ (about 80 or 150 kHz, depending on the value of C2).
VFO Range Adjustment
Make sure the VFO knob is rotated fully counter-clockwise.
If the frequency shown is now higher than 3.100 MHz,
squeeze the turns of L1 (bunch them more closely together) to
lower the frequency. You can squeeze the turns by hand, or use the
tuning tool. Watch the frequency display as you adjust the turns.
Figure 7-1
Insert L1’s leads into their pads and solder.
Connect the power supply and turn the K1 on.
If the frequency shown is lower than 3.090 MHz, spread
the turns of L1 out. This raises the VFO frequency. If the frequency
cannot be raised to at least 3.090 by spreading the turns out, you
may need to remove one turn from L1 (the non-grounded end).
Note: The final VFO frequency should be between 3.090 MHz and
3.100 MHz to make sure that the low end of each band is covered.
Once the turns on L1 have been correctly adjusted, tighten the
nylon screw so that the L1’s turns are held firmly in place. (This
may shift the indicated frequency slightly.)
ELECRAFT 39
Band Assignments
To see the correct display when you tap
specify which bands are covered by your Filter board.
If you re still in the C A L menu entry, tap M E N U to exit.
Locate the B 1 menu entry (note that the "b " actually appears
in lower-case). If B 2 , B 3 , or B 4 is shown, tap
to B 1 .
To check the present assignment for band 1, the lowest-
frequency band, hold
W P M - to specify band 1.
i
On 30 meters, you have a choice of two band edges (1 0 . 0
or 1 0 . 1 ), depending on your VFO range selection (from page 12).
The appropriate band edge is set by holding
Tap M E N U to return to the B 1 display, then tap B A N D to
switch to B 2 . Hold
Use W P M + and W P M - to specify band 2. If band 2 is 30
meters, select the band edge using
In the same manner, specify band 3 and band 4, if applicable
(four-band module only; see KFL1-4 manual, page 16).
E D I T . The default is 7 . 0 MHz. Use W P M + or
E D I T again to show the band 2 assignment.
D I S P L A Y .
B A N D
, you’ll need to
B A N D to change it
D I S P L A Y .
Receiver Alignment
This section applies only to the two-band Filter board.
If you have a four-band Filter board installed, refer to the
KFL1-4 manual, page 17.
Set the BFO trimmer, C20, so that its adjustment slot is
parallel to the nearby crystal. (C20 is located near the front edge of
the RF board.) The final setting of C20 will be determined later.
If the present band is not band 1 (the lower frequency band),
B A N D twice quickly to select it.
tap
Make sure that the attenuator (yellow LED) is off.
Plug in a pair of headphones or an external speaker, and adjust
the AF GAIN control until you hear some background noise. If you
do not hear any background noise, refer to Troubleshooting.
Set the VFO to about the mid-point of the present band (7.050
MHz on 40 meters, 10.125 MHz on 30 meters, etc.). Tap
necessary to verify that you’re in the right 100-kHz band segment.
Connect an appropriate antenna for band 1. At minimum,
connect approximately 20-30 feet (6 to 9 meters) of any type of
wire to the center conductor of J5. In general, the longer and higher
the antenna, the more signal strength that will be available during
receiver alignment.
B A N D if
Tap M E N U twice to exit the menu.
To re-check the band assignments, tap B A N D . The current
band will be displayed (in MHz), followed by a 3-digit display (1
kHz resolution), followed by the normal frequency display (to 100
Hz). For example, if the band is 40 meters and the VFO is set to
7025.3 kHz, tapping
2 5 . 3 . Tapping
B A N D will show 7 , then 0 2 5 , and finally
B A N D twice (quickly) switches to the other band.
i
Receiver alignment will be easiest if you use a ham-band
transmitter or signal generator to create a very strong signal that
can be located with the K1. If you use a transmitter, be sure to
connect it to a dummy load and operate it at low power.
40 ELECRAFT
Band-Pass Filter Alignment
While listening to noise or a weak signal, peak the band-2
On the Filter board, there are premix filters and RF filters for each
band, as shown in Figure 7-2. Each filter has two slug-tuned
inductors. These filters will be peaked in the following steps.
Premix RF
Premix inductors, L3 and L4.
Peak the two band-2 RF inductors, L7 and L8.
Re-peak L3 and L4, then L7 and L8, until no further
improvement is noted.
Band 1
Band 2
Figure 7-2
Locate the plastic tuning tool. The smaller end of the tool will
be used to adjust the slug-tuned inductors.
While listening to atmospheric noise or a CW signal, peak the
two band-1 Premix inductors, L1 and L2. Do not continue to turn
the slug if it has bottomed-out. Stop when you feel resistance. If
you cannot find a peak for L1 and L2, set them to about the midpoint of their range for now and go on to the next step.
Peak the two band-1 RF inductors, L5 and L6. If no signals are
heard while peaking either L1/L2 or L5/L6, use a transmitter to
generate a stronger signal, or scramble the settings and try again.
Re-peak L1 and L2, then L5 and L6, until no further
improvement is noted. Once all four inductors have been peaked,
received signals and noise should be quite strong.
Tap B A N D twice (quickly) to select band 2.
Switch to an appropriate antenna for this band, if available,
and set the VFO for the mid-point of the band.
Coarse BFO Alignment
The K1 three crystal filter bandwidths are selected by holding
X F I L switch. Hold X F I L until you see F L 3 on the LCD.
the
Note: FL1, 2, and 3 are pre-set to bandwidths of about 800, 400,
and 250 Hz. They can be set up differently using F L x (page 53).
Tune in a moderately-strong signal. Adjust the VFO slowly to
find the pitch where the signal is strongest. At this point, the signal
will be centered in the crystal filter.
Locate the BFO trimmer, C20, near the front edge of the RF
board. Adjust C20 for approximately the desired signal pitch.
Fine BFO Alignment Using the Sidetone Pitch
Select your desired sidetone pitch using the S T P menu entry.
(Many CW operators use 500-600 Hz or lower.) Exit the menu.
Tune in a strong signal, adjusting the VFO slowly until the
signal strength is centered in the filter, as you did above.
Turn on the sidetone again using the S T P menu entry.
Adjust C20 so that the pitch of the received signal matches
your sidetone pitch. This is best done with both the received signal
and sidetone at about the same amplitude. The received signal will
seem to "disappear under" or "merge with" the sidetone when the
pitch is closely matched.
Tap M E N U twice to return to normal operation.
ELECRAFT 41
Operating Frequency Calibration
The operating frequency display may be off by up to 10 kHz until
calibrated, due mostly to variations in the crystals on the Filter
board. Accuracy of +/- 100 Hz can be obtained.
Note: The approximate lower band edges in MHz are as follows:
3.50, 7.00, 10.00 or 10.10 (selected earlier), 14.00, 18.05, 21.00.
Select the lower-frequency band using B A N D . Also select the
narrowest filter (F L 3 ) by holding
X F I L .
Tune in a signal at a known frequency, centering the signal in
the crystal filter passband. Use a signal from a known-accurate
signal generator, or check the signal’s frequency using a second
receiver.
To access the operating frequency calibration display, locate
C A L in the menu, then hold
E D I T . You’ll see O P F briefly, then
the operating frequency will be shown, with the 100-Hz digit
flashing. (If you see E 4 2 , the VFO is not functioning.)
Tap W P M + or W P M - until the displayed frequency matches
the frequency of the known signal. In the case of the internally-
generated signal, tap
W P M + or W P M - until the display reads 9 9 . 7 .
Tap M E N U twice to return to the normal display.
Tap B A N D twice quickly to switch to band 2.
Repeat the calibration procedure on this band. If you have a 4band Filter board installed, repeat the procedure for bands 3 and 4.
AGC (Automatic Gain Control) and S-Meter Test
Turn the K1 on and connect an antenna or signal generator.
S-meter display mode provides a bar graph to indicate
approximate received signal strength. To select this mode, hold
D I S P L A Y . You should see a brief bar-graph test pattern, then the
display may go blank or show one or more bars.
Tune in a strong signal. (Anytime you are actually moving the
VFO, the S-meter bargraph will be replaced with the frequency
display.) Once the signal is tune in, the AGC should be activated, as
indicated by an increase S-meter reading.
2
The S-meter zero point
and scale can be adjusted (page 53). AGC can also be turned off if
necessary (page 57).
Note: Since the K1 uses audio-derived AGC, the initial code
element from a very strong station may be heard at louder volume.
This is due to the time it takes for the AGC detector capacitor to
charge up. If this is objectionable, the attenuator can be used.
Turning on the attenuator adds one bar to the S-meter reading to
roughly compensate for the loss in signal strength.
Receive Current Drain Test (Optional)
Typical current drain for the K1 in receive mode is approximately
55 mA (with all LEDs off). If the current drain is significantly
lower or higher than this, it could indicate a problem.
To check the current drain, set your DMM for DC milliamps and
temporarily insert the DMM in series between the K1 and the
power supply. Turn the K1 on and note the current: _____ mA.
i
You can calibrate the dial on transmit rather than receive if
desired, after completing Alignment and Test, Part II. In this case
you ll need either a frequency counter or a calibrated ham-band
receiver to verify the actual transmit frequency. You ll then use the
C A L menu entry, as described above, to check and adjust the
operating frequency after each transmission.
This completes receiver alignment.
2
Each bar corresponds to roughly two S-units, so that 4 or 5 bars indicates
about an "S-9" signal.
42 ELECRAFT
8. RF Board, Part II
In this section you’ll install the transmitter components.
On the bottom of the board near the antenna jack, install a
Turn off the K1 and disconnect the power supply.
Unplug the Filter board and set it aside.
i
If you have difficulty installing components in the
remaining assembly steps, unplug the Front Panel assembly and
remove the side panels.
Install the following capacitors, starting with C3, which is in
the back-left corner of the RF board.
1.50 k, 1% resistor at R36 (BRN-GRN-BLK-BRN), and a 226-ohm,
1% resistor at R37 (RED-RED-BLU-BLK).
i
Be sure to check the orientation of the banded end of each
diode in the following steps.
Install the 36-volt zener diode, D19 (type 1N4753), which has
a large glass or silver-colored body. D19 is on the right side of the
board, between transformers T3 and T4 (not yet installed).
__ C3, 10 (10) ⇒ __ C62, 330 (331) ⇒ __ C56, .047 (473)
__ C15, .001 (102) __ C58, .01 (103) __ C51, .001 (102)
__ C14, .001 (102) __ C16, .001 (102) __ C60, .01 (103)
__ C76, .01 (103) __ C57, .047 (473) __ C47, .01 (103)
__ C44, .01 (103) __ C46, 0.1 (104) __ C50, .047 (473)
__ C55, 0.1 (104) __ C52, 0.1 (104) __ C43, .01 (103)
Install the following 5% resistors, starting with R35 on the left
side of the board near J6.
__ R35, 120 (BRN-RED-BRN) ⇒ __ R10, 470 (YEL-VIO-BRN)
__ R11, 82 (GRAY-RED-BLK) __ R22, 33 (ORG-ORG-BLK)
__ R12, 820 (GRAY-RED-BRN) __ R24, 2.7 k (RED-VIO-RED)
__ R38, 270 (RED-VIO-BRN) __ R28, 820 (GRAY-RED-BRN)
__ R29, 270 (RED-VIO-BRN) __ R30, 3.3 Ω (ORG-ORG-GOLD)
__ R33, 470 (YEL-VIO-BRN) __ R25, 100 k (BRN-BLK-YEL)
__ R31, 33 (ORG-ORG-BLK) __ R32, 33 (ORG-ORG-BLK)
The remaining diodes to be installed are all type 1N4007. D18
is on the left side of the board, near J6.
__ D18 __ D14 __ D13 __ D9
Install a 100-µH RF choke (BRN-BLK-BRN) at RFC3 (located
near S1).
Install 22-µH RF chokes (RED-RED-BLK) at RFC2 and RFC5.
Refer to Figure 5-4 (page 19) when installing these transistors.
__ Q5, J309 (near J6) __ Q14, 2N4124 (back-left corner)
Install C1 (150 pF, “151”) on the bottom of the board. Before
soldering, fold C1 down towards the pads of R31 and R32 (but make
sure it isn’t touching these pads). C1’s overall height should be no
more than 0.15” (4 mm) above the bottom of the board.
ELECRAFT 43
i
TO-220 package transistors Q6 and Q7 look identical, but are
different types. Locate the 2SC1969 (labeled "C1969"), Q7, and set it
aside. The remaining transistor, Q6, will be either a 2SC2166 (C2166)
or a 2SC5739 (C5739). This transistor will be installed first.
Attach a self-adhesive thermal pad to the PC board on top of the
component outline for Q6. The hole in the thermal pad must be aligned
precisely with Q6's mounting hole on the board.
Prepare the leads of Q6 as shown below, bending them
downwards to match their pads. To avoid stressing the leads, use
smooth bends, rolling them over a small screwdriver blade or forming
them using long-nose pliers.
Use smooth
bend, not 90°
Figure 8-1
Identify the hole in the right side panel where the thermal
insulator will be placed (Figure 8-2). If the edge of the hole is not
completely smooth, use a large drill bit to de-burr the hole by hand.
Follow with a small amount of light sanding of the indicated area.
Attach a self-adhesive thermal pad to the side panel at the
location shown in Figure 8-2. The hole in the thermal pad must be
aligned precisely with the hole in the panel. The pad must be straight,
not tilted or skewed in either direction.
The rmal insulator
Figure 8-2
Attach Q7 to the right side panel using the hardware shown in
Figure 8-3: a 5/16" (8 mm) x 4-40 flat-head screw, shoulder washer
(black plastic), #4 internal-tooth lock washer, and 4-40 nut. The small-
diameter part of the shoulder washer must be inserted into the hole
in Q7's tab. Do not over-tighten the hardware.
Secure Q6 to the board using a 4-40 x 3/8" (9.5 mm) pan-head
screw (shiny finish, not black), #4 internal-tooth lock washer, and 4-40
nut. The screw should be inserted from the bottom side (Figure 8-1).
Verify the part number on Q6 (2SC2166, C2166 or 2SC2166,
C2166), then solder. Trim the pins on the bottom.
Remove the right side panel if it is still attached.
Figure 8-3
44 ELECRAFT
Bend the center lead of Q7 slightly away from the side panel,
forming it as shown in Figure 8-3.
Hold the right side panel up to the right edge of the RF board.
Insert Q7's leads into their pads while guiding the panel into
position. Secure the right side panel to the RF board using two
3/16" (4.8 mm) flat-head screws.
Solder and trim the leads of Q7 on the bottom of the board.
