Diamonds and Devils 5 Reel locking up

[Nepa Coin Op]

Here is the situation, I have 2 of these machines, both of these machine were just cleared and freshly setup, problem is on either game when you get 3 diamonds it freezes, displays start flashing "8"s and it wont add up the 2000 credits it just is stuck playing the win tune thats it, if I reboot the machine it will come back up with the correct credits displayed. I cleared it again and swapped SW from one to the other both games do it. I had no clue of this issue till I sold one and customer made me aware when he hit 3 dia, not sure if this is faulty SW or if the brain is running out of memory at that point which is what I am leaning towards, if anyone has any ideas or input to cure this condition please chime in


Thanks