Picked up a CYCLONE last week, and made the trip home. After setting it up, I started to do a little work on a few lights and a flipper diode that was broken off, but kept getting a Switch error message (System 11 Williams) on SW53 SW54 SW55 and SW 56, the Out-lanes and return-lanes...

After the normal switch test and the edge test, all of which I'm new at using, I turned the playfield up and started to ring out the wires back to the J8 connector on the MPU. I used the opportunity and the newness of the game to engage the help of my 13 year old son to learn about Diode testing, using switches, the DMM and the continuity test. We unsoldered one end of the diodes and used the DMM to test all 4, but they were OK. He was impressed at the bundle of the wires on the bottom of the playfield, but that by taking a single wire approach, we could see and "hear" the continuity and where we lost it.

As it turns out... there was no problem with the wire, but the problem was in the black colored multi pin connector between the playfield pig tail bundle, and the MPU bundle. This connector showed some dusty white corrosion, so a Dremel bristle brush, and simply plugging it in and out a few times returned the continuity to the MPU. Upon restart the switch errors were still there, but they were now working, after one more successive electric restart, the errors went away, and the game is back to 100% working. I attribute the holding of the errors to the fact that the MPU must see the switches "work" during gameplay, so after depressing all 4 rollover switches in the first startup and trying a game with the glass off, that reset the MPU, and threw out the errors.

Very nice to be working on a machine with some diagnosis capability.
My son was really enjoying the troubleshooting task as well, and he can now tell me what a diode does, and it forced me to polish up on my electrical troubleshooting skills too. It was a great learning experience for both of us.