I assume you are talking about the displays?

The flicker is typically caused by cracked solder joints on the header pins on the display boards or display board connector problems.

Easy fix.

That "LED flicker" stuff you found is unrelated (used for replacing the lamps with LEDs on Bally pins---nothing to do with displays).

Credits and ball in play are the same display. Just pull the display board, reflow the solder on the header pins, reinstall, and see if it works.

If not, you should replace the header pins and female connector and you should have it sorted.

Not surprising. You reflowed solder on the header pins, right?

Next step is the replace the header pins and the connectors.