Focus FK-2001 Left Control Key Issue

thefarside

24 Feb 2021, 04:33

I have three FK-2001 keyboards and two of them intermittently do not register a key press on only the left Control key. One has Alps clones and the other has genuine Alps.

My third FK-2001 is a new old stock which I think is why it’s issue free.

I think the issue is me pressing the key too hard and possibly off-center key presses. Has anyone ever experienced an issue like this? I took apart the genuine Alps switch and everything looks good. Pressing lightly on the contact leaf reliably registers key presses and the slider looks fine. I attached a picture of the switch in case there’s something I missed.

Any help would be appreciated. I might try to be lighter on the key but I’d prefer it to take my abuse :D
Attachments
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poyovimenakafudraga

24 Feb 2021, 04:49

You can clip off the pusher leaf from the top and then split the plate (carefully, it's still riveted on the bottom). Then you can try blowing the dust out, or soaking it with alcohol and then blowing out, you get the idea. The problem is caused either by dust or by oxidation, the latter being harder to fix. If this doesn't fix it, you'll have to transplant a contact plate from a working switch.
EDIT: just crossed my mind, it might be a shoddy solder joint, it's a pretty common fault on Focus, Chicony, Ortek and similar boards. Check that out before fiddling with the contact plate.

thefarside

24 Feb 2021, 23:44

Thanks I’ll check out the solder joints first. The case is easy to open - no screws!

User avatar
Polecat

25 Feb 2021, 03:06

thefarside wrote:
24 Feb 2021, 23:44
Thanks I’ll check out the solder joints first. The case is easy to open - no screws!
Also check for cracked traces on the PC board going to that switch. The switches at the corners are especially vulnerable as they hit the deck first if the keyboard gets dropped.

thefarside

27 Mar 2021, 20:01

Thanks again for the advice! I followed both tips and first checked out the PCB. There were no obvious cracks on any of the traces. I included a picture of the left control key PCB area and the whole board.
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I then removed the contact leaf and blew some compressed air but that didn’t seem to make improve the key. This was my first time opening up the switch plate assembly and I wasn’t sure if I could remove the switch plate, so I decided to open up the assembly a little more and blow air at different angles. I’m not sure if this is the best method but I used a toothpick to open up the assembly.
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I also swapped the contact leaf from the blank key next to it. That seemed to fix it! It’s 99% reliable now based on my limited testing, and can go back to being one of my daily drivers.

I also learned about a nice way to dampen ping/resonance on FK-2001 keyboards. I purchased this from eBay and the seller told me he cleaned the switches and keyboard, which look brand new and feel great. He also put some rubber grip padding under the PCB which explains why the sound is so nice compared to my other FK-2001 boards.
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Thanks again for the help! It’s great to have place with such knowledgeable and helpful people. Attached some pictures for reference.

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