MV-4F - dots in sprite/background layers only on right side of screen

[The Webmiester]

Hi all,

Wow I haven't posted here in a long time. Anyway, I have an MV-4F I got on eBay untested. It's mostly working except for the dots in the sprite/background layers, but only on the right side.

I have a multiple top boards so I'm sure it's a problem on the bottom board. Reading around, I got some info to look for a break in comms between PRO-B0, PRO-C0 and LSPC-A0, but all seem to be accounted for. I reflowed solder for those chips as well.

Could one of these chips be bad? Which one would it be likely to be? Any other ideas?

 

[maki]

try the DIAG BIOS

also, the MV-4F has the newer chipset, not the first one

 

[BIG BEAR]

You have to examine that board and look for any corrosion on chips.If you spot any corrosion,reflow the chip.
BB

 

[The Webmiester]

try the DIAG BIOS

also, the MV-4F has the newer chipset, not the first one

Diagnostic passes all tests.

 

[The Webmiester]

You have to examine that board and look for any corrosion on chips.If you spot any corrosion,reflow the chip.
BB

As I said in my original post I inspected and reflowed all three chips in question, sadly didn't help. I replaced the PRO-B0 chip with one from another board, which did fix the graphics faults but now I'm getting Z80 fault, and I actually noticed a physical crack in the replacement PRO-B0. So I ordered a couple on eBay, hopefully they are real and work lol.

 

[The Webmiester]

Just to wrap this up, a NOS PRO-B0 chip fixed up my problem completely.