Using an ohmmeter on a low resistance scale, check for a
short from Q7's tab to ground. (The tab is connected to the
collector lead.) The metal hardware used to hold Q7 to the side
panel may show low resistance to ground, but the tab should be
floating (> 1 k).
Install 8-pin ICs U8 (SA602 or SA612AN) and U9 (LT1252).
Orient the ICs as indicated by their component outlines.
i
Toroidal transformers T3 and T4 must be wound exactly as
described in the following steps. Recall that transformer windings
are identified by numbered pairs of leads, which correspond to the
numbered PC board pads.
T3 is wound on an FT37-43 core (dark gray), the smaller of
the two cores remaining. Start with the 1-2 winding, which uses 12
turns of red enamel wire (9", 22 cm). See Figure 8-4.
3, GRN
1, RED
2, RED
4, GRN
Figure 8-4
T3's 3–4 winding uses 4 turns of green enamel wire (6", 16
cm). The turns of the 3-4 winding must be tightly interlaced with
the 1-2 winding as shown in Figure 8-4.
Strip and tin T3’s leads.
Install T3 flat against the PC board, to the right of Q6. Pull
the leads taut on the bottom side before soldering.
ELECRAFT 45
If you plan to operate the K1 on 80 meters, and your K1 RF
i
T4 uses a bi-filar winding, which means that two wires are
wound on the core together. The wires for the two windings will be
twisted together (see Figure 8-5).
1
(RED)
2
(GRN )
Figure 8-5
3
(RED)
4
(GRN )
board is revision D or earlier, you may need to make a minor
modification to the PC board. Please refer to the errata sheet included
with the K1B80 (80-m Band Kit).
Uninstalled Components
Make sure that all component locations on the RF board have
been filled, except for two: J1, which is supplied with the noise
blanker option kit (KNB1), and C78, which may be supplied with the
80-m band kit for the 2-band Filter board. If you have the 80 meter
board, install C78 at this time on the bottom of the board near the PA
and 12V labels with the (+) lead oriented as shown on t he outline.
Fold C78 down flat against the board before soldering.
Visual Inspection
Examine the bottom (solder side) of the RF board carefully for
unsoldered pins, solder bridges, or cold solder joints.
Resistance Checks
Cut two 8" (20 cm) lengths of enamel wire, one red and one
green. Twist the wires together over their entire length. The wires
should cross over each other approximately every 1/2" (1 cm).
Wind the twisted wires onto the 1/2" (12.7 mm) dia. ferrite core
(FT50-43, dark gray), using 5 turns and covering about 85% of the
core. Figure 8-5 shows how the winding should look.
Separate T4’s leads as shown in Figure 8-5. Strip and tin the
leads. Be careful not to let the red and green wires short together.
Install T4 flat against the PC board as indicated by its outline.
Using your DMM on a low resistance scale, measure continuity
between the #1 and #2 pads of T3. If you get a reading over 5 ohms,
re-strip the affected lead(s). Similarly, check the 3-4
Then check T4's 1-3
and 2-4 windings.
winding of T3.
For the following measurements, connect the (-) lead of your
DMM to a ground jumper. When making measurements at J7 and J8,
use a component lead or hookup wire as a probe tip.
Test Points (+) Resistance
J7 pin 1 2.4-3.0 k
J7 pin 4 > 1 k
J7 pin 5 > 100 k
J7 pin 6 5 - 7 k
J7 pin 8 1.5-2.0 k
J8 pin 1 > 100 k
D9 cathode (banded end) 1.5-2.0 k
J8 pin 5 90-110 k
J8 pin 7 1.6-1.9 k
U4 pin 7 > 1 k
U8 pin 8 > 100 ohms
U9 pin 7 > 1 k
D9 anode > 100 ohms
46 ELECRAFT
g
9. Alignment and Test, Part II
In this section you’ll align and test the transmitter stages.
Turn off the K1. Plug in the Filter board.
Attach the side panels, then plug in the Front Panel assembly.
Connect an antenna that is adequate for receiver testing.
Make sure the Filter board is not installed.
Plug in a pair of stereo headphones or a speaker at J2.
Place the power switch, S1, in the OFF position (out).
Connect a 12 to 14-V, 1-amp power supply (or battery) to J4.
Turn on the K1. You should see E 2 7 on the LCD due to the
missing Filter board. Tap any switch to clear the message.
Place the transmitter in TUNE mode (key-down), by holding
W P M + and W P M - switches simultaneously. The display should
the
show 0 . 1 watts, even though actual power output is zero.
Make the following transmit-mode DC voltage measurements.
Connect the (-) lead of the DMM to a ground jumper. Note: The
banded end of diodes is the cathode.
Test Point DC Volta
J7 pin 1 5.1-6.7 D9 anode 4.3-4.6
J7 pin 4 5.9-6.1 D9 cathode 3.8-4.1
J7 pin 6 < 0.2 D10 anode < 0.2
J7 pin 8 3.8-4.1 D10 cathode 3.8-4.1
U8 pin 1 1.3-1.5 D11 anode < 0.2
U8 pin 8 5.1-5.5 D11 cathode 4.0-4.6
U9 pin 3 6.0-7.0 D13 anode 0.6-0.7
U9 pin 6 6.0-7.0 D13 cathode < 0.2
U9 pin 7 12-14
e Test Point DC Voltage
Turn on the K1 and test receive performance. If receiver gain
seems to be too low, you may have an assembly error in the
transmit stages or T-R switch. Remove the Filter board and recheck the orientation of all diodes, transistors, and ICs. Also look
for shorts on both the top and bottom of the board in the
transmitter area. (Also see Troubleshooting.)
Switch to the voltmeter display to make sure that the battery
or power supply voltage is not being pulled down when the K1 is
turned on. (Hold
second time to select voltmeter mode.)
Preparation for Transmit Alignment
Turn the K1 off. Secure the Filter board to its three standoffs
using 3/16" (4.8 mm) pan-head screws and #4 split lock washers.
Connect a 50-ohm dummy load at the antenna jack. The
dummy load should be rated at 5 watts or higher.
Connect a key or keyer paddle.
Turn the K1 on.
Tap M E N U and locate the O U T entry (power output level).
E D I T , then use W P M + and W P M - to set power to 2 . 0 watts.
Hold
D I S P L A Y once to select S-meter mode, and a
ELECRAFT 47
Band 1 Alignment
If a 4-band Filter board is in use, refer to the KFL1-4 manual, page 19.
All filters are shared between receiver and transmitter, so transmit
alignment should already be close. However, it's important to repeak the filters on transmit. An analog wattmeter, ham-band
receiver, or the K1’s built-in digital wattmeter can be used.
Switch to lower-frequency band using B A N D . Set the VFO to
approximately the middle of the desired band.
Refer Figure 7-2 to identify the band 1 inductors.
i
The K1 can be placed in TUNE mode by holding the
W P M + and W P M - switches together. During TUNE, the power in
watts will be shown on the LCD (e.g., P 2 . 0 ). Hitting the key or
pressing any switch except
W P M + and W P M - will cancel TUNE.
Put the K1 into TUNE mode. Using the alignment tool, adjust
L1, L2, L5 and L6 for maximum output. If the output jumps up to
well above 2 watts, exit TUNE mode, then re-enter it again.
3
If necessary, repeat the adjustment of the filters two or three
times to be sure that you have the inductors peaked correctly. If
output is < 2 w or is not stable, see Troubleshooting.
If possible, verify that the K1 is transmitting on the correct
frequency using an external ham-band receiver. Connect a short
length of wire to the receiver's antenna jack. (Do not connect the
K1 directly to the receiver.) Key the K1 and locate the signal.
To make sure that the filters are peaked at the correct
frequency, vary each inductor a small amount while observing the
receiver's S-meter.
3
The transmitter's ALC (automatic level control) attempts to set the power
you specify. ALC is activated for 1-2 seconds when you enter TUNE mode.
After that, it is "open-loop," allowing you to adjust the filters. If the power
jumps, re-starting TUNE mode will activate the ALC again, reducing the
drive back down to the level needed to stay at about 2 watts.
Band 2 Alignment
Switch to band 2, and set the VFO to about mid-band.
Put the K1 into TUNE mode and adjust L3, L4, L7, and L8
for maximum output (refer to Figure 7-2 if necessary).
Verify that the K1 is transmitting at the intended frequency.
5-watt Test
Set power output to 5 . 0 watts using the O U T menu entry.
Enter TUNE mode briefly. The wattmeter should display
approximately 5 watts. Test 5-watt output on both bands.
Transmit Offset Adjustment
Locate the offset test switch (S2) on the bottom of the RF
board. Place it in the TEST position. You should hear a tone in the
headphones; its pitch is equal to the transmit offset. If you don’t
hear a tone, try rotating C13 (back left corner, near the key jack).
Using the menu, locate S T P (sidetone pitch), and go into edit
mode to turn on the sidetone. You should now hear two tones: the
sidetone and the transmit offset tone. If the sidetone is very weak
or very strong compared to the transmit offset tone, use the S T L
menu entry to adjust the sidetone volume. Note: The receiver is
muted in S T L edit mode, so you'll have to return to S T P after
making any change to the sidetone setting.
Adjust C13 so that the transmit offset pitch is as close as
possible to your selected sidetone pitch. The two will seem to
"merge" when the pitches are matched.
Exit the menu, and set S2 back to the OPER position.
If necessary, use the C A L menu entry to calibrate the
operating frequency on transmit (see page 41).
This completes transmitter alignment.
48 ELECRAFT
1. Final Assembly
Remove any masking tape from the top and bottom covers. Use
the technique described on page 23.
Remove and save the hardware supplied with the antenna and key
jacks.
The components on the bottom of the board must have an overall
height of no more than about 0.2” (5 mm) above the PC board. Fold
down or re-solder components if necessary.
Install the bottom cover by sliding it over the rear-panel controls.
Secure it to the rest of the assembly using six 3/16" (4.8 mm) pan-head
screws.
Install the hardware supplied with the antenna and key jacks. Be
careful not to strip the plastic threads on the antenna jack.
Set the top cover upside-down in front of you, with the back edge
facing away. Place the speaker over its holes, with the lugs to the left.
(Figure 10-1) .
Trim the speaker grille cloth so it is the same size as the speaker
frame and then trim the corners so it fits between the fiber washers.
Keep the grille cloth in place as you secure the speaker to the top
cover using four 5/16" (8 mm) flat-head screws, #4 fiber washers
(black), #4 metal flat washers, #4 internal-tooth lock washers, and 440 nuts (Figure 10-2). The fiber washers go between the speaker and
the top cover. Do not over-tighten the nuts, as this can flex the
speaker frame, causing damage to the speaker and/or distorted
audio.
lockwasher
metal fla t washer
Figure 10-1
fi ber w as her
Figure 10-2
ELECRAFT 49
Cut a 5" (13 cm) length of two-conductor speaker cable.
Remove 1/4" (6 mm) of insulation from the wires at both ends.
Solder crimp pins to the two wires at one end (Figure 10-3).
Copper wire
Pin 1 side
Crimp pin
Figure 10-3
i
When you insert the crimp pins into the housing in the
next step, they should snap into place. Each pin has a small tab on
the back that latches into a hole in the housing when inserted.
Insert the copper wire into the pin 1 position of a two-pin
housing as shown. Insert the other wire into the pin 2 position.
Connect the other end of this cable to the speaker terminals.
The copper wire should be connected to the lug marked (+) on the
speaker. Solder both wires.
If there are any missing chassis screws in the bottom cover,
side panels, or front panel, install them now.
Housing
Plug the internal speaker cable into P2 on the RF board. The
connector is keyed and can only be plugged in one way.
i
When you install the top cover in the next step,
route the speaker cable along the right side of the cabinet,
away from the pins of the microcontroller (front panel, U1).
The speaker wire could pick up signals from the microcontroller,
causing receiver interference.
Place the top cover onto the chassis. Secure the top cover
using two pan-head and two flat-head 3/16 (4.8 mm) screws.
Four self-adhesive feet are supplied for the bottom cover.
Install one at each corner, approximately 1/4" (6 mm) from edges.
Attach the self-adhesive serial number label to the rear panel
of the bottom cover in the space provided.
Write the serial number on the inside cover of your manual.
If you have the KTS1 wide-range tilt-stand, you should
configure it for desk-top use (using the short arms) and attach it to
the K1 at this time. Refer to the KTS1 instructions.
This completes assembly of your K1 Transceiver. You should have a
number of washers, screws, and other hardware left over. These
items have been provided as spares. Please read the Operation
section, which follows, and try each of the K1's features. If you're
new to QRP, be sure to read the QRP Operating Tips (page 56).
i
If you have purchased K1 internal options, we recommend
that you do not install them until becoming familiar with basic K1
operation. Once you're ready to build option kits, the suggested
order of assembly is: KFL1-2 or KFL1-4, KAT1, KNB1, KBT1.
(All K1 options are described on page 57.)
50 ELECRAFT
11. Operation
This section explains how to set up and operate the K1. We suggest
you read the first few pages as an overview, then follow the
tutorial, which starts on page 54 (Basic K1 Operation). There's also
a Quick Reference, Appendix G, which shows the locations of
front-panel controls and describes each of the menu entries.
Connections
Power Supply
You can use any 9-15 V DC power supply; current drain is about
0.5-1A on transmit. A mating DC power connector is provided
with the kit. Use an in-line 2A fuse when operating from a
battery or power supply that does not include its own fuse.
Low Battery warnings: If your battery (or power supply) voltage
drops below about 9 V, you’ll see a brief B A T L O message flashed
on the LCD once every 5 minutes (approx.). This voltage level was
chosen to be compatible with an 8-cell NiMH or NiCd battery back.
Other battery types may have a different end-of-life
voltage; check the voltage using BAT display mode often.
12-V gel-cell batteries must be recharged at 10.5-11.0 V.
Keying Device
Any type of hand key, bug, or external keyer can be plugged into
the KEY jack, or you can connect a paddle and use the K1's built-in
memory keyer. In all cases, you must use a stereo plug with the
keying device (a suitable plug is provided with the kit). It is also
possible to connect both a keyer paddle and another keying device
at the same time; see Keying Device Selection (page 55).
Antenna
Any well-matched, unbalanced (usually coax-fed) antenna can be
used with the K1. With non-resonant antennas or balanced
feedlines a suitable balun and/or antenna tuner will be required. If
you have the KAT1 automatic antenna tuner option installed, you
can connect a wide range of random length or non-resonant
antennas directly to the K1 and use them on one or more bands.
Power setting accuracy with internal RF detector: Power
readings using the K1's built-in RF detector (D15) are only accurate
when the SWR is low. If you use a poorly-matched load, you should
check your power output with an external wattmeter. In some cases
a high-SWR load can result in excessive current drain.
