I've been neglecting the BOP at work. Haven't checked on her in 3 or more months.
On Friday; I went down there to play her... still functional; but very dark.
None of the helmet lights were working... and I'm pretty sure at least one string of GI was out.
The manual still lacks key information I needed - but couldn't specificially pinpoint what I was looking for. Maybe it was how the Chaser board hooks to the helmet and cpu boards.
I did some troubleshooting; and the chaser board is getting 12V and the regulator is outputting 5V...
Fuses were good via ohm check.
So I'm more inclined to believe that the GI transistors are out. I think Q18 drives the helmet "hot" side - correct? Q18 is one of the heatsinked jobs in the lower left hand corner of the PDB.
I'm not sure why the GI has developed a problem or for how long... maybe just old age.
Anyone have any specific suggestions to check? I really don't want to pull that PDB again... as it's always a chore. That said; I'm pretty sure I'm going to have no choice.