I'm having a really annoying problem with a Bally 7 digit display. One of four displays in this game was toasted—literally. It had a hole burned through the PCB. The other 4 displays (including the 6 digit credit/ball) had the 10k digit flickering as can be seen in the video attached. I fixed the 6 digit and one 7 digit by replacing only the 4543 and R44. The display in the video however has had the 10k digit parts Q5, Q11 and R44 replaced along with the 4543 segment driver but still exhibits the same flicker. The new 4543 seems slightly better than the old one but only ever so slightly. The video is of the original part in a new socket on the board. The 9.1K (IIRC) resister at R44 was visibly burnt but was still measuring ~9k when I pulled and replaced it. R44 also shows heat damage on both the displays that I've yet to replace it on. Is there something else in the segment driver circuit that I need to look at? None of the parts check out bad with a DMM but that isn't always foolproof.

Yeah, I replaced the digit circuit parts (relevent to the 10k digit) to no avail.

I've reflowed pins but have not replaced R9 as it is does not show any signs of failure visibly or measurably, but I have plenty of 100k resistors lying around to have a go.

Also, the problem was on all displays (in varying amounts) but two are working now as noted in the first post. I forgot to mention that this problem follows the displays around no matter which player location or even which game I test them in, so it shouldn't be a bad MPU or connector. Same goes for the working ones... they're fine in P1-4 or another game.

Resolved this. It was a single bad resistor on the alltek board (next to the connector for the displays) causing this. It appeared to follow the board but was actually just failing when the game was loaded down with more boards plugged in. Found the failure point comparing to a known good alltek and fixed it.