MV1FZS graphics error

[pierpa86]

Hello Guys,
I got this board MV1FZS, on first power on i got BACKUP RAM ERROR...
Replaced 74HC32 and ram 1 to 4 and error is gone but i get this video output.
What you thinks about ?

 

[pierpa86]

I can read only " All test PASS "
Guys what can cause this lines ?

 

[ack]

I would suspect something with your slow vram. Since the chars on screen appear to be changing I wonder if one of the data lines is floating? But its curious why the diag bios wouldn't see that issue.

 

[pierpa86]

Lower vram changed, but problem still the same.

 

[ack]

It may not be the ram itself, but trace or something else. I would try applying downward pressure on the larger chips one at a time while the board is on, on that screen and see if stuff changes/fixes itself.

 

[pierpa86]

The trace seems realy ok, checked also with pressure to see if something change at screen.

 

[pierpa86]

Aggressive of dark combat: maybe this board have more than one problem but board seems realy crean and no bad trace.

 

[ack]

It looks like D0 is stuck high on the slow vram.

 

[pierpa86]

I guess now I have to test the D0 pins :-)
I really appreciate your help but I don't know exactly how to do it.
Which pin and what should I measure and what should I expect.
I apologize in advance for my ignorance, but I try to learn where I can.
Unfortunately I have no spare parts for the D0. I only have a two slot card with no video signal and I don't trust using the spare from this card.

 

[pierpa86]

Found a bad trace, rear up board.
Restored but no changes

 

[ack]

I'm talking about D0 data line on the slow vram, not the NEO-D0 chip.

 

[pierpa86]

How i can test it ? strange if error is on vram since diagnostic bios do not found it, and ram is new.