[G] fixing a mechanical

HwangjaeTerran

Finland5967 Posts

May 01 2013 20:08 GMT

So you bought yourself a loud, expensive mechanical hoping it would somehow raise you from the pool of pus known as bronze league (or the MOBA equivalent: something something jungle carry)?
Then you accidentally the whole keyboard in coke/water/pee (it happens)?
You rip the cord in half, wash the fucking thing and dump your moms weekend booze all over it but oh the humanity! your ever precious g,f,a and y keys are unresponsive. Your ability to communicate over the internet is gone ~~forever~~ until you drop another 100 bucks on a new keyboard or worse: shame your whole family by using one of those membrane abominations! But you don't have 100 valuable animals to liberate from the burden of having skin, enter this guide or some other, better guide.

This is a guide for fixing some dead keys only. If none of your keys work it's likely that the microcontroller is busted and you are better off if you throw away the pcb and build your own keyboard. You'll still save some. It doesn't look difficult, just google.

Note also that this guide is for keyboards with a back plate. With a keyboard without a plate, the process is even more simple and takes no effort at all. I left out the parts that take little to no brain activity to figure out or google.

And obviously you need to let the keyboard dry properly first

What you need, probably
+ Show Spoiler +

Multimeter
Soldering Iron
Something to remove solder: solder pump, vacuum plunger, soldering wick
Solder duh
A couple of screwdrivers
A marker
A conductive marker and/or some wire
Diodes (1N4148 are common)
some candy and music

You can probably get all of that for less than 20€/$ apart from the conductive marker

~~Admitting~~ Identifying the problem
Easy, open the keyboard, grab your multimeter and check each diode (next to the keys not working only ofc) first. Most multimeters should have a setting for testing diodes. Just look for the sign of the diode [image loading]

It basically sends a small current through and measures the voltage drop. If you don't have that setting, you need to have the keyboard powered and use some other option. Remember that diodes let current through in one way only so one way it's supposed to give a really high resistance and the other way very low. The numbers aren't of any value, what we are checking is whether or not the diode does anything.

If you find dead diodes, well, you are going to be sad. Wield the power of marker and mark the problematic areas. Now, you could simply solder the replacement diode on the visible side of the PCB, but that's nasty and you have OCD so you decide to do it the hard way.
+ Show Spoiler +

The hard way — your own fault, for buying a keyboard with a back plate, douchebag

Remove all the solder that connect the keys themselves to the PCB, you might aswell desolder the broken diodes too. Once all solder is gone, flip the keyboard and start removing the keys using two flat-head screwdrivers. The keys have a little thingamalingies you press in after which you can lift them out easily.

Once that's over with you can separate the pcb and plate ( but be careful of all kinds of plastic pieces or screws that might still be holding them together, the manufacturer has thought of many ways to make your adventure more exciting) The rest should be straightforward enough, just remember to check that your replacement diode works and you have a good solder joint before putting it all together again.

If you did not find dead diodes (or fixed them), check the solder joints of the keys themselves next. Use a setting for small voltages on the multimeter. Sometimes there could simply be a bad solder joint, my keyboard had a few ugly looking coming from the factory. If that doesn't do it, or there is more than one dead key, start tracing the "wiring" of the pcb connected to one dead key.
You might chance upon two things gazing into the matrix:
a) The dead keys are connected to each other
b) There is a scratch on the line between the last dead and the next working key
The fix is to either to use the conductive marker and draw over the cut or take a piece of wire and make an alternative route from the healthy key to the dead one. I tried to go all pimp and fix it with a tiny bit of solder but it's not worth the risk. So here's what you do instead:

If that did it, YAY. If it ain't goddamn working, you dun goofed. If you aren't an experienced solderer, you might need a few tries to get a good connection.

docvoc

United States5491 Posts

May 02 2013 00:13 GMT

This is way over my head O.o. Taking physics in highschool for two years with non-stop labs has not prepared me for this LOL. This was very cool though, I guess if you have all that equipment and your keyboard breaks from getting peed on (it does happen), then you are good to go :D.

micronesia

United States24758 Posts

May 02 2013 00:18 GMT

Not to be unappreciative, but I feel like the demographic for this guide is very narrow. If you have all this equipment and are familiar with how to use it, then you probably don't even need this guide. If you don't have soldering equipment or experience then you probably won't be doing this.

I also found it interesting as a read, though.

HwangjaeTerran

Finland5967 Posts

May 02 2013 08:21 GMT

On May 02 2013 09:18 micronesia wrote:
Not to be unappreciative, but I feel like the demographic for this guide is very narrow. If you have all this equipment and are familiar with how to use it, then you probably don't even need this guide. If you don't have soldering equipment or experience then you probably won't be doing this.

I also found it interesting as a read, though.

I've seen a lot of people saying that you need to buy a new keyboard if you spill something and some of your keys end up dying. It's cheaper to fix it and who knows just how cheap in the long run. The demographic might be narrow but there still might be a few people who want to know how to fix their dead keys and know nothing of electronics. I'm someone whose first reaction is to try to fix something so why wouldn't there be others? I looked on the internet and found no guide to this quite simple process so I thought it's good to have. Now someone might hit this on google and think:"I can do that"
Maybe I'll make a proper guide to building a keyboard from scratch in the summer or fall, to show how keyboard actually works, but there are a few of those on the internet already."

HwangjaeTerran

Finland5967 Posts

May 02 2013 08:26 GMT

e. double

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[G] fixing a mechanical

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