# Gameboy Color Button A not working



## acho (Oct 29, 2020)

Got a cheap partially working gbc. Thought I could give it a try to fix it. Turns out the pads/contacts on the A button were already ripped.  Any idea how to fix it? Or is it a goner? Thank you.


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## TheJeweler (Oct 29, 2020)

You could try a pcb pen, just retrace the old connections


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## E1ite007 (Oct 29, 2020)

In theory, if you could find the traces where those contacts start, you would be able to solder thin wiring to new contacts; some people do this with thin foil or copper paper.


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## acho (Oct 30, 2020)

is there a guide on how to retrace to origin contracts? its quite hard to locate them for sure.


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## FAST6191 (Oct 30, 2020)

I can see where the traces wander off to on that image. Or if you mean what shape do I make them then if the negative of the now missing thing is not enough then the b button (which looks like it might want a cleanup as well) looks to be the same size.


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## acho (Nov 6, 2020)

FAST6191 said:


> I can see where the traces wander off to on that image. Or if you mean what shape do I make them then if the negative of the now missing thing is not enough then the b button (which looks like it might want a cleanup as well) looks to be the same size.


do you mind pointing out the traces in the picture? I don't understand what I should do with them. so I just have to solder 4 wires on the 4 broken pads on the A button? If I see it correctly, do they all merge into 1 trace? thank you.


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## FAST6191 (Nov 6, 2020)

Most simple pressed or not switches on game consoles will either be pull up or pull down switches, which is to say going to a chip somewhere (or maybe a straight wire on some really old stuff) will be a switch and then it either connects to the positive rail aka pulls it high aka pull up or goes the other way and instead is a switch in line with the ground/negative and thus pulls it low/pulls it down.

Soldering a wire is only really going to help you if you are also replacing the whole switch assembly. Great if you want to make a nice positive mechanical microswitch gameboy (microswitches are the best switches).

If instead you wanted to repair it what you would more likely be doing is cutting out a bit of foil (copper is what is originally there but anything you can solder to should do) in a suitable shape (you can see the outline there in the earlier picture, or just copy the b button as it should be the same dimensions), scraping back the board a bit, scraping back a bit of the solder mask, gluing down the new bit of foil (superglue might work but does have a nasty habit of decomposing with heat, like a soldering iron, I like epoxy myself but is harder to use) and then making sure it is connected to the trace beyond (that is part of what I can see in the original -- just a little trace snaking its way out under the white colouring). You might swap a few steps around depending upon how comfortable you are with some of the steps -- might be easier to solder to a remaining trace before gluing down, though you do then run the risk of pulling more trace up if you are not careful.

Not sure offhand if p10 and p11 are vias or test points. If they are test points then great (can even use them to use your switch). If they are vias then they are used to go to the other side of the board (or a layer in the middle) and transmit power and signals around.


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## Vornskar (Jun 3, 2021)

Any conclusion to this? I have a gbc will all buttons working except the a button, it seems. Only real physical damage seems to be the p10 point so wondering if it’s not a test point and actually important for the pads to provide input. All cleaned multiple times so it’s not residue on the pads


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## darkangel5000 (Jun 3, 2021)

Vornskar said:


> Any conclusion to this? I have a gbc will all buttons working except the a button, it seems. Only real physical damage seems to be the p10 point so wondering if it’s not a test point and actually important for the pads to provide input. All cleaned multiple times so it’s not residue on the pads


P10 is just a test pad. But the via for the a button is right next to it and emerges again somewhere above the U10BE silkscreen marking. If you have continuity between the button pad and those vias, it could be a problem with the CPU CGB, where it directly connects to pin 125 if I'm not mistaken.


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