Headphones or External Speaker
The front-panel headphone jack can accommodate either
headphones or an external speaker, with an impedance of 8 ohms
or higher. A stereo plug or mono/stereo adapter is required,
unless you modify the RF board (see 2
nd
step on page 31).
Power setting accuracy with KAT1: If you have the KAT1
installed, power output display will be much more accurate under all
SWR conditions, since the tuner provides its own calibrated SWR
bridge/wattmeter.
ELECRAFT 51
Controls and Display
LCD
The 3-digit LCD (liquid crystal display) shows the operating
frequency or relative signal strength (S-meter) on receive, power
output on transmit, menu parameters, and status information.
Decimal Point: The decimal point is flashed when RIT or XIT is
enabled. This acts as a reminder that RIT or XIT is on.
Error Messages: If a problem is detected on power-up or during
normal operation, the display may show E 4 2 or a similar message.
If this happens, see Troubleshooting.
LEDs
RIT/XIT (dual-color): RIT (green) or XIT (orange)
ATTN: Attenuator (yellow)
Note: The LEDs can be disabled using the L E D menu entry. This
can save up to about 20 mA of receive-mode current drain.
Switch Functions
T A P a switch to access its upper function; H O L D a switch for 1/2
second to access its lower function. All functions are listed below.
The "1" and "2" labels near
message buffers 1 and 2 (see
near these switches is a reminder that TUNE mode is activated by
holding both
T A P and H O L D Switch Functions
B A N D show present band/freq.; tap twice to change bands
D I S P L A Y select display mode (normal, S-meter, or battery)
M E N U enter the menu (see Menu)
E D I T edit current menu parameter
R I T turn RIT on or off
X I T [ P F n ] turn XIT on or off, or select P F n (see Menu)
W P M + increment keyer speed or menu parameter
X F I L select next crystal filter (FL1-3)
W P M + and W P M - simultaneously (see page 54).
W P M + and W P M - correspond to CW
M S G and R E C , below). The "T" label
VFO
The VFO covers about 80 or 150 kHz of each CW band, as selected
during assembly. The approximate lower band edges in MHz are:
3.50, 7.00, 10.00 or 10.10, 14.00, 18.05, and 21.00.
Potentiometers
AF GAIN: Sets the receive audio output level. It also affects the
sidetone volume, in conjunction with the STL menu entry. Note:
The gain setting for headphones will be lower than for the speaker.
OFFSET: Adjusts the offset when
range is about +/- 3 kHz. (The range is set by RF-C7.)
R I T or X I T is turned on. The
W P M - decrement keyer speed or menu parameter
A T T N attenuator on/off
M S G play CW message 1 or 2 (to repeat, hold 1 or 2 )
R E C record CW message 1 or 2 (M S G cancels record)
Fast-Tap
If you tap
W P M + or W P M - two or more times quickly, the keyer
speed will change by two WPM at a time. In the O U T menu entry,
fast-tapping will change the power in 0.5-watt steps.
52 ELECRAFT
Using the Menu
To access the menu, tap M E N U . Scroll menu entries by tapping W P M + / W P M - .
E D I T to display a menu entry's parameter, which can then be changed by tapping W P M + / W P M - . Tap M E N U to return to scrolling.
Hold
Another tap of
Edit Shortcut: If the menu entry you want is the last one you accessed, you can jump directly into edit mode by holding
exit by holding
All menu entries are listed below. They are arranged so that the ones used most often are at the beginning and end of the list, allowing you to
get to them quickly by scrolling forwards or backwards. The F L x , B x , C A L , and S I G entries are described under Calibration Functions.
M E N U will return you to normal operation. If a parameter appears as "- - ", the associated option is not installed.
E D I T . After editing,
E D I T once more. Note: The AGC and NB parameters are not saved. On power-up, AGC is ON, and NB is OFF.
O U T power output level: 0 . 1 -7 . 0 watts
D I S P L A Y to select P = 0 , for keyer/msg test)
(hold
S T L sidetone level (volume): 0 -3 1
S T P sidetone pitch: 4 0 0 to 8 0 0 Hz in 10 Hz steps
(can also be used to SPOT, since RX is not muted)
T - R transmit-receive (QSK) delay: 0 to 9 0 0 ms
(50 ms recommended for casual operation)
R P T CW message repeat interval: 0 to 2 5 5 seconds
I N P CW input device selection:
H n d (hand key or external keying device)
P D n (internal keyer, paddles normal)
P D r (internal keyer, paddles reversed)
I A B iambic mode: A or B
A G C AGC O N or O F F ; no S-meter if O F F
L E D RIT/XIT/ATTN LEDs O N or O F F
(hold D I S P L A Y to turn switch audio tones on/off4)
F L x crystal filter bandwidth, 2 0 0 -8 5 0 Hz
(hold X F I L to select F L 1 / 2 / 3 , then
W P M + / W P M - to set bandwidth)
tap
B x band assignments, in MHz (1 . 8 to 2 8 . 0 )
B A N D to select B 1 through B 4 ; on 30 m,
(tap
D I S P L A Y to select 1 0 . 0 or 1 0 . 1 )
hold
C A L operating frequency cal (O P F ), per-band
(hold D I S P L A Y to select O S C for VFO test)
S I G S-meter zero set: L x x , where x x = 3 0 -7 0
(hold D I S P L A Y for scale: H x , where x = 2 -6 )
N B noise blanker mode: O F F , H I , L O
A T U automatic antenna tuner mode (see KAT1 manual)
P F n programmable function (PFn) assignment;
sets up
X I T [ P F n ] switch as a shortcut to a selected
menu entry. Set to N O R (normal) to use XIT.
4
Tones are only available on the RIT, XIT, and ATTN switches; they are
useful when you have the LEDs turned off. When you hold D I S P L A Y , the
menu parameter will flash A F if tones are enabled and N O R if disabled.
ELECRAFT 53
Calibration Functions
The F L x , B x , C A L , and S I G menu entries are typically used
during initial test and setup of the K1. B x and C A L are also used
whenever you plug in a different Filter module to allow the K1 to
display the correct frequencies.
Crystal Filter Bandwidth Selection (FLx)
The K1 provides three crystal filter bandwidths, FL1, 2, and 3,
which are selected using
the filters are set to about 800, 400, and 250 Hz. You can change
these settings using the F L x menu entry.
To modify the bandwidth for a particular filter, enter the menu and
scroll to F L x (where x is 1 , 2 , or 3 ). Use
entry to the desired filter. Hold
select one of the available bandwidths, in Hz. The bandwidth
settings are approximate.
The BFO is not programmable. One setting of C20 on the RF board
is used for all filters (see page 40).
Band Assignment (Bx)
This menu entry is used to tell the K1 firmware what bands your
Filter board covers, allowing the
the correct frequencies. You should set up B 1 and B 2 (as well as B 3
and B 4 if applicable), then do VFO calibration using C A L .
The B x parameter can be set to any band from 1 . 8 to 2 8 . 0 MHz,
corresponding to the components on the Filter board. Some of
these bands may not available from Elecraft, but can still be used if
you obtain the necessary components.
On 30 meters, you have a choice of two different band edges,
corresponding to your selected VFO range (see page 12). Hold
D I S P L A Y to select either 1 0 . 0 or 1 0 . 1 MHz.
X F I L during normal operation. By default,
X F I L to change the menu
E D I T , then tap W P M + / W P M - to
B A N D switch and VFO to display
Operating Frequency Calibration and VFO Test (CAL)
This menu entry is used to calibrate the operating frequency
display, or to align the VFO. (VFO test and alignment is covered in
detail on page 38.)
To calibrate the operating frequency: Switch to the band to be
calibrated and tune in a signal at a known frequency. Then select
C A L in the menu and hold
E D I T . You'll see O P F briefly, then the
operating frequency will be displayed to 100 Hz. The last digit
flashes as a reminder that you're in calibration mode. Use
W P M +
and W P M - to set the reading to match the known frequency.
Note: Each band must be set independently since they use different
crystals on the Filter board.
To check the range of the VFO: After holding
E D I T , hold D I S P L A Y
to switch to O S C . The display will then show you the MHz and
kHz portion of the VFO frequency, alternating about once per
second. Turn the VFO pot all the way in both directions to check
the range. Holding
D I S P L A Y again will switch back to O P F
(operating frequency calibration display).
S-Meter Calibration (SIG)
To check the S-meter zero setting, use
D I S P L A Y to switch to S-
meter mode, make sure the attenuator is OFF, and disconnect the
antenna. With no signal, the S-meter should indicate 0 bars, or the
first bar may just be flickering on. If not, you can use the S I G
menu entry to change the L x x parameter. After each change to
L x x , hold
E D I T to exit the menu and return to the S-meter display
to see the effect on the S-meter reading.
To check the S-meter full-scale setting, re-connect the antenna and
tune in a very strong signal. If the S-meter's reading appears to be
too low or too high for the given signal strength, use the S I G menu
entry to change the H x parameter. (To get to the H x parameter,
D I S P L A Y while the L x x parameter is displayed.) Reducing the
hold
Hx parameter value will increase the S-meter reading.
54 ELECRAFT
Basic K1 Operation
Self-Test: A number of tests are done at power-up. If you see an
error message (such as E 4 2 ), refer to Troubleshooting.
Band and Frequency Display: When you turn on the K1 or tap
B A N D , the current band and operating frequency will be displayed.
For example, if the last band used was 40 meters and the VFO was
set to 7025.3 kHz, the LCD would show 7 , then 0 2 5 , and finally
2 5 . 3 .
Changing Bands: To change bands, tap
more times.
Receiver Setup
Display Mode: Holding D I S P L A Y alternates between three
receive-mode displays: frequency (default), S-meter, and
voltmeter. For normal operation, use frequency or S-meter mode.
(In S-meter mode, the frequency is re-displayed automatically
whenever the VFO is moved.)
AF GAIN: Adjust the AF GAIN control for comfortable headphone
or speaker volume. The sidetone volume can be set higher or lower
in relation to receiver audio using the S T L menu entry.
Crystal Filter Selection: Filter FL1 (usually the widest filter) is
selected on power-up. Holding
narrower filters to reduce interference from nearby stations.
Attenuator: Holding
A T T N switches in about 14 dB of attenuation.
This may be useful if extremely strong signals are causing receiver
overload. The receiver has sufficient sensitivity to allow the
attenuator to be left in at all times, if necessary. If you turn the
attenuator on when the display is in S-meter mode, an extra bar is
added to the S-meter display to compensate. (Note: You can disable
LEDs to save current using the L E D menu entry.)
X F I L cycles through the filters. Use
B A N D quickly two or
Transmitter Setup
Display Mode: During transmit the LCD normally shows a
bargraph (1 bar per watt). If you select supply voltage display mode
(using
shown, flashing slowly. In TUNE mode, power is shown in watts
(see below). SWR can be displayed if the KAT1 ATU is installed.
Setting Power Output: Approximate power output can be set
using the O U T menu entry (0 . 1 to 7 . 0 watts). Anytime you
change the power level or change bands, you’ll see power start out
near zero, then go up while you send the first few characters of
CW. This is due to the transmitter’s ALC (automatic level
control). Caution: When working into non-50-ohm loads, the
power display may not be accurate.
TUNE Mode: To put the transmitter into TUNE mode (keydown), press the
watts, the display would show P 5 . 0 . (It is normal for this number
to vary over as much as several tenths of a watt.) While in TUNE
mode, you can change power output using
Keyer Test Mode: It is possible to completely disable the
transmitter to do keyer or message buffer testing (page 55).
QSK Delay and Sidetone: The QSK delay is set with the T - R
menu entry. Sidetone volume and pitch are set using the S T L and
S T P menu entries, respectively.
Transmit Offset: The transmit offset should be matched to your
selected sidetone pitch using C13 on the RF board. This is normally
accomplished during alignment (page 47).
Transmit Frequency Limits: Some countries require transmit to
be disabled outside of specified amateur bands. Your K1 may include
such limits encoded in firmware. In this case, if you key the
transmitter with the VFO set outside the usable range, you’ll see
E n d on the LCD.
D I S P L A Y ), the power supply or battery voltage will be
W P M + and W P M - switches simultaneously. At 5
W P M + and W P M - .
ELECRAFT 55
RIT and XIT
RIT (receive incremental tuning) can be used to fine-tune the pitch
of a received signal without affecting your transmit frequency. This
is most often used when a station calls you off frequency. To turn
on RIT, tap
R I T . The RIT LED (green) will turn on, and the LCD's
decimal point will flash slowly. You can then use the OFFSET
control to vary the receive frequency.
XIT works similarly to RIT, except that the transmit frequency is
varied with the offset control. For example, suppose a DX station
says to call "up". First, turn on
find a clear spot above the DX station's frequency. Then turn on
XIT by holding
X I T [ P F n ] .
R I T and use the OFFSET control to
5
The XIT LED (orange) will turn on. If
you need to determine the transmit frequency when using XIT,
briefly turn on
R I T , then switch back to X I T .
OFFSET Range: The range of the OFFSET control is determined
by the value of C7, in the VFO area of the RF board. A larger or
smaller value of C7 will increase or decrease the OFFSET range,
respectively.
Keying Device Selection
Internal Keyer: To use a keyer paddle, use the menu to set I N P
to P D n or P D r (normal or reverse paddle). With P D n selected,
the "tip" contact on the stereo key jack is DOT and "ring" (the
middle contact) is DASH. P D r is the reverse.
Keyer Setup
Keyer Speed: Use the W P M + and W P M - switches to select the
desired CW speed. The display will show the speed in WPM.
Tapping either switch quickly two or more times will cause the
speed to jump in 2 WPM increments.
Iambic Mode Selection: If you use a keyer paddle with two
mechanically-independent levers, you can use iambic keying,
meaning that both the DOT and DASH paddles can be pressed at
the same time to generate a repeating DOT-DASH or DASH-DOT
pattern. With practice, this can improve sending efficiency. The
I A B menu entry allows you to select from two Iambic modes: A or
B . If you're not sure which to use, select mode A (the default)
which has more forgiving timing characteristics. Mode A is similar
to mode A of the Curtis keyer IC; mode B is similar to Super CMOS
Keyer III mode B.
A single connector in the back is provided for your keyer paddle,
hand key, keyer, or computer. You must use a stereo (2-circuit)
plug, even if you use only a hand key or external keyer. This should
not affect the use of the keying device with other equipment, since
the middle contact on the plug (often called the "ring" contact) is
only used with keyer paddles.
Hand key or External Keying Device: To use a hand key,
external keyer, computer, or external keying device, set I N P to
H n d using the menu. You can key the K1 externally at up to 70
WPM. Note: The K1's message memories can only be programmed
using a directly-connected keyer paddle.
