Help with a Rotel RSX965, 2V neg offset, all outputs

I've been fooling with this thing on and off for a while with no luck so I thought I might find someone who knows their way around one of these.

I've unplugged everything from the amp board except the power and the spkr outs, and there is still a couple volts neg offset at all 5 amp outputs so whatever it is it is common to all 5 amps. As near as I can tell, all the common circuitry seems to be protection related, but there is a good chance that I'm seriously in error.

Anyone out there that can straighten me out on this?
I do have the service manual.

Thanks in advance, Bill
Thanks for the reply. There is one trace marked bias on the dwg that is tied to the main board, and goes to the front end CS of all the amps but I believe it is also protection related, but I'm not sure.

There really isn't much common circuitry on the board so replacing all of it seems to be the logical solution for me, unless someone has had the same problem and can pinpoint it.