Peavey Bandit Problem - Hum, no output

[TeleTim911]

New member here, hello everyone!

I have an older model Peavey Bandit 50-watt. The power cord was stored in back, and pulled out cord and plugged in, turned it on - nothing. Messed around with controls for a few minutes, nothing. Shut it off. Found one of the speaker wires had come off (guessing the power cord did it when pulling it out). Put speaker wire on, turned back on, it came on with a hum...and does nothing else.

Any ideas? Not even sure where to start but I'm thinking output transistors - since it was powered up without a load?

Thanks guys.

PS: I am not a professional repair person, just a tinkerer.

[52 Bill]

Welcome!
Powering up a transistor amp with no load will not cause a problem.

When you turn on the amp does the speaker cone push or pull out and stay there? If it does, then there is a dc voltage on the output. Turn off the amp and unplug the speaker until you have found the problem.

If it doesn't, then your hum is ac voltage, caused by a circuit problem or maybe a bad or unsoldered filter cap.

If you thump the top of the amp with your fist, can you cause the hum to stop and or start?

[TeleTim911]

Thanks 52 Bill for reply. When I turn amp on, the cone does jump out and stay out, and hitting amp will not make it stop.
I guess I'll start testing components huh? LOL!

Thanks.

[TeleTim911]

update: found a thread on a Peavey Pacer with exact same problem/symptoms. Pacer needed new Outputs. I pulled my two SJ6392's out, tested with diode test on DMM, one showed no conductance in any direction, other one had conductance on all tests...they are both fried.

GOOD NEWS: They are only about $3 each plus s/h...LOL!

[52 Bill]

Be sure to check the driver transistors and the emitter resistors as well.

[TeleTim911]

52 Bill, once again, thanks! I'll try to do that in next couple of days.