Shot in the dark...
Check the diode on the buy-in button. Make sure it's not backwards or touching a solder lug it shouldn't.

After that, get into switch test again.
Remove the left most switch matrix connector (white and green wires); the one just above the (orange wires) direct switch connector.
Retest.

Report back.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

So what's the issue with 84 center lock?

Are all other switches working as they should?

Are you saying when you interrupt opto 73, opto 74 also activates? If that's the case and you're getting phantom switch closures with the optos, you've likely got a bad LM339 chip on the opto board under the playfield.

never mind......started to post and had a situation pop up before I could send.....didn't see your report back before posting. Good call Chris.

Why thank you sir!

Removing J212 takes the cabinet switches out of the matrix.
I suspected that the buy-in button diode may be the issue since the buy-in button, switch 73, 74, and the always closed switch 24 (which is on the coin door interface board) make a rectangle. Switch matrix problems like this always manifest in a rectangle.

You're buy-in button will have two diodes. One is for the lamp and one is for the switch. In the first picture, you can see the switch diode, with the banded end connected to rear-most lug of the switch.
image.jpg
In the second picture, you can see the white wire is connected closest to the coin door, and the green wire right behind it. The non-banded end of the switch diode connects to the same lug as the white wire.
image-827.jpg
An additional requirement for the buy-in button to help "cause" this problem is that the buy-in button must be closed, or damaged/miswired in such a way as to appear closed. If the white wire and the green wire conductors were touching on the switch, this would cause the problem.

--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

My pleasure swedishc!
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info