VCO Coil Adjustment points and Transmit Balance adjustment points:

PL102A:

Manufacturer Model VCO Coil Adj Transmit Bal Adj
BOMAN
BOMAN
BOMAN
COLT
GEMTRONICS
GEMTRONICS
GENERAL ELECTRIC
GENERAL-ELECTRIC
GENERAL ELECTRIC
GENERAL ELECTRIC
GENERAL ELECTRIC
JC PENNY
KRACO
KRACO
LA FAYETTE
MIDLAND
MIDLAND
MIDLAND
MIDLAND
MIDLAND
PEARCE SIMPSON
RCA
RCA
RCA
TRUETONE
TRUETONE
TRUETONE
CB-910
CB-920
CB-930
390
GTX-44
GT-55
3-5804D
3-5811B
3-5812A
3-5813B
3-5819A
981-6204
KCB-4030
KCB-4045
HB-640
77-882
77-830
77-857
77-882
77-955
L1ON 40
14T260
14T270
14T304
CYJ4832A-87
CYJ4834A-87
CYJ4862A-87
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L5,T3
L5,T3
L5,T3
L5.T3
L5,T3
L5,T3
L5.T3
L5,T3
L5,T3
L5.T3
L5,T3
L5,T3
L5,T3
L5.T3
L5,T3
L5,T3
L5,T3
L5,T3
L5,T3
L5.T3
L5.T3
L5,T3
L5,T3
L5,T3
L5,T3
L5,T3
L5,T3

uPD858c AM Chassis:

Manufacturer Model VCO Coil Adj Transmit Bal Adj
COBRA
COBRA
PRESIDENT
PRESIDENT
PRESIDENT
PRESIDENT
PRESIDENT
PRESIDENT
ROBYN
SEARS
TEABERRY
TEABERRY
TEABERRY
TEABERRY
29XLR
89XLR
HONEST ABE
JOHN Q
TEDDY R
ZACHARY T
DWIGHT D
TEDDY R
AM-500D
663-38070700
T BEAR
IT COMMAND
T DISPATCH
TITAN T
L20
L20
L20
L19
L20
L20
L20
L20
L20
L20
L20
L20
L22
L20
L17
1,17
L17
L17
L17
L17
L17
L17
L17
L17
L17
L17
L9,L10,L11
L17

uPD858c SSB Chassis:

Manufacturer Model VCO Col Adj Transmit Bal Adj
COBRA
COBRA
PRESIDENT
PRESIDENT
PRESIDENT
REALISTIC
REALISTIC
REALISTIC
ROBYN
ROBYN
138XLR
139XLR
GRANT
MADISON
WASHINGTON
TRC-449
TRC-457
TRC-458
SB-510D
SB-520D
L17
L17
L17
L17
L17
L17
L17
L17
L17
L17
L37
L37
L37
L37
L37
L37
L37
L37
L37
L37

Broadbanding the uPD858c SSB Chassis:

Broadbanding the upd858c Uniden Chassis 

1. Locate L37 - Transmit Balance Adjust. Perform the modification above.
Be sure to completely isolate the pins. Place the jumpers as shown.
Keep these jumpers as short as possible and use only an isolated soldering
iron. Then adjust L37 for balanced output power coverage between your
highest and lowest channel. You may have to settle for a little less power
on one end on some units.

Clarifier broadband for uPD858c SSB Chassis:

upd858c SSB Chassis Clarifier Unlock

1. Cut D30 as shown and jumper D29.

2. Cut R 119 as shown and add the jumper to D44.

3. Trace the purple & white wire from the clarifier to where it connects to
the circuit board and cut it loose.  Re-solder this wire to the circuit
board ground.  This should give you about 3 KHz down and 1 KHz up of slide.

Broadbanding the Cobra 2000 Chassis:

The Cobra 2000GTL comes from the factory with a MB8734 PLL chip installed.
Frequency modification will work on the Cobra 2000GTL after changing this
chip to a MB8719 PLL chip. Procedure is to carefully unsolder and remove
the MB8734 chip, taking special note to how it was installed. The MB8719
is a direct replacement for the MB8734 chip. We strongly recommend that
you use a 18 pin IC socket to install the new MB8719 chip. Once that you
are sure that you that you have the new MB8719 chip installed correctly,
and that the radio works properly, then you may proceed with expanding
the frequencies.

Clarifier broadband for the MB8719; Grant and Madison:

1. Locate and cut one end of D52, and R148, thus effectively removing them
from the circuit. Locate R174 and solder a jumper across this resistor.

2. Now trace the red wire from the clarifier control to where it connects
to the circuit board and cut loose. Resolder the red wire to circuit
board ground. Next trace the orange wire from the clarifier control to
where it connects to the circuit board and cut loose also.
Resolder this wire to pin 3 of IC4 (MB3756 IC Regulator).

