Classe CA-100 Soft Start Help Needed

[stoutblock]

Stout- Do you think the bias alone (with me turning the power of and on many times quickly) would cause the burn of R240 or is there something upstream I also need to check before replacing R240 and trying again?

Here's the SM I have...

The bias would have to be way, way off to cause that kind of damage. Have you checked bias? Per the SM turn them all the way CCW and then up (once you get that resistor fixed).

Do you have a schematic that shows R140 and R240? All of the schematics that I have found do not include the input/driver schematic, hard to troubleshoot and/or answer questions without it.

Craig

I cannot find R140 or R240 on my schematic. The schematic in the SM just shows the output circuit and not the whole PCB.

 

[psarahtonen]

Do you have a schematic that shows R140 and R240? All of the schematics that I have found do not include the input/driver schematic, hard to troubleshoot and/or answer questions without it.

Craig

Sorry... no I have not found a schematic that detailed yet. But thanks!

 

[psarahtonen]

The bias would have to be way, way off to cause that kind of damage. Have you checked bias? Per the SM turn them all the way CCW and then up (once you get that resistor fixed)..

No, the bias was not possibly that far off. I think it has suffered a cascading failure from a faulty relay... somewhere. I don't know where to start now. I don't think throttling back the bias won't take me below tolerance. I'll see of I can borrow a varian somewhere and see what I can come up with but honestly, I'm still pretty gun-shy and angry to jump back into it right now.

Thanks Stout!