U make a good point. my scope was set to ac for some reason so it looked like rail to rail, my mistake. are the relays part of the ps or the output section. in my mind it seems to be a part of the ps.
Relays are virtually always one of the last components in the circuit before the speaker terminals, in the output of the audio circuit. See attached for a similar amp.
When the relays won't engage, does the amp show that it's in protect mode?
