Ramsey Electronics WCT3 User manual

WCT3  1
Wireless Control
Tester
Ramsey Electronics Model WCT3
FEATURES
 Verifies presence of 315MHz, 433MHz, 125KHz, 20KHz and
Infrared control signals remote control signals generated by
remote control devices such as:
 Automotive keyless entry key fobs, keyless ignition , tire pressure sensors
 Building keyless access systems
 Entertainment / media systems
 Simple one button operation
 Surface Mount Technology Components
 Operates on standard 9V battery
The WCT3 is designed to provide an easy to use diagnostic tool to aid in
identifying problems with wireless remote control devices and systems.
These include but are not limited to automotive keyless entry, starter and tire
pressure systems, wireless building access systems and even your
entertainment remote control devices using 315MHz, 433MHz, 125KHz,
20KHz and Infrared signals.

WCT3 2
PARTIAL LIST OF AVAILABLE KITS:
RAMSEY TRANSMITTER KITS
FM10A, FM25B, FM30, FM Stereo Transmitters
FM100B, FM35 Professional FM Stereo Transmitters
AM1, AM25 AM Broadcast Band Transmitters
RAMSEY RECEIVER KITS
FR1 FM Broadcast Receiver
AR1 Aircraft Band Receiver
SR2 Shortwave Receiver
SC1 Shortwave Converter
RAMSEY HOBBY KITS
LBC6K Laser Beam Communicator
SG7 Personal Speed Radar
SS70C Speech Scrambler/Descrambler
TT1 Telephone Recorder
LLS1 Laser Light Show
MD3 Microwave Motion Detector
LEDS1 LED Strobe Light
BE66 Blinky Eyes Animated Display
LTS1 Laser Trip Sensor
ICI1C Infrared Switch Control Interface
RAMSEY AMATEUR RADIO KITS
HR Series HF All Mode Receivers
DDF1 Doppler Direction Finder Kit
QRP Series HF CW Transmitters and QAMP Power Amplifiers
CW7 CW Keyer
RAMSEY MINI-KITS
Many other kits are available for hobby, school, scouts and just plain FUN. New
kits are always under development. Write or call for our free Ramsey catalog.
WCT3 Wireless Control Tester
Ramsey Electronics publication No. WCT3 Rev 1.0
This Printing: March 2011
COPYRIGHT 2010 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York
14564. All rights reserved. No portion of this publication may be copied or duplicated without the
written permission of Ramsey Electronics, Inc. Printed in the United States of America.

WCT3  3
WCT3
Wireless Control Tester
Ramsey Publication No. WCT3:
Manual Price Only $5.00
TABLE OF CONTENTS
Introduction ** ......................................4
Theory of Operation.............................5
Parts List............................................10
Parts Layout Diagram........................11
“Learn as you Build” **.......................12
Assembly Steps.................................14
Schematic Diagram............................18
Operational Check.............................23
Final Case Assembly.........................24
Using The WCT3 ...............................25
Troubleshooting.................................27
How To Get Help From Ramsey........32
User Notes.........................................31
Warranty ............................................33
** IMPORTANT!: Please read notes about cleaning the circuit board.
INSTRUCTION MANUALAND
ASSEMBLY STEPS FOR
RAMSEY ELECTRONICS, INC.
590 Fishers Station Drive
Victor, New York 14564
Phone [phone]
Fax [phone]
www.ramseykits.com

