04-08-2020, 08:12 AM
As I suspected, the C21 was only dubious, not the fault. It's still there.
Next I'll replace the two BC148, because they were a stupid idea and inferior to TO92. Likely they are fine, but badly fitted so one might later suffer an internal fracture. They need a precision PCB.
I'll put meters on three or four likely places and scope and/or amp on the IF output to confirm supply points and that the fault is in the audio amplifier and not the IF module. The zero volume quiescent current seems to be 13.5 mA or 16.8mA when it's working. Perhaps I'd had it on AM vs FM or something.
Maybe tomorrow. I've other more important things to do.
Next I'll replace the two BC148, because they were a stupid idea and inferior to TO92. Likely they are fine, but badly fitted so one might later suffer an internal fracture. They need a precision PCB.
I'll put meters on three or four likely places and scope and/or amp on the IF output to confirm supply points and that the fault is in the audio amplifier and not the IF module. The zero volume quiescent current seems to be 13.5 mA or 16.8mA when it's working. Perhaps I'd had it on AM vs FM or something.
Maybe tomorrow. I've other more important things to do.
