update

i popped the speakers with a 1.5 battery to verify the factory amps are bypassed. they are.

i have gone over the harness carefully. there does not seem to be any harness wiring problem. I think that somehow i have either fried it or switched it into a no amp output mode (pre-amp out only??). cannot find any switch on it or control on the panel.

would a deck like this have a diagnostic/program mode you can switch into by pressing a combo of dash controls? there is no reset button anywhere.