First up.. GTB sys1 games are pretty much an attempt by GTB to enter the SS new generation system. They got it very wrong compared to what we know today.. given that, its the same logic that got man to the moon in 69 and knowing what we now know, its a miracle they got back!
Biggest weak link of any sys 1 game is that as soon as any coil locks on, the associated IC would have fried also.. the current backwash just goes straight up the line and kills the IC. If this has happened then your CPU is pretty much dead as the spider chips are obsolete and have been for some time. You see sys1 CPU boards for sale often on Ebay.. listed as untested which is BS.. it means they don't work and will not work.
test ALL your spider chips..  a simple visual test that any that have burn marks in them means your CPU is dead and you need a replacement.. don't even bother going any further.
 If you do get it going then put diodes in line to stop the current switch off trailing backwards

totally agree
once a spider chip is dead then kiss it goodbye.
even if the the switch matrix spider chip fails (hope i have labeled it correctly) then your board is cactus