Carvin Pro Bass II

[Wes]

I can't seem to find a schematic for this amp, but it is built with what appears to be two 200W power amps
that are bridgeable or what have you.

One of the power amps is totally fried. Every transistor and several associated components in that side are
blown open and burnt.

Crazy thing is- the amp fires up and sounds great apparently using the good side. There is a little hum from the bad side
and of course every transistor shows a dead short.

This seems to me a dangerous situation and I don't understand why the fuse hasn't blown.

I'm wondering if it's possible to just clip all of those shorted transistors away or power down that side and still operate
the amp safely.

Does that seem to be a possibility?

[g1]

Possibly there are burnt traces so that the bad side is no longer being powered anyway. Self-made fuse.

[Wes]

All pins on all of the transistors have full voltage on them from the short.

One side has -65V or so and the other has 65V. Certainly strange and makes me worry about using it.

[g1]

All the emitter resistors for the power transistors have probably opened, that is why there is no more current or fuse blowing.
You can remove the output transistors if it makes you feel safer. Measuring out of circuit you may even find some are not shorted.

[Wes]

What are the odds of that? Heh.

I was thinking about clipping them all out. I was just wondering if it would be safe to operate after having done so.

It's a pretty good sounding amp for what it is. Too bad that channel is bad.

thanks for your time and input, g1!

[MarkusBass]

Do you mean one of PB200 amps? In this case schematics are available here: The Carvin Museum - Technical Documents

Mark