sirhcman
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Posted this over on DP but thought I might get better help over here...I have been fixing up a Gameboy Color that had some battery corrosion and sound issues... I was able to get the sound problem fixed and cleaned up the corrosion and got everything running however I am having an issue with the down button on the D pad not working. I don't believe it is related to the corrosion issues because that seemed to be isolated to the other side of the board. I cleaned the rubber switch and plastic d pad and the contacts on the board look good. I tested the traces for the down direction with a multimeter and it has continuity. All the other directions work fine (UP/LEFT/RIGHT) the B/A/Start/Select buttons all work too. I am at my wits end at this point, does anyone have any suggestions?

Any help or input is appreciated! smile

Teh D3th St4r
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Santa Cruz, California

Try cleaning the contacts on the board with a q-tip and white vinegar.
If that doesn't work, try DNA or acetone.
BUT, if I were to hazard a guess; I'd say you need to replace the silicone parts.

I'll dig out a CGB, and see if I can come up with any other possibilities.
Nitro might be more helpful than I am in this department.

Good luck.

sirhcman
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Thanks for the response, I already cleaned the contacts with a q-tip and isopropyl alcohol and even tried other silicone parts that are known to work and it still won't register the down on the D Pad. I am really stumped!

Pardon my ignorance but what is "DNA"?

Teh D3th St4r
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Santa Cruz, California

Denatured Alcohol.
I'm going over some schematics to see if something might be burned out or if the gameboy is just bricked.

Last edited by Teh D3th St4r (May 5, 2013 2:40 am)

sirhcman
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Teh D3th St4r wrote:

Denatured Alcohol.
I'm going over some schematics to see if something might be burned out or if the gameboy is just bricked.

Thanks for the help! If you find anything please let me know.. I should mention that the power jack doesnt work (I haven't even messed with diagnosing the problem on that, been using batteries to test it) but I don't know if that would have any effect on the down on the d-pad.

Teh D3th St4r
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Santa Cruz, California

I got nothin' man.
Talk to Nitro about it. He's a little condescending, but he's usually right.

sirhcman
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Teh D3th St4r wrote:

I got nothin' man.
Talk to Nitro about it. He's a little condescending, but he's usually right.

I appreciate all the help, hopefully someone else can provide more insight. I would hate to have to chuck this thing because the dpad won't work properly!

Saskrotch
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Chicago IL
Teh D3th St4r wrote:

Talk to Nitro about it. He's a little condescending, but he's usually right.

I think he's just condescending when someone is wrong about something and doesn't know it

Teh D3th St4r
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Santa Cruz, California
Saskrotch wrote:
Teh D3th St4r wrote:

Talk to Nitro about it. He's a little condescending, but he's usually right.

I think he's just condescending when someone is wrong about something and doesn't know it

Of which I have been... more often than I'd like to admit...

nitro2k01
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Sweeeeeeden

Time to be a little condescending but hopefully right, then!

sirhcman wrote:

I don't believe it is related to the corrosion issues because that seemed to be isolated to the other side of the board.

Incorrect assumption. It's not actually just the area around the D pad that matters. If the connection is severed at any point on the way, the button will not work. The copper pad under the down button has two connections. The right one pad goes to ground whereas the left pad has a trace that goes up to the CPU. The right pad should have a solid connection, and is probably not where the problem lies.The left pad has a trace that goes up and changes side a couple of times. Here are two images where I've traced out the path of this trace. Note that the trace is covered by the cartridge slot on the front side.

Back:


Front:


Try testing for continuity using a multimeter between the left copper (actually probably gold plated) pad of the down button and the topmost spot on the same side. Ie, the via (as the connections between the sides are called) above the 03. You may to wiggle slightly with the probe to get contact.
If you find that this connection is broken, do not solder a wire directly to the pad where the button goes, but instead to the test pad named P03 near the button pad. Do this using as thin wires as you can get and route it all the way to a point along the indicated path which has a good connection the rest of the way to the CPU. Route it in such a way that the wire doesn't block any of the other buttons.

Good luck. (Hey wait, I'm supposed to be condescending.) Yeah, "good luck", I guess.

Teh D3th St4r
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Santa Cruz, California

I told you Nitro would know!
Cheers, dude.

sirhcman
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Thanks for the help nitro, I had previously tested for continuity on the left pad of the down button and the top most point on the same side as you mentioned and I have continuity. I also tested the trace on the "back" photo you posted and the trace on the "front" photo coming off the cpu and both are good. I guess the only other trace I haven't tried is the one behind the cartridge slot and I just cant imagine there being an issue with that but without testing it I can't say for sure. I tested the ground to another ground point and had continuity...

I really appreciate all the help!!

Last edited by sirhcman (May 5, 2013 5:37 am)

nitro2k01
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Sweeeeeeden

If you have continuity between the pad and and via near the CPU, how could the trace between under the cartridge slot be broken?

You may want to use this btw:
http://blog.gg8.se/wordpress/2013/01/28 … lcome-rom/
It can be used to check the buttons if you want to experiment with things. It also plays notes (a different one for each button) so you don't have to have access to the screen to use it.

Teh D3th St4r
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Santa Cruz, California
nitro2k01 wrote:

If you have continuity between the pad and and via near the CPU, how could the trace between under the cartridge slot be broken?

You may want to use this btw:
http://blog.gg8.se/wordpress/2013/01/28 … lcome-rom/
It can be used to check the buttons if you want to experiment with things. It also plays notes (a different one for each button) so you don't have to have access to the screen to use it.

We use it over at the game store to test old gameboys that people bring in.
It's awesome.

sirhcman
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nitro2k01 wrote:

If you have continuity between the pad and and via near the CPU, how could the trace between under the cartridge slot be broken?

You may want to use this btw:
http://blog.gg8.se/wordpress/2013/01/28 … lcome-rom/
It can be used to check the buttons if you want to experiment with things. It also plays notes (a different one for each button) so you don't have to have access to the screen to use it.


No I meant I checked the trace that is right below the cpu. I just tested the trace that runs behind the cartridge slot and it is indeed the culprit. Now I just need to rig a wire from one side of the board to the other. Thanks so much for helping me troubleshoot the problem! smile

SketchMan3
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NC in the US of America

Could you post pics of the wire job when it's done? I'm curious to see what it looks like. Or, if anybody else has a pic of this type of repair job, I'd settle for those.