Repair advice for G80

[IvanIvanovich]

I received this poor victim today... it's all scorched and the pads are gone, traces are in bad state. I think using some wire to fix it is the best way now... but I suck at understanding matrix and I am not 100% sure where I need to use wire to jumper it... to which adjacent switch and diodes (NKRO model)?

[wheybags]

By looking at the other switches poking through, I think this is what you want

[Muirium]

This is the first time I've been diagram ninja'd! Well done, Wheybags!

Here's mine:

Matrix Guess.jpg (862.4 KiB) Viewed 2028 times

Functionally the same as Wheybags. Just make sure there's continuity in the half destroyed traces you rely on. Obviously A and B are the switch pins while X and Y are the diode's.

Edit: I'm wrong: B connects to Y but not to the horizontal line. That vertical trace is just there to hook the switch and diode up in series, and does not join anything else. Looks like it should be like this:

Matrix Guess 2.jpg (875.27 KiB) Viewed 2019 times

Watch out for both those horizontal rails. They need to conduct signals from other switches, while not shorting with the right hand pin of the diode.

[IvanIvanovich]

Thanks guys. This was pretty much what I thought but I wanted to get another opinion. Definitely looking for a one shot one kill fix as I don't think the area will survive much more soldering/desoldering abuse.

[Aleksander]

OMG, what size soldering iron was used to rape this board like that?

[IvanIvanovich]

I'm not really sure how this was managed. I got it 2nd hand, and discovered it after opening the case to see if there was anything obvious to why it was not functioning. An unhappy surprise... but I do finally have a JIS G80.

[wheybags]

Does it work fine apart from that switch?

[IvanIvanovich]

So far... no. I've only got lock lights to respond. Pressing key turn them leds on and off, but yet aqua does not show those keys as registered while doing so. Nothing else does a thing.

[wheybags]

That's odd, because those leds are controlled by the computer, not the keyboard controller, so it must be sending some sort of signal.

[IvanIvanovich]

I finally have it repaired and functioning properly. It was a bit tricky for me as I had a lot of trouble getting solder to 'stick' to keep the switch where it belongs without any pads at all. I suppose I will have to try and remember to be extra careful of that key if I ever switch the keycaps.
Oddly though, it does not work at all with my Windows 8.1 computers, but works fine on older version of Windows and crunchbang... kind of mysterious.
Thanks for your help on this.