3. Now if everything has been done properly you should have about 4KHz
of down slide and 1KHz of up slide.

Clarifier broadband for the MB8719; Cobra 148GTL

1. Locate and cut one end of R44, and D52. Locate R174 and solder a
jumper across this resistor.

2. Now trace the red wire -
(some earlier units had a white wire instead of red)-
from the clarifier control to where it connects to the circuit board
and cut it loose. Now solder the red wire to the circuit board ground.
Next trace the orange wire from the clarifier control to where it connects
to the circuit board and cut it loose also. Resolder the orange wire to
pin 3 of the MB3756 IC Regulator.

3. Now if everything was done properly you should have about 5KHz of
down slide and 1KHz of up slide.

Clarifier broadband for the MB8719; Cobra 2000GTL

1. Locate and cut one end of R44, and D52.
Locate R174 and solder a jumper across it.

2. Now trace the yellow wire from the clarifier to where it connects
to the circuit board and cut it loose. Solder the yellow wire to the
circuit board ground. Next trace the red wire from the clarifier to
where it connects to the circuit board and cut it loose also.
Resolder the red wire to pin 3 of the MB3756 IC Regulator.
Next cut the brown wire loose from the clarifier and tape back.

3. Now if everything was done properly you should have about 5KHz of
down slide and 1 KHz of up slide. The fine tune will also slide.

Clarifier broadband for the MB8719; Single Conversion Chassis;
*Washington, McKinley, P400, Cobra 140GTL, 142GTL*

1. Locate and cut one end of R187, and D36. Locate the red & orange
wires coming from the clarifier control.

2. Next trace the red wire from the clarifier control to where it
connects on the circuit board and cut it loose. Resolder the red
wire to pin 3 of the MB3756 IC Regulator. You may need to add another
piece of wire in order to reach pin

3. Now trace the orange wire from the clarifier control to where it
connects to the circuit board and cut it loose also. Resolder the orange
wire to the circuit board ground. On some units the orange and red wires
may need to be reversed in order for the slide to work correctly.
Now the unit should slide about 4 KHz down and 1 KHz up.

Clarifier broadband for the MB8719 export chassis; Grant Export et al.

1. Locate on the circuit board R120. This is an used resistor space
located near the front of the circuit board next to the radio's crystals.
Install a 470 Ohm (1/4 Watt) resistor in its place.

2. Now trace the Blue wire that comes from the clarifier control to
it's circuit board connection. Unsolder the Blue wire from the board and
resolder it in the empty hole just to right of R120. Now trace the Gray
wire that comes from the clarifier control and again unsolder it and
resolder it to the center leg of TR39. This will supply the constant
8.5 volts to the clarifier circuit.

3. Locate D79 and solder a jumper across it. Find and cut one end of D45,
effectively removing it from the circuit. Now if everything works like it
should you will have about 2 to 3 KHz of slide.

Clarifier broadband for the MB8734 / dual-conversion chassis; Tram D300, TRC-490 et. al.

Uniden Dual Conversion chassis clarifier mod 

1. Locate and cut one end of R187, and D36. Locate the Red & Brown wires coming from the clarifier control.

2. Next trace the Red wire from the clarifier control to where it connects on the circuit board and cut it loose. Resolder the red wire to pin 3 of the MB3756 IC Regulator. You may need to add another piece of wire in order to reach pin 3. Now trace the Brown wire from the clarifier control to where it connects to the circuit board and cut it loose also. Next resolder the Brown wire to the circuit board ground. At this point the unit should slide about 4 KHz down and 1 KHz up.

3. Additional slide may be obtained by adding a 5.6 ÁH choke in series with D37 as shown in the above diagram. The choke must be added between the varactor and ground in order to function properly. Once this choke has been added you will find that center slot is now at or near to the 3 o'clock position. You may also find that the stock clarifier is now somewhat unstable and covers the tuning range rather quickly. This could make the unit somewhat difficult to clarify. If this is the case, replace the stock clarifier with a new 20K ten-turn pot in order to remedy this problem.

Clarifier Broadband for the MB8719 or uPD2824 Chassis:
Cobra 146GTL, President AR-144, etc.

8719 and upd2824 clarifier unlock

Note- The above clarifier modification is also basically the same for the Uniden AX-144 radio. The main difference is that R405 is R415 in the AX-144 and the clarifier control layout is different. Just remember that the center wiper of the clarifier control always goes to the clarifier circuit. One of the other two legs will either be at or near to ground potential - (usually below 2 volts) . This leg will need to shorted to ground as shown. The other leg will be at source voltage potential - (usually ~8.5 volts receive source). This leg with the source voltage will need to be isolated completely, then connected to a constant 8 volt source,in order to have slide capabilities on both transmit and receive. Solder this wire to the junction of R106 and R107 located just in front of L18 adjustment can.

Clarifier Broadband for the Royce 1-632

Cut R48.  Cut white wire from clarifier.  Replace white wire with jumper from 9V source. Clarifier is now unlocked.