I started from this condition:
First of all I replaced original ROMS with a couple of 2716
a couple of wires are enough to adapt 2716 pinout to 9316’s
then, following the block diagram, I began to test the “line len.” Block and I could immediately see that one of 74193 had been replaced in the past. Removing it I found some broken circuit tracks, so with an easy fix now I can see this:
Everything now works. I’ll post cabinet pictures once restoration is finished (just a couple of wires to the coin door and a small part of t-moulding to replace)
thank you,
vernimark