weird sound problem on MV-1FZ

Cavia

Neo Bubble Buster
Joined
Jul 13, 2015
Posts
42
Hey guys,

I'm getting no sound on the following setup.

Board: MV-1FZ with 5V Mod and Stereo MKL mod.
Note: I'm testing with the MVS sound test (no cartridge).

My oscilloscope was already showing no sound coming out from the YM2610 and its pin 56 (IRQ going to Z80) was not responsive when activating sound on left/right/center (while it's clearly responsive on my working board).

I've changed the YM2610 with a new one but the exact some problem is persisting.

I'm trying to go up to the Z80 the Neo-D0 and eventually the processor 68k, but I found very difficult to follow the audio flow from the beginning.

For example, in the Z80 pins 1 to 5 are outputting something significant in my working board, but not in my broken one. But I'm not sure what's the meaning of that.

Can anyone help me in this scenario??
Thanks.

PS.: On the schematics of the Neo-D0, pin 61 is supposed to be A4 (68k address line) according to this https://wiki.neogeodev.org/index.php?title=NEO-D0, but both on my working and non-working board it's ground (??).
 

pier

Crazed MVS Addict
Joined
Jan 24, 2020
Posts
137
Hey guys,

I'm getting no sound on the following setup.

Board: MV-1FZ with 5V Mod and Stereo MKL mod.
Note: I'm testing with the MVS sound test (no cartridge).

My oscilloscope was already showing no sound coming out from the YM2610 and its pin 56 (IRQ going to Z80) was not responsive when activating sound on left/right/center (while it's clearly responsive on my working board).

I've changed the YM2610 with a new one but the exact some problem is persisting.

I'm trying to go up to the Z80 the Neo-D0 and eventually the processor 68k, but I found very difficult to follow the audio flow from the beginning.

For example, in the Z80 pins 1 to 5 are outputting something significant in my working board, but not in my broken one. But I'm not sure what's the meaning of that.

Can anyone help me in this scenario??
Thanks.

PS.: On the schematics of the Neo-D0, pin 61 is supposed to be A4 (68k address line) according to this https://wiki.neogeodev.org/index.php?title=NEO-D0, but both on my working and non-working board it's ground (??).

flash a diagnostic bios and test it with a diagnostic card. 1fz ha a socketed bios it is easy to swap. by the way some neogeodev schematics are wrong, i don't remember what in particular but for my 1fz i had the same problem. It is strange to talk with an italian in english XD
 

Cavia

Neo Bubble Buster
Joined
Jul 13, 2015
Posts
42
Ciao,

I have no experience with diagnostic cards (I think you are referring to the CHA board with a Z80 testing software on it, which is the one for the sound system).
Could you please point me anywhere I can learn and code such boards (I think I can reuse some of my crappy mvs games if they are CHA)?

Grazie
 

pier

Crazed MVS Addict
Joined
Jan 24, 2020
Posts
137
the cheapest way to go is to buy the tl866 plus and a uv eraser, download diagnostic bios from smkdan site and flash diagnostic bios file "sm1.bin" on a 27C1024 and m1.bin on a 27c010 and solder or socket it on any cha board with Any CHA board that uses a NEO-ZMC or zmc2

EDIT: by the way can you provide me a picture of the area around the u14?
 
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Cavia

Neo Bubble Buster
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Jul 13, 2015
Posts
42
Ok, I have everything except the 27c010 and eventually a CHA board (btw do you know if the 161-1 is good?)

Here is the area around u14.
3FcfkH8
 

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pier

Crazed MVS Addict
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Posts
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(btw do you know if the 161-1 is good?)
absolutely no.

EDIT: but by the way, are you sure that the sound was working before the 5v mod?
 
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Cavia

Neo Bubble Buster
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Jul 13, 2015
Posts
42
Nope, sound was not working even before the 5V mod.
Both with cartridges and test mode.
I did the 5V to bypass all the caps, but that was not the problem :(
 

pier

Crazed MVS Addict
Joined
Jan 24, 2020
Posts
137
first of all. before every mod you should be make everything work FIRST. if something related sound hardware: ym2610,z80,6116 isn't working it should display a generic z80 error.
 

Cavia

Neo Bubble Buster
Joined
Jul 13, 2015
Posts
42
Yes you are right.
You mean it will display an error with the Z80 game debugger, because it's not showing anything and I can clearly see with the oscilloscope that the YM2610 is not emitting a single sound pulse (if compared to the working board).
 

pier

Crazed MVS Addict
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Jan 24, 2020
Posts
137
mmmm are you testing it with the 161in1 multigame or are you using a single game cart?
 

