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// I finally took the covers off a pushbuton Volvo radio. The problem with no FM in most alll Volvo radios is probably an ignition noise suppressor diode package in the antenna circuit. (Failed shorted) A fifty cent part.
From the schematic symbol silk screened on the circuit board it is a switching diode pair.
Removal brings the FM back as long as the engine is off. The spark plug pulses suppress the gain control circuits and the radio won't work well on the road without this diode package.
The part id is AG 20 and the name is TAIYO. I think any small voltage switching diodes can be wired to replace this part. I have down loaded Mouser and ordered Digikey but not located a close replacement. (I can't find the jelly jar with all my junk box small diodes.)
Any one is welcomed to jump in and help. Do you have a supplier for this particular part? A radio repair parts site emailed me that Clarion, California is the US supplier for Volvo radio and Robert Bosch, Chicago is the US company for Blaupunkt.
STILL LOOKING for free schematics, I have the Howard Sams Index.
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