Afterburner SRAM issue

I picked up an Afterburner that works but most of the graphics are missing
during play (can't see your plane, other planes, background, etc. Pretty
much all you can see is a horizontal line for the horizon. Alot of the text
is also really hard to read.

I was able to get into test mode and it's complaining that IC125 is bad
(verified this by looking at this test screen in MAME since the text was
impossible to read on the game).

The markings on this chip are MB81C78A-35P-SK. It's an 8KX8 CMOS 28 pin
SRAM. Anyone know where I can get one of these?

Also, I did a dump of all the ROM's on the board to make sure they were
good. The weird thing is two of the ROM's which are marked EPR-11109 and
EPR-1110 both came up as unknown with ROMIdent. All the other ROM's checked
out.

So I thought these were bad. I have another non-working Afterburner board so
I pulled those two ROM's from that board and dumped them and checked them
with ROMIdent. They both came up as unknown. The respective chips from board
A have the same checksum as the chips from board B so I'm pretty sure the
ROMs are good.

I downloaded the MAME ROM images for Afterburner and they compare to mine
except for those two I mentioned above. Anyone have any more info regarding
this?

Thanks.

Rodney

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Received on Thu Dec 2 00:19:59 2010