Ok, that has a pwr supply in the cab so its do-able. But....the Ms Pac wants to see AC voltages instead of the DC that the pwr supply is putting out. You *can* run a pac board off straight DC, but it involves soldering wires onto the board to bypass the onboard regulator circuitry.
http://arcarc.xmission.com/PDF_Arcade_Bally_Midway/Pac-Man_Parts_and_Operating_Manual_(Dec_1980).pdfThe schematic for the board is on page 34. In the lower L corner the pwr supply is detailed. The 12vac inputs are the easy part. You can just pick one and put 12vdc on it. Its only used for the audio amp, so there's not a lot of constant current there.
Now notice at the top there is a 5v output they brought out to the edge connector. You can use that to get 5v onto the board, but one wire won't be enough to make it run reliably (it may burn from too much current pulled thru it) so you'd need to jump an extra 5v wire straight to the board. No big deal....
Just get the right edge connector (44 pin) for the pac and the correct fingerboards and you should be in business.