The short version: Right flipper opto switch is bad. Instead of sending a clean on/off signal, it's sending a stream of pulses, causing the high-power side of the flipper coil to buzz. That's why I had to replace this particular coil. Read on for the long version.
I can't believe how fast the folks at PB Resource provide service. I love these guys.
OK. So I've rebuilt both right-side flippers, coils and all. The top right coil was fine but I replaced it anyway because I suspected the weak bottom right flipper (even after total rebuild) was due to the top right sucking away too much juice.
As they say in the science community, this hypothesis was not borne out by the available evidence.
Additional screwing around showed that the bottom right flipper, still too weak, is buzzing when I hold down the button. Sure enough, my new coil is super-hot, evidence that the high power side is staying on too much, too long. No wonder the last one was toasted.
More troubleshooting: EOS switches were never malfunctioning. Flipper coil test in diagnostics A-OK. Uh oh, that suggests it's a switch problem. Unplug and replug all the fliptronics connectors under the PF a couple times: no change. Blow some air into the right flipper opto switch: no change.
Unplugged right flipper opto connector. Used a staple to repeatedly short the connection between "GND" and "SW1". No buzzing. Flipper works perfectly, again and again and again. Flipper coil cool.
Harumph. Bad opto?
...or is it? After replugging the connector life seems good again...but only for awhile. Let's examine the opto board, resolder the joints.
Better, but still not perfect. Take it out again, clean the optos with a glass wipe, blow dry, even worse. Swap flipper opto boards, problem moves to other side. It's time for a new flipper opto board. Maybe two.
Here is a heated and interesting discussion about this very problem.
Posted by spblat at December 29, 2004 03:17 PM