Have you Q tipped the receive opto? Else, if no wires have broken off the optos, try reflowing their solder pads. Otherwise the transmitter is usually shot.

Two tiny boards mounted to the VUK underneath. I'm assuming, I don't have a FT. (So sorry, no photos either.) They'd each have two wires, all four going to one connector. Make sure that connector is tight, and the boards themselves, if one's loose they won't line up and the game will think there's a ball in there.

There'd be only one component on each board, LED shaped, those are the optos. Clean em, if that doesn't do it just reheat the solder where they attach to the board, the clunking of the solenoid often fractures a solder joint. If still no go the transmit LED (clear one) probably needs replacing, you could change the LED or the whole board, it's cheap. If you can't see it glowing it ought to show up brightly on a cell phone camera if it's working. If it's not dark but dim that'd still be why things aren't working. Might want to replace the receiver too, apparently modern replacements and old ones don't always play nice.

Uhhh, ok, that uses a leaf switch, not optos!

So what I said above does not apply.

It looks like maybe the switch is closed without a ball being in there. That'd do it! You could test it in the switch test, or just go ahead and visually check/adjust it so it is open when no ball is in there and closed when there is. Use a ball, not your finger, and do it with the power off!

Your switch test is probably the easiest way to check it. The manual at IPDB shows the switch matrix on page 98. Number 47 is the ball popper, I think that is the VUK.

Using your DMM set to continuity place one lead on the switch where the brown wire is connected, one lead on the switch where the black wire is connected. Without a ball in place there should be no continuity. With a ball in place there should be continuity.

Hang on a minute, I was so transfixed on the contacts that I didn't even look at the paddle(?)!

Looks stuck down to me, I don't see where it could ever go more down!

Is the one side bent and wedged in? Probably because that rubber(?) thing on the end of the solenoid's plunger does not match the manual drawing.

That switch is only supposed to close when a ball is resting on it.

smush (resized).png

poppertop (resized).png

Great! I assume you bent that paddle back where it belonged. Good for a quick fix, but you may want to eventually get the correct part for a permanent fix.

No, sir he's talking about the ball cup that rides on the top of the plunger (see the exploded view drawing). You don't put in an opto but if the cup part is interfering with the switch blade you should order the correct cup for the ball to rest on.

In post #9 above there is a picture of your switch and a black rubber piece on the end of the plunger that ejects the pinball. Look down below that there is a little drawing with numbered parts. What he is saying is that the cup (marked 3) in the drawing is what is supposed to be on your game, not the black piece that is there in the picture.

http://www.marcospecialties.com/pinball-parts/565-0029-01
http://www.marcospecialties.com/pinball-parts/03-8053

Two links above. First one the the VUK popper replacement kit and second one is just the black cup so that you can see it. NOTE: if you buy just the cup, you will also need the small round elongated roll pin that holds it in place. See the first kit to see details.

Why do I get the feeling he's "not gonna fix it if it ain't broke"?

Good team effort, though, everyone! Helping out someone with their pin, somewhere in the world, we don't even know where!