WCT3 4
INTRODUCTION
The WCT3 can be used to detect 315MHz, 433MHz, 125KHz, 20KHz and In-
frared signals generated by various devices such as, but not limited to, auto-
motive key fobs, tire pressure sensors, building access control systems, and
infrared remote control devices. The WCT3 provides verification of the pres-
ence of the various types of signals. It does not provide any information about
the actual data transmitted by the device.
It should be noted that all remote control devices and systems are not created
equal. There are different signal levels, signal radiation and data patterns
generated by these devices. Because of this you may find that it is necessary
to adjust the position of the WCT3 and device being tested in relation to each
other in order to obtain signal indication. This is normal operation. Remem-
ber that the WCT3 provides a basic indication of signal generation. This indi-
cation does not assure the data included on a signal is correct.
!!! PLEASE NOTE !!!
Please take note that because of the extreme sensitivity of the WCT3 we
highly recommend the use of a NO-CLEAN, ROSIN CORE solder to assem-
ble your WCT3. Also note that you should avoid use of any type of cleaning
solution to remove rosin residue. Any attempt to use cleaning solutions may
degrade the performance of your WCT3. You can purchase the recom-
mended solder from Ramsey Electronics, LLC or call us at 585-924-4560 if
you any questions.
About the signals detected:
The 315MHz section of the WCT3 is optimized to detect signals in the
315MHz range but is also useful in detecting a fairly wide range of signal fre-
quencies including 433MHz signals often used for some types of remote con-
trol systems. The sensitivity may be decreased for these signals but an indi-
cation is still possible. The 315/433MHz indicator will indicate presence of
these signals.
The 125KHz and 20KHz functions of the WCT3 are precisely tuned to detect
signals within a few kilohertz above or below the indicated frequency.
Infrared signals will be detected only if the signal is modulated with data. If an
un-modulated infrared source is present you may find that the indicator will
flash only if the source is being moved and there may be no indication if the
source is held stationary. This is normal operation and does not indicate a
problem with the WCT3.

WCT3  5
THEORY OF OPERATION
The WCT3 consists of 4 separate stages, one for each of the wireless control
signals to be detected. The sections are basically identical in operation but
each is specifically designed to detect the signal of interest. In order to keep
things simple we will describe the basic operation of one section and then
briefly describe the differences between the sections.
Looking at the schematic on pages 18 & 19 you will notice that it is divided
into 5 columns titled “INPUT/FILTER”, “DETECTOR”, “AMPLIFIER”,
“COMPARATOR”, and “POWER SUPPLY”. There are also 4 apparent rows
left to right which correspond to the 315/433MHz, 125KHz, 20KHz and Infra-
red sections from top to bottom respectively. The power supply is common to
all sections and is the right most column. We’ll look at the 125KHz section for
this discussion.
Starting on the left side of the schematic in the “INPUT/FILTER” column is the
antenna, “ANT2”, which essentially ‘collects’ the 125KHz signal to be de-
tected. Next is coil L1 and capacitor C4. L1 is a specialized coil called an
RFID (Radio Frequency Identification) transponder coil. L1 along with C4 are
designed, or tuned, to allow a very narrow band of frequencies centered
around 125KHz to pass on to the detector stage of the WCT3. Any frequen-
cies outside the desired band are blocked from passing into the circuit. The
technical term for this circuit is a band pass filter.
Now that we have captured only the desired signal we want it needs to be de-
tected and this is done in the detector section. Diode D2, which is actually a
small package that contains 2 diodes, forms the detector. Without getting into
the details of how a detector works just know that D2 actually converts the
125KHz signal into a DC(direct current) signal. The diode connected between
C5 and R25 provides a positive DC signal to the amplifier, U1B pin 5, thru R25
and the other diode connected to ground prevents any negative part of the
signal from interfering with the operation of the rest of the circuit. C5 and R25
are in the circuit to provide a little more filtering of the 125KHz signal and help
stabilize the captured signal before being detected. Resistor R5 is a very high
resistance, 3,900,000 ohms and provides a very high resistance for the output
of the detector. This is necessary because the detected signal has an ex-
tremely low power level.
Up to this point the circuit design had to take into consideration the frequency
of the signal we were working with. Now that it has been detected by D2 the
signal is a simple DC level which will have an amplitude, or DC level, that is
proportional to the strength of the detected signal. Because the signal is now
a DC level it is much easier to amplify and provide an indication of a signal
being present.
As you have probably guessed the nice DC signal will now be amplified by the

