MV1FZS "MMIO dead output" Error [SOLVED/ HC32 & NEO-FO]

[Retro Mecano]

Hello.

So i got this MV1FZS slot initially witch back up ram error, and i tracked it town to U17 (HC32 chip in back up are). Swapped it and the error disappeared.

Now i got a new error "MMIO dead output", showing some bad connection i assume between Neo-C1 (1) and Neo-F0 (47)

I checked continuity between those pins 47 and 1, and they were connected fine.

Putting back unibios i can see the crosshatch, and when putting a game, it does not go through the Unibios splash screen. It goes straight to a black screen. Game doesn't boot. Cleaned connector without result.

Tried to reset the RAM with 8DIPs down, but it doesn't seem to work. Checked continuity of dip and they were ok.

Any clue?

 

[Retro Mecano]

UPDATE

Following up the Neo-F0 schematics, found that it control also the DIPs configurations. (Remeber that i cant launch the wram test screen)

Tried for the first time my probe (neh still a lot to learn lol) to read the DIP signals, and found out that DIPRDO (pin47) should behave differently depending on A7, either low or high. But A7 was always pulsing and DIPRDO had no sign of life. Not sure if my first time reading a probe was correct lol.

Making sure that continuity was there between 8 DIP pins and NEO-FO pins, i jumped on swapping it from a dead board.

Et voila!

Besides a "farting" sound at start up (may be caps or volule pot), it works finally fine.