Neo Geo help, not working

dyno

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Just picked up a neo geo for $100, it is not working. When powered up the monitor works but all I am getting on the screen is a few vertical blue lines, even if i pull out the cartridge I get the same thing. The power led on the circuit board is lite but I am not getting anything when I try to coin up the game, not even the coin sound.
 
That's the GREEN SCREEN OF DEATH. It means that you have a calendar error.

What Type of NEO board do you have?

I ask 'cause SNK make a lot of different boards:

1) 1 Slot boards: MV-1, MV-1A, MV-1AX, MV-1B, MV-1C, MV-1F, MV-1FS, MV-1FZ, MV-1T, MV-2,
2) 2 Slot board: MV-2F
3) 4Slot boards: MV-4F, MV-4T
4) 6 Slot board: MV-6F
 
Stuck on Calendar Error.

Check the area around the battery for corrosion damage. Also check the crystal next to the D4990 chip *IF* it is in close proximity to the battery.

The 2 slot boards put the D4990 chip across the board. On those you have to pay close attention to the power trace that goes from the battery backup across the board to the D4990 chip. What tends to happen is that trace has a plated thru hole that gets damaged by the battery acid then the power never makes it to the chip.

The other boards tend to suffer from damaged traces and from damage to the 32KHz clock crystal. If the crystal is all corroded then you may be able to clean it and get it to work. If not, replace it. I carry those on my website.

RJ
 
My board is a 1 slot mv1, I removed the battery and there was some corrsion in the area and on the crystal. I will try to clean the crystal and see what happens or if no luck replace the crystal. Can the board run without the battery or do I need to replace that also? Is this a commom problem with this board? Does replacing the crystal usually fix the calender error?
 
It's a very common fault, in most cases the cause is actual track damage caused by the battery leak, crystal death is less likely. You can leave the battery off the board and it will still run games.
 
NEO bards can run with out batteries but not clock, video chips, and backup ram chips.

Without a battery, a board will not save any CMOS settings.

Corrosion likes to eat traces and board parts; so, gently clean the acid based corrosion off the board with a light baking soda & water solution and a Q-Tip or Soft Toothbrush.

Post some before and after pics of your board--esp. the corrosion areas.
 
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It's a very common fault, in most cases the cause is actual track damage caused by the battery leak, crystal death is less likely. You can leave the battery off the board and it will still run games.

Actually on the older MV1, crystal death is very likely from the corrosion. The only traces between it and the battery are traces going to the DIP switches which the OP will need to check too.

You can leave the battery off, or remove it and the 470 ohm resistor near it and put a coin cell battery & holder in its place. All it is for is for saving soft dips, date/time, and statistics.

RJ
 
Thanks for all the info, I will take a look at the traces and clean the corrsion off and I have already ordered a new crystal so hopefulyy that will fix the problem. I will let you know how it goes. :)
 
Worked like a charm

Ive been watching this post as I had the same problem, and after 6 months I can finally play again... You Rock!!!

Thanks
 
Always happy to help. :D

If you look at my repair logs, I repair a LOT of Neo Geo systems.
 
Just took the pcb out again and there seemd to be alot of corrosion on other parts near the crystal also and on the 4990 ic, what is the best way to clean the corrosion of these components? I am hoping that once I get it cleaned it will work.
 
Just took the pcb out again and there seemd to be alot of corrosion on other parts near the crystal also and on the 4990 ic, what is the best way to clean the corrosion of these components? I am hoping that once I get it cleaned it will work.

I use white vinegar and a tooth brush. Rinse well when done since vinegar is an acid and you don't want it to continue eating copper traces. ;)

Be sure to take the battery off first.

Also, after cleaning you can pull back the cardboard from the bottom of the board and get to the solder joints. Re-solder the crystal and the caps next to it and see if that revives it. Sometimes you get crystalline growth from the bad battery down in the solder joints and resoldering may bring that circuit back to life without having to swap the crystal.
 
Hey guys, I get this screen for a split second when I first power up. I take it I should follow your advice and take off the battery, etc.
 
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This screen is part of the normal boot process so you will see it briefly, it doesn't indicate a fault is looming. But yes if you still have the original battery on the board you should remove it, its a bit of a timebomb.
 
Cleaned up the board with vinegar and checked for continuity which there was and put the board back in and still the green screen of death.:( I checked pin 14 on the 4990 ic and it was getting 5v when the board was powered on so does that point to a dead crystal?
 
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