5
If you have assigned the XIT [PFn] switch to another function using the
PFn menu entry, you cannot use XIT.
Keyer Test Mode
At times you may want to disable the transmitter completely so
that you can practice recording messages or just sending code with
the keyer. The K1 has a built-in Keyer Test mode for this.
To activate keyer test mode, first select the O U T menu entry and
E D I T to display the power output level. Next, hold D I S P L A Y .
hold
The power output parameter will change to P = 0 , indicating that
the transmitter is disabled. To restore the original power level
setting, hold
Note: Turning power to the K1 off and back on cancels keyer test
mode and restores the original power level.
D I S P L A Y again.
56 ELECRAFT
Recording and Playing Messages
The K1 provides two CW message memories of 90 bytes each. CW
messages can only be recorded using a keyer paddle connected
directly to the K1's key jack. Set I N P to P D n or P D r . Messages are
stored in EEPROM, so they won't be lost when power is turned off.
To Record a Message: Hold
tap either
1 or 2 . The display will then show REC 90, indicating
that 90 bytes of storage are available in this message buffer. This
number will count down toward 0 as long as you are sending.
Whenever you stop sending completely, up to two standard-length
word spaces will be inserted. To stop recording, tap
this before starting to send, the original message contents will not
be lost.
To Play a Message: Tap
1 or 2 . Message play can be canceled at any time by hitting
either
M S G again or by tapping the keyer paddle. You can also change the
keyer speed while messages are playing, using
usual.
Keyer Test Mode: To play back messages without transmitting,
use keyer test mode (page 55). In this mode, you'll see P = 0 on the
LCD during message play, rather than the transmit bargraph.
R E C , and when prompted with 1 - 2 ,
M S G . If you do
M S G , then select a message by tapping
W P M + and W P M - as
Setting the Auto-Repeat Interval: The length of the pause
between messages during auto-repeat can be programmed using the
R P T menu entry (0 -2 5 5 sec.). Long delays are useful for beacons.
Using RIT During Message Repeat: You can use RIT (if it is
turned on) to listen above and below your receive frequency
between calls. This is useful when stations call you off-frequency.
QRP Operating Tips
Antennas: When you're using low power, a good antenna and
ground system can make a big difference. In general, antennas
should be mounted as high off the ground as possible, and resonant
or multi-element antennas will be the most effective. An excellent
choice for light-weight, multi-band portable use is a long, end-fed
wire, used in conjunction with two or more ground radials and an
antenna tuner. There are many references on antennas available,
including the ARRL Antenna Handbook.
QRP Frequencies: Low-power enthusiasts can be found at certain
"watering holes" on each band, listed below (MHz). An asterisk (*)
indicates European or alternative QRP frequencies.
80 m: 3.560 40 m: 7.040 (*7.030)
30 m: 10.106 (*10.116) 20 m: 14.060
17 m: 18.096 15 m: 21.060
Using Auto-Repeat
Either message memory can be auto-repeated when played, which is
useful when calling CQ on a quiet band or during contests.
Sometimes a band will be open but will "sound" dead, simply because
no one is calling CQ at that moment. This is a great time to let
auto-repeat do the work.
To use Auto-Repeat: Tap
2 . The message will then play back continuously until you tap M S G
again or hit your key or paddle. You'll see R P T on the display in-
between message transmissions.
M S G as usual, but then hold either 1 or
Calling and Listening: Calling CQ with low power may be
frustrating unless you have a good antenna. Usually, you'll spend far
more time listening. Keep transmissions short, especially when
working other QRP stations, which will often be at or even below
the noise level. Narrower filters (< 500 Hz) and slower code speeds
should be used when conditions are marginal.
Contests: Both general interest and QRP-only contests provide a
great way to work new states or countries. The K1, with its low
current drain and compact size, is particularly well-suited to outdoor
events such as Field Day and QRP To The Field.
ELECRAFT 57
Advanced Operating Features
Programmable Function Switch (XIT [PFn])
By default, the X I T [ P F n ] switch turns XIT on and off.
Alternatively, this switch can be set up as a direct edit shortcut to
any menu entry. To program the switch function, enter the menu
and scroll to P F n , then change the parameter to the desired menu
entry. Setting it to N O R (normal) assigns the switch to XIT.
Spotting
The S T P menu entry can be used to "spot," or match the pitch of
received signals, so that you'll be exactly on frequency when you
transmit. To spot a signal, select the S T P menu entry, hold
then adjust the VFO until the received signal pitch matches the
sidetone pitch. The received signal may seem to disappear when the
pitch is exactly matched. You can assign S T P to the
programmable function switch if you don’t use XIT (see above).
X I T [ P F n ] will then activate the spot signal.
AGC Control
Some operators prefer to turn AGC off and use manual gain control
under certain weak-signal conditions. To turn AGC off, use the
A G C menu entry. The attenuator may help with strong signals.
E D I T ,
K1 Options
Four- and Two-Band Filter Modules (KFL1-4, -2)
The KFL1-4 and KFL1-2 options provide additional bands of your
choice, allowing you to select the best combination of bands for
home use, field trips or specific operating events. The KFL1-4
includes 40, 30, 20, and either 17 or 15 meters.
Wide-Range Tilt Stand (KTS1)
When hiking or camping, you may find that there's no table or
other smooth surface on which to operate a transceiver. The KTS1
solves this problem by allowing you to rest the K1 on nearly any
rough surface (rock, dirt, etc.) and tilt the display upwards to the
ideal viewing angle. It also keeps antenna and power connections
away from the ground, and provides a mounting point for a keyer
paddle. (Refer to our web site for information on custom paddles.)
Noise Blanker (KNB1)
The KNB1 is effective in reducing pulse-type noise, such as that
from power poles or automobile ignition systems.
Automatic Antenna Tuner (KAT1)
Checking the Firmware Revision
Hold any switch on power-up to display the revision (e.g. 1 0 8 ).
Resetting to Factory Defaults (requires rev. 108 or higher)
Reset to defaults takes two steps. Step 1: Hold B A N D and M E N U
together on power-up, releasing the switches after the LED test.
You should see E 0 9 . Step 2: Turn power off and back on again;
you should see E 1 0 . You’ll then need to re-do VFO calibration, etc.
If the KAT1 internal automatic antenna tuner is installed, you can
connect coax-fed or random-length wire antennas directly to the
K1. An inexpensive home-made balun can be used with balanced
lines. In most cases the tuner will allow you to match one antenna
on all bands. Once you've tuned up an antenna, the tuner's L and C
settings will be recalled instantly when the band is changed.
Internal Battery (KBT1)
The KBT1 includes an 8-AA-cell socket and a replacement top
cover with a quick-access battery door. Any cell type may be used.
58 ELECRAFT
12. Circuit Details
While reading this section, refer to the Block Diagram (Appendix
B) and schematics (Appendix C).
Overview
The K1 is a compact, high-efficiency CW transceiver capable of
operating over a wide range of frequencies. The two (or four) bands
of operation are determined by a single plug-in filter module,
allowing the builder to swap in a different set of bands if desired.
The firmware will recognize whether a two- or four-band board is
installed.
The filter module includes the band-pass filters and crystals for the
K1's pre-mix conversion scheme, in which a low-frequency (~3
MHz) VFO is subtracted from a high-frequency crystal oscillator to
produce a "pre-mixed" injection frequency for the transmit and
receive mixers. Because of the VFO's low operating frequency,
stability is excellent. An analog VFO is used, resulting in a lower
noise floor than most synthesized transceivers. The filter board
also has RF band-pass and low-pass filters for each band.
The receiver is a single-conversion superhet, using downconversion to a low intermediate frequency (I.F.) of about 4.915
MHz. Down-conversion minimizes complexity and receive-chain
noise, while the low I.F. allows good CW selectivity with a 4-pole
crystal filter. The use of active mixers keeps current consumption
low, compatible with portable operation.
There are three stages of transmitter amplification. Maximum
power output from the final stage (class C) is about 5 to 7 watts,
depending on the band and supply voltage. The T-R circuitry is all
solid-state (no relays), resulting in smooth, fast QSK.
A low-power microcontroller (MCU) on the front-panel board is
used to control the transceiver and handle user interface elements,
such as the display and switches. A second, smaller microcontroller,
the I/O controller (IOC), acts as a driver for the filter and
attenuator relays. The IOC is controlled by the main MCU via a
one-line network, the auxBus. Option microcontrollers (i.e., on the
noise blanker and antenna tuner) also communicate via the auxBus.
Front Panel Board
Microcontroller (MCU) U1 is used to control all K1 functions, and
doubles as the driver for the LCD, DS1. U1 runs at just below 4
MHz. The crystal, X1, is intentionally kept under 4 MHz (by using
large oscillator capacitors), so that any internally-generated bandedge signals will be below the bottom edge of the band.
The LCD segments are driven with 50% duty cycle square waves to
ensure that the average DC voltage on each segment is 0 volts. The
LCD backplane (pin 24) is also driven by a low-frequency square
wave. To turn on a segment, it must be driven 180-degrees out of
phase with the backplane. In-phase segments remain off.
The MCU has a number of miscellaneous functions. It reads the
states of the switches (S1-S6) by periodically making the associated
LCD drive lines into inputs. The VFO signal is amplified by Q1,
then counted at MCU pin 6 (RA4). Pin 3 (RA1) is made an A-to-D
(analog-to-digital) input to read the battery voltage, or an output to
turn the ATTN LED on or off. Pin 4 (RA2) drives to 6 V or 0 V to
turn on the RIT or XIT LEDs, respectively (both part of D1), by
ELECRAFT 59
virtue of an intermediate voltage supplied by op-amp U5A. To turn
both elements of D1 off, pin 4 is made an input.
The states of the DOT and DASH lines are sampled on analog input
RA3 (pin 5). If both DOT and DASH are open, the voltage at RA3
will be about 6 V. If both are closed, the voltage will be 0 V. If only
one paddle is closed, an intermediate voltage results, either 2 V or 4
V. (See RF board, sheet 2.)
Q2 defeats the RIT/XIT offset when its gate voltage is at 6 V,
since its low drain-source resistance forces a fixed 3 V to appear at
the wiper of the offset pot, R3.
U2 and U3 are controlled by the SDA (data) and SCL (clock) lines,
using the industry-standard I2C protocol. U2 is a dual-output D-toA converter that controls the power level and generates audio
tones. When tones are not being generated, the tone output is used
to set the crystal filter bandwidth. U3 is a 512-byte EEPROM,
which stores all K1 operating parameters and CW messages.
VFO pot R1 is physically part of the front panel assembly, but its
wiper voltage (0-6 V) is routed to the RF board via J1. R19, located
between the wiper and the high end of the pot, improves tuning
linearity.
Filter Board
L5-L8 and associated capacitors form two RF bandpass filters, one
for each band. T-R switching circuits on the RF board place these
filters in either the receive or transmit path. L9-L12 and associated
capacitors form the two low-pass filters.
All filters and the two crystals are switched by latching relays K1K3. Microcontroller U1 pulses the relay coils bidirectionally to
switch them on or off. The reset condition of each relay selects
band 1. Latching relays are only energized when switched between
set and reset, so they consume no power during normal operation.
RF Board
VFO (Sheet 1)
Q8 is used in a varactor-tuned Colpitts VFO. The VFO tunes
"backward." For example, its frequency is about 3.080 MHz when
the operating frequency is 7.000 MHz, and 2.930 MHz when the
operating frequency is 7.150 MHz. This is due to the fact that the
VFO is subtracted from the crystal oscillator in the premixer (U7).
The use of varactor diodes (electronic tuning) results in a
compromise between circuit complexity, tuning range, and stability.
While VFO drift can never be eliminated entirely, steps were taken
to minimize it.
Note: This section applies to the 2-band filter module (KFL1-2).
For details on the four-band module, refer to the KFL1-4 manual.
L1-L4 and associated capacitors form two band-pass filters, one for
the premix signal on each band. There are also crystals for each
band (X1, X2). For example, on 40 m (7.000 MHz), the premixer
(U7, RF board) mixes a 3.085-MHz signal from the VFO with a
15.000 MHz crystal oscillator to obtain a difference signal at
11.915 MHz. There is also a sum frequency, 18.085 MHz, which is
rejected by the band-pass filter. The 11.915 MHz signal is routed to
the RF board at P1 pin 6.
First, the VFO supply voltage is double-regulated (explained in the
next paragraph). This improves stability by guaranteeing a very
stable voltage reference for the varactor diodes. Since the
transmitter circuits run from a different regulator, and since the
VFO is also well-buffered from the transmitter, there is virtually no
VFO frequency shift or chirp on key down over the full power
output range (0.1-7 watts). Second, temperature-compensation
techniques are used in the VFO itself, including careful selection of
capacitor types. The inductor used has a low temperature
coefficient, and its turns are adjusted to select the desired range,
which eliminates drift-prone trimmer capacitors.
60 ELECRAFT
Q9 isolates the VFO from noise pickup on the frequency counter
line. U5 and U6 double-regulate the VFO supply voltage for
improved stability. Since U5 is a low-dropout 8-volt regulator, the
K1's supply voltage can drop to as low as about 8.5 V without
affecting the VFO frequency. U6 is a 6.0-volt regulator with a very
tight tolerance of 2.5%.
Premixer U7 mixes the VFO with one of the crystals on the Filter
board.
Receiver (Sheet 1)
U1 is a double-balanced receive mixer, which provides an excellent
noise figure at low current drain. If input levels are too high, an
attenuator can be switched in via K1. RFC9 (across K1) suppresses
attenuator on/off switching noise that might otherwise be audible.
Emitter-follower Q3 provides some power gain while providing a
low driving impedance for the crystal filter (X1-X4). The crystal
filter has variable bandwidth, by virtue of varactor diodes D6-D8.
T2 steps up the crystal filter output to match the 1500-ohm input
impedance of the product detector/BFO, U2. The BFO is mixed
with the I.F. to produce an audio signal.
U3 amplifies the audio signal enough to drive the audio-derived
AGC detector, D2. R21 and C18 remove high-frequency hiss.
U4 amplifies the received audio signal and sidetone to headphone or
speaker level. The AF GAIN control is located on the front panel,
but is electrically connected between Q11 and U4 at the AF1 and
AF2 points.
In receive mode, the AGC signal is routed onto the RF/SMTR line,
which is then sampled by an A-to-D input on the MCU (U1, front
panel). Q1 is used to connect or disconnect the AGC signal from
the RF/SMTR line.
Transmitter (Sheet 2)
To vary the power output, JFET Q5 and PIN diode D18 control
the amount of premix signal input to the transmit mixer, U8. The
DC control voltage at the drain of Q5 is set by the MCU (U1, front
panel). ALC (automatic level control) is implemented in firmware.
