MV1ACH not working on OSSC

[vidarw]

So I purchased a MVS MV1ACH from AliExpress as I wanted a front loaded NeoGeo for my multi-JAMMA arcade.
The device does not seem to like my OSSC routed through Franks Minigun.

A brief check with my analogue oscilloscope showed values quite similar to my working MV1C so I tested it on my B&O CRT TV where it works flawlessly.
Any idea what causes the board to not cooperate with the OSSC?

Added pictures of the boards. Quite obvious that someone messed with the caps and the backup battery is a bit sad, but seems OK overall.

 

[vidarw]

Okay to reply with an answer to my own problem.
Turns out this board is even more off than the special NeoGeo settings found here: http://junkerhq.net/xrgb/index.php?title=Neo_Geo_MVS
Had to push the HSync Tolerance to 8.64us before I finally got a picture.

 

[nem]

Quite obvious that someone messed with the caps

Those are original caps.

You will need to recap it at some point.

 

[vidarw]

thanks for the info. Thought that the mismatch between the size of the cap and pcb was a sign of tampering.