Quoted from supermoot:
Hey pinup, I'm no data east board expert and I don't want to muddle things more for you, but you can use leon's test rom to probe the bejezus out of your pia. http://www.pinwiki.com/wiki/index.php?title=Leon_Borre_Data_East_CPU_Board_Repair
I just saw this too
(I just realized most is this is linked from the first post, sorry if you have been over all this I am a little sleepy)
Hey Supermoot. I'll have to get a data east test chip then. I've got one for my Williams boards. Will that tell me that my boards are putting out all of the signals for the displays properly and then narrow it down to the display driver board?
I've gone over the service bulletin as well and have set those jumpers mentioned in the bulletin properly. However, someone had been messing around with the jumpers on this board prior to my purchase of the game, probably in hopes of getting the displays to work as well, and as far as I've seen, I cannot find anyone who has posted their complete jumper configuration for a version 3 board in a Laser War that is fully working. If someone could note that all down that would be perfect. Then I can match where the jumpers are supposed to be and rule that out 100% as a possible issue. The only jumper that might not need to be the same as mine would be if they had a different game rom chip type in socket C5 than I did, as there are 2 types used and one requires jumper j4 to be in and one requires jumper j5 to be in.
I've also resurected that old "laser war not fully booting" thread and gone through that as well, which leads me back to "where are all of the jumpers supposed to be in the first place that someone else felt the need to move them around and cross them". UGH! Why would you put a jumper on a diagonal between 2 different jumpers? I don't get it.
I also have all of the pinrepair guides on my computer here and have read through all of the display information there. Nothing refers to having all of the displays out, other than if the HV section on the power supply is bad. I've rebuilt the HV section on this games power supply, and it's working properly (purchased full rebuild kit from actionpinball.com).
If the test chip can verify that the MPU is outputting everything it should to the display driver, then that narrows it down to the display driver not working correctly, which then would lead me to think that all 4 of the udn6118 chips are bad and not putting out any strobe pulses.
Guessing the test chip doesn't tell you anything about the display driver board not working correctly.....