Blown-Fuse

 

It sure can. I had this happen to our Fender 400 PA system (used 4 Svetlana 6L6GC's) and Vox AC30 (used Ei EL84's). 

In both cases, there was a bad power tube. We've talked to our amp techs, and coupled with our own experiences, 80%-90% of the time a fuse is blown, its a tube.

Tube roll to find the bad seed. It's good to have extra tubes and fuses lying around.

 

-Matt