I discovered that one switch on my Zaccaria Magic Castle was disconnected. It was obvious that the operator had done it intentionally, but I couldn't imagine why. Please see the attached photo. The switch is contact 47, 50.000 PTS CENTRAL BANK.
Because this was completely disconnected, the central droptarget bank was also not registering.

So I connected the two green wires to one lug of the switch, and the two white/purple on the other side.
When I fired up the game, IC38 on the CPU board exploded! That must have been the reason why the op had disconnected it.

I read on zaccaria-pinball.com that this may be caused by a short circuit between the +39V solenoid voltage and the switch matrix. After the accident I measured between each of the four wires and ground, and I didn't find any +39V. The results were +5V,0V,0V,+5V.
I also tried checking for continuity between each of the wires and the lugs of all solenoids, but couldn't find anything.

Do you have any suggestion how I should continue troubleshooting? I read that all the solenoids are powered all the time, and that they are activated by switching them to ground. So could it be that one of the four wires are stripped and is somehow shorting one of the solenoids to ground?

If I connect up the two green wires now, all of (or many of) the coils are firing. But I don't know if that is to be expected now that IC38 is blown.

wires.jpg