Motorola GM300 Mic Modification to Kenwood TM-261A Transceiver
I have a Kenwood TM-261A transceiver and needed a hand mike. I found a Motorola GM300 microphone, but when it was plugged in, it did not work. So I re-wired it. Here's how...
Remove the three captive screws on the back of the microphone and pull the two halves apart.
De-solder the small black wire from the ground plate on the back side of the microphone
Remove the CCA from the housing, and remove the rubber boot over the microphone. (no screws holding it in)
From the CCA, de-solder the blue, black, red and green wires.
On the CCA, the holes are labeled BL, BLK, RED, GRN
Solder the blue wire to the BLK pad
Solder the black wire to the RED pad
Solder the red wire to the GRN pad
Solder the green wire directly to the electret microphone positive
Re-solder the wire to the ground plate and test the unit.
Re-assemble the mic assembly and you are done.