B-52 AT100 head trouble

[backporchcustoms]

when i turn on my b52, all the leds and all the tubes light up, but i get no sound. however, when i switch from solid state to tube a or tube ab, i hear a pop through the cab. i have already disabled the reverb, but thats not it either. any ideas?

[booj]

internal fuse blown?

[backporchcustoms]

whats the easiest way to check that? i honestly dont know much past how to change the tubes out.

[cablercdd1]

Looking at a schematic for the 212 model, I see a 1 amp fuse (f4) in the B+ supply to the output tubes. It's been a while since I've seen one of those but I believe the fuse is on the circuit board. Just be careful because of the high voltages in that circuit. You should also isolate the area where the problem is in by sending the send output to another amp. If that works then you know your problem is after the preamp section. likewise sending a low power signal into the return jack, like the send from another amp or sound board will tell you if the power amp section is working or not. Btw, if the fuse is blown it could mean other problems is the output section. Hope this helps

[Amp Kat]

Not trying to be negative here but these amps are a continuous problem and it's been covered in depth. They sound great when working right but the problem is they very rarely stay working right. There was a tech that came on here and said most of the problems were from the connectors on the main board loosing connectivity at power points which explains why they do so much damage when they fail. He redid all of the connectors and had no further problems. I also agree that a fuse has blown and needs replacing and do go over it and make sure the connectors are all tight.

[toddplesko]

Did you figure it out becuase I am having identical issue!

when i turn on my b52, all the leds and all the tubes light up, but i get no sound. however, when i switch from solid state to tube a or tube ab, i hear a pop through the cab. i have already disabled the reverb, but thats not it either. any ideas?

Hi there, this is the EXACT same problem I am having - just curious and I know this is a very old thread, were you able to solve the issue? A reply to toddplesko@yahoo.com would be awesome, thanks so much.

[Enzo]

We may never know. Problem is, the symptom described means essentially that there is current through the power tubes, and switching the B+ voltage affects it. Basic troubleshooting gets this. Start by looking for power supply on all tubes. Is ther B+ on the screens and plates of the power tubes? Is there plate voltage on every triode through the preamp? And are all teh cathodes showing signs of current flow?