Quoted from radial_head:Well I've doubled up the grounds on the CPU-Driver interconnect and repined all of the driver board connections driving the coils, so I don't think that's the issue. I've swapped out driver boards with two other drivers I had around (one original and one a NiWumpf) and that didn't change the issue.
What should I be looking for that would cause something like this to trigger? No reason that I should be suspecting the bridge rectifier for some reason?
You're right, the CPU does seem to look like the culprit but in sone ways I'm not even sure where to begin to look to start testing it. 5V and solid ground at Z16 or try swapping out Z16 with a new chip? Would the 6532 chips be the looking point?
Happily will accept any guidance here. I'll be back in front of the game on tuesday.
When a z16 gets shorted or goes, it takes out the whole switch line. I would be eye balling each coil on that knocker circuit for a faulty diode or short, and at the very least, clip the knocker for now if it’s the only thing causing other games issues and voltage dips.
As for the grounding, it’s been debated for years. Is the extra ground enough on the cpu/driver connector? Or is it best to take an hour and tie each board to the ground plane on the cabinet floor. I do the latter, and I’ve never had an issue since that has become my practice. It also gives me solid peace of mind.
The reason is, it’s just more stable.
Adding an extra ground to one connector is still depending on that lone pin in the harness not to fail, which is then responsible for keeping ground on all other circuit boards in the game.
Gottliebs service bulletin 40 years ago was the fix for bare minimum.
Grounding each board tied back to the ground plane is why they call it “bullet proofing”