I'll try to make this long story as short as possible...
I was given a partially (playfield) parted out SWE1 game, also the OEM computer would not boot (definitely the motherboard) my plan was to finish parting it, keep some generic stuff for myself and sell off the rest. Then suddenly an opportunity to score a brand new complete SWE1 kit presented itself, so I decided to save this game instead of junking it.
For a computer, I decided to build a Pinbox system with the ton of old PC parts I have collected over the years, and that seems to work just fine... the game boots, plays great and every feature and function works perfectly... But here is the problem...

Every 44/555 bulb (original incondescents) in the playfield is working and seemingly controlled properly, but they are all VERY dim and flickering/strobing horribly and constantly in-game and in attract mode.

I have checked every single socket for shorts and diode issues, and everything is perfect! All the on screen diagnostics say everything is fine too. So I was convinced it was the Pinbox parallel port signals causing the problem, but I have changed all the hardware (motherboard, etc) with several different options, and they all work, but the lights are also the same with all of them. So now I have to assume its a power/driver board issue. All of my input voltages from the transformer are good-to-high, and I have already replaced all the related ULN2803's on the board (neon wasn't working), this fixed the neon, but no change to the PF lights. I feel like its maybe an IC that handles strobing or blanking??

Any thoughts on what to look at next? I believe myself a damn good Williams pinball tech and board tech, but I just dont know squat about the P/D board in these Pin2K machines.
BTW, I also couldn't help but notice that the 2, 330ohm resistors at R296 & R297 are hotter than hell! That doesn't seem normal to me. And the "HEALTH" LED 2 is flashing?

Thanks for clearing up the "health LED" thing, I kindof suspected...
I have 20.7v at all points where 18v should be, average 10.1v ripple. I probably should have mentioned that I checked all the obvious before I did much of anything. This is absolutely a ground/trigger issue, and logic keeps smashing me over the head and telling me "because ALL the PF lights are affected (matrix A&B), I need to look at elements/components that are central to ALL the PF light circuits".
1. The emulator PC (I keep defaulting too, but after swapping through several different MB's and chipsets, with identical results, its harder to blame)
2. The power/driver board (but everything seems to test just fine, I cannot isolate any bad components)
3. The brand new, right out of the box PF (I have ohm'd out every socket and tested every diode.) Everything is as perfect as brand new should be!!

Actually, my Fluke starts at 200v on the AC scale, so I probably wasn't paying attention to the decimal, I was probably getting 1.01v, or possibly even .10v. I'll check it again tomorrow after work.

Yes, I tried the F-keys, and the relay clicks and the lights flash, but no difference. Yes, every MB I tried had a different CPU. The current MB/CPU i'm using is an Intel Micro ATX (DQ965GF), Core2-Duo 2.13GHz, 2GB RAM. According to the ton of stuff I have read, this setup should be golden! all 4 MB/CPU's that I have tried run the game just fine, but the light issue is exactly the same with every one.

Yes, the relay controls the high voltage. Post a pic of what? I cant do videos, I dont do YouTube or anything like that.
I suspect the flickering my be from voltage or ground loop interference, so I ordered some heavy duty 500MHz ferrite clamps to test. And I also have an OEM computer on the way, so I will have this BS resolved one way or another.

I think it works, and it adjusts the timing like its intended, and the dim/flicker is caused by something else unrelated. Williams put ferrite clamps all over the place in this game for a reason, and I think i'm onto something, but it wont be until the end of the week when I receive them, so my project is stalled for a few days.