My Panasonic has had the power supply replaced once and it now will
run for 1-2 then just go off. You can unplug the set, wait about
15-30 sec and plug in and the set will turn on and run again another
1-2 hours.

What could the problem be? I do not have a wiring diagram or schematic
for the set, so I don't realy know what is in the circuit. It reminds
me of a computer with a lock-out relay protection in the event of a
power outage.