Crate BV 60- sudden loss of power - new tubes didn't help

[Ripzappa]

I was hoping someone might have a clue as to what may be wrong with this amp....It was playing fine, and suddenly lost about 85 to 90 percent power! Now it plays, but only if you crank it all the way up, and even then it is not loud at all, and always distorted even on the clean channel. I changed the power tubes and a couple of the preamp tubes but it didn't fix the problem.... nothing inside looks to be "cooked".... when I plugged my axe into the effects return jack, it played clean, but with very little volume. (I don't know if that is normal or not).... anyways, I would appreciate any feedback on this!
Oh one more thing.... there are two transformers on this thing...the big one gets warm after a while, but the smaller one doesn't.... could this be the problem???

[Mars Amp Repair]

It might possibly just be the loop jack switches. Have you put a straight 1/4" cable from the send to the return?

You also can connect the send jack to another amp to see how that sounds to help isolate the problem...glen

[Ripzappa]

Thanx 4 responding, Glen...I DID try....

looping thru and it seemed to diminish the output even further.... BUT...when I went line out to another amp, the output seemed fine...??? I'm still puzzledSO...I guess the PREAMP stages are OK....would you agree???

[rockon1]

OK you put a guitar cable from the send to the return of the FX loop and it didnt help -right? The pre amp section seems ok since the line out works...You say you replaced "a couple " of pre amp tubes. Which ones? Maybe the PI is bad. I would swap out a known good 12AX7 into each spot one at a time to eliminate any of them being the cause. Bob

[Ripzappa]

Thanks for the reply... I have swapped....

...my preamp tubes all around to see if that would make a difference... it didn't.... I've been to the flea market forum and there are a couple of inexpensive output transformers on there. just starting to think I should get one and try that.... my owners manual says I have a DC filament somethin somethin on my first input tube.... what does that mean???? I read somewhere that this can cause the output trans to run hot....
If you please, I am a bit of a dum dum with all of this stuff, ... can someone please tell me- there are two transformers attached to the bottom of the chassis- a larger one and a smaller one... is the smaller one the output tranny?? Thats my GUESS, I would like someone to confirm or deny this for me... thank you all for posting comments!