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Sunfire Jr turn on thump and 60hz hum

Does anyone have any schematic on this Sunfire Sub Jr? I have a turn on thump issue and a 60hz hum that I can seem to get rid of. I tried replacing all the electrolytic capacitors and that did not work. Any ideas?



Sunfire Jr turn on thump and 60hz hum

check the main filter capacitor/s & bridge rectifiers primary power supply & if it was intermittent before it failed check for dry joints all over the board/s in the area they get a fair shake up when running & can cause cracks etc.

Sunfire Jr turn on thump and 60hz hum

Thump is usually DC getting to the speakers. Your bias may be wrong, which can be an adjustment, failing components or leaky semiconductors.
I strongly suggest using load resistors instead of speakers to test the amp while troubleshooting the problem.