January 30, 2005
Fixing the damage
So here's what seems to have happened.
A few weeks ago I was messing around with the ramp diverter. When reinstalling the coil that drives the diverter, I left the wires in a state where there was considerable physical load on them, sort of wrapped around the coil.
It took some time to take its toll, but what ultimately happened is the power source driving the ramp diverter coil got shorted and 68VDC found its way to the ramp diverter itself and everything electrically connected to it. I discovered this while messing around with the mini playfield: trying to figure out what on earth was going on, I received a shock from the side rail on the cabinet. Probing around led to the discovery of this serious (and for that matter dangerous) problem. If I had a full comprehension of the way this game is designed and wired, I might have been able to figure out what might have been zapped, but I don't, so I cried for help.
It's a big world out there. How big? Well it turns out that I'm not the first person to have his TZ's ramp diverter coil short to the diverter itself, causing 68VDC to go places it shouldn't and blow stuff up. Not only has it happened to Kevin Ramsey, he was reading rec.games.pinball at around the time I cried for help, and told me of his experience.
So you can click that link above for more gory detail, but enough's enough. Present status: I found some spare parts from several years ago and replaced the optos at the lower exit of the power playfield (their failure got this whole thread started with me wondering why the flippers were firing when the ball entered the powerfield) and they work again. Every switch in column 4 still causes its row to close (which is very very bad), and I have ordered some new chips to replace U14 and U20 on the CPU board (picture above), a slightly scary prospect. With any luck those new chips will make the game happy again.
Now to figure out why the lights won't turn on in my office...
Posted by spblat at January 30, 2005 10:26 PM