WCT3 6
amplifier stage formed by U1B and the resistors R5, R6, R8 and capacitor C7.
U1B is a high gain, high frequency, high input resistance, low noise amplifier.
There are 4 of these amplifiers in the U1 package and one is used for each of
the 4 sections of the WCT3. The reason an amplifier with the characteristics
of U1 is needed is because the detected signal level is extremely small, actu-
ally in the micro volt, (that’s 0.000001 volts), range. The amplifier in the case
of the 125KHz signal amplifies the signal about 330 times so, for example, a
signal level of 100 micro volts, (0.0001 volts), will result in a level of 33 mil-
livolts, (0.033 volts), at the output of the amplifier. This gain is determined by
R6 and R8 and is calculated by dividing the value of R6 by R8. So R6 / R8 =
330,000 / 1000 which equals 330. Believe it or not we now have a signal level
that is easy to work with.
Now that we have a workable signal level it is time to indicate that a signal has
been detected. This is the job of the comparator circuit formed by U2B and
resistors R14 and R15. U2 , like U1, has 4 identical parts with one being used
for each of the WCT3 sections. What U2B does is look at the signal applied to
U2B pin 6 from amplifier U1B pin 7 and compares it to a predetermined volt-
age level set by R14 and R15 on U2B pin 5. This is a simple voltage divider
and for the 125KHz signal provides a level of about 685 millivolts. You will
notice that this level is shown on the schematic near the junction of R14, R15
and U2B pin 5. If the voltage level applied to U2B pin 6 from the amplifier
goes above 685mV the output, U2B pin 7, goes low and LED D7 lights indicat-
ing a signal has been detected.
Operation Of The Other Sections
If you look at the other sections of the schematic you will notice that they all
look about the same as the 125KHz section. The component values are dif-
ferent for each section but the basic operation is the same. The major differ-
ence is in the Input/Filter sections because it is necessary to allow signals of
different frequencies to be detected. Notice that the 20KHz section uses the
same transponder coil but has a different value for capacitor C17 compared to
C4 in the 125KHz section so only signals in the 20KHz frequency range will be
detected. Changing the capacitor value changes the resonance of the circuit.
The transponder coils, L1 and L2, are identical and have an inductance value
of about 7.5 millihenries. To learn more about resonance try searching on the
Web for “resonance frequency”. There is lots of information available.
For the 315/433MHz section the filter has a different type of coil. It actually
works the same way as L1 and L2 but because of the much higher frequency
the coil is constructed differently. In this case the coil, M2, is actually formed
by a copper trace which is physically part of the circuit board. This is called a
strip-line inductor and makes it much easier to accurately construct the coil.
It’s inductance value is about 0.18microhenries (0.00000018 henries), much
smaller than L1 and L2. If you look at the circuit board you will see M2 which

WCT3  7
is a spiral circuit trace near the ANT1 connection on the left side of the board.
You will also notice that the detector diodes D3 and D4 are a different type.
This is because of the much higher frequency we are working with. The diode
package used on the other sections will not function at these frequencies.
The Infrared section of the WCT3 is the least critical section even though the
infrared signal is near the frequency range of visible light. This is because the
device that captures the infrared signal, Q1, easily responds to signals in the
frequency range of light. Q1 is called a photo transistor which acts like a
switch and turns on when it ’sees’ infrared or light. The infrared signal from a
control is turned on and off, modulated, so Q1 actually turns on and off at the
rate of the modulated signal. The frequency of the modulation is typically in
the range of 38KHz and is therefore extremely easy to work with. You can
think of Q1 as the antenna and filter, and the detector is actually detecting the
modulation signal rather than the actual infrared signal.
The amplifier and comparator stages of all the sections are identical in opera-
tion with the only differences being in the amplifier stage gain and comparator
reference levels. Each of these areas is designed specifically for the charac-
teristics of signal to be detected.
Power Supply Operation
Power for the WCT3 is provided by a standard 9V battery. Looking at the
power supply section of the schematic you will see the battery on the left.
When push button switch S1 is pressed power is applied to operate the
WCT3. Capacitor C3 is a filter which insures a stable 9 volts under sudden
heavy loads, such as when an LED lights. It acts like a big reserve reservoir
for sudden power surges.
Now you are asking why the voltage connection after switch S1 is labeled
“+4.5V”. Good question. You will notice that there are two types of ‘ground’
connection symbols used in the schematic. One is a simple triangle and the
other is a triangle made up of three parallel lines. Notice that the ‘-‘ connec-
tion of the 9 volt battery as well as the, ‘-‘ lead of C3, Pin 11 of U1-D and U2-
D, and one lead of R7 and R22 are connected to the triangle. If a measure-
ment is taken with reference to this ground connection a reading of +9 volts
will be seen. This is actually the power ground reference but is not the signal
ground reference point used for the detected signals.
The ground connection indicated by the other triangle symbol is the signal
ground reference. Resistors R22 and R23 are used to create a reference
point half way between the 9 volt supply and power ground that supplies
power to U1 and U2. This allows the amplifier and comparator to accept a
signal that swings between a positive and negative level with reference to the
signal ground point which is the connection between the resistors. The