During keying, the ALC determines what DC voltage is needed to
get to the requested power level, as well as what voltage
corresponds to zero output. As you key the transmitter, the control
voltage alternates between these two levels so that that the keying
waveform can be effectively shaped by R10 and C59.
Video amplifier U9 buffers and amplifies the TX mixer output. Q14
keeps U9 fully turned off during receive. The low-level transmit
signal is passed through the RF band-pass filter on the Filter board
via J7.
D2 is DC-biased just below the level needed to turn on darlington
transistor Q2. When a signal is present, Q2 will turn on in
proportion to the signal amplitude, pulling the AGC line down from
its nominal 1.2 V to as low as 0.6 V. The AGC line is connected to
the input bias pins of both U1 and U2, so that the gain of both
mixers is reduced as signal strength increases. R1 limits the gain
reduction at U1, so most of the AGC action is due to U2, which
minimizes the chance of front-end overload when AGC is activated.
Only signals in the passband of the crystal filter can cause AGC in
any case, so the AGC line stays at about 1.2 V most of the time.
Q10 and Q11 are shunt and series mute devices, respectively. Both
are required due to the large amount of audio gain in the receiver.
D9-D13 form a fast, high-isolation T-R switch that allows the
appropriate RF band-pass filter to be shared between receive and
transmit. On transmit the signal is routed through D9 to the driver
transistor, Q6. On receive, D10, 11, and 12 are turned on,
bypassing the transmit stages.
Q7 is the class-C final amplifier. It operates at a nominal collector
impedance of 12.5 ohms, which is stepped up to 50 ohms by T4.
Q7's output is filtered by one of the low-pass filters on the Filter
board, with signals routed through J8. RF detector diode D15
samples some of the RF output voltage to provide a power output
indication. If the KAT1 antenna tuner is installed, its SWR
bridge/wattmeter output takes over from D15, via pin 5 of J8.
Appendix A K1 Packing Box Parts List Revised 11-30-2000
PICTURE Designators Description Part Number
QTY
Misc. RF PC board E100094
B1 Left side panel E100097L
B2 Right side panel E100097R
B3 Front panel, silkscreened E100096SS
B4 Bottom cover, silkscreened E100098SS
B5 Top cover E100099
Bag, Misc. Hardware and miscellaneous components E850024
Bag, Wire Wire and coax E850023
Bag, Filter Board Components for 2 or 4-band Filter PC board KFL1-2 or KFL1-4
Additional Filter board components for two selected
bands (2-band K1 kit only).
Bag, Per-Band Components
Bag, Front Panel Board Components for Front panel PC board E850021
Bag, RF Board Components for RF PC board E850020
Elecraft order numbers shown at right.
K1B80, K1B40,
K1B30, K1B20,
K1B17, K1B15
1
1
1
1
1
1
1
1
1
2
1
1
HW (in envelope) Thermal insulator, TO220; for Q6, Q7 (RF BOARD) E700002
Page 1 Box
2
Appendix A K1 Packing Box Parts List Revised 11-30-2000
PICTURE Designators Description Part Number
QTY
Misc (in envelope) Acrylic display bezel; for LCD (Front Panel) E100108
Misc (in envelope) Serial Number Label E980024
SP1 Speaker, 8-ohm, 1 watt E980032
KN1 Large knob, 1.25" dia, 0.25" shaft; Rogan #RB-67-3-M E980021
KN2, KN3 Small knob, 0.5" diam, 6mm shaft E980016
1
1
1
1
2
Page 2 Box
Appendix A K1 Front Panel Board Parts List
PICTURE Designators Description Part Number
QTY
C1, C2 82 pF NPO disc; label: "82" E530038
C5, C6 .01 µF, monolithic; label: "103" E530009
C4 .047 µF, monolithic; label: "473" E530025
LED, dual, orange/green; LiteOn LTL-298WJ
D1
D2 LED, yellow; LiteOn LTL-4253 (Digikey 160-1133) E570001
D3 Diode (not used at present)
(Digikey 160-1037) E570000
2
2
1
1
1
0
3-character, 7-segment LCD
DS1
J1 20 pin x 1 female socket E620025
Q1 2N4124 transistor, TO-92 plastic E580006
Q2 2N7000 transistor, TO-92 plastic E580002
(V.L. Electronics p/n VI-321-DP-RC-S-12) E600015
Page 1 Front Panel
1
1
1
1
NOTE: Many of the resistors are supplied attached to strips of tape in assembly order, however some are also supplied loose
Be sure to check the color codes of all resistors during assembly to be sure you're installing the correct part.
Appendix A K1 Front Panel Board Parts List
PICTURE Designators Description Part Number
QTY
S1-S6 Switch, push button E640005
U1 PIC16C77MCU, programmed ("K1"), 40 pins E610005
MAX518BCPA; Dual D/A converter, 8 pins
U2
U3 24LC04B/P; EEPROM, 8 pins (alternate: 24WC04P) E600021
U5 LM358, 8 pins E600010
U4
X1 4.000 MHz crystal; HC-49, standard height E660006
Misc. Front Panel PC board E100093
Misc 40 pin DIP socket (for U1) E620017
Alt: MAX518ACPA E600013
ZR78L06C; Voltage regulator, 6V, 2.5% (Zetex);
TO-92 plastic, 3 pins E600017
6
1
1
1
1
1
1
1
1
Misc switch spacing tool (made from PCB material) E980033
Misc nylon washer, 0.75" O.D., 0.385" I.D. (Keystone #3227) E700019
Misc Keycap, rectangular, black E980000
Misc Keycap, square, black E980009
Page 3 Front Panel
1
1
5
1
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
C14, C15, C16, C19, C22, C28,
C29, C51 .001 µF, monolithic; label: "102" E530001
C4, C6, C17, C18, C21, C23,
C25, C36, C37, C40, C43, C44,
C45, C47, C48, C49, C58, C60,
C64, C66, C72, C74, C75, C76 .01 µF, monolithic; label: "103" E530009
C24, C30, C32, C41, C50, C56,
C57, C61 .047 µF, monolithic; label: "473" E530025
C34, C46, C52, C55, C68, C70,
C71, C73 0.1 µF, monolithic; label: "104" E530011
C3 10 pF NPO mono or disc, 5%; label: "10" E530006
C65 22 pF NPO mono or disc, 5%; label: "22" E530017
C7, C26, C27 39 pF NPO mono or disc, 5%; label: "39" E530036
C2 68 pF NPO mono or disc, 5%; label: "68" E530007
C8 82 pF NPO mono or disc, 5%; label: "82" E530038
C1 150 pF NPO mono or disc, 5%; label: "151" E530049
C38, C39, C42, C69 220 pF NPO mono or disc, 5%; label: "221" E530042
C62, C63 330 pF NPO mono or disc, 5%; label: "331" E530043
C2A (alternate for C2) 120 pF polystyrene, axial leads, 5%; label: "120J" E530070
QTY
8
24
8
8
1
1
3
1
1
1
4
2
1
C11, C12 1200 pF polystyrene, axial leads, 5%; label: "1200J" E530069
C5 3300 pF polystyrene, axial leads, 5%; label: "3300J" E530071
C31, C54, C67 2.2 µF electrolytic, 25V E530023
Electrolytic capacitor, supplied with 80-m band kit
C78
C33, C35, C59 10 µF electrolytic, 35V; low-profile (Digikey P922-ND) E530045
C9, C10, C53 220 µF electrolytic, 25V (Digikey P6240-ND) E530046
(2-band module only)
Page 1 RF
2
1
3
0
3
3
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
QTY
C13, C20 Ceramic trimmer capacitor, 8-50pF E530000
D2, D15 1N5711 Shottky diode, small glass pkg E560004
D5, D9-D14, D18 1N4007 PIN diode, large plastic pkg, black E560001
D19 1N4753 zener diode, 36 V, 1 watt E560007
D1, D17 1N4148 switching diode, small glass pkg E560002
SB530 Shottky diode, 5A, very large plastic pkg (black)
D16
D4 MV209 E560006
D3, D6, D7, D8 1SV149; TO-92 pkg E560005
J6, J7, J8 8-pin 0.1" conn., female; Samtec SSW-108-01-G-S. E620005
J1 Supplied with noise blanker option (KNB1) E620005
J4 2.1 mm DC barrel connector E620026
(alternate: 1N5821) E560003
2
2
8
1
2
1
1
4
3
0
1
J5 BNC jack E620020
Page 2 RF
1
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
Keyer Jack, threaded bushing, Stereo, vertical mount
J3
J2
J9, J10 2-pin, pads only (coax soldered to connections--see text)
E620027
Headphone jack, non-threaded, Stereo, with switch,
horizontal mount E620028
QTY
1
1
0
K1 Latching Relay, 5V; in plastic tube E640001
L1 T50-6; Toroid (yellow), approx. 4.4µH; 33 turns E680010
L2 FT37-43; Toroid (gray); 16 turns E680003
T1 FT37-43; Toroid (GRAY), 4:20, receiver mixer input E680003
T2 FT37-43; Toroid (GRAY), 5:20, product detector input E680003
T3 FT37-43; Toroid (GRAY), 12:4, driver to final E680003
T4 FT50-43; Toroid (GRAY, larger), 5 turns bifilar E680008
RFC8 Supplied with 80-m band kit (2-band module only)
RFC9 15 µH RF choke; min. solenoidal; color code: brn-grn-black E690012
RFC2, RFC5 22 µH RF choke; soleniodal, color code: red-red-black E690000
33 µH RF choke; soleniodal, color code: orange-orange-
RFC1
RFC3, RFC4, RFC6, RFC7
black (NOTE: orange bands may appear brown) E690007
100 µH RF choke; soleniodal,
color code: brown-black-brown E690004
1
1
1
1
1
1
1
0
1
2
1
4
Page 3 RF
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
20 x 1 ,male, RA; 20 pin male, right angle. To Front Panel,
P1
P2 2 pin, male, 0.1" conn with locking ramp; for speaker E620024
P3 3 pin, male, 0.1" conn.; RF detector select E620007
J1 E620029
QTY
1
1
1
Q6 2SC5739 or 2SC2166; driver E5800
Q7 2SC1969; PA (Power Amp) E580008
Q5, Q8, Q11 J309, JFET, TO-92 E580009
Q9 2N3906, PNP, TO-92 E580000
Q3, Q14 2N4124, NPN, TO-92 E580010
Q1, Q10 2N7000, MOSFET, TO-92 E580002
Q2 MPSA14, NPN Darlington, TO-92 E580011
Q4 ZVN4424A, MOSFET, Hi-V; Thinner TO-92 Style E580005
R37 226 Ω, 1/4W, 1%; color code: red-red-blue-black E500033
R36 1.50 k, 1/4W, 1%; color code: brown-green-black-brown E500034
R3 8.25 k, 1/4W, 1%; color code: gray-red-green-brown E500065
R23 1.5 Ω, 1/4W, 5%; color code: brown-green-gold E500044
R30 3.3 Ω, 1/4W, 5%; color code: orange-orange-gold E500064
R15 10 Ω, 1/4W, 5%; color code: brown-black-black E500054
R22, R31, R32 33 Ω, 1/4W, 5%; color code: orange-orange-black E500036
R16, R18 75 Ω, 1/4W, 5%; color code: violet-green-black E500037
R11 82 Ω, 1/4W, 5%; color code: gray-red-black E500038
R17, R35 120 Ω, 1/4W, 5%; color code: brown-red-brown E500022
R29, R38 270 Ω, 1/4W, 5%; color code: red-violet-brown E500039
1
1
3
1
2
2
1
1
1
1
1
1
1
1
3
2
1
2
2
Page 4 RF
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
R10, R33 470 Ω, 1/4W, 5%; color code: yellow-violet-brown E500003
R7 680 Ω, 1/4W, 5%; color code: blue-gray-brown E500040
R12, R28 820 Ω, 1/4W, 5%; color code: gray-red-brown E500001
R1, R26, R27, R39 1.8 k, 1/4W, 5%; color code: brown-gray-red E500004
R5, R6, R9, R14, R21, R24 2.7 k, 1/4W, 5%; color code: red-violet-red E500005
R4 5.6 k, 1/4W, 5%; color code: green-blue-red E500007
R20 20 k, 1/4W, 5%; color code: red-black-orange E500041
R19 39 k, 1/4W, 5%; color code: orange-white-orange E500042
R2, R25, R34 100 k, 1/4W, 5%; color code: brown-black-yellow E500006
R13 2.2 M, 1/4W, 5%; color code: red-red-green E500043
100 k SIP resistor pack, 8 pins, 4 resistors
RP1, RP2
RP4, RP5
RP6
RP3
p/n 8A3104G (alt: 77083104, L83C104, etc.) E510018
3.9 k SIP resistor pack, 6 pins, 3 resistors
p/n 6A3392G (alt: 77063392, L63C392, etc.) E510008
27 k SIP resistor pack, 6 pins, 3 resistors
p/n 6A3273G (alt: 77063273, L63C273, etc.) E510009
47 k SIP resistor pack, 10 pins, 5 resistors
p/n 10A3473G (alt: 770103473, L103C473, etc.) E510007
QTY
2
1
2
4
6
1
1
1
3
1
2
2
1
1
U5 LM2930T-8, 8-volt regulator; TO-220 package E600018
Page 5 RF
1
Appendix A K1 RF Board Parts List
PICTURE Designators Description Part Number
QTY
U4 LM380N-8, 8 pin DIP, AF amplifier E600019
U3 LM386N-1, 8 pin DIP, AF amplifier E600022
U9 LT1252, 8 pin DIP, VFO Buffer; TX Buffer E600020
SA602AN, 8 pin DIP, TX Mixer; Prod. Detector
U1, U2, U7, U8
U6 ZR78L06C, 6-volt reg., 2.5%; TO-92 package, 3 pins E600017
W1 Jumper, RG174 coax, From J9 to J10; see text
X1-X6
S1 DPDT Power Switch E640006
Alt: SA/NE612AN E600006
4.9152MHz Crystal; "ECS V4.9136" or similar.
Filter/BFO Xtals; Parallel mode, matched, HC-49 E660000
1
1
1
4
1
0
6
1
S2 Miniature DPDT slide switch E640009
MISC 2-pin shorting jumper for use at P3 (RF detector select) E620055
MISC Keycap, rectangular, for S1 (p/n TAC-BLK) E980023
#4, washer, nylon;
HW
HW #4-32, nut, nylon; nut, nylon (For VFO inductor) E700021
HW
Washer, nylon, 0.375" diameter (For VFO inductor) E700035
4-32,screw, nylon x 1/2"
screw, pan head, nylon (For VFO inductor) E700022
Page 6 RF
1
1
1
2
1
1
All capacitors are NPO disc or monolithic, 5% 0.2" lead spacing. Values are in pF.
