APEX JR. subwoofer amp blowing fuses, bad caps found

[kellys_eye]

I watched the component side of the board when I did and it did immediately blow the fuse and the transformed sparked on the coils on the opposite side from the output wiring. Next, I disconnected the transformer wiring connection from the board and powered it up again with a new fuse and the fuse did not blow.

Looks like the transformer had a short (in the primary) - initially - that caused the fuse to blow but the reapplication of power through another fuse has 'blown' the short apart which has left it open circuit. Fuse no longer blows but transformer has zero output. It's quite a rare occurrence. Shame.

Does the equipment have a 110/220V selector switch?

The transformer looks to be a very basic one - centre-tapped secondary possibly rated anywhere between 18-0-18V and 30-0-30V at 3 to 5A. Such transformers are still available and finding one to fit is quite possible. My 'junk box' has a few. The physical dimensions are important and can reveal the VA rating (near enough). The actual DC voltages that the amplifier section runs at would be the key to finding the right secondary voltage.

Either way, if you can source 'any' transformer with a centre-tapped output you can temporarily wire it in to see if the remainder of the circuitry is still operational.

 

[timsch]

Looks like the transformer had a short (in the primary) - initially - that caused the fuse to blow but the reapplication of power through another fuse has 'blown' the short apart which has left it open circuit. Fuse no longer blows but transformer has zero output. It's quite a rare occurrence. Shame.

Does the equipment have a 110/220V selector switch?

The transformer looks to be a very basic one - centre-tapped secondary possibly rated anywhere between 18-0-18V and 30-0-30V at 3 to 5A. Such transformers are still available and finding one to fit is quite possible. My 'junk box' has a few. The physical dimensions are important and can reveal the VA rating (near enough). The actual DC voltages that the amplifier section runs at would be the key to finding the right secondary voltage.

Either way, if you can source 'any' transformer with a centre-tapped output you can temporarily wire it in to see if the remainder of the circuitry is still operational.

I had a Gainclone amp I built many year ago that died due to a flood. I should have kept the transformers from that, but can't recall where they might be now. Gotta start digging. Thanks for the suggestion.