Diagnosing issue with solid state power amp

[lonearranger]

Fired up my solton sta240 power amp yesterday. Both channels worked fine for a few minutes, then the right channel started to make sound like hi pitched feedback, pretty loud. The amp has not been used for over 10 years. Any ideas of what might be causing it or what components to check would be appreciated.

Cheers

[Sammas]

Fired up my solton sta240 power amp yesterday. Both channels worked fine for a few minutes, then the right channel started to make sound like hi pitched feedback, pretty loud. The amp has not been used for over 10 years. Any ideas of what might be causing it or what components to check would be appreciated.

Cheers

I had an active monitor that did the same thing, strangely enough. In cold weather it might have lasted 8 hours of work before the high pitched whine began. In hot weather, maybe 3 minutes.

...strangely enough, it just stopped doing it one day. I have no idea why. I suspect years of inactivity may have effected the electrolytic capacitors and caused some kind of parasitic oscillation. After a bunch of use the capacitors reformed and the amp was back to its old self.

This probably isn't the most sage advice, but you could try wiring the two speakers out of phase form one another, face them together at close proximity and left them run for a few days... hoping for the best.


...It would probably be a lot more productive to get the oscilloscope out and chase down the source and replace it though.