Resoldered M1 and V chips, still no sound? MVS Metal Slug

[Xian Xi]

Sometimes there are differences between revisions. If you want you can burn a copy of the M1 you are comparing it to and install it and see if the sound works.

Try going into the Unibios jukebox, if there is a hardware problem usually it will say something like "problem in the sound section" or something like that. Also you still need to get a probe because it's also a possibility that the ZMC is bad. I've only had 2 carts with bad ZMC chips so it's possible but not very common.

 

[mmmonkey]

Thanks once again. Will pickup a probe next time I have some spare funds in paypal :-) I am getting a MC271001-12F1 to try the downloaded M1 rom on also (it was very cheap)

 

[CafeineCake]

check the sha1 / crc323 of the dumped rom against neogeodrv.c (of the top of my head) from mame source. i dont know if this has all the signatures but it should give u an idea.

 

[mmmonkey]

Hey CafeineCake :-) at risk of getting shot down by someone else, I've no idea what that means :-( can you put it in complete noob speak for me - do you mean compare the CRC with the ones posted on the web - like this site - http://maws.mameworld.info/minimaws/set/mslug

Pete

 

[Xian Xi]

Baically just verify the chip against the mame dump of the M1. I think for MS there is only 1 set so if it doesn't verify then burn a new one.

 

[mmmonkey]

really must get a probe! The ones I keep seeing have crocodile clips for power and say that they are to be powered by the circuit being tested. Is that necessary, or can it just be powered by an external source?

Anyway, I thought I flashed an eprom with the M1 rom I downloaded, fitted it, and it didn't work. So I thought I'd make more use of the desoldering gun and transplant M1, S1, C1, C2, C3 and C4 to another known good CHA256 board. Made sure all the jumpers were setup correctly and I have exactly the same problem, no sound at all. C chips are graphics and sprites which are working fine, M1 has been replaced, leaving just S1 right? (the other chips on the CHA256 board are fine as the game that the board belongs to worked fine - KOF94).

I've smelt enough solder fumes for the day!! Is it worth desoldering S1 and dumping it to see if it's okay and burning a new one - will the MC271001-12F1 chip be okay for this? I can erase it and program it.

ta
Pete

 

[Xian Xi]

Only the M1 and V roms would affect sound. If you are using the same PROG board then it's most likely the NEO custom chip on the PROG board.

 

[mmmonkey]

I'm confused then, as the prog board works fine with a cha board from another cart. Does that make any sense?

 

[Xian Xi]

That is weird. You sure you don't have any broken traces on the M1? If you have no broken traces and the M1 has been verified then check the ZMC with a probe.

 

[mmmonkey]

It's working :-) Big thank you to Xian Xi for all the advice and to CafeineCake for the PM's explaining how to confirm some details.



This morning I took the CHA board that I transplanted all the ROMs onto, checked the traces again (all fine), so removed the original M1 and put on the EPROM with the download ROM on it. Works fine now. So the original M1 must have a problem AND the ZMC on the original CHA board.

Now I have a KOF94 cart that's dead

I'll leave it for now, and look at repairing that another time one I get a probe and confirm it is the ZMC, and do a bit of digging around to see what the LS74 and LS139 do, as these are easily replaced on the CHA156B board.

Thanks again
Pete