Cobra 146 GTL Very low RX audio

[StaplerUk]

TX perfect with excellent output and audio

RX i can see the signals coming in ok.

But the RX audio is very very low, I have to have the volume control all the way up and even then i can hardly make anything out, Squelch still works as i can hear what sound i have shut off when squelch is adjusted, I dont think its the audio amp at fault.

Any pointers will be appreciated.

Edit: If i press my finger down on the ribbon cable that goes to the vol control & ANL switch [4 wire ribbon] i get full volume AM, But nothing on SSB...Signal is there on SSB but no sound [just a slight hiss].

Thanks

[zodiac]

Nick,
Have you replaced C132 next to the audio IC yet.

[lbcomms]

Change ALL of the light grey 10 volt electrolytics (and make sure you get them all!)

This will, in 97% of cases, cure this chassis of common faults:
- no tx audio (but PA audio is OK, clearing the mic)
- stuck on PTT / in transmit mode
- tries to tx and rx at the same time
- very low audio on rx (can only hear people talking if you put your ear right up to radio speaker)
- after letting go of mic, the rx takes a few seconds to activate
- no tx or rx (due to PLL supply rail shorted to ground)
- no squelch control operational
- feedback howl type sound at high volume levels
- outboard engine type noise at high volume levels

Don't be tempted to just change the faulty one(s), any that are good won't be good for long.
There are about 20 or so to change, all easily obtainable. Replace them ALL with the same value but use 16V or higher, not 10V types, if you want the repair to last.
Use low ESR, RBLL, 105 degree types where you can get them, if not the normal ones will do.

Sue

[StaplerUk]

Solved:

R36 [47k] & TR10 [C945] blown...