I have searched posts regarding repair of the Gottlieb System 1 power supply and the recommendations to throw it out and get an aftermarket board...but I want to try to repair my original board. Hoping someone is willing to walk me through some detailed troubleshooting here. My power supply not outputting 5V at J2-1,2 nor is it outputting 4V at J3-7. Those terminals measure 0V. All other input and output voltages on the board are normal. I have a schematic. I have not replaced any caps or done any ground mods (yet). What tests can I perform to identify the defective part(s) in the 4V and 5V circuits? TIA.