I recommend we start by finding the 12v and ground we need to power the control board and panels. Based on the service manuals this is black (GND) and yellow(12v) so it should be easy to find and as far as I know this is only used for the MVS and the coin door lights. My initial testing has told me of 4 possible power supplies’ so far.
1.Hantarex 250
2.Peter Chou
3.Hap controls 80-0001-10
4.Pesco model 01-1115
The Hantarex has only shown up in the 6 slot, but I have seen all of the others in uprights, big reds and tall boys. Lucky for us they all stick with the Black and Yellow colours, but the Hantarex has a different power plug. The Peter chou, Hap and Pesco have all had the same 9 way Molex connector with the same 5v, GND, 12v positive and negative connections. I have made up leads that go between the PSU and the MVS harness, so you do not need to modify anything to grab the 12v we need. We just plug which ever lead matches your power supply in and feed the 12v wires to the position of the control board. Always make sure the connections are the same as our leads, who knows what mods someone has made in the past that could be very bad news for your MVS.
If you’re happy to mod the harness and save the cost of the cable you can use automotive wire splices to patch 12v from the wires, cut them and solder back together with heat shrink to stop any short circuits or re-pin the molex connector if you have the tools. Ground can be taken from any black wire, but I think it’s safer to use one direct from the PSU at the same point as the 12v.
Secure the 12v leads for easy access later.