Peavey M2600 Mark V no audio

[jessadr]

Had fuse with alum foil on it when I got it, put a 5 amp circuit breaker in place. With no speaker load it will not pop breaker. With speaker load on A channel OK. Pops breaker when Channel B has load. I can have amp on and just push Channel B jack in and as soon as it makes contact it blows a blue spark and pops the breaker. No audio on A or B except when I plug A in it will make a small pop. This amp has no signs of ever being opened up.
I have a factory paper Peavey schematic

[Jazz P Bass]

Peavey M2600

It sounds like Ch B output section is blown.
Put a meter on Ch B output, without a load.
I'll bet you will find a very high dc voltage.

[jessadr]

you are right

44.2 volts. I have the B channel unpluged from the output board. Channel A doesn't have any voltage on output, but is quiet no audio. I am sure this has been asked before, but what is the best way to check to3 type transistors in circuit ? This amp has 4 67376(2n5630) per side plus a 5332 and 5331

[jessadr]

is this normal

I read 44 volts on the top of all the to3 transistors to ground with a dvm

[Jazz P Bass]

Peavey 200H

I read 44 volts on the top of all the to3 transistors to ground with a dvm

Yes, I would expect +42 volts on all the collectors.
The top half of the circuit the collector is at +VDC.
The bottom half the collectors are at output.
It appears that the top half is full on.

I would diode check every transistor on the output board.
Check all of the resistors also.

Checking NPN transistors:

-DVM on Diode Check.

-Red Lead on transistor Base.
-Black Lead on transistor Collector.
- Should read something like .540

-Red Lead on transistor Base.
-Black lead on transistor Collector.
-Should read a lttle less than Base/Collector.

This circuit & schematic is great for troubleshooting!
Peavey was nice enough to indicate static voltages.

If you check the output transistors in circuit be aware of the Base/Emitter resistors. A diode check reading is not possible.

Check the power supply + = Vdc & the + - 15 volt rail.

Take out Q1 & Q2 to check. A shorted Q2 will tie the output rail high.

Thanks for the correct schematic, Enzo

[Enzo]

Well, we ought to give him the right schematic. Oddly enough, his amp doesn;t have a Q1 or Q2. It starts with Q3. Q1 and Q2 were on an earlier version across the input volume control as limiters. They were eliminated for the later version.

[jessadr]

Thanks Enzo

That is the schematic I have. I emailled Peavey about all of the transistors in the amp.
I made a dumb mistake. I had power on it while checking voltages while talking on 2 meters and crossed the leg of a 5332 to the heatsink. Pop goes the circuit breaker. Now it pops everytime I turn it on. I have a cs800 that is in the parts pile I might just use those parts if the factory stuff is worth more than the amp.
Thanks for all the help, I will do a better job of testing from now on. I really enjoy this site and all the info. Just getting back into working on stuff I have gathered up is real fun. Retired with too much time on my hands
Tomorrow I have 2 100watt 6 channel Shure Vocal masters to check out. While waiting on parts for the Marshal