parallax power supply 7345ru parts PWM

I got it. It was topside +. Resistors look ok, they look as though they been replaced at some point in the past buy a repair facility that employs drunk moneys judgeing buy the soldering :-)...ugly but still functional.
All three if the caps you mentiond show slight signs of bulging on top. (Hydrogen buildup) GOOD CALL. I'll replace all three.

Thanks so much.