I wanted to throw this one out to the community to see if someone with more experience can save me time by keeping me from barking up the wrong tree.
I own a Stern Flight 2000 and have worked on that but have done very little on a Data East machine. I'm still new to fixing these.
The Laser War is my father's machine and I'm trying to fix this problem for him. He has owned the machine for many years and it has been relatively trouble free.
A few months back I was over there playing and the yellow pop-bumper locked on. I figured the diode blew and took the transistor with it locking it in the on state. I returned with parts and replaced the diode on the bumper and the TIP 102 transistor on the board. When I fired it up everything worked great and we were back in business. I played a few games and everything seemed fine.
When I returned recently I played a few games and all worked well until suddenly the game went nuts. Many switches were activating two or even three results. The game would tilt or or think I had hit ramps etc, simply by going though one lane at the top. I should note that the game was not played at all between visits.
At first blush based on my limited experience I was thinking a problem with the switch matrix and perhaps another failed diode that was the same age as the other one that failed. But, given that I just swapped out parts that were part of the same drive line of switches I also suspect I either did something wrong or another part may have been fried when the original diode blew. I'm not sure why it would not have shown up immediately though. I also do not know enough about these data east boards and how they behave when parts fail.
I think pretty much every switch in drive column 6, (switches 41-48) are causing problems. The yellow pop bumper is right in the middle of that at switch #44. Activating switches in that column causes other switches (mostly within the same row as the switch) to be activated as well.
Any thoughts? Is this just an unrelated bad diode in the same column or more likely to be related to the issue I was having with the yellow pop bumper.
Thank you ever so much for any thoughts you may have.