Left channel of Sony amplifier not working intermittently

[sharpless.beck]

I recently got an old Sony AX401 amplifier--was probably purchased 25-30 years ago.

Occasionally, the left channel on the amplifier goes out. The problem isn't my speakers. I've switched L/R, and it's always the left channel that goes out. Same problem comes up when I'm listening on headphones.

The left channel often drops out when I'm listening on low volume. If I kind of lightly whack the amplifier on the side, it may come back in. Turning up the volume also sometimes causes the left channel to kick back in.

I took the receiver to my local record shop, and a guy opened it up and cleaned it out. He said he tested it on four different sets of speakers and that it ran OK the whole time. I brought the receiver back home, and I'm still having the same problem.

The guy at the record shop says he doesn't know what else to suggest if he can't get the problem to show up.

Any suggestions? It's a good-sounding amplifier, and I'd hate to have to get rid of it.

 

[kanewolf]

A bad solder joint or a burn/dirt in the volume control could cause the symptoms. If you took it to a shop they would have cleaned/lubricated the volume control. Bad solder joint is my guess (since I haven't seen it). It might require extensive disassembly to find the problem. Several of that model have sold on E-Bay for $50. You might be better off replacing it.

 

[jsmithepa]

If by turning the vol knob restores it, clean or replace vol knob.

If you hear a relay click when powering on, this relay may needs replacing.

 

[americanaudiophile]

One thing you can try is to operate each switch and control 20-30 times with the amp off. Sometimes this will help. Sometimes a control has to be replaced.