WCT3 8
“+4.5V” voltage is referenced to the signal ground and not the power ground.
If a reading is taken between the power ground and signal ground with refer-
ence to the signal ground you will see a reading of “-4.5V”. So the difference
between the “+4.5V” and “-4.5V”, (measurements referenced to signal
ground), points of the circuit is now +9 volts with reference to the power
ground.
A Little More About Wireless Remote Control Signals
Here’s a little more information about how most wireless remote control sys-
tems work and how the WCT3 detects the signals. The 315/433MHz, 125KHz
and 20KHz sections of the WCT3 will detect the presence of virtually any sig-
nal that is within the design frequency range. It doesn’t matter if there is data,
modulation, on the signal or not. The simple presence of the signal will be
indicated. The infrared section operates in a slightly different way. We’ll take
a look at the circuit operation differences here.
When you see the indicator flashing when you activate any wireless remote
control you are seeing the modulation signal. Most remote controls, both RF
and infrared type systems, modulate the signal by turning the signal on and
off. This is often referred to as OOK, On-Off_Keying, modulation. When the
indicator flashes you are seeing the result of the modulation. Actually an un-
modulated signal is constantly turning on and off at the frequency of the un-
modulated signal. This unmodulated signal is called the carrier, (i.e. it carries
the data). The frequency of the carriers, except for the infrared, detected by
the WCT3 are 315MHZ, 433MHz, 120KHz and 20KHz. If the indicator does
not flash but simply stays on that indicates that the signal is not being modu-
lated and only the fact that a signal in the proper frequency range is present.
(Actually the indicator may be flashing or flickering but it is so fast that your
eyes think it’s on all the time, but that’s beyond the scope of this manual.)
The infrared section also indicates the modulation by flashing but it will not
provide an indication if the signal is not modulated. That’s because the fre-
quency of the infrared carrier is so high that Q1 simply turns on and turns off
when light is present and removed. The detector section actually detects only
the 38KHz carrier signal. You can think of Q1 as both the antenna and filter
part of the “Input/Filter” section of the infrared section. This means that virtu-
ally any infrared or light signal will be indicated by the WCT3 as long as it is
modulated so you can use it to test any virtually any remote that uses infrared
and a carrier signal.
An interesting experiment you can try is to use the WCT3 to detect movement
of a light source or of an object moving between the light source and WCT3.
If you point the infrared detector of the WCT3 toward a light source you may
see a brief flash of the IR indicator. By simply moving your hand between the
light and WCT3 rapidly you will see the indicator flicker or even stay on if you

WCT3  9
can move your hand REALLY, REALLY, REALLY …. fast. (If you can move
that fast there are probably some military research facilities that would like to
talk to you). For the same reason, if the light source is moved rapidly past the
WCT3 you may also see the indicator flash indicating detection of the light.
You are actually modulating the IR signal seen by the WCT3 by blocking and
unblocking or moving the light source, (OOK modulation). An infrared control
turns the signal on and off in specific patterns and rates which are decoded by
the device being controlled.
Conclusion
Now that you are completely confused, don’t worry about it, (I’m often con-
fused too), and enjoy your WCT3. Hopefully you have gained a basic under-
standing of the WCT3 operation. This description is intended to give a simple
overview of the unit. A more detailed description of the operation is beyond
the scope of this manual. If it has inspired you to learn more that’s great.
There’s a lot of information about electronic circuit design available on the
Web and with a little searching you can find much more detailed information
about the operation of the basic circuits described here. After years of elec-
tronics engineering I find lots of things I didn’t know, (or is it that I forgot ….?),
out there. I forget……. ENJOY!!!!!

