Peavey XR600B repairs

[XR600B repair]

Hello!

I bought a 2nd hand Peavey XR600B amplifier (this type: https://www.youtube.com/watch?v=-BDLPDQi1qA). But it has issues. The fuse blows when i turn it on. So some part of the machine must be broken.

I emailed Peavey and they gave me the schemetics. I dont know what is up with the machine. Some parts looked blown, while it had black stuff around them. But when they were disconnected from the pcb board they measured good values. So its kind of strange.

I hope you people have experience with this kind of amplifier.

There was a fuse of 1.25A 250V that wasnt blown yet in the machine when i turned it on. When i turned it off it would not turn on again. Then i put in a 4A 250V fuse in the machine like is written on the back of the machine. Same issue. It goes on once, then it either died on me while it was on or when i put it off and tried to turn it on. So i dont know what is up with it.

I want to have this machine running while i have some awesome JAMO D 165 set of 2 speakers. Making 4 ohm (2, 8ohm speakers in parrallel). The amplifier can feed 2 to 4 ohm boxes. And the speakers do work while i tried them out on the headphone connection of a working device, and they worked. I also have 2 electrical guitars i want to rock with. Those do work. I also have bought some electrical contact spray, to fix the potentiometers cracking sound (if there was any), like in this video: https://www.youtube.com/watch?v=dUoDKf2ljrE.

If this thing runs it will produce some good sound, but for now. I dont know what is up with it.

The schematics are in the adds.


Greetings,


XR600B repair

[nickb]

Which parts were blackened? e.g R23, Q6...

[Enzo]

"Black stuff around them" sounds more like the glue they put on caps and stuff.

Stop blowing fuses.

MOST likely failure is shorted output transistors, they ar on the heat sink.

[XR600B repair]

Hi i saw you on the other forum too Enzo. Okey the heat sink attached to the output transistors. Are those the "Q" parts on the 400BH output BD? Could you point them out on the schemetics that are attached to the first post?

So i take these off and measure them and replace the faulty an that probably is all that needs to be done?

Greetings,


XR600B repair.

[Enzo]

The outputs are Q2,Q#,etc. They are identified on the layout drawing. Before you remove a ton of stuff, just check for shorted transistors. Easy from the top. The body of those transistors is the collector, and the emitters are wired to the long 10 watt resistors nearby. SO measure from case to the resistors, and good ones won't read shorted together.

ANy shorted, tes replace, but also check for open power resistors. And I can't say nothing else will be wrong. Often times that is the whole of it, but not always.