Neo Diagnostics ROMs

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
The bank error board is a lot closer to working since if it got that far, almost every other part tested OK. If you are completely sure that it's none of the traces on the page or my post, can you probe the NEO-D0 pin with any 1991+ game inserted and see if you get any pulsing? It should pulse frequently when a song is supposed to be playing for example.

The other board is in a worse spot since the Z80 is possibly not running at all. There's more to check for (Z80 clk should pulse, RD/WR/IO signals should be pulsing, SM1/RAM/NEO-D0 traces between Z80 should be checked etc....). I'd like to make a full writeup on everything to test but there's a lot of info on the wiki currently. Pretty much any Z80 connection excluding the cart slot is potentially the cause. What have you tried so far?
 

DEL 707

Cheng's Errand Boy
Joined
Jan 9, 2014
Posts
120
Sorry for the late reply.

Regarding the M1 bank error, I'll try getting my board back into work so I can see if that NEO-D0 pin is pulsing.

With the other board with the Z80 error, my boss dug out his old oscilloscope and did some checking on the Z80 RAM and thought dataline 6 looked a bit weird.

MVSData1.jpeg


Sorry it's not much to go on, he used to repair Amiga's and Atari's back in the day, no Neo Geo's.
 

hitz

Timid Neo Newbie
Joined
Aug 5, 2013
Posts
1
Just used this on a 4 slot with a Z80 error, found out it was a bad SM1 and replaced it. Board finally boots up, this bios is really amazing smkdan!
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,702
Have you checked palette ram or the latches on the DAC?

edit: on second thought, check the p-bus lines connecting b1 to lspc2 to the cart slot.

I'll check the latches but I already checked the B1>Cart Slot>LSPC2 lines.
 

shadowkn55

Genbu's Turtle Keeper
Joined
Dec 9, 2006
Posts
2,386
I'll check the latches but I already checked the B1>Cart Slot>LSPC2 lines.

It looks like the sprites are in the right location so it has to do with some concerning the color palettes. The things involved are slow vram, b1, lspc, palette ram, or the dac latches. Judging by the fix layer being correct, I would probably rule out the 74ls273 latches but it wouldn't hurt to check.
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,702
It looks like the sprites are in the right location so it has to do with some concerning the color palettes. The things involved are slow vram, b1, lspc, palette ram, or the dac latches. Judging by the fix layer being correct, I would probably rule out the 74ls273 latches but it wouldn't hurt to check.

Latches are fine. Slow VRAM is fine, Palette RAM is fine, LSPC is fine and B1 is fine.
 

shadowkn55

Genbu's Turtle Keeper
Joined
Dec 9, 2006
Posts
2,386
Latches are fine. Slow VRAM is fine, Palette RAM is fine, LSPC is fine and B1 is fine.

Have you checked GAD and GBD? These connect from the cartridge slot to B1. I'm running out of ideas if this checks out.
 

fremen

Hardened Shock Trooper
Joined
Aug 4, 2010
Posts
433
Hi dudes,

I'm not an expert but I've read that sometimes the 74ls seems to be Ok, all checks have been passed, but actually they are wrong. This issue is common in arcade pcb's.

Un saludo
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,702
Turned out to be a missing P22. I must have probed P23 and thought it was P22.
 

Footix

Bashful Neophyte
Joined
Apr 13, 2014
Posts
19
Got another baby that states:
Z80 Dead / Errored / Comm. Issue

expected 03
actual 00

it said before the test that the SM1 was unresponsive

I believe I tested all pins ok. I could not catch any shorted pins.

Dead Z80?

Thanks
 

Razoola

Divine Hand of the UniBIOS,
Staff member
Joined
Nov 12, 2002
Posts
4,632
Has anyone heard from smkdan recently?

I have been trying to contact him with no success via a couple of methods. Has anyone heard from him since he last visited the forums on 09-21-2014 10:00?

I'm hoping everything is ok with him.

Raz
 

Cyberdemon

Bashful Neophyte
Joined
Jan 14, 2011
Posts
16
I have the following message from bios v0.19: "vram 2k unwritable (upper)".
Anyone can helpme please? the board is an AES3-5
Thx!
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,702
I have the following message from bios v0.19: "vram 2k unwritable (upper)".
Anyone can helpme please? the board is an AES3-5
Thx!

