Burned up RF Choke on Cobra 2000 and now....

[Brian G]

burned up L39 while working on a no tx power issue. when it had that surge something else has happened. The radio will not transmit. When you key the mike, the receive light stays on and very bright. When I flip the CB PA switch to PA, the receive light stays on bright. When you key the mike then, the receive light stays on but dims while keyed.

I took the mike off and tried to key the radio by touching the pins on the mike jack which I have done before. It sparked really bad at the jack and the clock and frequency counter blinked out for a second. That’s definitely not normal.

Finally the frequency counter is stuck in the same channel (26.51 approximately).

Any ideas where to check?

i checked voltage readings at the voltage regulator and they seem to be ok there and other places. So I think I toasted another component. Hope it isn’t the VCO or PLL though quick voltage checks in both are ok.

 

[Brian G]

Update. I replaced the voltage regulator because i didn’t have voltage at pin 5 where I should have had 13 volts into TR35. I could get 13v at the pad if I unsoldered the pin but not with it soldered. As soon as I turned back on , L39’started to burn up again so I think that is what popped the regulator before. What can I do to stop that burning up so I can work on it at least? What could the issue be over there?