I've got a Gilligan's Island I'm working on for a guy. A few months ago I replaced the island motor opto and board as it wasn't registering at all, not even when I tested it by hand with a nice thick piece of plastic. Turned out the board was cracked and had a broken trace, hence the full replacement.

Went to check it out tonight on an unrelated issue(that got fixed), and after a couple of fun games, the island is turning and stopping in strange locations. Started up the switch edge test and the wheel opto is flickering and going crazy. I started checking other switches in the same row and column just as part of the standard testing procedure I've learned to do(thanks to previous experiences with my TZ).

Well, the strangeness ensued. The wheel opto is 77, when I hit the Top Eject switch, 67, the opto stops flickering and stays open. Then, I hit one or both of two other switches 62 and 72, and it affects the opto. It'll either get it flickering again or stop it. With all three depressed, 67, 62, and 72, the opto flickers.

I'm guessing it's a bad diode somewhere in the line, but it's been a while since I had my last class in switch matrix theory so I'm not 100% sure.

Thoughts? Ideas? Experience? Solutions?

Thanks in advance!

The top eject, switch 67, was the only single switch that directly affected the opto's performance. I checked that diode and it was intact. I guess I should've put my DMM on it, too?

I guess a dead diode on switch 67 would really only affect switch 77 since switch 87 isn't used. Does that sound right?

Bump

Any other ideas or suggestions on what/how to check?

I'll give that a shot, can't hurt to try!

Out of curiosity, did his top eject hole affect that wheel opto the way this one does? Seems like one switch should have no bearing on what the other one does.