I wasn't sure where exactly to put this thread, as I'm not sure if I have a board issue or an issue with my power setup. I am attempting to bench test Williams System 3-7 MPU/Driver boards. I plan on making something more permanent in the future but for now I made a few wires with spade connectors on one end, and alligator clips on the other. I made 3 for 12v, 5v and ground, and hooked them into my arcade JAMMA test setup which is using a Suzo-Happ Power Pro
Power supply is good, and when I measure the power at the alligator clips I'm getting the proper 12v and 5v, but when I hook them up to the board, the 5v supply drops to ~3.6v. The 12v remains at 12v when hooked onto the board. I tried hooking them up at IJ2 and TP 9/TP 10. I'm trying to figure out if this is because the power supply is ill-equipped for the job, or it's something wrong with the board. I tried it on another MPU I have (that's very corroded, I didn't expect it to boot), and the 5v supply dropped to ~4.1v. This makes me think the power setup I'm using is insufficient.
Any help appreciated, I plan on making a more permanent pinball-specific test rig in the future but just wanted to try it out with what I already had. Would like to figure out exactly why what I'm doing isn't working. Do I just need to crank up the 5v adjust? I'm worried that's gonna raise the 12v too high