MV2F - Video RAM error - address is all p's

touche112

n00b
Joined
May 18, 2020
Posts
14
Hello all,

I have a MV2F with a weird video RAM error. Normally I'd replace the VRAM but instead of an address, I have all p's. I've recapped the board and I can't see any bad traces. :annoyed:

https://i.imgur.com/FuiWkTj.png

Any ideas on where I should start?
 

ack

Ninja Combat Warrior
15 Year Member
Joined
Apr 9, 2009
Posts
537
This is the same thing I replied to you on the other forum you asked this on.

"It looks like bit 5 of your lower 32k/slow vram is stuck high. This is causing drawing of fix tiles to be wrong if the tile being draw doesn't already have that bit set.

The actual error would be for address 0000000, write 5555, read 5575"
 

shadowkn55

Genbu's Turtle Keeper
15 Year Member
Joined
Dec 9, 2006
Posts
2,386
What cartridge are you running? Legit carts show the snk logo up top on the unibios splash screen.
 

ack

Ninja Combat Warrior
15 Year Member
Joined
Apr 9, 2009
Posts
537
Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.
 

touche112

n00b
Joined
May 18, 2020
Posts
14
What cartridge are you running? Legit carts show the snk logo up top on the unibios splash screen.

Fatal Fury 3

Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.

Is there someone around here that sells pre-burned eproms? I don't have a burner. I guess I probably should order one
 
Last edited:

shadowkn55

Genbu's Turtle Keeper
15 Year Member
Joined
Dec 9, 2006
Posts
2,386
What speed ram did you use for both fast and slow vram?
 

touche112

n00b
Joined
May 18, 2020
Posts
14
Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.

Found that issue, it was a loose green going to the JAMMA harness. Color is fixed now.


Hahaha no, not the same board. That one was fucked a while ago and I was just messing around with it. Some backstory, I got three MV2Fs from a guy on Craigslist. The one with the fucked up backup RAM was/is a POS already, with a bunch of ICs that were bridged and corrosion everywhere. The one in this thread with the video issues is a different board altogether.

What speed ram did you use for both fast and slow vram?

Fast VRAM is 15ns, slow VRAM is 55ns. Just to make it clear the Reddit post I made was a different board - I did replace the right chips on this one ;)
 
Last edited:

touche112

n00b
Joined
May 18, 2020
Posts
14
Okay I just tested with a second game I just got in. I get the same address range in my exception error for both carts, which makes me think its not a cart problem: 00C11622

Slots and carts have been cleaned with Deoxit.
 

shadowkn55

Genbu's Turtle Keeper
15 Year Member
Joined
Dec 9, 2006
Posts
2,386
Did the original vram error go away when you replaced all the vram chips?
 

shadowkn55

Genbu's Turtle Keeper
15 Year Member
Joined
Dec 9, 2006
Posts
2,386
Throw all the dip switches down and see if any other errors show up.
 

touche112

n00b
Joined
May 18, 2020
Posts
14
Throw all the dip switches down and see if any other errors show up.

Ok well, I did that, and the screen flashed, and then went to nothing. Now it's acting like there's no BIOS chip. I reflowed the BIOS socket and I can't see any damaged traces around the BIOS socket... Same behavior with original chip and Unibios. :annoyed:
 

BIG BEAR

SHOCKbox Developer,
20 Year Member
Joined
Dec 14, 2001
Posts
8,222
you are going to have to check your traces between the LO chip and your 5814's...it look like somethig is going on with that 531000
BB
 
Top