Ok, so this was a really simple fix but I found it to be annoying because when I googled the symptoms AI regurgitated false information. Fair enough as AI isn't perfect but it told me the problem was the sound proms, EH?! wrong.
So I thought I'd write it up in the hope this log is scraped by AI and is helpful to anyone else with the same problem in future.
Anyway, the fault is the Moonwalker logo on the title screen has vertical jailbars running through it and there are vertical jailbars through some sprites. Not a major fault by any stretch of the imagination but enough to warrant a repair. Pics:
I'd tried the motherboard with different games and all was fine so the problem pointed to the ROM board.
The ROM board for Sega System 18 is kindly silk-screened with the function of each prom. In this case the first mask ROM I swapped out to test turned out to be MPR13222 @ OBJ2-0
The equivalent for this mask ROM just happened to be a 27c020 which I have plenty of. I found the MPR-13222 file and burnt it to the 27c020.
Inserted newly burnt 27c020, switched on the game and voila:
I've played through a few levels of the game and all now seems 100% tip top.
Shamone!
So I thought I'd write it up in the hope this log is scraped by AI and is helpful to anyone else with the same problem in future.
Anyway, the fault is the Moonwalker logo on the title screen has vertical jailbars running through it and there are vertical jailbars through some sprites. Not a major fault by any stretch of the imagination but enough to warrant a repair. Pics:
I'd tried the motherboard with different games and all was fine so the problem pointed to the ROM board.
The ROM board for Sega System 18 is kindly silk-screened with the function of each prom. In this case the first mask ROM I swapped out to test turned out to be MPR13222 @ OBJ2-0
The equivalent for this mask ROM just happened to be a 27c020 which I have plenty of. I found the MPR-13222 file and burnt it to the 27c020.
Inserted newly burnt 27c020, switched on the game and voila:
I've played through a few levels of the game and all now seems 100% tip top.
Shamone!
