Mortal kombat 2 help

The3ngineer

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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.
 
i would continuity test all the legs of that chip and all of it's traces, sounds like there might be a break. you might need to look into getting a logic probe tho.

you do not need the soundboard plugged in to test the main board

you might just want to try and find a replacement main board as they can be found fairly cheap instead of pulling your hair out with this one (try and find a single board unit tho it will give you less headaches).
 
PM sent hopefully we can work it out as I am at wits end and I just hate to scrap something that might be fixable. Continuing with the start button after the error the game will play it's just hard to see with the garbled image but it does work, so I figure there can't be to much wrong.
 
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I got a single board MK2 last year that had a rom error on it. I burned a fresh rom, still a rom error.

quite certain channelmanic lent me this piece of advice, take your meter on continuity test and test the same exact pins on the rom socket between the "bad" rom and the leftmost socket adjacent to it.

I wound up finding a dead pin on the rom socket, which is probably due to a bad trace or something or another "inside" the socket that I couldn't get to.
 
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