Blowen Channel

did you buy it from a flea market, or just some guy or something?

if you really want to, you can pull it apart, and check the transistors, RF is usually pretty good about using parts that you can find at a electronics store, like mouser or national semi conductors. problem is, in a decent sized amp, there are probably about 40 of these things (the black 3 pin chips hanging off the side) and you really need a special tester to test them corectly,, AND, they can test as bad when they are still soldered in, a lot of times you have to take them out and test them one by one.... it's not that bad if you have the right tools, but you can pull it apart, take the circuit bord off the chassi, and check for ovious failures, see if any chips are black, or look like they've burnt, and check the large power pathways on the underside of the circuit bord to see if any of them burnt up or got disconected from being too hot..

(if it's under warentee, don't do any of this, just take it back in, especially if you don't really know what you're doing)