Vectronics VEC-821K User Manual
TABLE OF CONTENTS
Introduction
................................
................................
................................
....................
2
Tools and Supplies .......................................................................................................2
Before You Start Building ............................................................................................3
Soldering Tips: ...............................................................................................................3
Desoldering Tips:..........................................................................................................4
Work Habits:..................................................................................................................4
Sorting and Reading Resistors: ...................................................................................4
Reading Capacitors:......................................................................................................5
Diodes:............................................................................................................................5
Transistors:.....................................................................................................................6
Integrated Circuits: ........................................................................................................6
Parts List ........................................................................................................................7
Parts Placement Diagram..............................................................................................8
Step-By -Step Assembly ........................................................................................8
Phase 1:...........................................................................................................................9
Phase 2:..........................................................................................................................11
Phase 3:..........................................................................................................................14
PC Board Inspection: ...................................................................................................16
Testing and Alignment...............................................................................................17
Operating Instructions ...............................................................................................18
Receiver or Scanner Operation..................................................................................18
In Case of Difficulty ....................................................................................................19
No Signal Filtering:.......................................................................................................19
Intermittent Filter Operation:......................................................................................19
Filter Stops Filtering:....................................................................................................19
No Speaker Audio: .......................................................................................................20
Theory of Operation and Specifications .................................................................20
Circuit Description:......................................................................................................20
Specifications:..............................................................................................................20
Enclosure ......................................................................................................................20
Schematic .....................................................................................................................21
VEC-821 K Instruction Manual
Super CW F
ilter Kit
821K consists
of a four stage, switch selectable band pass CW filter, using selected
components that will make "cleaning up" CW signals effortless and easy.
r sharp selectivity and extremely steep sided skirts, even the
weakest signal stands out. Also, the VEC
built
easy
features
headphones.
rmance and
transistor radio battery, or
lighted
losing
them. An inexpensive sheet of white poster board makes an excellent
desk.
ntensity
important
INTRODUCTION
Thank you for purchasing the VEC-821K CW Filter kit. The VEC-
Featuring razo
-821K has a 1 watt audio amplifier
in that will easily drive headphones or an external speaker. With the VEC821K you bring up any hard to hear signal out of a "band pile up" for
listening -or get rid of unwanted, annoying signals. The VEC-821K also
a headphone output that will allow the use of standard monoral
Although physically small in size, the VEC-821K is high on perfo
reliability. The VEC-821K is powered from a 9 -volt
any 9-18 volt DC power supply.
TOOLS AND SUPPLIES
Construction Area: Kit construction requires a clean, smooth, and well
area where you can easily organize and handle small parts without
construction surface, while providing protection for the underlying table or
Well-diffused overhead lighting is a plus, and a supplemental highi
desk lamp will prove especially helpful for close-up work. Safety is an
consideration. Be sure to use a suitable high-temperature stand for
your soldering iron, and keep the work area free of combustible clutter. Universal
Kit-building Tools: Although your particular kit may require additional items to
complete, virtually all construction projects require a work area outfitted with the
following tools and supplies:
• 30-60 watt Soldering Iron
• High-temperature Iron Holder with a Moist Cleani ng Sponge
• Rosin-core Solder (thin wire-size preferred)
• Needle Nose Pliers or Surgical Hemostats
• Diagonal Cutters or "Nippy Cutters"
• Wire Strippers
• Solder Sucker, Vacuum Pump, or Desoldering Braid
• Bright Desk Lamp
• Magnifying Glass
VEC-821 K Instruction M
anual
Super CW Filter Kit
these, and
check each step. A 1 K and a
differently in an
102 (or .001 uF) may
2. Installing Parts Backwards: Always check the polarity of electrolytic
capacitors to make sure the positive (+) lead goes in the (+) hole on the
Transistors have a flat side or emitter tab to help you
position. ICs have a notch or dot at one end
indicating the correct direction of insertion. Diodes have a banded end
applying
bridges.
or when
lead or pad. Solder
ogether (see
think!
assembly
e two secrets of professional
soldering. Before you install and solder each part, inspect leads or pins for
oxidation. If the metal surface is dull, sand with fine emery paper until shiny.
tip to
ensure maximum heat transfer. Allow the tip of your iron to contact both the lead
solder
smoothly.
solder will wick
Apply solder
promote rapid
BEFORE YOU START BUILDING
Experience shows there are four common mistakes builders make. Avoid
your kit will probably work on the first try! Here's what they are:
1. Installing the Wrong Part: It always pays to double-
10K resistor may look almost the same, but they may act very
electronic circuit! Same for capacitors--a device marked
have very different operating characteristics from one marked 103 (or .01uF).
circuit board.
identify the correct mounting
indicating correct polarity. Always double-check--especially before
power to the circuit!
3. Faulty Solder Connections: Inspect fo r cold -solder joints and solder
Cold solder joints happen when you don't fully heat the connection-metallic corrosion and oxide contaminate a component
bridges form when a trail of excess solder shorts pads or tracks t
Soldering Tips below).