WCT3 10
WCT3 PARTS LIST
Each type and value of a surface mount component, (indicated by
“[smt]”), is placed in its own labeled baggie. Be aware not all [smt] com-
ponents have value markings so be careful not to mix them up. In the
parts list an “X” in the reference designation indicates that an extra com-
ponent or two is provided because they like to “fly away” due to the
small size.
Semiconductors
1 LF347F IC, marked LF347 ,(U1) [smt]
1 LM324M IC, marked LM324, (U2) [smt]
2 CDSH270 diode, CDSH270, (D3, D4)
3 BAV99 diode, marked A7 or A7X, (D2, D5, D9) [smt]
1 Infrared transistor, marked with green dot, (Q1)
2 RED LED (D1, D6)
2 GREEN LED (D7, D10)
1 YELLOW LED (D8)
Resistors (ALL [smt])
5 560 ohm resistors, marked 560, (R18, R19,R20, R32, X)
11 1k ohm resistors, marked 102, (R4, R7, R8, R9, R10, R11, R22, R23,
R29, R30, X)
2 1.2K ohm resistor, marked 122, (R26, X)
2 2.7K ohm resistor, marked 272, (R15, X)
2 5.6K ohm resistor, marked 562, (R13, X)
2 6.8K ohm resistor, marked 682, (R17, X)
6 10k ohm resistors, marked 103, (R12, R14, R16, R21, R27, X)
2 150k ohm resistors, marked 154, (R31, X)
3 330k ohm resistors, marked 334, (R3, R6, X)
7 3.9M ohm resistors, marked 395, (R2, R5, R24, R25, R28, R33, X)
Capacitors
4 0.001uF Ceramic disk, not marked, (C2, C11, C13, X) [smt]
11 0.01uF Ceramic disk, not marked, (C5, C6, C7, C8, C9, C10, C14,
C15, C16, C17, X) [smt]
2 8.2pF Ceramic, not marked, (C12, X) [smt]
2 220pF Ceramic, not marked, (C4, X) [smt]
1 10uF Electrolytic SMT, marked 10, (C3) [smt]
Miscellaneous
1 SPST Push Button switch (S1)
1 0.32” long round black switch cap
2 resonator coil, marked 715, (L1, L2) [smt]
1 Case cover label

WCT3  11
1 9V battery snap clip with red and black wires
1 Antenna bundle assembly (Pre-Assembled. DO NOT DEFORM)
1 WCT3 Circuit board
5 5/16” nylon LED spacers
1 Case assembly (includes 4 screws, red end cap (VERY dark red),
top & bottom case shell, belt clip)
WCT3 PARTS LAYOUT DIAGRAM
/R33
JUMPER WIRE

WCT3 12
RAMSEY “LEARN-AS-YOU-BUILD” ASSEMBLY STRATEGY
Completely read through all of the steps and check the boxes as you go to be
sure you didn't miss any important assembly instructions. Although you may
be in a hurry to see results, before you switch on the power check all wiring
diodes, transistors, IC’s, and capacitors for proper orientation. Also check the
board for any possible solder shorts and/or cold solder joints. Any of these
mistakes could have detrimental effects on your kit - not to mention your ego!
Kit building tips: !!! IMPORTANT !!!
DUE TO THE EXTREME SENSITIVITY OF THE WCT3, ATTEMPTING TO
CLEAN THE ROSIN FLUX FROM THE BOARD MAY RESULT IN DE-
GRADED PERFORMANCE OF THE UNIT. WE HIGHLY RECOMMEND
THE USE OF ONLY NO-CLEAN ROSIN CORE SOLDER.
Warning: Use only rosin core solder or solder designed to be used with elec-
tronic equipment. Use of acid core solder will void your warranty and produce
a board that will disintegrate in a short period of time.
For Through-Hole Components, the word "Install" means:
1. Pick the correct part type and value or part number.
2. Mount all electrical components on the top (silkscreened) side of the
PC board unless otherwise noted.
4. Orient the part correctly. Follow the PC board drawing or silk screen
and the written directions for every part! Certain types of parts must be
installed with the proper leads in specific holes. Things to watch for in-
clude diode bands, electrolytic capacitor polarity, transistor shapes, dotted
or notched ends of IC's, and so forth.
5. Insert the part into the correct PC board loca-
tion. Make sure the part is mounted as close to
the PC board as possible, unless otherwise
noted. Most parts, including lay down parts, have
holes or pads that are located inside or near a
rectangle, oval, or circle. Stand up resistors, di-
odes, or inductors have a circle around one pad
(part body location) with a line leading from that
circle to the other pad (lead only).
6. Bend the component and insert thru the
board and then bend leads on the backside of the
board to prevent the part falling out before soldering.
7. Flip board and solder all connections unless di-
rected otherwise. Apply a touch of solder to the iron
tip and then heat both the component lead and

