The keyboard is remarkably easy to open. It turns out that the 5150’s gray plastic is nice and flexi allowing easy removal of the innards. (The white/beige plastic seems to be similar to the F XT’s white plastic. It is more rigid than the Model F 122, and it is textured unlike the Model F AT.)
See these 3 tabs? Stick a screwdriver and pry. MUCH EASIER than any cooler master, Filco, Ducky, Rosewill.
Inside it looks exactly like a Model F XT. With the exception of a telephone cable being hooked to the same (Belkin?) connector.
I used a fridge magnet is to confirm my theory that this is a non ferrous metal. On the portable version, both the front and the back plates are aluminium. And the casing is of course plastic. On the non portable F XT, all 3 plates (front, back and casing bottom) are iron. This keyboard weighs far less than the F XT.
After examining it with some care I believe I can make this keyboard heavier simply by putting an F XT innards inside. But I’m not going to do that. My F XT is STILL in pieces after 1 year. I did buy a box of binder clips hoping to do the WCass binder clip thing to the F XT, but I haven’t figured out what to do about the fallen-off spacebar, that’s my problem.
It’s almost time for me to beg Wcass again for his Model M spacebar clips… (PM
will be sent once I have finished some earlier projects).
More information will come in the following months... sooner or later I will work up the courage to go back to fix my F XT. At the least, I intend to see whether the innards are swappable. They should be.
UPDATE
I washed the keyboard and scrubbed it down with a toothbrush. Was disappointed to see that this is painted plastic, so once the external layer is chipped off what's below is a different color.
After an entire day of drying in the hot Singapore sun (I even turned it over at different angles), the keyboard still COULD NOT dry completely due to the tabs/legs. But since that's a peripheral part I suppose I don't want to wait any longer. Besides, both legs and both bottom tabs (for fitting into the original housing) CANNOT be removed. It seems to be the way this plastic is constructed, around the tab, rather than having the tab inserted later. There's like 2mm of extra plastic even after pressing in the tabs/ legs fully, so they can't be pushed out even with brute force. I suspect they may have been inserted when the white casing plastic was still hot and expanded in the factory?
On closer examination of the connectors indeed this is exactly the same as the F XT. There are a lot of metal prongs inside that Belkin? connector, but actually only 4 of them are used.
After using a multimeter to figure out continuity, I ran jumper cables directly to a teensy on a breadboard for testing purposes. I don't intend to use this keyboard; am collecting it until such time as WCass and the other heroes of the Model F revival project successfully start producing suitable parts. The most infuriating part of this keyboard is definitely not the layout; it's the spacebar which seems to be the equivalent of 3 Cherry MX blacks.
Anyway, here is my final working setup. I typed the update on this post using the portable 5155. This is a very, very beautiful keyboard and I wish it was more user friendly. But I will be storing this keyboard because it is really impossible to use the spacebar unless I change all my typing habits and start using both thumbs on it.
The construction is very good and far exceeds a Ducky or Deck, even though it is already significantly lighter and 'flimslier' than the F XT non-portable version.
I pray that WCass and his team of geeks (spoken in a non-pejorative sense) will succeed in their project! I would really love to see a TKL F XT! Oh, and also a spacebar of reasonable weight/ stiffness.
