IBM 5291 Model F "Bigfoot" keyboard review (capacitive buckling springs)

Chyros · 18 Jan 2020, 11:37

Time to tackle one of the more overlooked members of the Model F family; the 5291 "Bigfoot"! Hope you enjoy the video

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sharktastica · 18 Jan 2020, 12:00

Great video as always!

I can confirm that once converted, it serves us well! It's just a super cool keyboard to grace your desk with! There's a lot more wires involved than the usual Soarer's since the thing has to act as the keyboard's processor, but Soarer did most of the work for us (pinout, firmware, and template .sc to use) before they left us. The only issue I've had with it is that getting debouncing right took me a about a week of tweaking and spending a fair bit of time trying to use it normally whilst looking out for any repeated characters or dead keys.

adamcobabe · 18 Jan 2020, 14:13

Nice review. As soon as I find a nice XT cable, I'm going to swap the Lexmark-ish assembly with the NOS F XT assembly I got from Redmaus, which feels very crisp.

manisteinn · 18 Jan 2020, 16:18

I got three of these a couple of years ago and made a controller board for them, it just slides on the pin header.

(Click for larger)

I'd be happy to send you one for free, I appreciate your reviews!

It was a very rushed addition to a PCB order and no rushed project is complete without an annoying error: strobe/data are swapped. It's a trivial change in Soarers configuration file though.

Now there's also a QMK project for it, I haven't tried that.

I panelized this and the xwhatsit solenoid boards, so I got 60/80pcs respectively for a total of $10

If anyone wants bare boards feel free to PM, I can send a couple of each for the cost of shipping (~3€).

BOM (I'll publish the full project on github "soon")

Spoiler:

Bass · 19 Jan 2020, 11:09

Have you tried mounting some caps from your other F's and seeing if that makes a difference in smoothness? I've long suspected that my 1386965 Unsaver was actually Lexmark made and have found that the stock caps it came with are scratchier than other F caps I have tried mounted on the same keyboard (regardless of whether or not they are one or two-piece) . It's especially noticeable on off-center key presses. Model M and Unicomp caps also reproduce this scratchiness in my testing. I have heard other people throw around theories that the newer caps are not "optimized" as well for Model F barrels, so to speak.

As you said in your review, they still feel great to type on and I don't really notice it when I am typing fast enough, but it would definitely be nice if I could find an F122 to harvest some 2-piece caps from and swap the bottom parts out. Which reminds me....

SneakyRobb · 19 Jan 2020, 22:55

Bass wrote: ↑
19 Jan 2020, 11:09
Have you tried mounting some caps from your other F's and seeing if that makes a difference in smoothness? I've long suspected that my 1386965 Unsaver was actually Lexmark made and have found that the stock caps it came with are scratchier than other F caps I have tried mounted on the same keyboard (regardless of whether or not they are one or two-piece) . It's especially noticeable on off-center key presses. Model M and Unicomp caps also reproduce this scratchiness in my testing. I have heard other people throw around theories that the newer caps are not "optimized" as well for Model F barrels, so to speak.

As you said in your review, they still feel great to type on and I don't really notice it when I am typing fast enough, but it would definitely be nice if I could find an F122 to harvest some 2-piece caps from and swap the bottom parts out. Which reminds me....

Hi, I will throw some theories. I don't have evidence but I personally consider Model M and Model F keycaps to be different key caps. They have the same dimensions, but they are not the same. Something about Model M keycaps is rougher when used in the Model F barrels.

I am convinced something about the formulation of the plastic barrel plate of the Model M allowed IBM to remove some kind of lubricating coating/additive from the keycaps. This doesn't mean Model M keycaps are bad, but IMHO the plastic is designed to work with the Model M barrel plate.

SneakyRobb · 19 Jan 2020, 23:05

Great video. This was the first Model F that I got. I didn't know what it was and how it was different from the XT. I just read that Model M was a cheaper Model F, so I got a Model F. They look so alike to the untrained eye!. I ordered one and just couldn't get it to work. Soarer actually sent me some information and messaged with me about how to get it to work properly which was really cool and is a fond memory.

It is kind of strange to try to reverse think the reason for the extreme bezel size. So often what seems like a reasonable design choice relies on considerations so far from what we can imagine.

Elrick · 22 Jan 2020, 02:09

SneakyRobb wrote: ↑
19 Jan 2020, 23:05
It is kind of strange to try to reverse think the reason for the extreme bezel size. So often what seems like a reasonable design choice relies on considerations so far from what we can imagine.

The huge Bezel size is what attracts all those that appreciate the importance of this design.

Having something around the switches to rest your hands on whilst typing huge scripts of code or writing a new book. Also using the surround to stick notes and stickers help to customize your own work space, which was this keyboard and the PC it was attached to all those years ago.

Love to have a resurrection of this design but using the standard ANSI layout. That would be the end-game of all keyboards if it was ever released.

You couldn't find another in that unique size

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Darkshado · 22 Jan 2020, 07:05

No reason you couldn't fit something like an XTant assembly in this case... viewtopic.php?f=7&t=3047&start=300

SneakyRobb · 22 Jan 2020, 17:41

Darkshado wrote: ↑
22 Jan 2020, 07:05
No reason you couldn't fit something like an XTant assembly in this case... viewtopic.php?f=7&t=3047&start=300

XTravagant idea