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Sound Issues on MV1-FT

mlaborda

mlaborda

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Hey everyone!

Finally got a Multi MVS, and couldn't be happier with the quality and attention to detail. I'm really impressed with how fast load times are, and this was my biggest concern. Really awesome job on this one!

I'm having an issue with sound and I can't figure out what I'm doing wrong.
The game select menu has no music at all, and when I try to change the track in the settings, I get "Z80 ERROR".
The Neo-Geo startup jingle sounds perfect, but in game, voice samples sound scratchy and really loud, wrong sound effects are being played, and there's no background music in some sections.
I've got an MV1-FT board with its original bios. I cleaned the edge connectors and cart game slots thoroughly, but the problem still persists.
Any help would be greatly appreciated!
 
Yes, it's at 5.09V. That should be good, right?

I need to test this board with an original cart to confirm the issue isn't with the sound chip. I can hear the expected intermitent tone in Hardware Test, so I assumed sound was working fine, but this is not always the case, from what I've been reading, correct?

I just bought an original Metal Slug X cart. I'll post an update when I can test it.
 
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mlaborda said:
Yes, it's at 5.09V. That should be good, right?

I need to test this board with an original cart to confirm the issue isn't with the sound chip. I can hear the expected intermitent tone in Hardware Test, so I assumed sound was working fine, but this is not always the case, from what I've been reading, correct?

I just bought an original Metal Slug X cart. I'll post an update when I can test it.
Click to expand...

Should be fine, some MVS carts are more picky than others. Test with another cart as you said, and then go from there.
 
I have the same sound issue with an original cart, so I'm afraid it's the MV1 PCB 😞
Wrong sound effects played, some sounds are distorted or non existent.

I've changed the title of the thread so that there's no confusion.

Does anyone know how to fix this? Would recapping the sound section fix this or is it unrelated?
 
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I've received my cap kit today, so I've decided I'm going to recap it anyway.

Not a lot of info on the MV1-FT out there. I've located the Z80A chip but don't know how to test it.

Any help would be appreciated.
 
mlaborda said:
I've received my cap kit today, so I've decided I'm going to recap it anyway.

Not a lot of info on the MV1-FT out there. I've located the Z80A chip but don't know how to test it.

Any help would be appreciated.
Click to expand...

Not sure how I would go about testing a Z80 myself. You can use a logic probe to do a really basic test, but other than that I would want to build a basic testing circuit
example:
View: https://www.youtube.com/watch?v=3bYXl9sGe3M

On the Neo Geo, I have the Neo Diagnostics BIOS and a MVS bootleg cart I customized with the M1 image for Z80 testing.
http://smkdan.eludevisibility.org/neo/diag/

If you can do that, it'd be your best option.
 
Its unlikely the issue is the z80 itself. The z80 handles all sound, so the fact you are getting some sound means the cpu isnt dead.

Your symptoms sound like either an issue with the communication between the main cpu and z80 or it could be the YM2610. My usual test for ym2610 is to listen to the start sequence of metal slug 2/x

View: https://www.youtube.com/watch?v=YEUCPasUXtQ


First 10 seconds of the above video. Listening to see if any of the bang bang .. metal slug X! sounds are missing. Its usually an indication the chip is bad/failing.
 
It's not going to be the Z80. You have sound sample ROMs on the top cartridge board (the one with the Program ROMs on it.) One of the address lines isn't connected to those Sound Sample ROMs properly. If you were getting just scratchy sounds, I'd say check for a missing data line... Incorrect sounds are address line issues. You have a broken / corroded trace or bad contact somewhere.

Grab the pinout for the slots off the MVS wiki and start checking continuity between the 2610 and those sound sample ROMs.
 
Thanks so much for all the helpful information!

Recapping didn't fix the issue, so I'm going to start looking for broken traces or bad contacts as you guys suggested.

Took a video of the start sequence of Metal Slug X. It's playing incorrect sound effects, and no "Metal Slug... X!".

 
mlaborda said:
Thanks so much for all the helpful information!

Recapping didn't fix the issue, so I'm going to start looking for broken traces or bad contacts as you guys suggested.

Took a video of the start sequence of Metal Slug X. It's playing incorrect sound effects, and no "Metal Slug... X!".

Click to expand...
Thinking on it, I have an AES around here with a similar issue I could never figure out. It’s like the wrong sound sample gets loaded into all of the ram. So for every effect it plays a single seemingly random sound.

For me it works some times without issue, which made diagnosing the problem a pain.

Keep us updated, may see if your findings match mine with the AES.
 
Finally had some time to test this. Found out there was no continuity between PROG Top - SDPA8 (A43) -> YM2610 - PA8 (41) and bridged it with wire.
Now all the background music in the game sounds fantastic and there's no distortion at all, BUT sound effects are still incorrect.

I've tested continuity of:

SDD0-7 CHABottom -> YM2610
SDD0-7 / D0-7 CHA Bottom -> Z80
SDA0-1 / A0-1 YM2610 -> Z80
SDA0-15 / A0-15 CHA Top -> Z80
SDA11-15 CHA Top -> NEO-D0
SDA2-4 CHA Top -> NEO-D0
SDRAD0-7 / RAD0-7 PROG Bottom -> YM2610
SDRA8-9 / RA8-9 PROG Top -> YM2610
SDRA20-23 / RA20-23 PROG Top -> YM2610
SDPA8-11 / PA8-11 PROG Top -> YM2610
SDROE PROG Top -> YM2610
SDRMPX PROG Top -> YM2610
SDPOE PROG Top -> YM2610
SDPMPX PROG Top -> YM2610

And they're all good now.

I bought a logic probe but I don't know how to use it or what I should be looking for lol.
Any help would be appreciated!
 
That's unfortunate, I was hoping I could fix this board without having to replace any additional parts.

The worst part is that a new problem has just appeared out of nowhere. Volume is super loud and it all sounds distorted like it's clipping. Only thing I did was test for continuity with a multimeter. Maybe a bad cap? How would I test this?

Also, what's the best place to order a compatible YM2610 from? Would I need an IC socket too?

Thanks for your help!
 
mlaborda said:
That's unfortunate, I was hoping I could fix this board without having to replace any additional parts.

The worst part is that a new problem has just appeared out of nowhere. Volume is super loud and it all sounds distorted like it's clipping. Only thing I did was test for continuity with a multimeter. Maybe a bad cap? How would I test this?

Also, what's the best place to order a compatible YM2610 from? Would I need an IC socket too?

Thanks for your help!
Click to expand...
You don’t need a socket, but whenever I replace an IC I like to add one for “next time”.
 
It's a 64 pin Shrink DIP socket.

I don't have enough YM2610 chips here to part with one. I need to keep them around for repairs.
 
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