I'm looking for a service manual and/or circuit description for the B&K ST-140 or ST-140M. I already have a few low resolution versions of the schematic, the minimalist owner's manual, and a one-pager on adjusting bias that applies to multiple amps. I'm not sure if they ever produced a model specific service manual but I'm hoping somebody can help me out. I've split a stereo version of this amp into two monoblocks, and on one of them the bias is low and will not adjust up when trimmed. Looking for insights into the circuit so I can address that. Thanks in advance!