mv2

Hello everyone, I'm repairing an SNK Neo Geo MVS MV2 motherboard. The board previously had a paddle circuit issue, which has now been resolved. It now passes all BIOS diagnostic tests, including the paddle/video RAM tests, but still freezes on the grid screen when cartridges are inserted...

I haven't used a 2F cartridge slot yet. Among these models, which ones use button batteries, and which ones use batteries that are prone to leakage? I only saw from the lower PCB diagram that the MV2B has the worst expandability, but the batteries in the PCB diagram have been removed, so I...