Quoted from ItsOnlyPinball:
Thanks Vipperrwk, I love your Game Plan tutorial post that you previously put up as well. Actually, though, I get the SS2 sounds and everything. Only problem I encountered was a little flakiness in the displays that I did not previously get with the Pinball Lizard.
Do you think I should still ask for the SS2-specific Rom? I would most likely use the new board in my SS2 since the previous MPU worked great in the Lizard.
First, I made a mistake for which I apologize. It turns out that Lizard uses the same three ROMs as OCI and Sharpshooter. The checksum at U26 is the same for all three - 1C21 (was looking at the wrong file yesterday.)
I had a MPU-2 board from a Sharpshooter that had the U26 from a Sharp Shooter 2 installed. It worked but sounds were not quite right. I also tried the U26 from Sharpshooter in the emulator for SS2. Again, it worked, but it wasn't quite right.
It is possible that you had the wrong ROM installed in your Sharp Shooter 2 so when you swapped boards, everything seemed normal.
if you have the original masked ROM, the U26 for Lizard should have P/N 26-30022 on it. I do not know what the P/N is for U26 in SS2 but the checksum is 2CA3. By comparison, the checksum for 26-30022N is 1C21.
Going by this, the ROM set on IPDB for Sharp Shooter 2 is wrong. It has the U26 from SS/OCI/Lizard in there.
It would be best to ask Jim which images he uses for each game and what are the checksums for the ROMs he combines for his boards. If he says they are the same between SS2 and Lizard, then I think he's not using the correct U26.