video problem with my neo geo mv4ft2

[emu002]

My neo geo has developed a video problem as you can see from these pics





If you go into service mode the crosshatch pattern and other parts work fine but as soon as you boot into a game it goes like this

All 4 slots do it

I have tried cleaning the jamma connector and all my cart contacts with alcohol

I have tried separating the top board and then re-seating it

The battery looks very clean with no corrosion

Any other ideas? I am in the UK and I don't know of anyone here that can fix neo geos

[retro]

There are a fair few logic chips on MVS boards that can cause graphical issues - it's a case of getting the logic probe out, really. And video RAM. Also, check for damage to the board.

I'm in the UK and repair them, but I'm snowed under at the moment so I can't look at it right now, unfortunately.

Here are a few repair logs to check:

http://persecutor.tamdb.net/index.ph...nd-MVS-Systems

Sorry I can't give more advice right now, but if you need further help, reply and I'll see what I can do.

[emu002]

I don't own a logic prob i'm afraid
My soldering skills only go as far as simple switches

Is there anyone else in the UK who can help at all?

[l_oliveira]

Considering it's a multi slot board, the mux or buffer chips (for graphics) on the slot selection circuitry broke. Make sure if you can check if games on all slots are affected.

Notice that the fixed font graphics are pefectly fine.

[retro]

He said all 4 slots do it ;)

I've got a lot on at the moment, but I might be able to take a look in a few weeks' time, perhaps.

[emu002]

I would be grateful of any help and am happy to pay the costs

Out of my 5 arcades the new geo is my favourite and I am very sad it has stopped working properly
Even though it is only a lordsvale I have spent extra money on it installing a credit led and memory card reader
I made my own new graphics for the side of the machine so restore the old scuffed ones

[l_oliveira]

Definitely this guy's problem has nothing to do with RAM. The board would fail self check (you happen to have universe bios on it ?) ...

It's either a multiplexer or buffer blown on the graphics bus or a broken (corroded) trace.

[emu002]

It is still running the standard bios