Archive for the 'Radio Shack' Category

Clarifier modification: TRC-453 and Uniden PC-122

Posted in CB Radio Mods, Radio Shack, Uniden on April 21st, 2005

1)Find the backside of the clarifier knob.
2)Solder the bottom pin to GROUND. 3)Solder a wire to the top pin of the PCB.
This pin should be cut loose from any traces going to it!)
4)Solder that wire to an 8VDC source.This can be found on the second jumper behind the PLL chip(IC-2).
5)Cut D-25.

TRC-485 Clarifier Mod

Posted in CB Radio Mods, Radio Shack on April 21st, 2005

Open clarifier

1)Remove the radio’s covers. Top & Bottom and face plate.
2)Behind the face plate find the clarifier control pot.
3)With a DC volt meter locate the pin, on the clarifier knob, with 5 VDC on it and cut the trace going to it.
4)Cut D-21 on the main PCB.
5)Jump R-181
6)Solder a 4.7 K resistor from SJ-32 to the closet leg of the clarifier.

Realistic TRC-453

Posted in CB Radio Mods, Radio Shack on April 14th, 2005

Peaks and Tweaks

VR 10 is AM power
VR 6 is ALC
VR 5 is AM Modulation
VR 7 is RF Power meter
VR 1 is S-meter adjust

TX coils- L34, L35, L36 and L26
RX coils- L3 - L8, L10 and L11

Radio Shack HTX-100

Posted in CB Radio Mods, Citizen Band Radio, Radio Shack on March 26th, 2005

Frequency expansion

Remove bottom and top covers.

Remove the PLL board and tray that is held in by 2 screws on each side of the radio.

After you remove the board you will see a 4 sided surface mount chip IC 1208 that has 64 pins.

Look to the right of the chip and locate the 4th and 5th pins from the top right of the chip, pins 28 and 29.

Notice they are soldered together and run to a trace to a surface mount resistor.

Carefully cut the trace next to the 2 pins. Now locate 2 rows of pins to the top of the chip.

The bottom row last pin on the right has 5 volts DC on it.

Solder a 10K resistor to that pin and to the pins 28 and 29.

Now reassemble the radio and your done.

The radio will now tune 26 MHZ thru 30 MHZ.

CHANGE DISPLAY COLOR

Remove top cover of the radio.

Locate the 2 white wires running into the display light housing.

Remove the light and remove the green cover on the light.

Put the light back into the housing, you can wedge the wires in between the 3 electrolytic capacitors to hold the light in place.

Reassemble the radio and now your radio will have a light brown display like the big rigs.

Microphone wiring

Pin 1 - Microphone input
Pin 2* - Push to talk
Pin 3* - Scan down
Pin 4* - Scan up
Pin 5 - 8 Volts
Pin 6 - Audio out
Pin 7 - Microphone Ground
Pin 8 - Ground

Realistic TRC 485

Posted in CB Radio Mods, Citizen Band Radio, Radio Shack on March 26th, 2005

Audio Limiter

Cut RV5 or cut R111 4.7K resistor

There is no Control for SSB ALC

AM Power Level RV 10

Open The Clarifier

Remove the 5 volt RX voltage from clarifier control. (REMOVE THE FACEæ PLATE TO CUT THE TRACE).

Solder 4.7k resistor from SJ32 to the closest leg of clarifier control.

Snip D 21 by crystal on main board.

Jump surface mount resistor 181 by clarifier control.



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