Fifty/Fifty circuitry question

[Cayce]

Greetings, Boogie Board;

My Fifty/Fifty developed an intermittent scratchiness a few years ago that my local repair shop couldn't seem to diagnose & fix, probably because it wasn't consistent. It would happen at random, not associated with signal pass or any kind of event. At times, even while at rest, this popping/scratching would flare up, almost like a radio would sound when there was a lot of lightning in the area. It might last for 20 or thirty seconds then fade out. I was told once it might be a filter. It finally happened with less frequency and almost completely went away. Just the other day the amp died. There is now a constant loud hum that didn't respond to tube replacement.

I think I'd like to replace the circuit board, if that's advisable, but can't find a place to get one, Can anyone advise me on this?

Thanks.

Cayce

 

[dgzieg]

Hi Cayce, sorry to hear about your 50/50. My guess would be that the scratchiness was an early indicator of the problem that eventually took out your 50/50. I seem to recall that AC on a potentiometer will cause scratchiness. This would point to a filter capacitor going bad. When the cap goes completely bad, the AC is not prevented from coming through the circuit and the loud hum results. Any competent repair shop should be able to resolve this. I'd ask on this board and others for recommendations for wherever you live. I'm not an amp technician, but I've been inside the 50/50 and I don't think there's even 20 components (counting both channels). Should be an easy fix. Best of luck.