New to me SOF, replaced all the insert lights and a row is burning out when I start the game. That row gets really bright than blows. The associated transistor Q58 was replaced today and it is still blowing the row. Q58 is getting incredibly hot in the few seconds the game is on. Any ideas of what might be causing this? The row is the one with multiball bonus 2x and 3x, the avenger score 50k, 150k, 250k, extra ball inserts.

Thanks for taking the time to answer! I changed Q57 and Q58 (again). Q58 really got hot and burnt the board when I had the game turned on for about 60-75 seconds before I had changed Q57. Two of the trace pads on the back fell off when I tried to remove it. I soldered the new one to the pads on the top side of the board. I feel like a total bone head for having it on this long and am afraid I have done way more damage. Something started smoking when I turned it back on. I can't tell if its relay K1 or if that relay is just were the smoke is gathering and dispersing from the components below it. The sides of this relay now have black marks on it. That row of lights is still getting to much juice and blowing. Soon as I saw the smoke I turned it off and haven't plugged it again.

So I got fed up and popped in the board from a working police force. Almost instantly the new working board started smoking in the same area. So I guess the problem isn't in the mpu?

Fixed. There was a flasher socket shorting to an insert light. After separating them and replacing the transistor and predriver again everything works. At least on one of the boards. The other is pretty toasted and I haven't attempted new transistors again. Thanks for the help!