I have a Williams comet, and am having an issue with a switch. I only got this pinball a week now and have repaired a few items and it was working ok.
Just now a problem came up that I didn't have before. When the ball activates the comet ramp upper switch (at the end of the ramp) the machine also think the outlane switch is activated (I think the right outlane). When I keep the switch of the right outlane activated the switch of the comet upper ramp works fine.

I disconnected J8 and J10 and when I connect J8-4 and J10-6 (the comet ramp upper) pins all works fine so it seems to be in the switches/wiring.

The reverse is not the case, so when activating the right outlane, the comet ramp upper switch does not get activated.

I don't fully understand the working of the switch matrix and how the diodes come into play, but I measured the diodes in circuit and they seem to be ok. There also doesn't seem to be a short, but the switches are connected right after each other.

Any suggestions are more than welcome!

Screenshot 2019-11-27 at 00.59.10 (resized).png

Just one more thing to clarify, with right outlane I mean the "right drain spcl" switch.

Thanks for your help, my credit/ball display is not working so that makes it hard to troubleshoot the switches.
I did however finally found out the slam tilt switch (7) was stuck. I had worked on the coindoor and got some cable in the the way of the switch. Freeing up the switch fixed it. But I guess I need to check the diodes on the 4 switches, as I understand one of them is shorting.

Thank you all for the help