Hacking the Happy Hacking Keyboard

17.07.2009 20:00

Last time I reported some weird problems with my new Happy Hacking Keyboard Lite2 USB. Escape and down cursor keys appeared unreliable and sometimes skipped keystrokes.

After some experimenting I found out that these two keys wouldn't register if I pressed them under some specific angles.

This got so annoying that I went back to my previous keyboard at work and decided to check if I can do something about it. Sending the keyboard back under warranty was pretty much out of the question: it took a month and coordination of three of my colleagues to get it from United States to Slovenia.

Opening the case is as simple as it gets: eight screws (one under the sticker with DIP switch instructions) and no plastic latches.

Disassembled Happy Hacking Keyboard Lite2 USB

There three layers here:

  • At the bottom is the membrane with switch matrix. It is itself composed of three layers of flexible plastic: bottom contacts, spacer and top contacts. They are only fused together at two spots (in contrast to the Sinclair Spectrum keyboard, where the contacts are hermetically sealed in bubbles in the membrane). This makes it possible to get finger grease on the contacts if your not careful handling it.
  • Flexible domes formed out of silicone-like substance. They act as springs that push keys back out after you press them.
  • Hard plastic keys, latched into the upper cover.

After visual inspection the most obvious problem appeared to be a couple of pieces of plastic freely floating on the membrane. They were most likely leftovers from the molding process (i. e. molding flash). Some keys (including the two I had problems with) also had irregularities on the bottom, so the surface that pushed onto the dome wasn't even. I carefully removed the excess plastic with a scalpel.

After assembling the keyboard back, the problem seems to be gone, but I guess it will take a couple of days of use to see if I really fixed it.

This is the second keyboard in a row that I had to repair after getting it brand-new from the factory (the first was on my Eee 901). They really don't make them as they used to (even when you pay $1.50 per key).

Posted by Tomaž | Categories: Digital

Comments

The HHKB seems to be a nice project/ideia. I hope to buy one soon.
Can I ask? How is your HHKB going? All right now?

Posted by luciano

Yes, after mending the cursor keys with a piece of cardboard, my HHKB works fine.

But considering the trouble I went through to get it to work properly I would hardly recommend it.

Posted by Tomaž

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