For the book case, since that harness moves. I'd check continuity of wiring from connector to bottom optos and top optos. Easy to have a break inside the wire casing you can't see, or to the top board in the book case.

LTG : )

check that capacitor, on my TAF I got the same problem, Check it with a ESR meter, or just change it,
In my experience small capacitors tend to fail more often than big caps

Also, with your cel phone, using your camera, and in video mode, (there's no need to film) just watch if you see violet color on each opto led on the bookcase, (the ones not in the floor the bookcase , those are the receivers).

Check with the cel phone, and you could see them with a violet glow.

And then in switch test mode, grab a TV remote control, and point to each of the opto receivers and see if the switch test register each opto!!.

That worked for me!. to troubleshooting them!

good luck

also, clean the emiters and the receivers with isop alcohol and a Q tip. You will need to disassemble in order to get them clean.

But , with the above , (TV control and cel phone camera) you will know which opto receivers or emitting diode is working or not, not mather if its dirty or not

That is the 1st problem to solve.
Measure voltage on J3-1 (+14V) and J3-3 (GND) on the 7-opto-board. (Do not measure from GND in machine.)
This power is coming from powerdriver J116/117/118.

TZ 10-opto and TAF 7-opto boards are not compatible
TZ is 2col. x5row
TAF is 1col. x 7row

I didn't want to start a new thread for this subject since it has been covered in multiple posts. I just rebuilt an Addams that I have reinstalled the playfield and have fired up. Everything is working with the exception of the error on startup of check bookcase optos, 53, 54, 55, 56, check Thing up and down. I also believe that the bumper lane opto #57 is not working. On the 7 Opto board, the LED is not lit, but I do have 14V at J3 pins 1 and 2. But I am only reading .520V at J2 pins 9 and 10. I confirmed with a camera that bookcase optos are not working. Does this sound like the board has failed or something else? This game came in with CPU acid damage that has been professionally repaired and the power/driver board was gone through at the same time. I can't confirm if Thing and the bookcase worked upon arrival, but I do know that there were a ton of standup switches, etc., that did not work.