Okay, made some headway & then probably made the problem worse Forgive me if this is long-winded, but I want to be as accurate in my description as possible.
Looking at schematics from manual online, traced all the wires from the triac back to the board & tested continuity. All wires continuity checked fine. Then I noticed what was probably the problem...the red wire which the manual states should go to J106-5, was plugged into the wrong place (J124-5). The correct place (J106) was completely empty, nothing connected.
The connector holding the red wire only has the red wire, nothing else. So I turned off machine, plugged it into J106 where it's supposed to go & rebooted...the GI lights were super duper bright, I smelled a smell, and shut the machine off. Upon further investigation, fuse F104 blew, so I swapped that out & put the connector back to where we started at J124-5.
So now everything is back to where we started which seems to be the connector being in the wrong place (so still haven't solved the beacon issue). The GI has returned to normal brightness. Now there are new problems though, the left & middle supercharger lights are on all the time. I don't know what is normal, but before this attempted fix only the middle supercharger light was on at startup. Also hold bonus, 4x, 6x, drive again & 4th gear lamps are out. I glanced at the matrix quickly, but these didn't appear to be in the same column or row. Help!
Grand total:
1) beacon still not activating in gameplay & appears to be hooked up to wrong place
2) left & middle supercharger lights on, 4x, 6x, hold bonus, drive again, 4th gear lamps out