It is truly an awesome machine. Four flippers, optical targets in the bookcase, automatic flip that learns to hit a particular shot…
The upper left flipper — the thing flipper — had recently started to behave a bit oddly. At first, it was flipping, but not holding (it would bounce at extension and then snap back to resting position). Later, it started holding at maximum extension at random.
Tonight, I dove in and discovered that there was a catastrophically cold solder joint. A Williams pinball flipper is actually two coils; a high power “flip” coil and a low power “hold” coil. Across each coil is a diode that prevents the induced current caused by the collapsing magnetic field from blasting the flipper control board.
Well, the cold solder joint was such that the flipper was “holding” when it shouldn’t have. When we (the machine is actually at my neighbor’s house as a party prop — I just haven’t dragged it back yet) discovered the problem, we shut the machine down. If it had been on location, this problem would have quickly escalated into a full blown flipper control board melt down.
Unfortunately, replacing the diodes didn’t lead to a working hold circuit. Turns out that the coil was on its last legs, too. Fortunately, I had a replacement. Unfortunately, replacing the coil requires enough disassembly of the flipper mech such that any caring maintainer cannot possibly do so without also doing a full flipper rebuild.
So, Thing’s flipper has been fully rebuilt. And now Thing is very confused — “he” has dropped from about 98% accuracy on his auto-shot down to about 20% accuracy. I’m sure he’ll get better soon. Just in time for me to tear down the machine, pack it up, and set it up at the Maker’s Faire. Which, of course, will mean that Thing will be right good confused once again.
Don’t know what the hell I’m talking about? Show up to the Maker’s Faire and I’ll explain. Better yet, I’ll show you because I will be bringing my Addams Family pinball machine to the show.