742A-326 is "horseshoe scamble" made for binion's casino. The schematic would be w-1046-685 and will be extremely difficult to find.
the glass, reel tapes, reel wiper wiring, payout counter wiring and slotted reel index discs appear to be unique to the machine, but the rest of the internals should be very similar to any 742A. You can poke around in
https://bingo.cdyn.com/slots/ for paperwork and manuals.
if your meter is popping fuses, the metal case can be removed so you can see the coil inside - look for folded over metal tabs which you unfold and slide off the case. Assuming it's not just the coil lugs shorting to the case where they go through the holes, the coil itself is probably bad and you'd be looking for another 50V "tab" meter.
I can probably scrounge meters from the pacific pinball museum warehouse if you can't find any.
meter are most interesting if you have "coin in" and "coin out" so you can see the actual payback of the game and compare it to the statistical payback which can be calculated using the frequency of the symbols on the tapes and the payout table.