Fender Excelsior - no output

[azrael]

A friend recently came to me with a non working Excelsior, and I promised him I'd take a look.
No component looks burnt out, all the tubes light up (and the fuses all look fine), and I've resoldered just about all the joints to eliminate the possibility of a cold solder joint. I've also retensioned and reseated the preamp tube sockets, but there is still no output. Not even hum. I tried plugging it into another cab I had, and still nothing. Switches and pots all still hold up under a multimeter.

I'm stumped.

Any ideas? Is it possible the output transformer was blown? Any common problems with these amps?

[Randall]

Sure it's possible the output transformer is dead. The way to find out is to put a scope on the plates of the tubes, that's the input side of the transformer. If you see signal there but not on the output side where the speaker connects, then you have a dead output tranny. You might also want to prove whether the speaker works or not.

[Enzo]

My car won;t start, do you think the engine block is cracked?

Transformers are THE most reliable part in an amp. They fail, but rarely.

You did a bunch of maintenance stuff, but did you get out the volt meter to see if high voltage was present in the circuit?

[azrael]

My car won;t start, do you think the engine block is cracked?

Transformers are THE most reliable part in an amp. They fail, but rarely.

You did a bunch of maintenance stuff, but did you get out the volt meter to see if high voltage was present in the circuit?

unfortunately my multimeter is on the fritz so I ordered a new one, waiting for it to come in. I will as soon as it comes in.

To clarify, I can sometimes get it work in resistance mode. Voltage was spotty. Everything else, it keeps freaking out.

[azrael]

My car won;t start, do you think the engine block is cracked?

Transformers are THE most reliable part in an amp. They fail, but rarely.

You did a bunch of maintenance stuff, but did you get out the volt meter to see if high voltage was present in the circuit?

Wanted to touch base, I got my new multimeter in, and indeed, high voltage wasn't getting past the first B+ resistor. Even though it looked fine, I measured it and it was an open circuit (I hadn't measured that one, earlier, I guess). I replaced it with a slightly higher wattage resistor and everything seems fine! Looks like it was some faulty resistor.

[drewl]

Looks can be deceiving!

Always measure things.
One regular customer was bummed out, thinking his 65 Vibrochamp had a major power supply problem because the fuse "looked" fine.

I could tell it was open and I measured it in front him to show that looks can be deceiving!