Hello there- found this forum while searching around. I recently purchased a GS logic board, still sealed in its electrostatic plastic. It seems to be a stealth board, actually. Anyway, I noticed the ROM chip has an IC number that doesn't match anything I've found online. ROM0 is 342-0077-A, ROM1 is 342-0077-B, and the ROM3 chips have their own separate set of numbers. Well, this chip happens to be 342-0077-C. If "9235" is the datestamp of the chip, then it would have been manufactured in 1992, after the ROM3 was released. I am guessing it is either a second rev of ROM1, or possibly some kind of updated "ROM 1.5" perhaps with other fixes, as a replacement part for ROM1 machines. This is a service item, so this was manufactured specifically as a replacement part. I've attached some photos, would appreciate any information.