Gameboy Color displaying odd screen issue - battery leak damage

[zincmann]

I have a gameboy color i purchased recently which seemed to have a come corrosion from battery leakage. I cleaned the board up and truly did not seem bad ( I have seen a LOT worse than this). If you look at the board you really cannot see anything anymore with the naked eye. Anyhow it didnt turn on initially before I cleaned it but after cleaning it extensively it turns on but now shows an inverted screen. Sound works just fine. I did test to see if it was a bad screen by doing a board swap and it is indeed the board but I am challenged to find out where the fault is. Please see attached pics to see what I am referring to. Third pic is when I go to turn it off as the artifact of the screen remains for a few seconds so you can see it more pronounced.

 

[FAST6191]

Sadly my usual source for PCB scans ( https://circuit-board.de/forum/index.php/Thread/13913-STRIP-CLUB-PCB-Scans/ ) does not feature a CGB. https://gbdev.io/pandocs/ similarly lacks much here compared to other similar works for other systems.

Invert was an option for many old school full (as opposed to character) LCD screens and externally controlled rather than software so it could well be something pulled one way or another, I normally see it more when the screen was rebuilt incorrectly (usually putting the polariser in the wrong way around) but that is unlikely the case here as it is all one sandwich part rather than individual components.
As far as I am aware there is no invert option (would make games look odd) and I don't see a software one in a quick scan of the pandocs above so we might be undocumented function territory.
In my case a working spare board would be time to break out an oscilloscope to see what might be changing.

Image remaining after being turned off is nothing too drastic as to make it black would have involved exciting the various parts to do and them returning to baseline takes a moment. Most just not turning off from a full black screen test or something. I would be surprised if it is some parasitic draw or anything.

 

[elk1007]

I have a gameboy color i purchased recently which seemed to have a come corrosion from battery leakage. I cleaned the board up and truly did not seem bad ( I have seen a LOT worse than this). If you look at the board you really cannot see anything anymore with the naked eye. Anyhow it didnt turn on initially before I cleaned it but after cleaning it extensively it turns on but now shows an inverted screen. Sound works just fine. I did test to see if it was a bad screen by doing a board swap and it is indeed the board but I am challenged to find out where the fault is. Please see attached pics to see what I am referring to. Third pic is when I go to turn it off as the artifact of the screen remains for a few seconds so you can see it more pronounced.

I would open it back up and focus around the ribbon cable and connector.
May be more extensive but that's the simplest place to start.

 

[zincmann]

I would open it back up and focus around the ribbon cable and connector.
May be more extensive but that's the simplest place to start.

So I checked that, I used the screen with a different board from a different GB Color and it worked fine. I can double check the connector for any corrosion or loose pins but it looked already clean up there any of the initial corrosion was below the cartridge slot towards the battery area

Post automatically merged: Jan 31, 2023

SO I did check out screen connector and was completely clean I even hit it with some IPA and no change. Its not cost effective to replace the board but there must be a capacitor or a resistor that must be bad? I dont know....

 

[elk1007]

I would open it back up and focus around the ribbon cable and connector.
May be more extensive but that's the simplest place to start.

So I checked that, I used the screen with a different board from a different GB Color and it worked fine. I can double check the connector for any corrosion or loose pins but it looked already clean up there any of the initial corrosion was below the cartridge slot towards the battery area

Post automatically merged: Jan 31, 2023

SO I did check out screen connector and was completely clean I even hit it with some IPA and no change. Its not cost effective to replace the board but there must be a capacitor or a resistor that must be bad? I dont know....

I'm not fully understanding what you tried here.
You put the inverted screen into a working GBC and it works fine?
Thereby narrowing the issue to the GBC motherboard?

 

[zincmann]

I'm not fully understanding what you tried here.
You put the inverted screen into a working GBC and it works fine?
Thereby narrowing the issue to the GBC motherboard?

1). Cleaned board completely I dont see any corrosion anywhere used a magnifying lens to check
2). Used a known good board with the screen of the faulty GB Color and the screen works as it should
3). Swapped out the good board with the faulty board and that screen then was inverted
4). Concluded the board still has something wrong with it
5). Cleaned the ribbon cable connector on the faulty board and no difference


Thats where I am at right now. Hope thats clearer

 

[elk1007]

1). Cleaned board completely I dont see any corrosion anywhere used a magnifying lens to check
2). Used a known good board with the screen of the faulty GB Color and the screen works as it should
3). Swapped out the good board with the faulty board and that screen then was inverted
4). Concluded the board still has something wrong with it
5). Cleaned the ribbon cable connector on the faulty board and no difference


Thats where I am at right now. Hope thats clearer

Yes, thank you.
I agree that the issue is isolated to the board itself since the screen works with a known good board.

This may be useless info, but you can change the color palletes on GBC by using button combos on startup.
I'm curious if you can use this to get the screen back to normal on the "bad" board.

 

[zincmann]

Yes, thank you.
I agree that the issue is isolated to the board itself since the screen works with a known good board.

This may be useless info, but you can change the color palletes on GBC by using button combos on startup.
I'm curious if you can use this to get the screen back to normal on the "bad" board.


View attachment 350663

Ill give it a whirl, I was thinking that could be a possibility but does the board save the settings in non volatile memory even when batteries are not connected for a period of time?

Post automatically merged: Feb 2, 2023

Ill give it a whirl, I was thinking that could be a possibility but does the board save the settings in non volatile memory even when batteries are not connected for a period of time?

So indeed I tried the "right + b" and nothing changed. I even tried some other combinations and nothing. So next question is which resistor or capacitor is bad? I would prefer not to test it all if there is a group of components that trace back to what is rendered on the screen UNLESS its a chip.

 

[hippy dave]

Ill give it a whirl, I was thinking that could be a possibility but does the board save the settings in non volatile memory even when batteries are not connected for a period of time?

Post automatically merged: Feb 2, 2023

So indeed I tried the "right + b" and nothing changed. I even tried some other combinations and nothing. So next question is which resistor or capacitor is bad? I would prefer not to test it all if there is a group of components that trace back to what is rendered on the screen UNLESS its a chip.

Those button controls on startup for changing colours only apply to mono GB games, so if you're playing a GBC game it won't do anything. And it doesn't save any settings for that, just applies it for the current boot.

I can't help with the hardware diagnosis, but good luck!

 

[zincmann]

Those button controls on startup for changing colours only apply to mono GB games, so if you're playing a GBC game it won't do anything. And it doesn't save any settings for that, just applies it for the current boot.

I can't help with the hardware diagnosis, but good luck!

Thanks for the fyi no matter what appreciate it.

 

[zfreeman]

I had this same issue. Eventually, the GBC wouldn't turn on. May be a capacitor issue, but I never looked into it.

 

[zincmann]

I had this same issue. Eventually, the GBC wouldn't turn on. May be a capacitor issue, but I never looked into it.

Ok so I know its NOT Just mine being possessed with some darkness LOL Ill keep this alive as I want to understand what it is.

 

[dubsmachine]

I may have a similar issue...picked up a GBC on eBay and appears in good condition (haven't opened up yet) and it doesn't show games in colour.
Even for Links Awakening DX so having trouble understanding the issue.