Latest update for my PowerBook Duo 280c.
I'm not the first.
@techknight demonstrated his earlier this year. I stumbled upon his video while working on mine.
Took a bit to get this to work, primarily because I made a small mistake on the first PCB and had to wait for the tariff situation to calm down to try again via JLCPCB.
View attachment 92150
There's not much height inside the Duo chassis so it's difficult to get everything to fit. I made the PCB thickness 1.0mm. I then needed something that would allow me to use the stock keyboard screw holes to mount it so I made a 3D printed backing plate. The PCB screws into the plate and the plate screws into the Duo chassis using the 3 stock screws (screwed in from the bottom of the Duo). The backing plate is also 1.0mm. I was flipping between Kailh and Gateron low profile switches, I believe they are close in height. Chose the Gaterons.
Then I had a choice between using the stock key caps by shaving off their stems and gluing a 3D printed mx stem to them, but I felt like that would be weak. In the end, I made my own 3D printed key caps modeled after the stock key caps. Not exactly the same because the stock key caps have a taller final row of keys (the row with the space bar) but I could not reproduce that as I didn't have remaining height to do that. I added a clear notch on the caps lock key cap like stock, and 3D printed a clear light tube for it. Surprisingly, the key stabilizers on the caps lock, return, command, space bar, shift keys all work. I thought that was going to be a nightmare but my first try seems to work ok.
Unfortunately the final result has the top of the key caps about 4mm higher than the original. The lid however still closes because when the keys are depressed, they are within the top of the chassis.
The labels are black instead of white -- because I'm using decals and I don't have a printer than can print white.
I will keep an eye open for even lower profile switches. There are cherry ultra low profile switches but they were hard to get (outside of harvesting them from a brand new keyboard) and/or super pricey in low volumes.
I am not going to be selling these keyboards. I'm not a vendor and don't have time to assemble these - these are a lot of work. But once I feel like the design is solid, I will freely publish the gerber files, the 3D models for the backing plate and key caps, and provide instructions on which parts I got (the cable ribbons, ribbon connectors, brass inserts, screws, surface mount LED for the caps lock, etc).
It's MUCH nicer to type on than the stock...