Fender Super 112 half power

A

amzavareei

New member
Hey. This amp runs pretty quiet. One of the 2 power sections isn't running, it seems. I can take it's tube out, and it's the same volume. It's not the tube, it's the socket, and it's corresponding power section. I poked around a good bit, and did a few obvious continuity tests, but can't seem to find any breaks. No caps or anything seem burned or loose. All the tubes glow, and every pin has continuity to the board! Does anyone have any hints on where I should look? Or possibly even a schematic. It's a real pain to get clear access to all the components on the board, the way everything is wired to it. Thanks for any leads.
 
Hmmm... well it's not any connection to the transformer. It's got to be something before the power tube. The tube that isn't outputting anything is still glowing. But it puts off much less heat than the other one. I can just pull it right out while it's on, and I can't hear anything happen. Interesting...
 
amzavareei said:
Hmmm... well it's not any connection to the transformer. It's got to be something before the power tube. The tube that isn't outputting anything is still glowing. But it puts off much less heat than the other one. I can just pull it right out while it's on, and I can't hear anything happen. Interesting...
Click to expand...

Have you tried swapping the power tubes around to see if the problem is in the socket (or underlying circuitry) or in the tube itself?
 
Yeah, it's not the tube. I swapped them. It doesn't follow the tube. It's something before the power tube. They're both getting juice. They glow, they are both getting around 475 volts. The one that is actually outputting though gets MUCH hotter. So at least I don't think it's the output transformer. I'll try comparing the voltages on each pin, and see if one of them has a significantly lower reading, and then go back from there. Don't REALLY know what I'm looking for. I don't see a single loose connection, any burnt components, I tested a couple diodes. But any difference I can read between the two tubes should give me some clue, I hope!
 
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