Gottlieb SS Solved Joker Poker (Gottlieb, 1978) score display issue

[njPinWiz]

Score displays on my Gottlieb Joker Poker solid state machine are acting up. When I turn on the machine each display for each of the 4 players show all 1's across the 6 positions and the current high score of 929,801 (1st photo).

When credit button pushed, each displays shows 1's straight across all 6 positions (2nd photo)

Any ideas of what to check first or what the cause could be? I am OK with fixing EMs but solid state machines are more of a mystery to me.

Thanks.

 

[pinballdaveh]

One of the best sites for system 1 is pinrepair.com. tons of great info. Grounding mods should be done. I read that flickering displays are usually power supply filter caps are going bad. Great plains electronics sells that cap kit. System 1 power supplies are not easy to work on for the novice getting into ss games. But there are good replacement power supplies out there. Does your machine have original boards in it? Did you buy the machine with this problem? Does everything else work correctly on the machine other than the displays? What shows up in the display self test?

 

[njPinWiz]

Thanks pinballdaveh, I had replaced the power supply with a Rottendog when I first got the machine (about a year ago). The machine was (and is) all working properly...just the issue with score displays. What I did yesterday was test each one separately, then I re-seated IC Z16 & Z17, and the problem went away. Perhaps I had a bad connection on one of those chips...will keep testing & see if the problem is in fact resolved.