The Radio Information Board

Not as clever as I thought I was...

Got the lights working in the back panel on the TK-760 but in the process lost my audio on transmit. I key up the mic, receiving radio receives a signal, I scream into the microphone but nothing comes out on the receiving radio...

By swapping various parts around on other TK-760 radios I have here I have determined the problem to be in the head.

First question. What is this mystery mini board? With the micro components it isn't something someone would cook up on their work bench.



red wire comes of IC 407 (voltage regulator)
Black wire goes to ground
Yelow wire to D 404 DC switch part of active filter amplifier
blue wire to C 488
Trace is cut on board between D404 and C488

Wondering if ripping this thing out would restore my audio on transmit?

Have you tried jumping the blue and yellow wires back together?

No, I haven't tried jumping the yellow and blue wires back together.

I stopped my trouble shooting when I noticed a broken variable 10K resistor that just so happens to be one of the few components the audio signal hits after entering the head... I have a co worker sourcing a replacement and should be able to test tomorrow.

So it would appear I am particularly ham fisted when it comes to handling small circuit boards...



edit:

Yup, the 10k pot gave me back my audio. Now to figure out what the baby board is all about....