Cavia

Neo Bubble Buster
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Unfortunately, I cannot get a sound even using the bios sound test (testing with a cart on the MV-1FZ makes it difficult to probe many SMD chips).
 

pier

Crazed MVS Addict
Joined
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Posts
137
don't use 161in1 to test sound, flash a diag bios and z80 test cart and test with it to have a general idea of what is happening. but for what i think it should have been better to don't mod stereo until sure that audio was working in mono. z80 test usually use mono speaker to beep sound codes. where do you live?
 

Cavia

Neo Bubble Buster
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Posts
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Yeah,you are absolutely right. Unfortunately, I was unexperienced 4 years ago (yes! this board has been haunting me for a long time). I discover that all my carts are PROG :crying:, so I'll need to hunt for a CHA. I live near Roma.
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,679
Yeah,you are absolutely right. Unfortunately, I was unexperienced 4 years ago (yes! this board has been haunting me for a long time). I discover that all my carts are PROG :crying:, so I'll need to hunt for a CHA. I live near Roma.

Just use the CHA from a working cart and put a socket on the M1.
 
Joined
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9,090
Yeah,you are absolutely right. Unfortunately, I was unexperienced 4 years ago (yes! this board has been haunting me for a long time). I discover that all my carts are PROG :crying:, so I'll need to hunt for a CHA. I live near Roma.
What do you mean "all your carts are PROG"? Every game has one PROG board and one CHA board.
 

Cavia

Neo Bubble Buster
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What do you mean "all your carts are PROG"? Every game has one PROG board and one CHA board.

Ops sorry, you now understand my ignorance on cartridges :(. I thought that a cart was only PROG or CHA. Ok then I'll check if my AoF cart has a NEO-ZMC.
Thanks!
 

pier

Crazed MVS Addict
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Jan 24, 2020
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I am from Caserta, by the way, if the sound was working in mono before modding, i must advice you that to have stereo from 1fz you must convert also the power to 5v. if power is 12v and you only modded to stereo you will never have sound.
 

Cavia

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Yes, I already have the 5V mod and, as I said before, sound was NOT working before any mod :(
 

pier

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Yes, I already have the 5V mod and, as I said before, sound was NOT working before any mod :(
tl866 2 plus->smkdan diag bios or jwestfall69 fork flashed to -> 27c1024 + smkdan z80 or jwestfall69 fork flashed to -> 27c010 soldered on any game pcb with neo-zmc.
 

Cavia

Neo Bubble Buster
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Ok, so I started doing some tests.
The bios test got me this (which should be ok).
https://ibb.co/9vKxr9X

Then, the Z80 test got me this:
https://ibb.co/JrDMpwn

Notes:
I've burned m1.bin on a ST-M27C1001 (should be equivalent to the 27c010) and socket it like this:
https://ibb.co/NKPwCS3
[I've tested the socket with the original cart chip and the game (AoF) is working properly including the audio, so I assume my socket is installed correctly).
Maybe the M27C1001 failed? (Programming went fine :( )

Also sorry for the jamming within the first two pictures... For some reason this 5V modded MV-1FZ board (the one with broken audio) does not give me a good sync with my testbench chinese supergun; but it works correctly with a MAK Strike supergun. On the contrary, my working MV-1FZ board (without any mod) outputs a perfect video signal using the chinese supergun. Weird problem.
 
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pier

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Jan 24, 2020
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the first picture is normal because the diag tested all the features without the z80/audio. about the second picture i don't think you misprogrammed the m1 rom, you can always verify it with the programmer and the m1 loaded into xgpro (if you are using the tl866)
 
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pier

Crazed MVS Addict
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Jan 24, 2020
Posts
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Sound ROM (SM1) 128K 27C1000/23C1000 1x 128Kx8 Z80 program ROM; desolder it and verify it with sm1 inside neogeo.zip bios
 
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Cavia

Neo Bubble Buster
Joined
Jul 13, 2015
Posts
42
Sound ROM (SM1) 128K 27C1000/23C1000 1x 128Kx8 Z80 program ROM; desolder it and verify it with sm1 inside neogeo.zip bios

sorry, are you saying that I should desolder the current SM1, get a replacement chip and program it with the sm1 inside the neogeo.zip bios, and finally resolder (resocket) it??
just to be sure that I'm not misunderstanding...
 
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