I have a weird issue going on with this amp. 

1.  The clean channel plays fine, the distortion channel cuts in/out.  If I hit a note it comes back, and then at some point it cuts out, instead of fading out.

2.   The 15V rail is low, only 11V.  This may or may not be related to the first issue.

Issue 1 seems to be happening around Q5.  OK before Q5 but cuts in/out at the Q5 Source.  Q5 Gate is around 0.5V and then at 8.5V when distortion channel is switched on.

Issue 2, I have the proper 21V at TP17, but only 11V at TP19 (should be 14V).  Something is pulling it down.  Maybe C47 is leaking, or D18 zener is bad.  All op-amps should have 14V at pin 8 but are actually 10.5V.

I would like to focus on the rail issue first, and once corrected see if issue 1 is resolved also.

Suggestions please!!!

Schematic link is https://www.audioservicemanuals.com/c/crate/crate-bt/7294892-crate-bt-50-pwa-bass-amplifier-pcb-schematics-848sch-a

I am not sure how to attach a PDF to this thread.

Also, anyone know if Music Electronics Forum is ever coming back online?

Thank you, Gonflable