WCT3  13
circuit board pad simultaneously. Apply a little more
solder to the component lead and the pad when they
are hot enough to melt the solder and remove the
iron. DO NOT move the component lead or board
until the solder cools a little. The finished joint should
look like a drop of water on paper, clean, shiny, with
joint completely filled.
8. Clip remaining component leads as close to the board as possible.
For Surface Mount Technology (SMT) Compo-
nents, the word "Install" means:
1. Pick the correct part type and value or part
number.
2. Melt a dab of solder on one pad of the PC
board for the component you wish to install.
3. Use tweezers to pick up the appropriate com-
ponent by grabbing it across the body, not the
solder connections.
4. Place the part in the assembly location as
noted by the silk-screen on the top layer of the
board (the bottom side has no writing on it). Use
one hand to hold the tweezers and part in place.
5. Use the other hand to re-heat the solder dab
to melt it to the component connection.
6. Let the solder cool and then let go with the
tweezers. Inspect orientation and make sure the
part is square over the correct pads. Make sure
stray solder connections don’t overlap or short
across any to adjacent pads.
7. Apply solder to the rest of the pads.
8. Apply a touch more solder to the initial pad to make sure there is a
good solder joint. The rosin core flux will clean the joint and insure stabil-
ity.
9. If you have too much solder and wish to remove it, use a solder
sucker or solder wick to “soak up” the extra solder. Solder bridges on SMT
IC pins are a frequent occurrence so you should always have some solder
wick handy.

WCT3 14
ASSEMBLY STEPS
Surface Mount Semiconductor Installation
1. Orient the board as shown in the board layout diagram on page 1
2. Install U1, the LF347 IC( marked LF347). Notice that there is an in-
dented dot near one corner of the IC. This indicates the location pin 1 and
the IC must be installed so this dot is to the upper left near the small white
dot printed on the circuit board. Place the IC on the board and make sure
all the leads on both sides of the IC align with all the solder pads on the
board. Note that once more than one lead is soldered it will be difficult to
reposition the IC if the placement is incorrect. Because of this we suggest
that you first carefully solder only one of the corner leads and then make
sure all other leads are aligned before soldering all other connections.
3. Install U2, the LM324 IC, (marked LM324), following the same instal-
lation procedure used in step #2 above for the LF347.
Locate the two(2) Resonator coils, L1 & L2, marked 715. The connections for
these coils are under the device body. To install them first apply a small coat-
ing of solder on each of the 4 pads on the circuit board. Try to keep the sur-
face as level and flat as possible or it will be difficult to properly place the coil.
Once the pads are coated place the coil so it is centered inside the white
printed white lines taking note that one of the corners is ‘marked’ at a 45 de-
gree angle. This will allow a portion of each pad to be visible so you can melt
the solder which will also heat the coil connection and the solder will flow onto
the coil. When the solder flows evenly apply a little more solder and remove
the soldering iron. Solder one of the smaller pads first, check alignment and
then solder the remaining pads. You may find it takes a little more time on
some pads because of the copper connected to the pad.
4. Install resonator coil L1.
5. Install resonator coil L2.
Locate the 3 BAV99 diodes, marked A7 or A7X, D2, D5 and D9.
6. Install D2 located just above the preinstalled L1 resonator on the left
side of the board. Again solder only one lead first, check alignment, and
then solder the remaining leads
7. Install D5 located to the right of U1 near the edge of the board.
8. Install D9 located just above D5 near the edge of the board.
Now we’ll start installing the resistors and capacitors. We will install each
value as a batch to keep from mixing them up. Unless otherwise instructed all
these components can be installed in either direction as long as they are
placed within the areas indicated for each.

