Sunn coliseum 300 pre amp trouble

[pontiacpete]

Thanks for the info on compressors and IC5.
Back to the tracing thru this pre amp. I'm fumbling around here. This is what I'm finding at this point. The amp is passing a very low signal. When plugging into the 'power amp in' the signal seems to be normal for a return. But when sending the pre amp to another amp the signal is very weak. Plugging into the input it is also very weak and out to a speaker it is the same very weak signal.
I changed all 8 send and return jacks, they were very stiff and hard to plug into.
On IC401a pin 1 there is signal that is clear but not a whole lot of gain. I wish I could some post photos from my scope. Can some tell me how to do this?
On IC6b pin 7 and with compressor pot turned down there is a smaller clipped signal.