4 Slot Text Glitch

R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I got a 4 slot today and the text layer (overlay?) has a problem:



It's sort of like the layer is outputting the right half of the image in both tiles. Both sprites and backgrounds are perfect, as is the sound.

I've looked over the board and can't find any damage other than the JAMMA edge. The power lines are really badly damaged and someone even drilled a few holes in it for whatever reason :spock:

It's had a repair done though and all the lines do reach where they are meant to. It just looks a mess.

At first I thought it must be an addressing problem but thing is, the Unibios I dropped in has the same problem.

So I have no idea what could be the issue here, maybe a techy person here can help me?

A few parting shots:





 
Last edited:
Xian Xi

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,762
When my PCB had that problem is was a broken trace on the LSPC.
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I don't suppose you recall were that trace led to? I can't see any damage on the board at all, it's pretty spotless aside from the JAMMA edge.
 
Xian Xi

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,762
You might want to check around the battery, too. Some of the batteries on a 4 slot look clean but underneath it's leaking and eating traces.
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I was thinking of replacing the battery. Does an MVS need it to function or can I safely remove it and replace it later?
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I thought as much, just wanted to make sure.

I'll take a look in the morning and report back. Thanks for the tips.
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
The base of the battery has started to crystalize and the negative terminal on the pcb is a touch blue. :(

So what might this have affected then? There doesn't appear to be much under there but I have a 1 slot where the battery leaked and the ZMC2 IC has perished which is across the other side of the board.
 
Last edited:
Hewitson

Hewitson

Metal Slug Mechanic
Joined
Mar 6, 2008
Posts
2,198
RetroRepair said:
I was thinking of replacing the battery. Does an MVS need it to function or can I safely remove it and replace it later?
Click to expand...
Don't just think about doing it, do it. It sounds like its already done damage.

Clean the area throughly with a toothbrush and isopropyl alcohol and replace with a CR2032-type lithium battery in series with a diode.
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I have done, I'm no stranger to cleaning up boards with battery damage (unfortunately) but now I need to figure out what it's done and how to fix it. Though I can't see visual evidence of any damage at all, the blue bit came right off.
 
channelmaniac

channelmaniac

Mr Neo Fix-it
15 Year Member
Joined
Nov 29, 2005
Posts
4,316
Look for a scratched/gouged trace on the bottom of the board.

Those types of errors are address line problems, not data. If it were data, you'd see stripes and not repeats of portions of characters.

RJ
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
I have spent over 4 hours looking for gouged traces, I can't find any. The bottom board is very tidy. There are a few scrapes on the top board but they check out in continuity testing.

I do see a RAM that goes the the LSPC2 which has some sort of stain around the top pins and vias, though I can't tell if it's flux or something else.

I have a 1 slot for parts so if I need to replace something I might be able to swap them out.
 
R

RetroRepair

n00b
Joined
Feb 26, 2010
Posts
46
As it goes, there's an HC32 near the battery secion that has a stain round it too, might that have something to do with my issue?
 
You must log in or register to reply here.
Top