VKB-SIM

It turns out that the button works when the handle is open and stops after assembly?

That happened once.

When it stopped working after assembly, I took it apart to the point where I could re-check the switch. So I removed the cover, removed the board, and tested the switch again.

The switch operates as follows, using the picture with your probes:
Red to Black: Switch off: open Switch On: Closed
The lead without the probe is always open to Red and Black.

Then I put the board back on but did not assemble the rest of the stick, hooked it up to VKBconfig and polled buttons. Everyone worked but C1.

I have removed/re-seated the board several times now with the same result.

Are you thinking there's a fault in the connection with the board? If I seat the board and remove the cable, are the places on the board I can probe to check that?

You can try to neatly close the same two pins with a paper clip when the backplane is installed and see the reaction in the configurator with the Poll checkbox turned on.
Be careful what you short out.

Did that, No reaction. It should have lit the red square, right?

Then we conclude that the board with the button is faulty, which needs to be replaced.

Do you know how I go about getting the part? I've put in a ticket, # 3138, but is there something else I have to do?

Just update the ticket with a link to Ron61's resolve, so they'll know what parts you need.
Thanks for your patience.

How long will it take? I heard back, and verified my address a week ago.

Means the parcel is prepared to get picked up by the courier. You'll get the tracking soon.