Older cobra 29 ST with no modulation

[Cityboy]

BC I replaced C42 and C45(just in case) and didn't help with modulation. Can I test the capacitors while they are in the circuit with my analog multimeter on the high resistance setting and what it fall back to infinity, or does each one have to be pulled in the circuit to analyze and see if it is bad. Could I use my Oscilliscope to test the capacitor to see if it is bad while in the circuit. Thx.

 

[Cityboy]

I found the problem and next time I will no better; and I should have this time. It was the dynamike control pot. All that work and finally it was something so simple that I should have looked at right after the mic plug connection; but I didn't and now I have learned something invaluable. Check the most obvious causes of no modulation-1. bad mic, 2. bad mic plug at radio or loose wire, 3. the control pot for the mic gain. So stupid after all this work, but it is fixed and I had no money into it. I got this for free and all the parts I threw at it were all extra parts. Thanks for all the help.

 

[Moleculo]

Wow.

Well, two good things came out of this: 1. You got it fixed 2. You got a lot of good information about places to look at in the radio if it ever happens again and isn't mic related.

 

[Bionic Chicken]

Stuff like the mike gain turned down can make you pull your hair out. That or either the radio being in the PA mode. But it is part of the learning process. When it becomes a real bad thing is when it happens more than once..............DOH!!!
One of the best ones I remember is on the Cobra/Uniden bases that were AC/DC powered. I'd fix them and the customer would pick them up only to get home and find out it wouldn't power up. They'd bring it back so I could move the switch on the back from DC to AC power. That would make them feel like a genius.

BC

 

[Cityboy]

The mic gain pot was bad and I had another one off of a cobra 25 and put it in and presto everything was good. dk = 5w and pep of 21-22w. It has a swing from set pt on my dosy from 40%- to 100% and a good clean and clear signal. I learned several things while messing with this soundcapper and that makes it worth all the mistakes I made. So hopefully something will get through my thick head and the next time something happens like this or even more serious like BC said I will be able to solve it very quickly. Thanks to all that suggested solutions.