S2K Buttons Not Lighting

[DoubleZero]

Old S2K still coming back to life ... Everything is working fine, it's finally playing great, and there are no errors. Buttons work perfectly, but none of them are illuminated. Any thoughts on where I ought to start with this? Before you ask, yes they have bulbs inserted!

[brianfink]

If your bulbs are good and the right ones than it is probably your door I/O card or the wiring.

[Bspun04]

off the top of my head because I was just working on a few, the wires connected to the micro switch and lamp socket have been reasons before why buttons wouldn't be lit...but seems if your switches are working fine with the buttons then they should be connected right.Make sure your red and blue wire connectors are on snug. If you are using LEDs instead of lamps it would matter how the bulb went in (+ -). I know you said you have bulbs inserted but are they new or ones that have been in the machine for years? If not new, throw some new ones in to rule out that being a problem. I can't think of much else being a problem when it comes to lighting up the buttons. If you have an extra door i/o board lying around, throw that in and see if anything changes in the chance something went wrong on the board. Seems like a good starting point in figuring it out. Good luck and hope you figure it out!

[DoubleZero]

Well, it took me several weeks, but I've finally fixed this issue.  I had swapped bulbs, I/Os and the MPU and verified all plugs and connectors were snug, but to no avail. My last idea - to swap out the button harness - proved to be the solution. Turns the old harness had some poorly spliced wires (although I'm not sure why) and a couple of spots where the insulation appears to have melted to the point of exposing the wire underneath.

Whatever. It's fixed now. Thanks to Ohio Gaming for the harness swap and thanks to you guys for the ideas and encouragement! Consider this topic closed!!