Wolfram 2400

Good evening

I have this wolfram 2400 here. It had damaged outputs and power supply. After replacing all the drivers for the power supply it would go straight into protect. No outputs, no 12v regulators, no power supply transistors.

After messing around for awhile removing and reinstalling drivers, 494, 393.. I've narrowed it down to everything is fine till I add the Q32/33 drivers. They drive the gates to Q52/53. With them out, no protect, every bank has nice drive. The base pads of Q32/33 have nice drive signals. One collector has ground, other power. The other half of the drivers connected to that circuit that drive Q49/50 (the other part of that transformer) is working fine...

Soon as I add the drivers Q32/33 it protects. Remove them, everything else seems fine. I've looked for solder bridges and stuff. Removed the diodes and stuff from that section. Checked everything and reinstalled. I'm stumped. Soon as I connect those 2 drivers on that one side. Without them, the other 7 sections work fine.

Any idea? Thanks in advance.


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It doesn't use a card in this amp. This is the drive and some of the protection circuit for this amp. It was never worked on previously. I'd like to think the board is still in pretty good shape. There are no signs of damage in that section.


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The drive leaves pins 9 and 10 and jump over to the drivers with a 100ohm resistors in series. Then leave there and have a 47 ohm resistor between emitter and gate pad. Seems pretty simple.. All the others connected to same circuit work fine. Soon as I add that pair, protection. Remove them, no protection, install, protection.
So, if I'm reading that right, it's possible that it's protecting just cause I don't have the ps transistors in, so no rail voltage? I had the rectifiers in for that part of that transformer, but then removed them trying to figure out problem. All the other 7 banks work with it missing... is it safe to say that must be the bank it monitors?

I'll add the transistors and see how it goes. Thanks Perry.
Sorry Q23... is a PNP driver designation for a ps transistor bank.

I put in the ps transistors and the rectifiers I pulled form that bank. No more protection issue. So that must have been it. Thank Perry. That was driving me nuts. I might still try to trace that transistor just to know where it is.

Hopefully all goes well with the output stuff. :) Thanks again, have a good night.