*
* : The 80-meter band
NOTE
kit also includes 10 F
µ
electolytic capacitor C78 that
is installed on the RF board.
Appendix A K1 Misc. Bag Parts List
PICTURE Designators Description Part Number
QTY
HW #4 int. tooth lockwasher (3 Spares) E700010
HW #4 split lockwasher (4 Spares) E700004
HW 2-56,screw , 1/8", stainless steel, fillister head (2 spares) E700023
HW 2-D Fastener E100078
HW 4-40 nut, Steel-zinc (2 spares) E700011
HW 4-40 screw, 1/4" Panhead phillips, steel-zinc E700005
HW 4-40 screw, 3/8" Panhead phillips, steel-zinc E700036
HW 4-40 screw, 3/16" Panhead phillips, black (5 spares) E700015
4-40 screw, 5/16" Flathead phillips (undercut), BLK
HW
HW
HW 4-40 standoff, round, 1/4" long x 3/16 dia. (for FP board) E700026
HW
(2 spares) E700027
4-40 screw, 3/16" Flathead phillips (undercut), BLK
(3 spares) E700025
4-40 male/female standoff, hex, 7/16" long x 3/16" dia.; RAF
4504-440-A (for Filter board) E700017
10
16
6
8
9
1
1
25
7
16
1
3
HW Shoulder washer, nylon, black (for PA transistor, Q7) E700001
HW Self-adhesive rubber foot (Digikey SJ5518-0-ND) E700024
Misc LCD spacer, 0.5 x 0.5 x 0.187", self-adhesive both sides E700020
HW #4 flat washer, steel-zinc (for speaker); one spare E700044
HW #4 washer, .047" thick, fiber, black (for speaker) E700028
Page 1 Misc and Wire
1
4
1
5
4
Appendix A K1 Misc. Bag Parts List
PICTURE Designators Description Part Number
2 pin female conn. Housing, 0.1” spacing, locking ramp.
SPK-J1
(for speaker) E620021
QTY
1
ACC-P1 2.1mm male conn. (mates with DC power jack) E620032
Stereo 1/8” phone plug
ACC-P2
Misc Female crimp pins for SPK-J1 E620022
Misc Plastic tuning tool, p/n MARS-12 E980012
Misc Allen wrench, 5/64", long handled (for large knob) E980004
Misc Allen wrench, .05", short handled (for small knobs) E980008
Appendix A K1 Wire Bag Parts List
PICTURE Designators Description Part Number
Misc #26 Red Enamel Wire (for toroids) E760002
Misc #26 Green Enamel Wire (for toroids) E760004
Misc #22 Dual-conductor wire (for speaker) E760012
Misc #24 solid-conductor hookup wire, insulated, green E760008
(for key, keyer, paddle, computer, or other keying device) E620033
1
1
2
1
1
1
QTY
(ft)
14
4
1
1
Misc Coax, RG174 (for jumper from J9 to J10, RF board) E760010
Page 2 Misc and Wire
0.5
ZN4424
2N7000
Transistors
2N3906
MPSA14
2N4124
J309
2SC5739
2SC1969
Diodes
MV209
1SV149
C
S
D
G
E
C
B
Integrated Circuits
PLASTIC DIP
(DUAL-INLINE PACKAGE)
1
2
3
45
COUNT PINS STARTING AT
PIN 1 AND GOING COUNTER-
CLOCKWISE (8-PIN DIP SHOWN)
8
7
6
AC
G
D
S
CBE
A = Anode, C = Cathode
AC
AC
LEDs
VOLTAGE REGULATORS
78L06
GND
IN
OUT
LM2930T
IN
GND
D1
BOTTOM VIEW
GND
NOTCH
GREEN ANODE
OUT
ORANGE ANODE
D2
BOTTOM VIEW
NOTCH
CATHODE
ANODE
Special Symbols
= On bottom of PC board.
Elecraft
By
W. Burdick
E.Swartz
K1 Schematic Key
Rev. Sht.
Date
A
9/4/00
Appendix B
1 of 1
DS1
LCD
COM
F
E
3E 3D 3C 2E 2D 2C 1E101D111C121B
123456789
2
3
A
A
B
F
G
C
E
D
D
DP DP
3DP 2DP
1
A
B
B
F
G
G
C
C
E
D
1
ccw
R1
100K
131A141F151G162B172A182F192G203B213A223F233G24
VFO
Tuning
2
cw
3
R19
100K
6B
VFO POT
Pushbutton Switches
First label corresponds to switch TAP,
second label corresponds to switch HOLD.
RF/SMTR
6A
6A
2.7K
R12
100K
2N4124
Counter Amp.
R11
Q1
D1
C4
.047
R8
22
GREEN (RIT)
ORANGE (XIT)
C1
82
C2
82
6A
1
/OFFSET
8
4
U5A
LM358
DVM/ATTN
KEYIN
6R/AUX
4.000MHz
R9
100K
3
+
2
-
G
Q2
2N7000
BAND
U2
MAX518
S1
AD0
AD1
RF/SMTR
DISPLAY
MENU
S2
EDIT
RIT
S3
PF1
EEPROM
U3
24LC04
81
7
6
5
1
A0
2
A1
3
A2
4
VSS
SDA
8
VCC
7
WP
6
SCL
5
R16
2.7K
C5
R13
470
.01
D2
YELLOW (ATTN)
+
7
-
U5B
5
6
DVM/ATTN
6A
R7
3.92K
1%
Elecraft
By
W. Burdick
E. Swartz
Appendix B
R14
1K
R15
2
4
6
XFIL/TONE
RP1
1K
SDA
1K
/OFFSET
1
3
5
78
D/A Converter
OUTA OUTB
2
GND V DD
3
SCL
4
SDA
POWER
RFC1, 2 =
82 µH
6A
1
MCLR
RA0
RA1
RA2
5
RA3
RA4
6T
X1
RA5
RE0
RE1
10
RE2
VDD
VSS
OSC1
OSC2
15
RC0
RC1
RC2
RC3
RD0
20
RD1 RD2
PIC16C77
R10
100K
U1
MCU
RB2
RB1
RB0
VDD
VSS
RD7
RD6
RD5
RD4
RC7
RC6
RC5
RC4
RD3
RB7
RB6
RB5
RB4
RB3
40
35
6A
30
25
21
SCL
6B
COUNTER
R4
10K
D
ccw
R3
10K
cw
S
R5
10K
Offset
R2
10K
AF Gain
cw
ccw
OFFSET
AF1
AF2
KEYIN
VFO POT
6B
6T
RFC2
6R/AUX
RFC1
10 11 12 13 14 15 16 17 18 19 20123456789
.01
C6
12V
J1
To RF-P1
WPM +
S4
FILTER
WPM -
S5
ATTEN
MSG
S6
REC
6A
U4
ZR78L06C
OUT
GND
R6
12.7K
1%
IN
12V
K1 Front Panel Board
Rev. Sht.
Date
1/15/02
E
1 of 1
C32
.047
RCV RF
6T
XFIL/TONE
Attenuator
-14 dB
RFC9
10 µH
R16
75
RP2
100K
NOT USED
R2
100K
C70
0.1
PD1
Q10
G
2N7000
PD2
C71
0.1
6R/AUX
4:20, FT37-43
2439
8
K1
7
R17
R18
120
75
6R/AUX
5
6
AF Preamp/Mute
C54
+
2.2µF
U3
LM386N-1
1
S
G1
2
BYPASSIN1
3
IN2
45
C17
.01
5
GND
RP3
47K
OUT
6
D
1N4148
C72
D1
Receive Mixer
T1
3
1
2
4
C23
.01
AGC
D2
1N5711
RP3
47K
R3
8.25K
1%
R21
2.7K
8
G2
7
6
V+
R13 2.2M
G
Q11
J309
C18
.01
8V
S
D
AF1AF2
C66
0.01
J10
Premix
10
C64
.01
C68
0.1
RP3
47K
C24
U1
SA602
9
1
2
3
.047
8
V+
V-
6
7
C19
.001
12
R1
1.8K
/AGC OFF
+
C31
2.2µF
RP3
8
7
47K
1.0VDC
(no signal)
C73
0.1
LM380N-8
1
NC
2
IN1
3
IN2
45
GND
AF Amp
34
C74
.01.01
4
5
12345678
Noise Blanker
AGC (1.2VDC, no signal)
Q2
MPSA14
6B
U4
8
BYPASS
7
V+
6
OUT
GND
C33
10µF
1
2
RP3
C69
47K
220pF
6R/AUX
R15
10
+
12V
*
RP6
27K
G
+
220µF
C22
.001
RF/SMTR
4.4 µH
C10
2
1
D
S
L1
+
R23
1.5
C30
.047
2N7000
Ω
J2
Q3
2N4124
4
3
RP6
6A
56
27K
RP6
J1
C22 must be removed when
*
the noise blanker is installed
Use 120 pF at C2 for ~150 kHz range
**
Q1
1
RP2
100K
2
C2
**
68
C7
39
RP2
100K
C9
220µF
Headphones,
Ext. Speaker
C5
7
D4
MV209
8
OFFSET
12
Int. Speaker
.01
C4
6R/AUX
C21
.01
R14
2.7K
VFO POT
C6
.01
D3
1SV149
3300
3
RP2
100K
4
D17
1N4148
3.080 MHz when RF = XX.000 MHz
2.930 MHz when RF = XX.150 MHz
AF1
AF2
123456789
P2
XFIL/TONE
220
VFO
1200
Buffer
C39
Q8
J309
C11
1200
C12
XFIL/TONE
100K
78
1
RP1
RP1
X1
RP1 RP1
2
D6 D7
1SV149
Crystal Filter
ZR78L06C
6B
G
POWER
6T
C41
.047
R7
680
6R/AUX
OUT
D
R5
S
2.7K
Q9
2N3906
C8
82
COUNTER
KEYIN
10 11 12P113 14 15 16 17 18 19 20
To FP-J1
3
4
U6
GND
IN
C40
.01
C42
220
C25
.01
R6
2.7K
VFO POT
4
5
C20
C65
C63
330
C61
.047
50
22
6A
PD2
PD1
5
C37
.01
8V
V-
X4X2
+
C35
10µF
V+
6
C38
220
Low-Dropout
8V Regulator6V Reg.
Premix
8
4
5
7
C27
39
C26
39
6
X3
D8
U7
SA602
1
2
3
5:20, FT37-43
1
2
U5
LM2930T-8
OUT
IN
GND
T2
3
4
+
C67
2.2µF
X5
4.915 MHz
RFC1
33 µH
U2
SA602
1
2
3
V-
Product Det./BFO
12V_2
J9
To Rcv Mixer (via W1)
12
12345678
8
V+
6
PREMIX
/AGC OFF
7
J6
To FIL-P1
6B
6A
RFC6
100µH
12V
RF/SMTR
C34
6B
0.1
C36
.01
Elecraft
W. Burdick
E.Swartz
K1 RF Board
Rev. Sht. DateBy
1/5/02
G
1 of 2
Appendix B
R9
2.7K
R22
33
6R_2
RCV RF
D5
1N4007
TR1
D14
1N4007
BUF
U9
LT1252
6
R12
820
3.9K
6R/AUX
6A
12345678
To FIL-P2
RFC8 is supplied with the
**
80-m band kit. If 80 m is not used,
install a jumper at RFC8.
**
RFC8
C57
12V_2
RP4
3.9K
3
2
Q14
2N4124
R39
1.8K
Buffer
7
4
RP4
C76
.01
.047
+
-
R11
82
C16
.001
12
3
4
12V
5
6
1
10
220µF
+
RP4
3.9K
RFC2
22 µH
C75
.01
K1
(ATTN Relay)
BPF
J7
R38
6T
C53
270
Transmit Mixer/Osc.
6T 6A
OPER
S2
C51
.001
4
MIX
5
U8
SA612
X6
4.915 MHz
C45
RFC4
100µH
C47
.01
R24
2.7K
C46
0.1
.01
D11
R25
100K
1N4007
ZVN4424A
D10
1N4007
R26
1.8K
D9
1N4007
RFC7
100µH
6R_2
RFC3
100µH
6R_2
D13
1N4007
TR3
T-R Switch
RFC5
22µH
DRV
3
4
T3
Q6
Driver
+
D
S
Q5
J309
Transmit signal-tracing points (see text)
C15
.001
C58
.01
+
R33
470
R35
120
C78
C78 is supplied with
the 80-m band kit
1
2
2SC2166 or 2SC5739
R30
Ω
3.3
C59
10µF
C60
.01
ATTN
D18
1N4007
Transmit Attenuator
C50
.047
C44
.01
TR2
R28
820
R29
270
OFS TEST
C56
.047
8 G
V+
1
2
V-
3
76
C3
10
OSC
C13
C62
50
330
R10
470
C49
L2
47µH
C48
.01
6R_2
12V
3
.01
241
C1 150
2SC1969
T4
C52
Q7
D12
R27
1.8K
D
G
S
Q4
C55
0.1
D19
1N4753
36V
R31
33
R32
33
J8
To FIL-P3
12345678
ANT
PA
RF/SMTR
R4
5.6K
R34
100K
RFD
D15
1N5711
C43
.01
R37
226
R36
1.5K
1%
1%
Ω
*
J5
Ant.
321
P3
RF Det
Source
RF Output Detector
0.1
If the KAT1 ATU is installed, jumper P3 pins 2-3.
*
If not, jumper P3 pins 1-2.
PA
Key/Keyer/Paddle
J3
C29 C28
POWER
C14
.001
1
RP5
3.9K
2
PREMIX
PRE
.001 .001
RP5
3
4
3.9K
R19
39K
KEYIN
/DOT/DASH
6A
RP5
5
6
3.9K
R20
20K
J4
Elecraft
W. Burdick
E.Swartz
12V DC
D16
SB530
OFF
12V
K1 RF Board
Rev. Sht. DateBy
G
ON
Power
1/5/02
Aux 12 V
+-
S1
2 of 2
Appendix B
To ATU-P2
Premix Band-Pass Filters RF Band-Pass Filters
C2
C7 C9
C6
Band 1
L1 L2
Band 2
L3 L4
C4
C3
C5C1
C8
C10
K1B
2
3
4
(See Note 2)
9
8
RF IN
C11
K2A
7
Band 1 Band 2
X1
K1A
9
8
XOSC
12345678 12345678
X2
7
PREMIX
/AGC OFF
P1
To RF-J6 To RF-J7
Band 1
C12 C14
C13
L6
L5
Band 2
C17 C19
C18
L7 L8
C15
C20C16
RF OUT
/AGC OFF
6A
RY COM
ATTN RY
P2
C23
10
J2
(Note 1)
2
3
K3B
4
To RF-J8
P3
12345678
PA
2
K2B
3
4
K3A
Low-Pass Filters
9
8
C21 C22
7
Band 1
L9
Band 2
L11 L12
123456789
L10
I/O Controller
1
RA2
2
RA3
3
RA4
4
MCLR
5
VSS
6
RB0
7
RB1
8
RB2
9
RB3
U1
PIC16C620A
10
10
RA1
RA0
OSC1
OSC2
VDD
RB7
RB6
RB5
RB4
Z1
4 MHz
18
17
16
15
14
13
12
11
10
1
K1
1
K2
1
C30
.001
100
R1
K3
C24 C25
10
C26
To ATU-P1
J1
(Note 1)
6R/AUX
123
C29
.001
C27
.047
Notes:
1. J1 and J2 are supplied with the KAT1 option (Antenna Tuner).
If the KAT1 is not installed, J2 pins 2 and 10 must be
connected using a jumper (see text).