4. Omitting or Misreading a Part: This is easier to do than you might
Always double-check to make sure you completed each step in an
sequence.
Soldering Tips:
Cleanliness and good heat distribution are th
Also, clean the oxidation and excess solder from the soldering iron
and pad for about one second (count "one-thousand-one") before feeding
to the connection. Surfaces must become hot enough for solder to flow
Feed sol der to the opposite side of the lead from your iron tiparound the lead toward the tip, wetting all exposed surfaces.
sparingly, and do not touch solder directly to the hot iron tip to
melting.
'EC-821
K Inst
ruction Manual
Super CW Filter Kit
Desoldering Tips:
When you look at a resistor, check its multiplier code first. Any resistor with a black
If you make a mistake and need to remove a part, follow these instructions
carefully! First, grasp the component with a pair of hemostats or needle-nose pliers.
Heat the pad beneath the lead you intend to extract, and pull gently. The lead should
come out. Repeat for the other lead. Solder may fill in behind the lead as you extract
it--especially if you are working on a doublesided board with plate-through holes.
Should this happen, try heating the pad again and inserting a common pin into the
hole. Solder won't stick to the pin's chromium plating. When the pad cools, remove
the pin and insert the correct component. For ICs or multi-pin parts, use desoldering
braid to remove excess solder before attempting to extract the part. Alternatively, a
low-cost vacuum-bulb or spring-loaded solder sucker may be used. Parts damaged
or severely overheated during extraction should be replaced rather than reinstalled.
Work Habits:
Kit construction requires the ability to follow detailed instructions and, in many
cases, to perform new and unfamiliar tasks. To avoid making needless mistakes,
work for short periods when you're fresh and alert. Recreational construction
projects are more informative and more fun when you take your time. Enjoy!
Sorting and Reading Resistors:
The electrical value of resistors is indicated by a color code (shown below). You
don't have to memorize this code to work with resistors, but you do need to
understand how it works:
1st Digit Brown = 1 (hundreds) Violet = 7
2nd Digit Red = 2 (K) Gray = 8
multiplier band falls between 10 and 99 ohms in value. Brown designates a value
between 100 and 999 ohms. Red indicates a value from 1000 to 9999 ohms, which is
also expressed as 1.0K to 9.9K. An orange multiplier band designates 10K to 99K,
etc. To sort and inventory resistors,
Resistor Color Code
Black = 0 (tens) Blue = 6
VEC-821 K Instruction Manual
first separate them into groups by multiplier band (make a pile of
10s, 100s,
Ks,
etc.).
This procedure makes the inventory easier, and also makes locating specific
find it
Some VEC kits may contain molded chokes which appear, at first glance,
will
chokes are generally larger in
diameter and fatter at the ends than resistors. When doing your inventory,
code
As with resistors, it's helpful to sort capacitors by type, and then to arrange
them
pF (or
The
transition from pF to uF occurs at 1000 pF (or .001 uF)*. Today, most
The
first two digits indicate a numerical value, while the last digit indicates a
Electrolytic capacitors are always marked in uF. Electrolytics are polarized
u become
confused by markings on the case, remember the uncut negative lead is slightly
look
10Ks, etc.). Next, sort each group by specific value (1K, 2.2K, 4.7K,
parts more convenient later on during construction. Some builders
especially helpful to arrange resistors in ascending order along a strip of doublesided tape.
similar to resistors in both shape and band marking. However, a closer look
enable you to differentiate between the two--
separate out any chokes and consult the parts list for specific colorinformation.
Reading Capacitors:
Unlike resistors, capacitors no longer use a color code for value identification.
Instead, the value, or a 3-number code, is printed on the body.
Super CW Filter Kit
in ascending order of value. Small-value capacitors are characterized in
pico-Farads), while larger values are labeled in uF (or micro-Farads).
monolithic and disc-ceramic capacitors are marked with a three-number code.
multiplier (same as resistors).
devices and must be oriented correctly during installation. If yo
shorter than the positive lead.
Diodes:
Diodes are also polarized devices that must be installed correctly. Always
for the banded or cathode end when installing, and follow instructions carefully.
VEC-821 K Instruction Manual Super CW Filter Kit
Transistors:
If transistors are installed incorrectly, damage may result when power is
Many
current voltage regulators also use this type
with
indicated by
Integrated Circuits:
end
board and
1C pin
always start
around the device,
applied. Transistors in metal cases have a small tab near the emitter lead to
identify correct positioning. Semiconductors housed in small plastic cases (TO-
92) have an easily-identified flat side to identify mounting orientation.
specialized diodes and lowpackaging. Larger plasti c transistors and voltage regulators use a case backed
a prominent metal tab to dissipate heat (T-220). Here orientation is
the positioning of the cooling tab.
Proper IC positioning is indicated by a dot or square marking located on one
of the device. A corresponding mark will be silk-screened on the PC
printed on the kit's parts-placement diagram. To identify specific
numbers for testing purposes, see the diagram below. Pin numbers
at the keyed end of the case and progress counter-clockwise
as shown:
Loading...