This model has a high failure rate with the power supply board. Typically, power resistors fail, which in turn burns out the big capacitors.

I have not heard of transformers failing though, so it shouldn't be too much to repair it.

Here are the schematics for the unit: Upper board and Lower board

I have the same problem. JavaMan is right. In one case someone even reported the bridge rectifier had failed. I have mine apart right now, trying to decide whether to attempt to fix it. The power board has been warped a little from the heat, and I can no longer read the color bands correctly on the power resistors to try to change them. Thanks for the schematics, JavaMan; unfortunately they don't match my boards, so I'm out of luck, and can't find anything else.

The components aren't expensive, so you might be able to take it someplace and have it repaired (or have a friend do it) fairly cheaply if the schematics here match your sub. I think I'm gonna chuck mine, which I hate to do since the speaker and cabinet are still good. I've just wasted too much time on it, and already have another in its place.

I know this is an OLD post, so I'm hoping it flags people into their email.

Is this amp 120w at 4 ohms? I got one, but the speaker blew and I tried an 8 ohm speaker and had lousy output.