If you bought the amp new, and it is still in warrenty, by all means take advantage of it!! If not, have someone who really know's what they're doing have a look at, instead of going in yourself and trying this and that out....not a good idea.

Those DSL 401's are notorious for getting supper hot and doing damage to themselves, especially the PCB. Once you get it fixed, you might want to look into installing one of those little computer cooling fans on it to keep things cooler.