Debugging Metal Slug 1 problem with CHA256 board

[pollsoda]

I purchased an untested Metal Slug, and it has severe graphics corruption while playing.

Gallery:
http://imgur.com/a/WeH2e

The corruption showed up even in the UniBIOS (program ROM) CRC cart check.

As a test, I used the CHAFIO (second) board from my KOF99 board and put that in place of the CHA256 that comes with Metal Slug. Lo and behold, the previously corrupt text showed up as readable. I was able to test the PRG portions of the cart successfully, and that seems to be okay:

http://i.imgur.com/4I8nSck.jpg

So it's obviously something with the CHA256 board. Is there any way to tell which one of these is at fault, or test them?

TC5332205AP 42-pin C ROM (labeled KM23C32000 underneath)
TC531000CP (S1)
TC531001CP (M1)

NEO-ZMC
74LS139A
74LS74A
NEO-273 (unlikely?)

I have a TL866A programmer - I wasn't sure if there was a way to dump the C ROMs with this device even with a 42 DIP adapter? I wanted to verify them against good dumps. Is there any way of confirming each of these chips somehow?

In any case, any suggestions for how to debug this further? I don't mind that it would be a hack fix/not original - I'm really just interested in learning (and maybe playing Metal Slug!).

Thanks

 

[mikejmoffitt]

Definitely at least there is a problem with one FIX ROM address line. Through the holes in the graphics, it looks like the C-ROM addressing is a bit wrong too.

 

[Xian Xi]

Looks like you have both high and low address problems from the C roms. Check for broken solder joints/traces. If someone sanded the cart edge, check to make sure they didn't severe the traces that connect to the cart edge, that's a common problem from sanding.

Of course, with everything being affected it does kinda point to the Neo-273.

 

[pollsoda]

Of course, with everything being affected it does kinda point to the Neo-273.

That's what I'm afraid of. Where do you source one, and if from another game, what's the cheapest suitable board with one?

I was able to dump S1 (TC531000CP) with my TL866 - it's basically a 27C010 with a couple of pins swapped:

View attachment 42817

From looking at the spec sheets, the M1 (TC531001CP) is basically pin-compatible with the 27C010.. <?>

View attachment 42818

I dumped both my S1 and M1 (as 27C010) and verified the checksums against the MAME ROMs and it looks like I'm good there.

59b0200b7ed4f9704e6f34fa6d05796e *s1_dumped.BIN
59b0200b7ed4f9704e6f34fa6d05796e *201-s1.s1

6449db0459bcf7584348792009e8f12c *m1_dumped.BIN
6449db0459bcf7584348792009e8f12c *201-m1.m1

For S&G I went ahead and swapped out the 74LS74A, no difference. Since I'm learning, I then burned 201-m1.m1 to an OTP 27C010 and dropped it in, also no change.

I'm waiting for a 27c322 adapter for my TL866 (I'm going to have to build it myself) so that I can try dumping and verifying the C ROMs, but I'm afraid like you said it may be the Neo-273.

If someone has a spare Neo-273, let me know. The cart isn't going to get any more unplayable, so I'm just using this to experiment and learn.

Thanks for your suggestions so far, let me know if anyone thinks of anything else!

 

[wingzrow]

If someone sanded the cart edge...

I thought people were joking when they said people did this. That's horrible.

 

[HeavyMachineGoob]

CHA256 is the most common character board in Neo Geo games. Below are some cheap examples:

Art of Fighting 2
Fatal Fury 3
King of Fighters 94, 95, 96
Samurai Shodown III
World Heroes 2 Jet

 

[Xian Xi]

If you need one, I probably have some spare boards sitting around, just cover shipping.

 

[pollsoda]

Just wanted to report back that this story has a happy ending!

@Xian Xi I pulled the Neo-273 off the board you sent me, and popped it onto my CHA256, and BOOM! Came right up.

THANKS DUDE!