I just rebuilt a Gottlieb System 1 power supply. All the voltages are good with the exception of the 60v and 42v lines. Both the 60 and 42v pins on the power supply give off 17.7vdc. The POT adjustment has no effect.
The transformer lugs read 74-75 VAC.
On the power supply, using the negative lead on C6 as ground for the DMM, I tested the voltage on the diodes at the bottom of the board (CR6, CR7), and they read 41.5vac. From the schematic, they appear to be on a 90.4v line.
So, did I loose that much voltage from the get-go? Or am I testing the voltage incorrectly, and the problem actually exists further down in the circuit?
All the diodes on the lower third of the board are fresh replacements (cr3, cr4, cr6-cr9, cr21, cr1, and cr2), as well as all the electrolytic pots, the large TO-3 regulator on the back, the POTs, and the header pins. Everything else is original. The regulators do not short to the backplate. The ground mod wire has been done on (on the back, so it's hidden).