I'm having intermittent switch malfunctions with the Castle Ball Lock switch (72) on my WoZ. When not working, every time the monkey drops the ball up there, I have to wait for ball search mode to open the door before anything else happens.

It'll work for a bit then just not at all. If I go into switch test, I can press it 10 times and get nothing then 10 more times it registers. After 10 or so successes, I say 'must be working now' and button everything up. Later, it'll fail in a game. Rinse and repeat.

It doesn't matter if I use a ball or my finger. In either case, I hear the click and if it's in the mood, it registers.

All other matrix switches in the row and column work fine.

A multimeter on the switch tells me (or appears to indicate) that the switch itself is functional. Every time I hear the click, electrically, the switch transitions.

Thoughts?

Whether I use my finger or a ball, the switch clicks and electrically closes (seen by multimeter). This leads me to believe that the switch is not goofed. Wiring perhaps. I've reseated the switch matrix column and row cables on the I/O board as well as the interconnect under the playfield.

It's working, at least for now.

What I'm seeing in-game seems a little goofy. If the monkey captures the ball and places it behind the castle door (and the switch works), I get a brief vibration from the shaker motor and a new ball is dumped into the shooter lane. This is my indication that the switch worked (this time). However, when the replacement ball eventually drains, the game doesn't recognize that the 'ball' is over. It sits until it goes into search mode and frees the ball in the castle; it then lets me play that ball until it's drained. I don't think this is normal.

All trough optos working.

To confirm what I've witnessed in game, I can repeat this with the glass off. Is there a glitch in the code?:
*Hit Monkey targets to enable ball capture.
*Make right orbit to freeze ball on magnet.
*Monkey captures ball and drops it behind door.
*New ball ejected into plunger lane.
*If new ball drains without achieving RESCUE multiball then
---Game continues with no balls
---Ball search opens castle door, releasing captured ball
---Game continues until captured ball drains
---No other ball can be captured (monkey targets are solid, not flashing)
*If RESCUE multiball is achieved with new ball then
---Game continues with captured ball and RESCUE ball (2-ball multiball)
---Once both balls drain, ball over
---Monkey targets are re-enabled (flashing) for another shot at monkey ball capture.

This is with v6.06.

It was the switch (or more specifically, poor wiring of it). Reluctantly I decided to remove the castle playfield to inspect the wiring on the switch and others in the matrix row/column. Low and behold, the gray/black wire had a poor solder joint and was loose to the touch. This explains the intermittent failures I was seeing.

Resoldering that fixed me up.

Thanks for your help, DCFAN.

woz switch (resized).JPG