Looking for some help with an issue I'm having on a Data East Jurassic Park. I thought I had gotten to the bottom of this, but now I'm not so sure.
A little background: Picked this game up from a fellow pinsider who was very upfront that it had an issue with the GI system. There are no GI lights at all. It appears the game and lights were working fine, but there was a fire and when I bought the game alot of the wires had been burnt and disconnected while the issue was investigated. I'm guessing now, but I think this game was functioning with a Rottendog MPU board and original power supply board. Then the fire happened and an Xpin power supply was added to the game along with a Inkochnito rectifier board. The issue wasn't solved and ended up smoking some traces on the new Xpin board.
So I bought the game and set about trying to fix the issue. I replaced all the burnt wires and GI connectors, header pins, and molex pins. I talked with the Xpin guys and ordered a new relay and diode to fix their board. Replaced that and repaired the trace. I also found a shorted Q28 transistor on the MPU. Q28 is the transistor that drives the relay coil. I figured this transistor was the original failure and it smoked the wires and traces and started the fire. I replaced the transistor along with the U1 and U5_f chips in case those were affected by the short.
That brings us to today and the reason I'm asking for help. After doing all that I turned it on and the Q28 transistor I had replaced shattered. Now I'm sure it's possible I just got a bad transistor, but most likely there is still an issue. I was thinking that if the transistor failed again, there must be a short. I checked for continuity to ground on each of the GI relay pins and don't have it. There is also no continuity between the two pins for the GI relay (checked that in case the repair I made on the trace was shorted). It also doesn't appear the transistor is shorted like it was before, if I check continuity from the metal tab to ground, I don't have continuity.
Given all of this information, can someone suggest something for me to check or try? I'm not sure where to go from here as I thought I had fixed this issue. Here are a few links for the schematics. Please help me figure this out
http://www.rottendog.us/MPU004.pdf - Rottendog MPU
http://mirror2.ipdb.org/files/2493/Tales_From_the_Crypt_Schematics.pdf - hi def schematics