Check all the column voltages. The signal is pulsed and column 6 will most likely be locked on and reading slightly higher than the other columns (this indicates a board problem). Best done with a logic probe, but a DMM will work.

In regards to the switches that don't work it is most likely the switch is not working or a broken wire to the switch. In each column all of the switches will have two grn-xxx wires, except the last switch which will have only one grn-xxx wire. Ditto for the rows except with wht-xxx wires.

P.S. - Very nice job of describing the problem and thanks for adding the switch matrix diagram. This is a great example for anyone having switch matrix problems of how to ask for help.

Not sure on Data East, but on Williams manuals there's a page that provides a generic schematic of the column/row drivers. Then all you have to do is check the specific column you're concerned with. If you can't find anything post back here and I'll dig out a manual and give more specific directions. The following page may help also.

http://pinballrehab.com/1-articles/solid-state-repair/repair-guides/146-switch-matrix-theory-and-troubleshooting

Have you isolated the problem to the board, as in disconnected the playfeild switches and jumped the pins to see if it is doing the same thing ? I had a recent problem where the diode was shorted to ground on one of my switches cause a similar problem. Otherwise on the board I would check the *going from memory* SIP resistor packs, the component that looks like a straight line with 9? legs somewhat in the middle of the board (as I recall they don't make the correct one anymore and you have to modify the replacement by cutting off one leg

I seen a similar problem and it was a ball trough switch broke

Just disconnect the column connector and then check with your scope again. No need to jumper the pins, this will tell you whether it's the board or a playfield short.

I agree the SIP's often cause problems, but let's not jump there yet.

check the SIP resistor pack, compare each leg against the others and see if one or more have a different value

See the attached image. You've already tested at point A. Proceed testing upstream at the other red dots: B, C, D and E. You can compare each reading to the green dots I placed.

Image3.jpg

If you're saying the collector has a problem and the base reads properly then I agree. In other words, point B reads differently than the other B and C reads the same as the other C.

Congratulations on getting it solved. This post should be put up as a sticky to show that's it's really not that hard to troubleshoot a problem rather than just shotgunning it.

That requires patience and reading though.