Add A Trackpoint To A Mechanical Keyboard

People love their tech, and feel like something’s missing when it’s not there. This is the story of one person’s desire to have the venerable trackpoint in their new keyboard.

[Klapse] loves a Lenovo old-style non-chicklet keyboard, so, despite the cost, five were ordered. They very quickly ended up with keys that didn’t work, although the trackpoints still did. After buying a sixth which ended up the same, [Klapse] decided that maybe giving up on the Lenovo keyboards was the best idea. A quick stop at a local store scored a fill-in mechanical keyboard, but in the back of [klapse]’s mind the need for a trackpoint remained. Maybe one could be frankensteined in to the keyboard that was just purchased?

Underside of the trackpoint, fitted to the keyboard PCB

The keyboard’s circuit board had traces everywhere, with nowhere to drill through between the correct keys, typically between the G, H and Y keys. But there was a hole used for mounting the PCB nearby. between the H, J, U and Y keys. The trackpoint needed to be extended to reach all the way through the key caps, so [klapse] searched the house looking for something that might do. Turns out that a knitting needle fits perfectly.

At this point a side-hack emerged. [Klapse] found a drill bit small enough to make the necessary hole in the trackpoint shaft to fit the needle. But the bit was too small for the drill chuck. In true hacking style, the bit was wrapped with duct tape and held in the drill. Sure, it wobbled a lot and it was really difficult to get it to drill in the center of the shaft, but it worked, eventually. The needle was cut off and glued into the hole, the key caps were modified a bit to allow the trackpoint through and the rubber tip put back on.

They say, “desire to cram old tech into new is the mother of invention.” Or something similar, anyway. Check out how a Teensy liberated a Lenovo laptop keyboard trackpoint and all. Also, check out this custom keyboard with integrated trackpoint, of course.

Thinkpad 701c: Reverse Engineering a Retro Processor Upgrade

[Noq2] has given his butterfly new wings with a CPU upgrade. Few laptops are as iconic as the IBM Thinkpad 701 series and its “butterfly” TrackWrite keyboard. So iconic in fact, that a 701c is part of the permanent collection of the Museum of Modern Art in New York.

Being a 1995 vintage laptop, [Noq2’s] 701c understandably was no speed demon by today’s standards. The fastest factory configuration was an Intel 486-DX4 running at 75 MHz. However, there have long been rumors and online auctions referring to a custom model modified to run an AMD AM-5×86 at 133 MHz. The mods were performed by shops like Hantz + Partner in Germany. With this in mind, [Noq2] set about reverse engineering the modification, and equipping his 701c with a new processor.

thinkpad-brainsurgeryThe first step was determining which AMD processor variant to use. It turns out that only a few models of AMD’s chips were pin compatible with the 208 pin Small Quad Flat Pack (SQFP) footprint on the 701c’s motherboard. [Noq2] was able to get one from an old Evergreen 486 upgrade module on everyone’s favorite auction site. He carefully de-soldered the AM-5×86 from the module, and the Intel DX4 from the 701c. A bit of soldering later, and the brain transplant was complete.

Some detailed datasheet research helped [noq2] find the how to increase the bus clock on his 5×86 chip, and enable the write-back cache. All he had to do was move a couple of passive components and short a couple pins on the processor.

The final result is a tricked out IBM 701c Thinkpad running an AMD 5×86 at 133 MHz. Still way too slow for today’s software – but absolutely the coolest retro mod we’ve seen in a long time.