2. See Parts List for values of all band-specific components.
3. K1-K3 are latching relays, and are shown in the RESET position.
Pins 5 and 6 of relays are not connected internally, but may be
used as tie points for other circuitry on the PC board.
4. This schematic is for the 2-band Filter board. Refer to KFL1-4
manual for 4-band Filter baord schematic.
Elecraft
K1 2-Band Filter Board
W. Burdick
E.Swartz
Rev. Sht.
E
By
Appendix B
Date
1/5/02
1 of 1
T-R
BUFFER
XMIT
MIXER
XMIT
ATTEN.
T-R
4.915 MHz
11.915 - 12.065 MHz (40 m)
BAND-
PASS
*
FILTERS
*
RCV
ATTEN.
FILTERS
BAND-
PASS
RCV
MIXER
T-R
DRIVER
CRYSTAL
FILTER
4.915 MHz
POWER
AMP
(5W)
PROD.
DETECTOR
BFO
4.915 MHz
*
LOWPASS
FILTERS
AGC
A.F.
PREAMP
AF AMP
VFO
3.085 - 2.935
KEY
Common Transmit Receive
PREMIX
15.000 MHz
*
On Filter
PC Board
(40 m)
MCU
*
DISPLAY
AND
CONTROLS
Appendix C K1 BLOCK DIAGRAM
W. Burdick/E. Swartz Rev. A 8-16-00
Appendix D. K1 Assembly Photographs
b
Completed K1 with
top cover and side panels
removed; Front Panel and
2-band Filter board shown
Plugged into the RF board.
Front Panel
RF board with
ottom cover
Attached
(headphone jack is
visible at left)
assembly
2-Band Filter Board
Appendix E, Troubleshooting
General Troubleshooting Procedure
Look for your problem in the Troubleshooting Tables.
Closely examine PC boards for poor solder joints and incorrect, broken or
missing components.
Follow the step-by-step receiver and transmitter Signal Tracing
procedures at the end of this section.
Check voltages using the DC Voltage Table at the end of this section.
Error Messages
If you see a message such as E 3 0 on the LCD, look up the corresponding
entry in the Troubleshooting Tables. Error messages can usually be cleared by
pressing any switch. However, the cause of the message should be investigated
before continuing to operate the transceiver.
Troubleshooting Tables
There are five troubleshooting tables (listed below). Within each table,
problems are identified by 2-digit numbers for cross-referencing purposes. In
most cases you’ll know which table to look in based on the symptoms you
observe. If in doubt, start with the General Troubleshooting table. Some
problem identifiers have corresponding error messages (see above).
General Troubleshooting 00-19
Display and Control Circuits 20-39
VFO and Premixer 40-59
Receiver 60-79
Transmitter and Keyer 80-99
Note: Components are identified by their PC board and reference designator.
For example, "FP-U1" means U1 on the Front Panel board.
General Troubleshooting (00-19)
Problem Troubleshooting Steps
00 Unit appears to be
completely dead when
power switch is turned
on (no display, no
audio); possible
smoke, hot
components, etc.
01 LCD or LED
problem
02 B A T L O
displayed
03 No audio See Receiver troubleshooting table (60)
04 Switches or
potentiometers do not
function correctly or
are intermittent
05 Current drain is
excessive on receive
06 Supply voltage
drops when K1 is on
07 Error in actual vs.
displayed frequency
08 Freq. drift or
instability
09 EEPROM init
is pending
10 EEPROM was
just initialized
15 E N D or P = 0 is
displayed on keydown
Make sure your power supply is connected,
turned on, and not plugged in backwards
Check fuses; examine cables for open/short
Check resistance to ground on 12V, 8V, and
6V lines; check for RF-Q7 tab short
Verify front panel and filter boards are
plugged in, with connectors fully seated
Measure the +6V and +8V regulated power
supplies (20)
Check the MCU, FP-U1 (26)
See control circuits (24)
Battery voltage may be below 9 V. Recharge
the battery as soon as possible.
Front panel board may not be plugged in
Check the MCU (26)
Check all regulated supply voltages (20)
Check switches and related components (21)
Check regulated voltages (20); look for a
component that’s warm to the touch
Check receive-mode current drain (05)
Battery not fully charged
See Operation section (VFO Calibration)
See VFO troubleshooting table (40)
See Advanced Operating Features,
Resetting to Factory Defaults (page 57)
You may see
if you install a new version of the firmware.
All K1 parameters are set to defaults.
E N D : TX out of range (see specifications)
P = 0 : TX disabled via O U T menu entry
E 1 0 one time on power-up, or
1
Display and Control Circuits (20-39)
Problem Troubleshooting Steps
20 Regulated
voltage(s) incorrect
21 General problem
with switches or
potentiometers
22 +6A or +6B
voltages too low
(< 5.7V)
23 +8V too low
(< 7.5V)
24 LCD or LED
problem
25 Relay Problem Relays installed backwards or not soldered
26 Possible MCU
problem
DC input voltage must be > 8.5V
Remove all option boards and re-check
If +6V is too low (< 5.7V) go to 22
If +8V is too low (< 7.5V) go to 23
Check switch resistance open/closed; check
R14, R15 and RP1
Check resistance of potentiometers; check
related connections to FP-J1
Remove socketed ICs, front panel board,
filter board, and options individually
Inspect the entire 6A or 6B path on the RF
and Front Panel boards.
Check for regulator ICs installed backwards
Lift the output lead of the affected regulator
and measure the voltage this lead; if the
voltage is still too low, replace the IC
Lift other component leads on the 6V line as
needed to find cause of excess loading
Use techniques given for 6V regulators
(above)
LCD in backwards or bent pin; check for
shorts to ground on each LCD pin
MCU pin bent or broken (FP-U1)
LEDs swapped or installed backwards
Check relay coil resistance, pins 1 and 10
I/O controller defective or backwards (27)
Check all DC voltages on FP-U1
Remove the Front Panel board and inspect
U1. Make sure it is not backwards, has no
bent pins, and is seated firmly in its socket.
Check oscillator components (X1, C1, C2).
Also see (33) if you suspect an error in a
menu parameter, etc.
27 Filter board not
plugged in, or I/O
controller (FIL-U1)
communication
problem
28 I/O controller data
error
29 AuxBus problem Try removing each option board
30 EEPROM
write/read test #1
failed
31 EEPROM
write/read test #2
failed
32 EEPROM data
error
33 Configuration data
or menu problem
If you saw the message
controller (IOC, FIL-U1) did not respond to
messages from the main processor (MCU,
FP-U1). Turn power OFF and back ON; if
you hear some relays switching, the IOC may
be OK, and the problem is likely to be with
the AuxBus (29)
If you do not hear any relays switching on
power-up, your IOC (FIL-U1) may be
defective. Inspect FIL-U1 to see if you have
installed it backwards or if any pins are bent.
With power ON, check all voltages
associated with U1. You should see 6V at
pins 1 and 14. See DC voltage table.
If you saw the message
controller (IOC, FIL-U1) sent an incorrect
response to the MCU (FP-U1). This may
indicate a firmware incompatibility.
If voltage at pin 13 of the IOC (FIL–U1), the
auxBus line may be shorted
Try tapping the
watching pin 13. It should drop below 6V
briefly if the MCU (FP-U1) is sending a
message to the IOC.
Check the AuxBus signal at the MCU, pin 8
(FP-U1). The voltage should drop below 6V
briefly when the band is changed.
If you
Verify that the Filter board is plugged in.
Check all voltages on the EEPROM (FP-U3)
Inspect FP-U3 and surrounding traces
Make sure FP-R16 is installed
If a menu parameter is out of range or can’t
E 3 0 , E 3 1 or E 3 2 on the LCD, one
of the EEPROM tests has failed. CW
memories cannot be used. Parameters will be
set to defaults, and band 1 will be selected.
be modified, EEPROM may need to be
reinitialized. See page 57 for instructions.
B A N D switch quickly while
E 2 7 , the I/O
E 2 8 , the I/O
2
VFO and Premixer (40-59)
Receiver (60-79)
Problem Troubleshooting Steps
40 General VFO
problem; frequency
jumps or drifts
Note: Some VFO drift will always be present
due to aging of components and heating or
cooling of the cabinet
The VFO will drift more if you used the
larger range (C2=120 pF).
Use
C A L menu entry to check actual VFO
frequency (hold
frequency calibration display, then switch to
E D I T to show the operating
O S C using D I S P L A Y )
Make sure supply voltage is above 8.5V
If you used solder with water-soluble flux,
clean the board with hot water and a Q-tip
Make sure L1 leads are properly stripped
Check crystals on Filter board
41 Can't tune VFO (or
RIT/XIT offset)
42 VFO inductor not
installed or VFO not
oscillating
45 VFO tunes the
wrong way
46 VFO or RIT/XIT
range is too large, too
small, or shifted
low/high
Check actual VFO range (40)
Measure voltage on anode of RF-D3 (VFO
main varactor diode) while tuning VFO pot
Measure voltage on anode of RF-D4 (offset
varactor diode) while tuning the OFFSET pot
Varactors may be installed backwards
If you see
missing or is too low in amplitude to be
counted by the MCU (FP-U1).
Check all VFO components
Check the counter amplifier and related
components (FP-Q1, R11, R12)
Use signal tracing to determine where the
VFO signal is getting lost
VFO pot (FP-R1) CCW and CW leads may
be reversed
Check actual VFO range (40)
Varactor diodes may be wrong type
Check all capacitors in VFO, esp. C2 and C7
See Alignment and Test, Part I.
E 4 2 , the VFO signal is either
Problem Troubleshooting Steps
60 Low (or no) audio
output from receiver,
or general receiver
gain problem
62 Signal loss only on
one band
65 AF amplifier not
working
70 AGC or S-meter
not working
If you hear normal audio output on one band
but not all bands, see 62
Make sure you have headphones or speaker
connected; turn AF GAIN clockwise
Check the key jack for a short to ground
Make sure the attenuator is turned off
Re-peak the band-pass filters
Check for ground shorts in the LPF and BPF
Turn the AF GAIN to maximum. If you don’t
hear any “hiss” at the receiver output,
troubleshoot the AF amplifier (65)
Check the 8V regulated supply voltage and
troubleshoot if necessary (20)
Try using signal tracing (see procedure later
in this section)
Re-do alignment on affected band
Check the band-pass and low-pass filters and
crystal for this band
Check functioning of the associated relays
(change bands, then measure relay leads that
should be open or shorted for that band)
Use the
level of 31. If you hear a strong tone, the A.F.
amplifier (RF-U4) is probably working, and
the problem is likely to be with the preamp
(RF-U3) or other RF board circuits.
Signal trace through the receive chain
backwards by touching a tool or wire to
various points along the receive path
Check all DC voltages in the receiver
Inspect the A.F. amp and preamp circuits
Make sure the attenuator is off
Check voltages on RF-U1, U2, Q1, Q2, D2
S T L menu entry to set a sidetone
3
Transmitter and Keyer (80-99)
Problem Troubleshooting Steps
80 General
Transmitter problem
86 Power output is
low or zero
If power output is too low, go to 86
If power output slowly increases during key-
down, go to 88
If current drain on transmit is too high for the
given power level, go to 92
If the transmitter output power seems to be
unstable go to 88
If the transmitter stops transmitting by itself
go to 90
If the keyer isn’t working properly, go to 95
Try signal tracing
Check power output when using a 50Ω
dummy load; if the output is correct on a
dummy load but not when using an antenna,
your antenna is probably not matched
Check all component values in the RF
detector; you may have two resistors
swapped (R36, R37) or the wrong detector
diode (D15, should be 1N5711)
You may have a short in the LPF or BPF;
also check relays (25)
Examine T3 and T4; these must be wound as
indicated in part II of the RF board assembly
Look for toroid leads that are not completely
stripped or are soldered poorly
Check all DC voltages in the transmitter (RF
board, Q5/Q6/Q7, U8, U9)
If drive is lacking, R35 (RF board, TX
attenuator) can be made larger, at the expense
of power-setting resolution.
Make an RF probe and signal-trace through
the transmitter to find where signal is lost
(see probe and procedure later in this section)
Check for any components getting hot
Check for RF-Q7's tab shorted to the right
side panel (ground)
88 Power output
fluctuates
90 Output power
drops to zero suddenly
92 Current drain too
high on transmit
95 Keyer Problem If the keyer is generally erratic when
If you stay in key-down (TUNE) mode for
several seconds, it is normal to see some
increase in power; this is due heating of the
final amplifier transistor.
If power goes up and down significantly
during normal keying, you may have a
poorly-matched antenna OR you may have
power set too high for your battery or power
supply to handle; try reducing power
Make sure none of the diodes in the T-R
switch circuits are in backwards
If the transmitter is unstable (oscillating)
even when connected to a 50-Ω load, you
may have an incorrect component value or a
toroid-winding error (86)
If you have transmit power set too high for
your battery or power supply, the supply
voltage may drop so low on transmit that it
resets the MCU (FP-U1) or the I/O controller
(FIL-U1). Reduce power.
You may have power set higher than the final
amplifier can achieve for a given load or
power supply voltage, resulting in overdrive
of transmitter stages. Reduce power to see if
normal current drain is restored.
Damaged PA transistors or other components
could cause inefficiency in any stage of the
transmitter. Check all DC voltages and
components; signal trace if necessarily (86)
transmitting and seems to get worse as power
is increased, you probably have RF leaking
into the keyline. Try bypassing your key with
.001 µF capacitors; also try 100 µH RF
chokes in series with the paddle connections.
Seek a better antenna match
Improve your ground system (if you have RF
problems, add two or more radials cut to 1/4wavelength at the affected frequency)
4
Signal Tracing
,
You can solve nearly all problems yourself by signal tracing using an RF probe
and signal source, such as the ones shown here.
