Cobra 2000 GTL with No Receive... Fix Suggestions?

as these radios are getting quite old by now, you can pretty much guarantee that the caps are going to dry out (especially if the radio has been sitting for a long time and then is put back into service) and when they dry out, weird things start happening.

over the past three years or so, as i have given out advice on this chassis, there has been much frustration because people will try to troubleshoot the radio and never get anywhere until they find the old caps that were the culprits.
many times more than one is bad or going bad.

so now my first piece of advice is always the same.
re-cap the radio with all new electrolytic capacitors, and see if the problem goes away. there is a good chance that it will.

if it does not, at least you can troubleshoot it like a normal radio without a million variables.

re-capping the radio will cost you less than 30 bucks (there are kits on ebay for this) and take you an afternoon to do. (or more depending on your soldering skills)
your radio will love you for this, and will perform better overall.

you will need to do an alignment afterwards.


now, all that being said, it is possible that your RF amp transistor (TR14) has blown.
this would cause the lack of signals being received, but you should still hear some hiss out of the speaker.
you may have another problem, like a bad mic, or bad speaker jack on the radio. (remember that the 2000 does not have an internal speaker)

D1 and D2 are part of the noise blanker circuit, and are probably not your culprits.

let me know what you are comfortable doing and what you are not comfortable doing and we will go from there.
LC

loosecannon wassup????:w00t:

577

Of course, there is the obvious fix for this radio.

The Cobra 2000 requires a mic to be wired for this radio for the receive circuit to work. The transmit and receive have separate ground wires in the mic. It may have a broken wire in the mic plug that grounds the receive circuit which will keep it from working. I'd check that first - BTW . . .

Mic Wiring

Stock
1- Audio
2- Shield
3- Receive
4- Sw Com
5- Transmit

thanks for the props Jeff.
as time goes on ive realized i can save myself a lot of frustration and maybe some carpel tunnel syndrome by talking about the re-cap first. LOL

im starting to see a change in the way "shops" are going to operate.
i believe there is going to be more call for "refurbishment" than for "repair".

many of these radios that we love so much just arent worth doing a repair on unless they are also refurbished with new parts and cosmetic upgrades.

just last night i was working on a D104 for a friend (he said he just needed a mic plug put on) and i found that the cord was pulled out of the base of the mic because the rubber/ plastic coating of the cord was crumbling away.
this one was savable, but i dont think ill be doing too much more D104 work without just replacing the cords in them.

time moves on with or without us.

oh, and wassup 577. i seem to catch you everywhere except where i met you! LOL
LC