Hey All - Working on a Gottlieb System 1, and I have run into a strange issue. I picked it up not-working (just GI was on). It has a brand new ni-wumpf and a Xpin power supply (previous owner had those installed). I replaced the connector between the MPU/Driver, and now I have it booting / playing, but the Displays are all dead.
* I swapped displays into my System 80 James Bond and they work, so I know the displays themselves are good.
* Note: I don't remove connectors when the game is on, so whenever I mention that, don't worry the game is off!
I removed A2J3 from the Power Supply board and tested the voltages. They all read about what they should:
Repair Guide / My Reading
A2 J3 pin 1 = 60 vdc / 62.1 VDC
A2 J3 pin 3 = 42 vdc / 43.9 VDC
A2 J3 pin 5 = Ground (common)
A2 J3 pin 7 = 4 vdc / 3.89 VDC
A2 J3 pin 8 = 8 vdc / 8.0 VDC
Now, I plug A2J3 in, power up, and take a reading from the back of the connector (as well as the wire destinations on the displays, etc.) Nothing. The 60 and 42 vdc are simply gone. The reference voltages (8vdc/4vdc) are still there. For some reason, whenever I plug in the connector, the voltages disappear.
I checked, and when the connector is plugged in, I read a short between 60 VDC (white/blue wire) and Ground (black). This is true even when all the displays are disconnected. If I unplug A2J3, no short between 60VDC and Ground. If I plug it in, short.
I'm a little stumped here. I checked the fuse in the cabinet and found that it was the wrong rating, which I know is bad. It was 1-1/4 Slow Blow, should be 1/4 Slow Blow. I swapped it out, put everything back together (but only hooked up one display I know works fine) and it immediately blew the fuse.
I have (1) 1/4A fuse left, so I want to try and figure this out before popping that in there (ordering more).
Anyone have thoughts as to what might be going on? I'm puzzled as to how I could read a short only when the connector is plugged in, when all the voltages read fine on the header for that connector with the connector off. Even if I check the wires on the Display end, they show continuity/short whenever I plug A2J3 connector in at the power supply, and no short when I remove it.