Radio Shack HTX-100
                                              EXPANDED RF
 

HTX-100

1-Remove Power and Antenna.

2-Remove screws and open the case.

3-Locate synthesizer board on the bottom of the radio.

4-If your radio has microprocessor # UC-1208 Unsolder and lift pins 28 & 29 of the microprocessor.
   You may wish to leave the pin soldered and etch the ground trace. Go to instruction #6

5-If your radio's microprocessor is NOT a UC-1208 Unsolder and lift pins 20 & 21 of the microprocessor.
   You may wish to leave the pin soldered and etch the ground trace Go to instruction #6

6-Connect the lifted pins together and jumper these pins to +5 volts through a 10K resistor
   (+5 volts can be found on the 7805 voltage regulator or from the Cap. right next to pins 28 & 29.)

7-Reassemble the radio.
 

 

 

Change display color for HTX-100

 

  • 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 for Radio Shack HTX-100
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

* NOTE - Connect these pins to ground for function to work

 

ATTENTION
The KB2LJJ takes no responsibility for any damage during the modification or for any wrong information made on this modification.