WCT3  15
Resistor Installation:
Let’s start with the four(4) 560 ohm resistors, marked 561.
9. Install R18, 560 ohm resistor
10. Install R19, 560 ohm resistor
11. Install R20, 560 ohm resistor
12. Install R32, 560 ohm resistor
Now located the ten(10) 1K ohm resistors, marked 102.
13. Install R4, 1K ohm resistor
14. Install R7, 1K ohm resistor
15. Install R8, 1K ohm resistor
16. Install R9, 1K ohm resistor
17. Install R10, 1K ohm resistor
18. Install R11, 1K ohm resistor
19. Install R22, 1K ohm resistor
20. Install R23, 1K ohm resistor
21. Install R29, 1K ohm resistor
22. Install R30, 1K ohm resistor
Ok… how ‘bout the one(1) 1.2K ohm resistor, marked 122.
23. Install 1.2K ohm resistor R26
Next comes the one(1) 2.7K ohm resistor, marked 272
24. Install 2.7K ohm resistor R15.
Next find the 5.6K ohm resistor, marked 562.
25. Install 5.6K ohm resistor R13
Where is that pesky 6.8K ohm resistor, marked 682..? Can you tell I’m getting
a little crazy writing the same thing over and over…??
26. Install R17, 6.8K ohm resistor
Find the little bag containing the five(5) 10K ohm resistors, marked 103.
27. Install R12, 10K ohm resistor
28. Install R14, 10K ohm resistor
29. Install R16, 10K ohm resistor
30. Install R21, 10K ohm resistor

WCT3 16
31. Install R27, 10K ohm resistor
Almost there… let’s do the 150K ohm resistor, marked 154.
32. Install R31, 150K ohm resistor
Locate the two(2) 330K ohm resistors marked 334.
33. Install R3, 330K ohm resistor
34. Install R6, 330K ohm resistor
Locate the last resistors, six(6) 3.9M ohm resistors, marked 395, (that’s 3mil-
lion, 900 thousand ohms.. 3,900,000 ohms). Three(3) of these resistors will
be installed now and the 4th will be installed in a little while. Don’t lose it!!!!
35. Install R2, 3.9M ohm resistor
36. Install R5, 3.9M ohm resistor
37. Install 3.9M ohm resistor R24
38. Install 3.9M ohm resistor R25
39 Install 3.9M ohm resistor R28
Why don’t you take a little break at this point and check over your work. Make
sure there are no solder bridges between the installed components and other
pads. Also check that each location has the correct value.
REMEMBER!! DO NOT clean the circuit board!!!
Capacitor Installation:
Next we’ll install the capacitors. With the exception of C3 all these capacitors
may be installed in either direction. Make sure to open only ONE package at
a time to avoid mixing up the values. This is especially true for the capacitors
since they have no markings of any kind.
Start buy locating the package of three(3) .001uF capacitors.
40. Install C2, .001uF capacitor
41. Install C11, .001uF capacitor
42. Install C13, .001uF capacitor
The ten(10) .0.01uF capacitors are next
43. Install C5, .01uF capacitor
44. Install C6, .01uF capacitor
45. Install C7, .01uF capacitor
46. Install C8, .01uF capacitor

WCT3  17
47. Install C9, .01uF capacitor
48. Install C10, .01uF capacitor
49. Install C14, .01uF capacitor
50. Install C15, .01uF capacitor
51. Install C16, .01uF capacitor
52. Install C17, .01uF capacitor
Remember that 3.9M ohm resistor, marked 395, we didn’t install? Well, it’s
R33 and now is the time to install it.
53 R33 is installed a little differently. We’re going to install it right on top
of C2 that you installed in step 40. Relax, you’re an expert SMT compo-
nent installer now and it’s not that hard. Simply place R33 on top of C2
and flow a little solder up from the connection on C2 next to D4 up to R33.
Then do the same for the other connection next to D3.
Find the 8.2pF capacitor package
54. Install C12, 8.2pF capacitor
Now for the 220pF capacitor
55. Install C4, 220pF capacitor
Ok, now you need to be careful and pay attention to the instructions. Locate
the 10uF electrolytic capacitor, marked 10.
56. Install C3, 10uF capacitor. This capacitor is a little silver cylinder with
a black base. You will notice that there is a black mark indicating the “-”
terminal on one side of the cylinder and the 2 corners of the base are
notched at a 45 degree angle indicating the “+” terminal. C3 MUST be
positioned so the black mark is to the left and the notches are on the right.
There are two small leads on the bottom of the capacitor which must be
placed over the two solder pads on the board. Apply a little solder on
each of the board pads and then place C3 over the pads and apply heat
to one of the pads, not the capacitor lead, at a time being careful to not
get the black plastic base too hot. This will melt the pad solder first and
allow it to flow onto the capacitor pad. Check the alignment and then sol-
der the other connection.
REMEMBER!! DO NOT clean the circuit board!!!

