Like many of the Williams games, Sinistar had labels on the roms from right to left making them upside down to all other print on ICs & the PCB. This causes the ID notch for pin 1 to be on the right side of the chip instead of the more common left side. Placing roms in backwards renders them to paperweight material, so ALWAYS check to be sure that the notched end is in the correct way...usually, all notched ends of chips on a PCB will be in the same direction, but trust in your eyes & mating pin 1... notched end of rom... to pin 1 of the socket as marked on the PCB, because many times the socket itself will be mounted backwards!
The notches on the rom board above are all on the right side as pic'd. Once again, NEVER use the label as a guide for inserting any roms, proms or eproms!