Hi there, it's hard not to notice that many people who like mechanical keyboards also tend to like trackpoint devices integrated into the keyboard. Now, when building a keyboard, one either has to use hard-to-get and expensive new trackpoints sold specifically for that purpose, or chooses the option of sacrificing one of those many ThinkPad keyboards with missing key caps out on ebay for the price of a cup of coffee. I haven't been able to find a database of the various models of the latter, along with its electrical and mechanical requirements, therefore I opened this topic. The idea is that we gather as many as possible of the various models of ThinkPoint, along with models they appeared in, so that when shopping for keyboards, we have a better chance of finding the one we're looking for.
For a start, this is the first one I came across:
- tp2.jpg (85.32 KiB) Viewed 3230 times
According to the seller, it's from a keyboard for the ThinkPad A22p, also compatible with A20, A21, A22 (none of which I can confirm). I think this is a common type, since it also appears in Suka's DIY keyboards (look at his thread for the electrical pinout). As far as mounting is concerned, here are my measurements:
- The trackpoint reaches through an 8mm hole in the keyboard "plate" from underneath.
- On the original keyboard, there is a space of 2mm between the bottom of the keyboard plate and the top of the PCB, so that the black triangular part (whose top is some kind of foam or rubber) is pushed against the keyboard plate when installed.
- Two of the mounting holes (ø2.5mm) are in a line with the trackpoint, at a distance of 10.5mm to either side of it.
- The other two (also ø2.5mm) are 19mm apart, 8mm across from the trackpoint (down in the photo).
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Here's the TP from the IBM SpaceSaver II:
