Gottlieb sys 80a Display Issue

[pinballnz]

Hi guys need your help.

I dont know whether this is a sys80a issue or general gottlieb issue.
My mate is working on it at present but we have come across this issue which has us stumped.

I have a Devil's Dare that I imported as a non worker. The cpu looked to be a nos  as it was much newer than the original boards , it didnt't go so I bought a gottlieb chip replacement pack from the US. Replaced most of the chips and it still didnt do much. My mate checked the displays and resoldered display connectors and he managed to get the credit display with zeros's and the bottom 2 displays working but all scrambled when the other 4 displays were connected. ( Devil's dare has 6 displays )

I bought a ni wumpf in as I thought I'd probably need one. Plugged that in and now the credit displays E's and the bottom 2 displays or any that are connected are scrambled. The ni wumpf appears to be working as it should as the led blinks 1 and then 7 seconds  later it boots up. ( you can tell as the displays "pulse" when the game boots). GI is ok and sound board test ok. We have swapped displays around and the result is the same. It seems that some signal that loops around the displays is scrambling it somehow.

We did spray the connectors with contact cleaner - for the most part they look ok.

What else do we need to do?

Have any of you had a similar issue?

Any help is greatly appreciated.
Clive

[humpalot]

Do the ground mods and then re pin the connectors, the connectors may look OK but they are a source of problems in these machines.

http://www.pinrepair.com/sys80/index.htm

[Retropin]

Had the same issue with my SPIDERMAN - E in the credit display that burns brighter than it should... check voltages from power supply and do ALL ground mods,,, this fixed my machine

[pinballnz]

Thanks. Ground mods sorted the problem!

Thanks again.  " The devil lives..."

[MartyJ]