I have a T2 that blows F105 on power up and also blows the 8amp fuse at the service plug port. It sounds like a coil/coils lock on with a loud buzzing sound before the fuses blow but I am unable to catch it. I am also unable to see anything on the DMD on boot up. This pin has been hacked a bit but the driver board and DOT matrix controller has been gone through by Chris Hibler recently.
If I pull J107 the game boots up with GI coming on. After research here on Pinside I have checked the ribbon cables and made sure they are installed correctly with the red stripe on pin 1 at each connection.
My plan is to check coils 1-8 per an earlier post I found here on Pinside. Should I disconnect each single wire from coils 1-8 then attach one at a time to find out what coil is blowing F105? Also it looks as though I should test the transistors (64, 66, 68, 70, 76, 78, 80 and 82) to see if any are shorted to ground.
Which move should I make first? Pull the board and test the transistors or disconnect the single wires on the coils and then reattach one at a time?
I also checked TP2 and TP3 test points. TP2 = -4.9V and TP3 = -12.0V not sure if this matters.
Thank you for any direction on this.