looking in more detail at the PCBs here is what we've determined so far:
2 on 2 Open Ice
U55 = Not Populated
U57 = A-20255
U62 =
LH52B256N-10LL (32Kx8 SRAM)
MK3/UMK3
U55 = Not Populated
U57 = A-20093
U62 = LH5268AN-10LL (8Kx8 SRAM)
NBA Hangtime/NBA Maximum Hangtime
U55 = Not Populated
U57 = A-20093
U62 =
LH52B256N-10LL (32Kx8 SRAM)
Rampage World Tour
U55 = Not Populated
U57 = A-20255
U62 =
LH52B256N-10LL (32Kx8 SRAM)
WWF Wrestlemania
U55 =
Populated
U57 = A-20093
U62 = LH5268AN-10LL (8Kx8 SRAM)
Populating U55 is a matter of installing
1. install a 32.768KHz crystal near U55
2. install an MK41T56N IC at U55
Upgrading U62 is a matter of
1. Remove U62 and install an LH52B256N-10LL.
2. Remove the 4.7K resistor at R138.
3. Add a zero ohm link at R644.
Thanks to
@Phil Bennett for the excellent info on U62 and to
@rocket for pointing out the U57 GAL differences
I've seen a few MK3 PCB with U55 populated, but it's clearly not necessary, I think that's a good indication that it can be populated and still work for games that don't use it. As for U62 It would be nice to see if an NBA Hangtime could be converted to MK3, that would let us know if the larger SRAM at U62 will still work with games that normally use the smaller SRAM. If so that would be good for a multi as it would mean we could have 1 hardware config that works with all games.