Recently my MNT Reform2’s keyboard has had a strange problem. The “N” key was producing duplicate key presses. Every time I hit the ‘N’ Key it would produce “nn” I pulled the key cap and cleaned out underneath.
I had the same problem!
I’n my case there was that an internal USB cable smushed between the heatsink and bottom cover. This pushed the motherboard closer to the keyboard… and pressing keys pushed the keyboard bottom onto the motherboard, leading to short circuits.
At least this is what I think was happening. The problem went away once I moved the internal cable out of the way.
Pulled everything out and taped off the n key. So the original problem is back. whenn i press the n key, it doubles. Seems like if i press the key downn annd hold it, the second nn comes up onn the key release… typos left for emphesis…
literally pulled the keyboard out of the laptop annd placed the acrylic bottom unnderneath it. I donnt think the problem could be what you are suggestinng…
Bad solder joints on that key or its diode perhaps? That could cause excess bounce on the key signal. Do you have flux and a soldering iron and could touch these up?
Put some flux on SW47 pins and D47 pads. Set your iron to ~380 degrees celsius. Clean the tip of the iron. Put a tiny bit of solder on the tip of the iron. Heat the SW47 pins and D47 pads so that the solder on them melts, then remove iron (one by one).
I’ve been having this problem with the “z” key for weeks now. Forgot others had also had this problem. Guess I’ll break out the soldering iron and report back on whether a bit of touch-up on those solder joints does the trick.
Edit: I broke out the multimeter for continuity testing after doing the touch-up, and it seems the circuit breaks when the key bottoms out. I wish I’d thought to test before the touch-up, as I can’t rule out having introduced this particular problem myself. However, if I did not just cause this particular problem with my attempted repair, it would explain the behavior I’ve been seeing. I suspect the switch itself may be defective now. I think I have some Choc switches in some bins in my son’s closet. He’s sleeping right now, so I’ll have to wait until tomorrow to test out this theory.
I’ve replaced the switch on the offending key and can confirm that this has resolved my problem. I also tried touching up the solder joints once more, just to be certain, to no avail. I can also confirm that the switch I just removed still breaks continuity between its pins when pressed all the way down, as it did before I removed it.
Final update. I decided to take apart the keyswitch I’d removed in order to see what might have gone wrong with it. There’s a little channel on the keyswitch stem, facing the contacts, which seems responsible for opening and closing the contacts as the stem slides up and down. Somehow, a bit of debris had gotten into that channel. Removing it seems to have fixed the switch.
You’ll probably still need a soldering iron, as I don’t think you can open the switch without removing it from the PCB (happy to be wrong on this point, of course), but given this finding, it may be that you can just repair your switches by cleaning them out a bit.
Edit: It seems that opening a Choc switch while it remains soldered to the PCB is not unheard of.
That is great to hear! I was hoping that choc switches were a bit more robust and it looks like they are. I’ve been very happy with the switches in the Reform, Penkesu, and I’m sure I’ll like them in the Pocket Reform!
For various reasons I set aside my reform for “a while” rather than get out my soldering iron to attempt a re-flow. I guess it’s been a couple years now.
A friend was asking me about the reform yesterday, so we dusted it off and tried to fix the keyboard. I unsoldered and swapped the Hyper and “n” keyswitches, but while we had them pulled we found that a bit of cruft in the channel that was causing a “double tap” in the switch mechanism.
My buddy got a video showing the problem and posted it to mastadon:
I pulled the key cap and cleaned out underneath.
