Author Topic: Dead Neo-Geo motherbord? (Read 12394 times)

MsG · « **on:** October 11, 2008, 08:09:43 am »

Hi guys,

I'm the happy owner of a Neo-Geo MVS machine, but it is dead since a few months. I get this screen all the time:

In the beginning I get that screen sometimes, but at the end I got it always

.

I tried a Tetris JAMMA PCB and that did work normally (although the controls didn't work, but I think that hasn't got anything to do with this).

Here are some other pics:

My unshielded motherboard:

My jamma-connector (is it normal that some connectors aren't attached to a wire?):

Do you guys maybe know what the problem could be? I really don't know, because other PCB's áre working. I'm glad though that the arcade monitor itself is in fully working order.

grantspain · « **Reply #1 on:** October 11, 2008, 10:16:58 am »

if it happens with more than one cart in both sockets then i would say you have an ic failure

MrMojoZ · « **Reply #2 on:** October 11, 2008, 11:41:39 am »

Looks like the MAME neogeo boot rom screen.

Bleagh · « **Reply #3 on:** October 11, 2008, 04:23:08 pm »

That screen will always come up first thing. Does it just sit on that screen?

MsG · « **Reply #4 on:** October 11, 2008, 06:56:57 pm »

Yeah, the only thing I get to see is this green screen

.

grantspain · « **Reply #5 on:** October 11, 2008, 07:11:06 pm »

i heard something about a debug bios for these boards somewhere,you should have a search regarding this

SirPeale · « **Reply #6 on:** October 11, 2008, 08:51:29 pm »

Have you metered power? I've seen this happen when the +5 drops really low.

Oni2382 · « **Reply #7 on:** October 11, 2008, 09:56:55 pm »

What MVS carts do you have? It could be the carts....

SirPeale · « **Reply #8 on:** October 12, 2008, 10:42:31 am »

Quote from: Oni2382 on October 11, 2008, 09:56:55 pm

What MVS carts do you have? It could be the carts....

Could be that too. Make sure the edge connector is clean.

MsG · « **Reply #9 on:** October 12, 2008, 01:57:33 pm »

I have about ten carts, but I will check this with other carts. You hear from me guys.

channelmaniac · « **Reply #10 on:** October 14, 2008, 12:21:14 pm »

Stuck on green screen is a clock/calendar problem.

Check for +5v on pin 14 of the D4990 chip when power is applied to the board. If it's not there then you have a corroded trace somewhere between the battery circuit and the other side of the board where that chip is.

Can also be caused by a bad D4990 chip or a bad crystal.

I've fixed a couple of MVS boards with this type of problem. Check my repair logs out on the forums at newlifegames.net.

johnnya · « **Reply #11 on:** October 17, 2008, 12:47:10 pm »

I was just gonna say, ask channelmaniac, haha.

MsG · « **Reply #12 on:** October 31, 2008, 11:40:09 am »

We measured the battery's voltage when the motherboard was unplugged. It said: 2,53 volts. Could that be wrong?

And by pin 14 you mean TP1? In the right upper corner of the chip seen from the motherboard when the battery is on bottom left.

But now I remember something. Could it be something with the door-closed system? I remember (but I don't know wether this is correct or not) that if I had the CP panel opened and then put the arcade machine on, I get the same green screen for ever. What does the screen display normally when you power on a arcade neo geo machine, with the cp panel or backside opened?

Malenko · « **Reply #13 on:** October 31, 2008, 11:59:31 am »

neither one of my cabs ever cared if the CP or back door were on. I have a 2 slot board Im trying to get rid of......

MsG · « **Reply #14 on:** October 31, 2008, 12:23:42 pm »

I am interested but you live in America and I live in Holland, Europe

so I think that would be a problem

Malenko · « **Reply #15 on:** October 31, 2008, 06:16:29 pm »

Quote from: MsG on October 31, 2008, 12:23:42 pm

I am interested but you live in America and I live in Holland, Europe so I think that would be a problem

you guys cant get mail over there?

channelmaniac · « **Reply #16 on:** November 02, 2008, 01:38:11 am »

What I mean is... Find the chip that is labeled D4990.

In the pictures you posted, it is on the bottom right of the board... just to the right of the 2 red resistor packs and above the 5 red resistor packs.

It has a notch on one side to signify pin one...

14 8
------------
) 4990 |
------------
1 7

When the board is powered up, pin 14 should have 5v on it. If it doesn't then you have a corroded trace you need to patch.

RJ

MonMotha · « **Reply #17 on:** November 03, 2008, 06:45:50 pm »

Had a 4 slot that was doing exactly this. Found a leaking battery (removed for now, will replace when I get time to hunt down a replacement) which resulted in two corroded traces from the NEO-F0 to the uPD4990. Reconnecting those two traces properly made it boot right up. I can get pictures if somebody wants.

Cyberflexx · « **Reply #18 on:** November 08, 2008, 10:35:47 pm »

Quote from: Peale on October 12, 2008, 10:42:31 am

Quote from: Oni2382 on October 11, 2008, 09:56:55 pm
What MVS carts do you have? It could be the carts....

Could be that too. Make sure the edge connector is clean.

Mine did the same thing with Puzzle Bobble was in the only cart in my 4 slot. It was a dirty edge connector on the cart. Clean your cart and see if that fixes it..

