Eight Ball Deluxe with Alltek board. Millions commas are on periodically illuminated even when not needed. Also they go bright then dim. I only see one other post but no resolve. Any ideas? Spent some time today changing IDC connector to crimp type. No change.
https://pinside.com/pinball/forum/topic/millions-comma-flickering-on-all-four-displays

PinRetail thank you. I will do that tomorrow and report back. It's nice to have a solid answer such as yours from your experience. And yes it is not LED.

Reflowed all header pins so I can rule that out, but honestly, through my magnifier, there were no cracks in other joints. All segments work correctly. The comma shows up, dim then bright repeating and sometimes disappearing on all 4 players. But not all at the same time. I will focus on Q 22 and take notes
on the schematic barakandI sent. THAT is a great help.
One thing I wonder is in the schematic specific resistor values are listed just for the comma. Since it's smaller (the comma itself) I'm assuming they are different than every other segment. Any possibility that voltage is higher through the Alltek power supply? (Head has all Alltek guts)

Yes, the makes sense however in my case, the score can be in the 1,000's and the millions comma will light with no numbers near it.
To be continued...
I do have one option although it goes against my grain. We have a Centaur that I could swap displays. But disturbing ANYTHING on these older machines sometimes creates more problems. But it is an option. One step at a time.

I measured 235 volts on the display board. I will measure the driver board soon, forgot to do so. I also changed the Q 22 transistor with same results. If this voltage is normal (like you indicated Alltek has no voltage pot) I think it's time for another Wolffpac build.

That was on TP2. There are 3 test points on the display board. TP1 reads good on 5vdc. 2 reads 235. Tp3 is constantly changing. I disregarded that.

I have not checked ground, from displays connecting from back box swing out panel to solid ground. Possibly there is resistance. I did check ground to the backbox boards and I did find resistance there and fixed that. Referencing ground to the swing out panel is my next step.

I began my day checking resistance from this TP to ground. About 2 ohms but the crappy Klein Home Depot
meter even when a dead short reads around a little less than half ohm. But, from experience 2 ohms is too much.

Measured that at 194 and the same at the display. Obviously my previous 235 v reading was wrong. I will take the full blame for that but am too embarrassed to divulge my mistake. Ok I will. The meter probes were on 10A sockets from the last fix.

But the ground bothered me. So I traced it to the solenoid driver board, removed and inspected pins and connectors, also D5'd a molex connector. Turned it back on and the commas were gone. So, this was a ground issue with a tad of resistance which someone had mentioned that the commas being low in the glass was jumping to... who knows where.
Actually, on Pinside this exact issue has come up several times without a resolution.
I appreciate everyones time and help solving this.

Well, the commas for some reason cured itself then came back. And yes I have reached out to Alltek and TP2 is reading 230. Oddly enough the cap associated with the regulator/heatsink is - missing. I bet it blew up. No trace of it though. I'll look at the bottom of the cabinet in the back and see if it's there.