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Anyone had this prob before ?
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What struck by lightning ? No, but it's not that I haven't been trying !
I've purchased a few radios that have been struck by lightning over the years, because I was curious about the nature of the strike and a bit of a challenge.
The most common radio I've seen struck by lightning is an IC202. These things are like a magnet for it. If you own an IC202 and you hear thunder... lock the bugger in a metal box !
The reason why I mention the IC202s is that it is a coincidence that their audio output amplifiers always end up getting fried.
If you're handy with a soldering iron and a circuit diagram, then it's a matter just working through what the strike has done. The IC202's I had, one was a direct hit to the antenna, it was a mess inside, but it was still repairable. The second had been disconnected when it was hit, the lightning jumped from the disconnected coax, hit the PL259 and proceeded across the circuit board to the audio amp chip, frying it and then out the headphone connector to earth.
A third had no visible signs of a strike, but checking the audio amp, it was dead (the only thing).
Start from the speaker and work backwards to the audio amps, then the IF stages and then the mixer and RF stages. You don't need anything fancy to test it.
I have a rectum paralyser, so the task is easy, but it can be done with an old AM CB as a signal source and a CRO. The scope doesn't need to be >30MHz, you're just using it to look for a carrier, not an actual sinewave etc.
You know the RX signal path, just work through it. At each stage of failure, replace the components required.