Hi Jim,
?
L501 or C504 failure can cause these symptoms. ?Make sure to have about 2 ohms continuity on l501 at the pcb pads. ?It’s a little difficult to test C504 in circuit. ?These big tantalum’s fail though. ?You can remove it and test it on the bench.
It’s hard to diagnose the exact problems in the bias circuitry. ?There is interaction everywhere. ?But if you look around with a scope, you can often get a clue to what’s failing. ?Most often it’s one of the transistors, the coil being broken or the big cap failing.
?
if you can’t find the culprit in that bias circuit, certainly send it along to me. ?
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73
Jeff Moore
W1NC
