Teaser photo/video I just got a chance to test these out yesterday -- BLUE LED digits on Players 2, 4 & CREDIT. WHITE LED digits on Player 1 with an overlay just over a single digit (doubled up amber overlay that doesn't quite match the original plasma). Player 3 is the original plasma display for comparison.
Video (sorry for the poor quality, need to take video with better equipment):
The overlays will tone down the brightness of the digit some, not sure you can really get away from that. I'll do a comparison of the BLUE digit versus WHITE with blue overlay as I get some more WHITE digit displays built out. Will also try running the segments at 15mA instead of about 10mA as they are currently to see if that makes a noticeable difference.
For the upgrade on these I was just doing modifications to the back.. a few things to cut off the front, but then just adding the couple dozen resistors to the back of the board, jumper wire and pulling pin #1 on J1. I didn't have to change out any digit drivers, but there's one I'll probably change out because the digit is slightly dimmer. Doesn't seem that will be as much of an issue as I thought it could be.
The conversion probably took 30-40min per display. I'd think hitting a 30min time wouldn't be too hard for experienced solderers after they assemble one or two of these and get a feel for things. If removing components instead of doing modifications to the back of the board, it'd probably be closer to 1hr per display.. I'll be assembling some like that too and getting a feel for things.
It was exciting getting these in a real machine for testing.. I've only been testing single displays at the bench. To me it's night and day over the plasmas, I like the slightly larger digits & segments personally. And led displays in general definitely make the machines feel more modern. Happy with how these are turning out.. more to be done, but coming along!