RF Probe
The RF probe shown in Figure 1 converts RF signals to DC so they can be
measured using a DMM.
COAX,
12-36" (30-90 cm)
J1
1
2
To DMM
E1
probe
tip
E2
ground
C1
.01µF
R1
4.7Mohm
D1
1N34A
Figure 1
The probe tip (E1) should be no longer than 3” (see any ARRL Handbook for
ideas), and you should not touch the tip while taking measurements. Use an
alligator clip at E2, with a 4” (13 cm) lead.
Note: With this RF probe, DC voltage readings on your DMM will be
approximately equal to the signal voltage in Vrms (root-mean-square).
However, the error in the reading is quite significant for small signals (typ.
–50% at 50 mVrms). The signal tracing procedures take this error into account.
Crystal Oscillator
The simple crystal oscillator shown in Figure 2 can be used in lieu of a
commercial signal generator. It will run on voltages as low as 8 V, but 12 V or
higher is recommended.
The components are not critical, and can vary 20% with little variation in
performance. Nearly any NPN RF transistor will work in the circuit. Crystal X1
should be chosen for the band in use. The potentiometer can be any small
trimmer or panel mount unit, but should not wire-wound.
+
-14VDC
-
2N2222A
N3904, etc.
560Ω
Receiver and VFO Signal Tracing
In the following steps you’ll use an RF probe, DMM, and a signal source to
find the stage where the received signal is getting lost or attenuated. You can
then use voltage tables and resistance checks to find the bad component or
connection. Space is provided at each step to record your measurements, which
can vary as much as 25% in most cases and still be acceptable. Test points and
components are on the RF board unless otherwise indicated.
1. Connect the RF probe’s output to your DMM’s +/- DC input jacks. Select a
2 or 3-V DC range.
2. The DMM should read close to 0.000 V DC, and the reading should
increase when you touch the RF probe tip with your finger.
3. Turn on the K1 and switch to the desired band. Use the menu to turn AGC
OFF. Set AF GAIN to minimum.
4. Connect the RF probe’s ground clip to the ground jumper near the VFO
inductor, L1. The probe tip will be touched to the points indicated in the
following steps.
5. VFO: U7, pin 1 (U7 is near the left edge of the RF board). Expected DMM
indication: .02-.04 V (DC). Actual: _______.
6. Premix crystal: U7, pin 7. Expected: .04-.25 V. Actual: _______.
9pF
150pF
X1 (see text)
RF
-
Figure 2
5
7. Premixer: U7, pin 4 or 5 (whichever is greater). Expected: .04-.25 V.
Actual: _______.
8. Premix band-pass filter: FIL-P1, pin 6. (FIL-P1 is an 8-pin connector on
the Filter board, near the crystals. Pin 6 is the third pin from the right end.)
Expected: .04-.15 V. Actual: _______. (Note: the expected voltage takes
into account the de-tuning effect of the RF probe. The signal level would
be higher if the filter was re-tuned to compensate for it.)
9. BFO: U2, pin 7. Expected: .015-.100 V. Actual: _______.
10. Connect a signal generator or test oscillator to the antenna jack. Set the
signal level to about 0.14 Vrms as indicated by the RF probe, with the
probe tip on pin 8 of FIL-P3 (right-hand end of the 8-pin connector on the
Filter board near the antenna jack).
11. Low-pass filter: FIL-P3, pin 1. Expected: .12-.16 V. Actual: ______.
12. T-R switch: FIL-P2, pin 8 (P2 is the front-center 8-pin connector on the
Filter board). Expected: .07-.12 V. Actual: _______.
13. RF band-pass filter: FIL-P2, pin 1. Expected: .06-.13 V. Actual: _____.
14. Attenuator and T1: U1, pin 1. Expected: .40-.70 V. Actual: ______.
15. Receive mixer: U1, pin 4. Expected: .50-.80 V. Actual: _______.
16. Post-mixer amp: R14, right end. Expected: .50-.80 V. Actual: ______.
17. Connect a pair of headphones or a speaker and adjust the AF GAIN so that
you can just hear some background noise. Tune the VFO until you can hear
the signal from your test generator peaked in the crystal filter. Since AGC
is turned off, the signal may be extremely loud and will probably be
clipping (distorted) at the AF output.
18. Crystal filter: U2, pin 1. Expected: .30-.50 V. Actual: _______. (Re-peak
the signal using the VFO as needed.)
19. Disconnect the RF probe from the DMM.
20. Set up the DMM to read AC volts, 20 or 30-V meter range. Connect the (-
) lead of the DMM to one of the ground test points using an alligator clip.
The (+) lead will be touched to the points indicated in the following steps.
21. Product detector (saturated output): U2, pin 4. Expected: .40-.80 V (AC
rms). Actual: _______. (Re-peak the signal using the VFO as needed.)
22. AF preamp: U3, pin 5. Expected: 2-4 V. Actual: _______.
23. AF amp: U4, pin 6. Output voltage should vary from 0 to about 4 or 5 V
as the AF GAIN control is varied.
Transmitter Signal Tracing
In the following steps an RF probe is used to determine where the transmitted
signal is getting lost or attenuated. These checks are made from the bottom side
of the RF board so that the Filter board can be left plugged in. Each transmit
test point is clearly labeled, with a small arrow pointing to the appropriate PC
board pad. You’ll want to refer to the transmitter schematic (K1 RF Board,
sheet 2) as you perform the measurements.
1. Do the VFO and receiver signal tracing first to check VFO/premix signals.
2. Connect a dummy load to the antenna jack.
3. Turn the K1 upside-down and remove the bottom cover.
4. Install a very short jumper from the point labeled DRV to ground. This
allows measurement of all low-level transmit stages.
5. Turn on the K1 and switch to the desired band. Set the power level to 3
watts using the OUT menu entry.
6. Connect the RF probe’s ground clip to the ground jumper on the bottom of
the RF board, near the center. Connect the RF probe’s output to the DMM,
and set the DMM for DC volts (2 or 3 V scale).
In the remaining steps, touch the RF probe tip to the indicated points and enter
TUNE mode to take a reading. (Hold WPM+/WPM- together to activate
TUNE.) Cancel TUNE after each reading by tapping any other switch.
Note: Do not key the transmitter for more than about 10 seconds at a time.
7. PRE (premix): Expected: .04-.09 V (DC). Actual: _______.
8. ATTN (TX attenuator): Expected: .02-.05 V. Actual: _______.
9. OSC (TX 4.915 MHz): Expected: .01-.04 V. Actual: _______.
10. MIX (TX mixer): Expected: 0.1-0.2 V. Actual: _______.
11. BUF (TX buffer): Expected: 1.5-2.0 V. Actual: _______.
12. TR1 (first TX T-R): Expected: 0.5-1.0 V. Actual: _______.
13. BPF (band-pass filter): Expected: 0.5-1.0 V. Actual: _______.
14. TR2 (second TX T-R): Expected: 0.5-1.0 V. Actual: _______.
15. TR3 (receive signal shunt): Expected: < .01 V. Actual: _______.
16. Remove the short from DRV to ground. Set DMM scale to 20 or 30 V.
17. DRV (driver): Expected: 0.9-1.6 V. Actual: _______.
18. PA (power amp): Expected: 10-15 V. Actual: _______.
19. ANT (low-pass filter): Expected: 10-12 V. Actual: _______.
20. Disconnect the RF probe. (The last measurement is DC volts, not RF.)
21. RFD (RF output detector): Expected: 1.7-2.0 V. Actual: _______.
6
DC Voltage Table
(
)
NOTES: Measurements listed for FIL-U1 apply only to the two-band Filter board; for 4-band Filter board voltages, refer to the KFL1-4
manual. Measurements were made with a 50-ohm dummy load connected and a supply voltage of 14 V. In general, your measurements should
be within 10% of the values shown. Pins NOT listed in the table should indicate 0.0 volts DC. Pins marked with (*) are hard to measure
due to noise pickup. Shaded areas show transmit-mode measurements (using TUNE), made with the Filter board removed.
Reference designators are prefixed with the board identifier: “FP” = front panel board, “RF” = RF board, “FIL” = filter board.
Ref. Pin VDC Ref. Pin VDC Ref. Pin VDC Ref. Pin VDC Ref. Pin VDC Ref. Pin VDC
FP-U1 1 6.0 FP-U2 1 1 to 5 3 0.8-1.0 RF-U1 1 1.4 RF-U4 6 6.6 RF-U9 2 6.8
2 1.1 3 6.0 4 6.0 2 1.4 7 13.6 3 6.8
3 6.0 4 6.0 13 5.5 4 4.9 8 6.8 6 6/8
4 1.8 7 6.0 14 6.0 5 4.9 7 13.6
5 6.0 15 < 0.3 6 6.0 RF-U7 1 1.4
6 2.5 FP-U3 5 6.0
8 5.6 6 6.0 8 6.0 4 4.8 C 13.6
9 3.0 8 6.0 5 4.8 E 0.5
10 3.0 RF-U2 1 * 6 6.0
11 6.0 FP-U5 1, 2, 3 3.0 2 1.4 7 5.3 RF-Q7 B 0.0
13 2.3 5 6.0 4 * 8 6.0 C 13.6
14 2.8 6 4.8 5 * E 0.0
15-17 3.0 7 4.8 6 6.0 RF-U8 1
18 6.0 8 6.0 7 5.4 2
19-22 3.0 8 6.0 4
23 6.0 5
24-30 3.0 RF-U3 1 1.3 6
32 6.0 2* 7
33-39 3.0 3* 8
40 6.0 5 4.0
FIL-U1
2-band
board
16 < 0.3 7 5.3 2 1.4 RF-Q6 B 1.1
6 8.0
7 4.0
8 1.3
7
APPENDIX F. PARTS PLACEMENT DRAWINGS (including 2-band Filter board)
R17
C71
C70
RFC1
S1
C75
K1
X5
R8
AUX
L2
12V
C49
1
Q4
C48
R25
RFC5
C50
1
2
R33
R30
Q6
C66
C19
U1
3
1
T1
2
4
+
4
U2
C20
2001 ELECRAFT
3
C61
K1 RF Rev. E
D1
J5
C55
T3
Q1
C22
R14
C37
R1
D2
J3
RFC2
Q14
602
C58
1
C14
D3
Q8
C69 C72 C18
C74
1
RP3
C9
U5
X6
U9
1252
Q5
+
J6
C2
D17
C6
C73 C64
C68
C10
C76
C59
R11
Q11
C60
D4
+
C54
L1
R13
R21
C45
J4
D13
D11
C47
R24
RFC4
RFC3
D10
D9
R26
C44
1
J7
D5
+
C7
C4
Q2
D1
D2
U3
R2
Q10
+
C17
C33
C13
C3
C62
U8
C15
D18
R19
R20
R35
RP5
1
U7
C40
R7
U6
Q9
U4
+
J2
S1
C4
S2
S3
R2
R3
RF DET
KAT1
K1
1
P3
J8
D15
C43
C52
R34
T4
4
1
3
2
3
Q7
4
C38
RP1
1
C34
Q3
X1 X2
X4 X3
P2
1
J1
SPKR
C21
D6
D7
D8
2
T2
1
C36
S4
RFD
R36
1
R37
RP1
C1
ANT
PA
DRV
20
K1 FP Rev. E
R7
R9
R4
RFC6
C78
12V
358
U5
S5
R6
R1
S6
R19
U4
20
R27
(NOT GND)
J10
10
P1
2001 ELECRAFT
R13
1
Q1
1
D12
TR2
C6
R12
RFC9
RFC1
R39
OSC
BUF
BPF
OFS
TESTOPER
MIX
ATTN
TR3
S2
TR1
PRE
1
J9
C5
R3
1
C8
(SOCKET)
U1
C1
RFC2
J1
1
C2
X1
R16
R5
R6
CUT=MONO
U3
C5
U2
R14
R15
1
P3
2000
P2
1
P1
1
C18
C13
L6
K1 FIL 2 Rev. D
ELECRAFT
C24
C25
C26
C22
L8
K2
R1
Z1
C21
U1
L9
J1
C23
K3
L10
L1
C1
C2
L3
C7
C6
X2
L2
C3
C8
L5
C4
C12
L4
L7
K1
X1
C29
Tap once to show band,
tap twice to change bands
Hold to select display
mode: normal, S-meter,
or BAT (supply voltage)
ELECRAFT K1 QUICK REFERENCE
LCD
RX: VFO freq or S-meter
TX: bargraph, 1 bar per watt
RIT / XIT - GREEN / ORANGE
ATTN - YELLOW
LEDs
Hold both for TUNE;
during TUNE, can
change power w/WPM+/-
BAND
DISPLAY
MENU
EDIT
MENU
Tap to enter menu, hold to edit; use WPM+/- to scroll menu or modify parameters
OUT POWER OUTPUT, 0.1-7.0 W
(hold DISPLAY to select P=0)
STL SIDETONE VOLUME LEVEL, 0-31
STP SIDETONE PITCH (Hz) or SPOT
T-R QSK DELAY, 0 - 900 ms
RPT AUTOREPEAT DELAY, 0-255 sec
INP KEYING DEVICE: Hnd, PDn, PDr
E L E C R A F T
TX
RX
K 1 T R A N S C E I V E R
AF GAIN
-
Tap for RIT on/off, hold for XIT on/off
(PFn normally = XIT; see MENU)
IAB IAMBIC MODE, A or B
AGC On or Off
LED RIT/XIT/ATTN LEDs On or Off
FLx XTAL FILTER BW, 200-900 Hz
(hold XFIL to select FL1/2/3,
then tap WPM +/- to set bandwidth)
Bx BAND ASSIGNMENT, MHz
(tap BAND to select B1 or B2; 30m:
hold DISPLAY to select 10.0/10.1)
RIT
+
XIT [PFn]
RIT / XIT ATTN
VFO
+
WPM
Tap for WPM up,
Hold for FL1/2/3
Tap for WPM down,
Hold for ATTN on/off
Tap to play message 1 or 2,
hold to record message 1 or 2
(when prompted with "1-2"
during message play,
tap 1 or 2 for single play,
hold 1 or 2 for auto-repeat)
XFIL
WPM
ATTN
MSG
REC
1
T
-
2
CAL Operating freq. cal (OPF), per-band;
hold DISPLAY for VFO display (OSC)
SIG S-METER ZERO SET: Lxx, xx = 30-70
(hold DISPLAY for scale: H x, x = 2-6)
NB NOISE BLANKER: Off, HIGH, LO
ATU AUTO-TUNER mode (see ATU manual)
PFn PROGRAMMABLE FUNCTION;
shortcut to selected menu entry, or
set to "NOR" (normal) to use as XIT
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