Check the /WE pin on the lower chip. It's the 5814 pair to the left of the LSPC2. Check to make sure that it has a connection to the LSPC2. If it doesn't then repair it. If it is connected then hopefully swapping the ram will fix it. You don't want a failing LSPC2.
 

Cyberdemon

Bashful Neophyte
Joined
Jan 14, 2011
Posts
16
Thx Xian Xi, but two 5814 are already swapped (brand new ones) and all traces to LSPC2 A2 are OK.... my LSPC2 its dead?
 

Newkid3

Timid Neo Newbie
Joined
Nov 2, 2015
Posts
1
Mv4

I just got a eprom in and programmed it for the test bios. I recieved the error in the pic i uploaded. Does anyone know what this actually means.
 

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keropi

Timid Neo Newbie
Joined
Aug 5, 2014
Posts
8
any ideas how to proceed with a MV1FZ if the diagnostick bios + cha board check out fine (with z80 tests too) but you get random Z80 errors on boot and have missing sfx in always the same parts in games?
I've only seen one time this error with the diag. bios:

Z80 DEAD / ERRORED / COMM. ISSUE
EXPECTED: 3C
ACTUAL: 4C

Z80 REPORTED ERROR CODE: 0C
Z80<->68k COMM. ERROR (DATA)

but I can't replicate it. I have recaped the MV1FZ board and reflowed the cartridge connectors - no change in behavior.
Any ideas?
 

aha2940

AH, A, COLUMBIAN!,
Joined
Dec 15, 2013
Posts
2,520
any ideas how to proceed with a MV1FZ if the diagnostick bios + cha board check out fine (with z80 tests too) but you get random Z80 errors on boot and have missing sfx in always the same parts in games?
I've only seen one time this error with the diag. bios:

Z80 DEAD / ERRORED / COMM. ISSUE
EXPECTED: 3C
ACTUAL: 4C

Z80 REPORTED ERROR CODE: 0C
Z80<->68k COMM. ERROR (DATA)

but I can't replicate it. I have recaped the MV1FZ board and reflowed the cartridge connectors - no change in behavior.
Any ideas?

If the Z80 threw error once, it may be failing. Replace it.
 

keropi

Timid Neo Newbie
Joined
Aug 5, 2014
Posts
8
^ I'll try that too, need to order one first... what do you think about z80 ram? Should I replace it as well just in case?
 

Xian Xi

JammaNationX,
Joined
Dec 1, 2005
Posts
27,702
Is there any tones playing when you get the error? Should be 6 tones/beeps.
 

keropi

Timid Neo Newbie
Joined
Aug 5, 2014
Posts
8
^ I cannot replicate the error with the diagnostics bios / cha board anymore : everything checks out OK. I remember that each time I do the Z80 test I hear some beeps, is that what you are asking about?

What I get is a Z80 error almost every time I cold boot the MVS with a game - and only the first time after a night powered off for example. If I do a power-cycle after the Z80 error the game boots fine.
I am testing with Metal Slug (original cart and verified working fine on my 2nd MVS board) and sfx go completely off each time I get to the part after the first helicopter in stage 1. Music keeps playing fine in the background but sfx are dead. Maybe I hear some when I pick a weapon, maybe not. They return completely 2-3 screens before the boss fight.
It's a strange error, maybe it happens when Z80 gets used more?
I just found out that gamegears have the same smd Z80 cpu, I'll transplant one tomorrow from a gg with a dead screen and report back if the Z80 was to blame.

edit:
bad luck, the gamegears I have all are the newer revision where the Z80 got integrated into a custom sega ic... so no quick test atm...
 
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sega8bit

Timid Neo Newbie
Joined
Nov 7, 2015
Posts
3
Thanks for much for making this Diag BIOS for the Neo Geo boards. It's saved me a few times already.

I have one AES board that passes all tests, but when holding D to test the Z80 it fails with:

Z80 Dead / Errored / Comm issue
Expected 03
Actual 00

NeoGeoAESZ80Error.jpg
 
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