I am working on an S2000 Triple Diamond Deluxe machine. I purchased it, no idea of the history. Overall it's a decently clean machine. It has a 50X board just for added context, the board is professionally repaired. The issue is some sort of power problem, if I pull the main power plug from the backplane and test voltages, they are all over the place, for all the voltages. +25, +13, and the 6~8v they are all over the place. Some start at 12v and then work themselves down. Some start and 5v and move around from 1 to 5v. There is absolutely no rhyme or reason as to what voltage i might get, and it's constantly moving in big swings. Usually starts at some higher value and as i'm watching it, it just slowly keeps creeping down.
For the sake of my testing, the MPU and backplane are not plugged in so they don't come into the equation here, since I have the main power molex unplugged and am probing it from that point.
Service outlet has a good constant 124v, so service outlet is fine.
Tested with 2 other known good power supplies, still the same result.
Unplugged all 3 ballasts
The top fan does comes on when I turn the power on
Doesn't make any sense, I've reseated the power supply many many times.
I guess I'm leaning towards the power distribution board in the inside, I opened it up though, and nothing seems visually wrong. Checked the top fuse on the distribution board and probed it for continuity and it was fine.
Anyone seen this behavior before? What should I try next?