WCT3 20
Thru hole component installation:
The remainder of the components are thru hole components. When installing
all except the LED’s they should be inserted and placed as close to the circuit
board as possible.
57. Next install D3 and D4, marked CDSH270. Notice that there is a
black band on one end of the diodes. Place the diodes so band matches
the wide white printed line on the board. Again place the body of the di-
odes against the circuit board. Cut the leads from the bottom of the
board, saving one for use in the next step.
58. Refer to the parts layout on page 11 and locate the position of U3 at
the bottom to the left of S1. U3 will not be installed, instead, take one of
the leads you cut from D3 or D4 in the previous step and use it as a
jumper between the round and square pad locations as indicated on the
layout diagram.
The next component is the Infrared detector transistor Q1. It is the small clear
device with 2 leads and a green dot painted on it. Be sure to follow the in-
structions exactly for proper installation. Refer to Figure 1.
59. Look closely at Q1 and notice that there is a flat
area on the base and the lead next to it is shorter
than the other. Hold Q1 so the leads are pointed
toward you with the flat area/shorter lead to your
right. While holding the leads near the base of Q1
with a pair of needle nose plies bend one lead at a
time with your fingers, not the pliers, downward to a
90 degree angle as shown in Figure 1. The bend
should be about 0.1 inch from the base of Q1.
60. Install Q1 with the shorter lead/flat side to the
right, corresponding to the small white dot on the
board. The front rounded edge of Q1 should be
positioned close to, but not extended past, the top
edge of the circuit board. You may leave the body
of Q1 slightly off the board to allow adjusting it’s position later.
The LED’s are next. Make sure the flat area/short lead, of the LED matches
the white printed pattern on the board. Spacers are provided to position the
LED’s at a precise distance above the circuit board. It is important that the
bodies of the LED’s be installed so they are tight against the spacer and the
spacers are tight against the board so the LED’s do not extend beyond the top
surface of the case when assembled. Insert the leads of each LED into a
spacer from the end with the large single opening. Place the LED leads thru
the correct holes in the board, bend the leads so the LED and spacer are held
firmly on the board and then solder the leads on the back of the board. You
may find that one or more of the LED’s does not have a flat area in which case
the short lead is used as the orientation indicator.
Figure 1

WCT3  21
61. Install D1, a RED LED
62. Install D6, a RED LED
63. Install D7, a GREEN LED
64. Install D10, a GREEN LED
65. Install D8, a Yellow LED
66. Install S1 push button switch Make sure to seat the body flush to the
circuit board.
Locate the 9 volt battery snap clip. This is the black connector with a red and
black wire attached.
67. Trim the leads of the battery clip so they are 2.25 (two and a quarter,
2 1/4), inches long measured from the black cover.
68. Carefully strip about 1/8 inch of insulation form both the red and black
leads.
69. Insert and solder the red wire on the battery snap clip into the “BAT1”
“+” hole at the bottom left of the circuit board.
70. Insert and solder the black wire on the battery snap clip into the
“BAT1” “-” hole at the bottom left of the circuit board.
The next steps will install the pre-assembled antenna bundle for the
315/433MHZ, 125KHz and 20KHz signals. The heavy black rectangular box
in Figure 2 on page 22 represents the main antenna bundle and the 6 smaller
lines extending from the bundle are the individual antenna connections. There
are 5 cable ties holding the bundle together at the locations indicated by the
oval symbols. Take note of the ties indicated as “TR1”, “TR2” and “TR3” in
the following steps. Be careful not to deform the bundle as overall perform-
ance of your WCT3 may be degraded.
71. Looking at the antenna bundle, identify the 2 wires exiting the bundle
on either side of cable tie “TR1”. Insert and solder these two wires at lo-
cations “A1” and “A2” as shown in Figure 2.
72. Identify the wire exiting the bundle just above cable tie “TR2”. Insert
and solder this wire at location “ANT2”.
73. Identify the remaining wire from the same side of the bundle. Insert
and solder this wire at location “ANT1”.
74. On the opposite side of the bundle insert and solder the wire exiting
just above cable tie “TR3” at location “ANT3”.
75. The remaining wire exiting from the upper right corner of the bundle is
inserted into location “A3” and soldered.
REMEMBER!! DO NOT CLEAN THE BOARD

WCT3 22
ANTENNA PLACEMENT
Figure 2
TR1
TR2
TR3
S1