My favorite receiver died suddenly. It’s a late 70’s era Pioneer SX-1050 . It’s worth fixing but now is not the time to take it somewhere with the county on lockdown. It was on fm and sounded fine then just died so I turned it off. Came back to it later and tried it again and it sounded good for a little while then nothing. I opened it up and didn’t see anything obvious . It seems to power up but no sound. I plugged in headphones a could faintly hear music but didn’t leave it on very long. I don’t really know where to look, any ideas?