1980 Bally display skipping numbers

[kehoe]

Hi there,

I'm fixing up a Space Invaders game. During the pinball diagnostic where the numbers 0-9 should cycle through the display we get numbers 4, 5, 6, 7, which repeats.

Previously we had all displays cycle 0, 1, 2, 3, 0, 1, 2, 3, 8, 9 . We removed the displays and fixed any cracked or missing solder. We also cleaned all the contacts to the boards and displays. It then switched to only showing 4, 5, 6, 7.

Any thoughts on what would be causing this?

Thanks,

Kehoe