Neo Geo slot not working

D

Delta

n00b
Joined
Mar 11, 2005
Posts
5
Hi,

Can anybody help me with this problem?

Picture:
Image

I got a lot of coloured garbage on my screen when I put the power on. The slot is in test mode and no cartridge is inserted, so normally the setup should be displayed.
Power +5 and +12 volt is ok.

Any idea?

Many thanks,
Geert
 
dogtoy

dogtoy

Haomaru's Blade Shiner
Joined
Nov 24, 2003
Posts
689
Do the colored dots change? What I mean is do they seem animated, squares changing color and pattern. If so, i'd say it's a bios problem, I had this happen to me when I improperly burned a universe bios.

If it stationary you may need to turn up your voltage. On my 4 slot, if the voltage on my +5v is set below about 5.24v i get colored dots all over the place if I have more than 1 slot filled. If +5V is set at 5.00v i get colored dots everywhere with no cartridge in any slots. At 5.00V I do not get colored dots if I remove the top board on my 4-slot (the board with the cartridge slots).
 
D

Delta

n00b
Joined
Mar 11, 2005
Posts
5
Yes indeed, the colored dots are changing.
My voltage is about 5.3 V without a catridge so I think this is good.
I have a MV-1A 1-slot MVS with serial number00184260 (1995).
Do you know how I can change the bios? Is it a Eprom that needs to be burned (I have an eraser and burner). Maybe you have a good hyperlink were I can find more information about this?
Many thanks!
Geert
 
Razoola

Razoola

Divine Hand of the UniBIOS,
Staff member
20 Year Member
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Nov 12, 2002
Posts
4,665
Looks like a bios problem. If you have a programmer and eraser I would advise you visit www.universebios.com and download the bios and burn that onto a 27C1024 and give it a whirl :)

Raz
 
dogtoy

dogtoy

Haomaru's Blade Shiner
Joined
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Posts
689
I would turn down the voltage too. My MV-1A runs perfectly on 5.03V. Won't help w/ the colored dots, but why run extra voltage if you don't need it?
 
D

Delta

n00b
Joined
Mar 11, 2005
Posts
5
Hi,
I just replaced the BIOS with the latest Universe BIOS 2.0 but still no change. The colored dots are still jumping from one pleace to another :crying:
What's the next step?
 
Razoola

Razoola

Divine Hand of the UniBIOS,
Staff member
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You will need to look over the pcb for scratches etc. Its possible a trace is broken somethere or a pin on the socket that holds the bios is damaged.

Raz
 
D

Delta

n00b
Joined
Mar 11, 2005
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No, the PCB is in a excellent condition. I measured some minor scratches but it was all okay.
 
Razoola

Razoola

Divine Hand of the UniBIOS,
Staff member
20 Year Member
Joined
Nov 12, 2002
Posts
4,665
The next posibility is that maybe the main 68000 cpu is dead or for some reason the bios isnt getting power.

Raz
 
D

Delta

n00b
Joined
Mar 11, 2005
Posts
5
Does anybody have a schematic about the SNK MV-A so I can find the problem?

Many thanks already!
 
dogtoy

dogtoy

Haomaru's Blade Shiner
Joined
Nov 24, 2003
Posts
689
You won't find any schematics, people have been searching for these schematics for a long long time. Sort of the Holy Grail of Neo-Geo repair.

I'd follow the advice given above and go over the whole board w/ a magnifying glass looking for cut traces, bad solder joints, burned out components, etc. After that, if I didn't find anything, I might replace the BIOS socket just to see if that was causing any problems.

-DT
 
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