MV1C issue?

[TwinX]

Hi,

I recently bought a MV1C (well actully i just bought a neo-geo mobo, not knowing so many versions existed after doing some research on my issue)

The board came in broken, and the seller wont refund because it was 2 months ago. I just fired it up this week due to other priorities...

So i have to fix it myself, but thats fun right.
So the issue. When i boot i get a garbled screen. I read alot about leaking batteries broken traces etc, however i can't find any (yet.)

I read it is advised to pull out battery so i will do that soon.

I have no logic probe (need to get one i think) so i depend on your advise.

Is this screen known error? (attached). Or do you have advise where to start with troubleshooting?

Thanks in advance to those willing to assist me.

-Jeffry

 

[xsq]

are those blocks static or do they move? Do you get a clicking sound?

My guess would be it's a bad trace between the BIOS, CPU and/or RAM....

 

[TwinX]

are those blocks static or do they move? Do you get a clicking sound?

My guess would be it's a bad trace between the BIOS, CPU and/or RAM....

There are a handfull of blocks that change sprites

I have not had any sound attached yet, wil try it when i am home.

Thanks xsq, much appreciated.

 

[Niko]

Is "Dip 8" turned "On"? From your pictures it looks like it is. Turn that dip off and try again.

 

[TwinX]

Is "Dip 8" turned "On"? From your pictures it looks like it is. Turn that dip off and try again.

Oh yes maybe wrong picture, i had done that after i took the picture, the result was the same.

Thanks NIko49

 

[Vendest]

A damaged trace caused by the battery leaking would be easy to spot I think due to the position of the battery.
I've been reading that the coin cell battery is rather reliable.

 

[TwinX]

So i tested the sound, no clicking to be discovered, actually no sound at all

Battery removed, did again some trace testing.
No broken traces found yet

Is there any schematic available so i know what IC pin need to connect to.

 

[Xian Xi]

Does it by chance do a work ram test if you flip all hard dips on?

 

[TwinX]

Unfortunatly the screen is blocked too if the dips are set to ram test

 

[Vendest]

Not sure if that helps.
Just picked up a MV1C which was working well until I installed a unibios and ended up with the same screen as shown by Twinx.
The change of bios is damn hard to do. 3 pads came off while desoldering the SMD chip so I followed the trace and tapped from the rams.

 

[Xian Xi]

Not sure if that helps.
Just picked up a MV1C which was working well until I installed a unibios and ended up with the same screen as shown by Twinx.
The change of bios is damn hard to do. 3 pads came off while desoldering the SMD chip so I followed the trace and tapped from the rams.

View attachment 40053

How did you install the Unibios, with an adapter or with wiring?

 

[Vendest]

How did you install the Unibios, with an adapter or with wiring?

With wiring. Didn't have AWG28 or 30 available so I went ahead with AWG24 which is tick compared to the pads to say the least. Continuity test checks clear though.
Will check for bad traces. In the other hand could the length and diameter of the wire induce a "slow down"?

 

[Xian Xi]

With wiring. Didn't have AWG28 or 30 available so I went ahead with AWG24 which is tick compared to the pads to say the least. Continuity test checks clear though.
Will check for bad traces. In the other hand could the length and diameter of the wire induce a "slow down"?

Did you bridge 38, 39 and 40? Sometimes you need to.

 

[Vendest]

Did you bridge 38, 39 and 40? Sometimes you need to.

Yes, same results w/ or w/o 40,39,38 connected together.
Got this error from the diagnostics bios (great tool!)



Does that mean the wiring is wrong at A13 & A15?

 

[Vendest]

It was a bad connection at A14 as per Neo Diagniostics error screen.
Unibios up and running!

@ TwinX, since we had a similar issue (garbled screen) it is likely to be a bad trace linked to the bios.

 

[TwinX]

Thank you vendest, you gave me a good lead to check.

 

[TwinX]

For reference, i fixed my board by buying neomasta and a unibios. I removed the original bios. And boom! board works flawlessly no errors nothing.
So i guess original bios was busted for some reason.

Thanks everyone.

 

[dragonpt]

Good to know.