Restoring a 90s mechanical keyboard

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April 13, 2018

I recently gave up on my Filco Minila Air because of the poor state of Bluetooth stacks in both FreeBSD and GNU/Linux. I just couldn’t get it pair reliably with my FreeBSD system, and experienced frequent dropouts on Linux. It’s a pity, because I loved the keyboard (Cherry Browns), and the compact layout was great for carrying in a backpack.

While hunting around on eBay, I discovered that Compaq made a mechanical keyboard back in the 1990s - the MX-11800! It was designed to be used with rackmount servers, so features a square-ish layout ideal for closing in drawers, Cherry Brown switches, and an integral trackball.

Here’s how it looks now:

Compaq MX-11800

When it arrived it was in used state (exactly as described by the seller). It was in need of a clean, a couple of the switches were a bit gammy, and the trackball was sticky.

Instead of putting it to use immediately, I tested it, then took it home for restoration. This proved pretty easy:

  1. Disassemble.
  2. Clean the case and keycaps with a toothbrush.
  3. Swap out the gammy space and backspace keyswitches with the F3 and F9 switches (thanks to Nicholas Bruning for this suggestion).
  4. Reassemble.

I made a couple of relevant discoveries along the way:

The end result is a mechanical keyboard that is very similar in feel to my old Filco; the 90s Cherry Browns were apparently slightly heavier than the modern Browns, which may have contributed to their still feeling good in 2018. I’m particularly pleased with the trackball, which has freed up nicely and is reminiscent of the trackball in my old Unicomp, just more conveniently located.

The cleaning made a massive difference. Here’s a photo of the back case, which I took when I’d finished cleaning the right hand side, but not the left:

Before and after

I connect it to my docking station (or, here, directly to my laptop for testing) with a dual PS/2 to USB adapter:

Dual PS/2 to USB adapter

I’ve also semi-permanently attached the adapter with some heatshrink, to stop things coming accidentally unplugged:

Heatshrink on adapter

Here are some more photos from the restoration process:

Plastic components drying in the sun Plastic components drying in the sun

Preparing to remove switches Preparing to remove switches

Switches bagged and ready for swapping over Switches bagged

Controller board - I think even I could do board-level repairs to this Controller board

Ready for keycaps (note the Cherry Grey switch is now on the F3 position) Ready for keycaps