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Hi, new here. I've got two copies of Roger Clemens MVP to use as donor boards, one is a 53361-2 (MC-ACC) and the other is a 51555-2 (MMC3B).

I also have two pairs of 27C020 (one each for CHR/PRG), one with Mega Man 5 and the other with Bonk's Adventure. Both EPROMs work properly on the 51555-2 (MMC3B) board.

The EPROMs, when put in the 53361-2 (MC-ACC) board, seem to boot fine, but the graphics are partially corrupt. I've tried rewiring the CHR EPROM a few different ways, but have had no luck.

I've seen mention that the 53361-2 (MC-ACC) is 27C101 compatible, but I don't have any of these to test with, not to mention they would be too small for my needs (I need 2Mbit).

Has anyone figured this out? Is there a way to run 27C020 CHR on a 53361-2 (MC-ACC) donor board properly? My gut tells me it's simply missing an address line, but I'm new to this and wouldn't know where to begin.

Thanks for your help!

I don't think it's missing an address line because the game you mentioned uses a 2 megabit CHR-ROM. I cannot tell you the pinout of the MaskROMs or the MC-ACC chip but it is apparently a MMC-3 clone. If they are compatible with standard EPROMs and you have sockets on the board, see if the original MaskROMs are working through your sockets still. Maybe you just have a bad connection somewhere. Or maybe the MaskROMs are not EPROM compatible.