Need some help with Neogeo MV1B Vertical lines

[kasaski]

I recently received a MV1B 1 slot and I'm having some issues with vertical lines on some sprites. I'm a complete noob in fixing these things and was hoping to get some direction from more experienced users.
After researching a bit it seems to be usually caused by a floating/shorted c rom trace to the zmc2 chip, but i tested all those traces and they seem fine. I even logic probed each pin and none seem stuck. I've also tried grounding each cr pin to find a possible culprit and cr7 seems to be the only one that doesn't change the image, but its traces are fine and it isn't stuck high or low. I'm completely lost now and not sure where else to look.

I've thoroughly cleaned all contacts on both the board and cartridges and still nothing. I also re-flowed all the pins on the zmc2 chip.

Is it possible the zmc2 chip is busted and the only fix would be replacing it, i'd assume there'd be more graphic issues if that were the case though?

Here's some images of the problem.

 

[stj]

i have had a couple of bad zmc2's - neo boards are a pain in the ass sometimes unless you have several to swap bits around!

 

[kasaski]

ah my guess that the zmc2 is bad is probably right then. That's a shame

 

[Niko]

I had the same issue with an MV1B. Turned out a few of the pins in the cart slot where bent and not making contact with the cart. Once I replaced the cart connector, my problem was resolved.

 

[kasaski]

tested all pins and they all make contact with the cartridge , 99% sure its a bad zmc2. i'll probably just look for another board, this one didnt cost my much at all.

 

[XianXi]

On the Neogeo boot screen, does the SNK logo also have lines through it?

 

[kasaski]

Nope, only the Neogeo text Logo has the lines, snk logo looks good

 

[kasaski]

In case anyone else comes across this with the sasme issue, and cleaning contacts doesnt work, I finally got around to swapping a ZMC2 from another dead board onto this board and now its working perfect