MsG · « **Reply #19 on:** December 16, 2008, 09:43:53 am »

A minor update:

Because we still didn't fix the 2 slot board I temporary put in my 4 slots (which officially doesn't fit, but I can use 3 of the 4 slots, but can not pull out the control panel anymore

).

But I was wondering why the colors are more intense than the other motherboard, because I thought the color settings are all in the monitor itself. Can someone explain it to me? And does more intense color kill your monitor more early?

channelmaniac · « **Reply #20 on:** December 19, 2008, 11:37:28 pm »

If the voltage levels coming off the board are higher then everything will look different than the other board.

If you want your 2 slot fixed, I can do that for you or I can do a swap for a refurbed board. PM or email me for details.

RJ

srarcade · « **Reply #21 on:** January 21, 2009, 04:47:58 pm »

Ok basic troubleshooting question but I didn't see this mentioned anywhere...Is the stop mode/freeze display dip accidentally turned on? Switch number 8 on the dip switches? That might possibly cause it to not start and keep it at the very most starting screen.

channelmaniac · « **Reply #22 on:** January 21, 2009, 06:07:12 pm »

Quote from: srarcade on January 21, 2009, 04:47:58 pm

Ok basic troubleshooting question but I didn't see this mentioned anywhere...Is the stop mode/freeze display dip accidentally turned on? Switch number 8 on the dip switches? That might possibly cause it to not start and keep it at the very most starting screen.

That won't cause it to stop on the green screen. It'll stop on a black screen if that switch is thrown.

Stuck on green is a calendar chip problem.

MsG · « **Reply #23 on:** March 01, 2009, 11:20:00 am »

Bump.

I sold my dead motherboard because I didn't know how to fix exactly. And ordered another one from a guy.

Built it in today but...

It still has the green repeating screen

$:-\$

.

What could it be again? Because my 4 slots motherboard DOES work, but it is just too big for my cabinet.

Can it be again that the battery on the board is empty? My dad said that maybe I need to put it on the whole day with the anoying screen to recharge the battery. Is that a logic thing or does it sound ridicilous?

I'm sad that it still doesn't work.

EDIT: I read on the internet that the calendar problem is that the green screen does not reset and loops, but just stays. My problem is that it kind of resets, and immediately shows the green screen again. So you see changing green screen every X second, it doesn't hang or something.

Cyberflexx · « **Reply #24 on:** March 03, 2009, 02:09:11 am »

My 4 slot would do that when I would install my 100 n 1 cart. They way i got around it was to jumper the game select switch closed while i play, then when i went back to the main menu, i un jumpered the wire. I am installing a little toggle switch this weekend for it. when I pop in a single game cart, it works fine for all 4 slots.

Just a thought you might try to see if your game would even load...

MsG · « **Reply #25 on:** March 03, 2009, 07:48:23 pm »

The battery gives about 0,8 volts. When I buy a new one is it possible it will work again?

channelmaniac · « **Reply #26 on:** March 10, 2009, 12:24:49 am »

No.

The battery has nothing to do with the green screen stuck problem. You need to check the voltage on the chip to see if it has voltage when the board is powered up.

You should read 5v between pins 7 (ground) and 14 (power) when the board is powered up. If you don't then you have a bad trace between the backup battery circuit and the D4990 clock/calendar chip.

The backup battery only keeps the clock/calendar going and the memory in the backup RAM from disappearing when the power is off. It has nothing to do with being stuck on a green screen other than when it leaks and eats the power trace that runs over to the clock/calendar chip.

RJ

MsG · « **Reply #27 on:** March 13, 2009, 10:21:55 pm »

And how am I supposed to fix a corroded trace? IF found one. Because soldering is way too big for the thin lines I suppose?

MonMotha · « **Reply #28 on:** March 13, 2009, 10:39:05 pm »

Grab some 30AWG wire and either patch up the trace itself or wire point-to-point from where the trace comes from to where it goes. Nothing is too small to solder. The chips on Neo-Geo MVS units are actually fairly big in comparison to some of the stuff I frequently work with.

WunderCade · « **Reply #29 on:** March 14, 2009, 04:45:10 pm »

It's as if you are on Ignore. You can lead a horse to water, but..........

Heck of a guy for being soo patient though.

Quote from: channelmaniac on March 10, 2009, 12:24:49 am

No.

The battery has nothing to do with the green screen stuck problem. You need to check the voltage on the chip to see if it has voltage when the board is powered up.

You should read 5v between pins 7 (ground) and 14 (power) when the board is powered up. If you don't then you have a bad trace between the backup battery circuit and the D4990 clock/calendar chip.

The backup battery only keeps the clock/calendar going and the memory in the backup RAM from disappearing when the power is off. It has nothing to do with being stuck on a green screen other than when it leaks and eats the power trace that runs over to the clock/calendar chip.

RJ

channelmaniac · « **Reply #30 on:** March 16, 2009, 10:01:55 am »

If you don't want to tackle board repair yourself, I repair them... and even specialize in repairing Neo Geo MVS/AES boards.

http://www.arcadecomponents.com is my site.

Here's my repair thread on the Neo-Geo.com site: http://www.neo-geo.com/forums/showthread.php?t=162467

I do them as a flat rate:
$35 for non-surface mount repairs (including audio cap kit installs)
$40 for surface mount repairs

Plus shipping.

Batteries and cart/memory card slot connectors not included.


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