I am not very familiar with WMS Sys 7 display but i tried to do my research with Pinwiki and Pinside, looked at the schematics and yet, i still can't figure that one out.
When turning on the game all the players display show garbage (Unit display is fine). When testing them one by one, P1 and 3 work fine but 2 and 4 show a very bright 7th digit and a sixth digit, nothing else.
The weird part is that when P1 is by itself it works fine but if I had P2 then P1 start displaying garbage, same principle with a working P3 by itself that start showing garbage if I plug in P4, but P4 does not impact P1...
i moved the ribbon cable arounds and the issues does not follow them or the display so i am 99.9% sure it is on the board. i tested the R1-R14 and they all within 9.6-10K, i tried testing R28 and R29 but they read 7.8 and 9.1K while the schematics call for 47K, not sure if that could be a reason for the issue?
I do not have a logic probe so i replaced some of the most common culprit and talked about chips, CPU IC6 was replaced, Master display IC9 and 10 as well as IC7 (i was pretty sure it wasn't it but i wanted to test anyway).
I do not have any other WMS game nearby to do a quick CPU or Master display board swap unfortunately. Any thoughts on what can cause issue across a pair of display like this?