Elecraft K1 User Manual
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.
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