Mortal kombat 2 help

[the3ngineer]

I just purchased a mortal kombat 2 pcb from craigslist. Of course the guy told me it worked but when I got it home it said CMOS error so I changed the battery and that went away. Now when I plugged it back in it said bad ROM (UA8) I replaced the UA8 chip which is a MS62256L-PC with a D43256BCZ-85L which the guy at Tanner electronics said "should work". When I looked it up it said that everything was the same but the speed (the last two numbers). Now for the great part, at this point I realized that the secondary expansion board was missing (to my credit I assumed it was the newer board that didn't require the extra board) so I called the guy and he miraculously located the board. I thought this might fix the problem but when I hooked it up and plugged it back in same error, bad UA8. Now I went a replaced other chips that are related to the UA8 and still same thing.

Here is what I have done.
1. reseated and sanded all legs on all ROMS
2. reseated and sanded UB21 and UF5
3. socketed and replaced ROM UA8 and UC8 with D43256BCZ-85L
4. socketed and replaced UB5, UC5, UA9, UB9, UA10, UB10, UC15, UC16
5. checked all legs on the back of both boards to verify that none of them are touching.
6. adjusted voltage to read 5 at rom chips, not at connector.
7. looked for broken solder with naked eye.

Questions
1. is it ok to use D43256BCZ-85L inplace of the other chips?
2. is it ok to use sn74als374n instead of sn74ls374n?
3. is there anything else I should check or any other chips up or downstream that I should change?
4. could the roms cause this issue?
5. do i need the sound board plugged in to test the main pcb or could it cause an error if not plugged in?

Any help would be greatly appreciated as I have a 10 year old that is wearing me out about fixing this. Thanks in Advance.

[paigeoliver]

Silly question, but did you actually program the chip at UA8 or just plug in a blank rom chip?