On my Williams Gorgar, the player 1 and the ball/credits display are sometimes finicky. Sometimes they look perfect...other times they flicker and the ball display gets really bright with an odd looking zero displayed...then it goes back to normal, perhaps with the ball digit not showing...then, tap the backbox and the display corrects itself. Reminds me of my old console TV - bang the top and the picture straightens out.

I know I can plunk down $200 and get new green LEDs as a replacement (really thinking about that option) and nice to know it would run off of low voltage. But, any thoughts on why the gas plasma does the strange dance?

Well, I replaced the bridge rectifiers with the new ones and discovered the + on the GI side was barely hanging on...resoldered the connector and moved each wire over one at a time. Used silicone grease (or whatever that white stuff is) and smeared it on the back to disapate the heat onto the aluminum base shield. All works fine...so I moved on to the flickering zero/ball digit and thought I discovered a very loose connector wire at the very bottom of it. Resoldered the connector wire, checked all the connectors in the white plastic thingy, gently bent all the connectors up and ran the game...seemed like I fixed it...until ball 2. (Funny thing is, my wife thinks I am playing when I am really troubleshooting...but I digress).

So, I suppose I finally have to take the ball/credit display board off of the backboard and investigate the underside.

It's the strangest thing...wiggle the bottom wires, the zero digit for the ball goes really bright, the other displays act up, then either it looks fine or goes blank (all the while the 1-4 displays look fine when its not hot flashing).

The fun continues...sounds like sealclubber's advice is the cuplrit (I hope). It's easier than dealing with anything on the inside of the machine...

Cheers,
Mike

Just a follow up...narrowed the problem down to the white connectors on the MPU board. If I touched the wires in either of the banks, I could get the first digit of the ball display dancing...if I touched other wires on the connector to the right, I could get the first digit of the credit display dancing...popped them off a few times, tried to move the connectors in the white plastic around a bit and then restarted. Semi success...the balls display now but the credits first digit is a bit fussy at times but better than it was. So, I shall leave it at that. It does not appear that anything is broken as far as solder joints...just my opinion and hopeful thinking!

I did remove the master display board and inspect the back, all looked fine. Even recut the lowest wire on the 7th white connector and resoldered that to ensure a good connection. That's when I traced the brown+stripe wire to the top of the MPU board. These machines seem like old English sports cars...nice to look at but dreadful electronics...luckily, the pinball machine is still better than an old British sports car.

I would but removing the boards is not in my future if I can avoid it. I also do not want to remove that crazy connector between the boards...