1994 deville radio won’t turn on

I really hate helping people sometimes.  Elderly neighbor across the street, power antenna quits working.  Looks like a no-brainer.  I tell him to go buy a replacement.  He comes back with some generic aftermarket deal.  I can't get it hooked up simply since I have to find switched power.  No way am I going to hack into his wiring harness.  I try several combinations from the OEM relay and finally give up (the antenna lead keeps 6v on the circuit with the radio off).  The entire time I'm telling him to turn radio on and off so I can figure out the wires.  He speaks so softly I can't hear him with cars going up and down the street.  Frustrating. Arrgh.

So he decides to get a junkyard antenna that we can plug in and go.  I hook up the old antenna which was fully extended and stuck and just lay it in the trunk so he can at least listen to the radio.  I look at his radio, no display, cassette won't work, nothing.  Find one accessory fuse blown, replace that, no go.  I can hear the factory amp thump when I push the power button but nothing on the radio works.  Checked every fuse and relay, all are good.  Now I am stuck.  I downloaded a pin-out for the radio.  Guess I'll test his radio harness tomorrow.  Any thoughts?