Got a weird board error from a vintage Pioneer receiver from 1978

Last month I picked up a Pioneer SX-780 from a garage sale in Austin. It powered on but the left channel was completely dead. After poking around with my multimeter I found a cracked solder joint on the main amp board near a big resistor. Fixed it with a quick reflow and now it sounds perfect. Has anyone else run into cracked joints on these old silver face receivers?

2 comments

2 Comments

baker.simon13d ago

Honestly I used to think cracked solder joints were overblown by audiophiles who just wanted to sound smart. But then I fixed my 1977 Kenwood KR-4070 with the exact same problem - dead channel, found a hairline crack near a transistor. Now I check every old receiver I buy for cold joints first thing. It's wild how much heat cycles over decades can make the solder just give up. The SX-780 is a great find by the way, those things are tanks once you sort out the power supply caps too.

aaron_gonzalez13d ago

You ever get that moment where you feel like a total idiot for not noticing something sooner? Same thing happened to me with a Pioneer SA-7500 I picked up. Had this intermittent crackling in the right channel, spent weeks chasing caps and transistors. Finally got a magnifying lamp and found a cracked solder joint on the relay. One quick reflow and it was perfect. Now I just hit every joint on old gear with a bright light before I even plug it in. Saves so much headache.