Recent content by Realred

Tried shorting across C450 and no joy.

I will try that after dinner. Thanks

I appreciate the analysis Brandon. I don't have a jumper in the vicinity. I just broke vr6 pulling it out to test. I'll find something to replace it with and start poking around. TR19 and TR24 test good. This radio has the lcd screen not just a light. I'm wondering if I have a bad chip on the...

Thanks, I have tried adjusting VR6 as per Cobra's instructions but it has no effect.

Hi all, I have a Cobra 29Lx displaying "antenna warning" even into a 50 ohm dummy load. The radio receives fine but has no Tx. Driver and final test fine. Does this antenna warning disable output? If so, How do I troubleshoot this?

Thanks for the replies. Seeing the B&K 1040 procedure does illustrate the uncritical nature of that procedure I guess. It just bugs me that they would specify an actual number but then leave me hangin'.

Most alignment instructions call for a 1khz tone at 30mv injected into mic input. I've always assumed it was RMS but I saw a video the other day where the guy's sig gen was clearly visible and set for 30mv p-p. Just wondering.

Wow! You've given me a whole lot to absorb here. I'm a hobbyist who works on audio stuff, amps, tape decks, turntables that sort of stuff so I have basic test equipment and some knowledge of audio circuits but this RF stuff is like witchcraft or something. The big current draw and subsequent...

That 324ma current draw was at idle unkeyed. When I key the mic (no audio) it draws 7.4 amps and climbs slowly. Should I be trying to adjust this down?

Thanks Andy. I put an ammeter inline with the power fuse and show 324 ma current draw. This being a dual final radio, do I just adjust the driver trimpot and then each final trimpot until the current won't go any lower and then adjust up from there?

Thanks for the reply sp5it. It will burn your finger. Can you educate me on those mods?

I have this radio which a friend gave me to fix. When I took the covers off a little green capacitor fell out. I have no way to know where it goes as there are many intentionally empty capacitor spots on the board. There is also one tacked on the solder side. The radio had a shorted final...