A little background -

After moving all the pins from the Bat City Open my BSD decided to have a melt down (almost literally, the 12 volt UR fuse burst into magic smoke)
After moving the machine into place I powered it on and everything was fine for about 30 minutes. After that I hear the mist motor start running, and some coils start firing, I look up and notice that my display is all kinds of screwy, and then I smell smoke.
I turned it off opened it up and saw nothing melted or burnt, strange, but so far so good. I start going through the DMD looks wrong list, ribons, fuses, connectors, all fine. Power the machine back up, no smoke, still no picture, and the mist motor is still running. Ok, so the game thinks there is no ball in either mist gate, great, a place to start, no optos, must be the 12 volts. Since it worked for 30 minutes before hand it's got to be a fuse. Pulled both of them, and sure enough the 12 volt UR fuse is blown (pretty warm too, and smells burnt. AH-HA) replace it, power up, everything comes back like normal. Then I notice that the fuse is glowing orange, not good I think to myself, while powering down again. I replace the fuse again, this time, I have my meter on the TP for the UR line. before the fuse melts again I see a reading of about 300+ volts there. Power off again, pull the fuse, power on again with no fuse this time, DMD gone, mist motor running, all the same stuff as before. Put the meter on the TP again and still see 300+ volts.

Now that I've found the problem, what the hell do I do about it?

Tell me about it, at first I thought my meter was broken.
But no, this machine is unmodded.
I've never seen any voltage even remotely this high before, which is why I have no idea where to start, or what to look for.

Thanks, zaza, I'll report what I find, hopefully, tomorrow evening.

zaza OK, so far it seems like I am getting 200 to 300 vDC through everywhere that runs off the 12 unregulated. The 12 regulated line is at 11.99 and stable. 18V, 20V, and 50V lines all test within range.

OK, so I have no idea what happened, while I was poking around checking voltages I must have un shorted whatever was causing the problem. There must have been something pushing display voltage to the 12 V UR supply.
I'm going to keep this thread open for a bit in case the problem returns.
Thanks everyone for the input.

Still holding strong, still no Idea what caused this...