IBM Model F122 Restoration

Lucid

11 Nov 2021, 14:14

I recently bought an IBM Model F122 off of eBay, and it was thoroughly abused. I posted a topic in the main forum in regard to a faulty switch column. After it was resolved, I decided to post the restoration process for everyone to see. This was my first time restoring a Model F. It was fun and I could see myself doing it again.

Here is a quick before and after in case that is only what you want to see:

Before
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After
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You can see pictures and description of the full restoration here:
Spoiler:
This F122 is dated October 26, 1984. As you can see from the stickers on the back, it looks like it was used in some type of Jeep automotive facility. My guess is that it was some type of testing or repair facility because of how dirty and damaged it was. Although that could be the result of a subsequent owner.

There was a huge crack in the back of the top case. There were many mismatched keycaps (looks like they may have been pulled from another keyboard). At least 10 keys were stuck and would not actuate. And I found out later that one of the switch columns including Home, Page Up, Page Down, Right Arrow, Numpad 7, Numpad 4, and Numpad 1 did not work at all.

Additional before pictures
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My plan for this restoration was to replace the top case, replace the foam, convert the board to USB with a detachable cable, convert the board to ANSI, and to floss mod the springs. You can see the replacement case in the above picture. Big thanks to Unicomp for the supply the replacement case. It's a very early Model M122 case with the push-button flip-out feet like the F122 has. The difference is that it is the Model M plastic, which should make it more durable. I only had to remove some of the plastic ribs on the inside of the top case to get it to work.

Here it is with the top case off
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The switch assembly removed
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Popping the barrel plate off the back plate. This is the easy part.
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Here's the barrel plate with all the switches and flipper removed. It was pretty dirty.
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The foam was pretty much fully disintegrated. However, the backing of the foam was still in tact and sticky, which made it pretty easy to remove.
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I gave the barrel plate a light sanding on both sides
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And then gave it a coat of flat black paint
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While the paint was drying, I cleaned off the sticker from the bottom cover. The bottom cover was in decent enough shape that I decided not to do anything further to it.
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I also cleaned up the keycaps
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I decided not to reuse the original keycaps for two reasons. 1) Because of how mismatched they were. Some of the fonts were completely different from other keycaps, and it really stood out. 2) The colors did not match the replacement keycaps that I had to use for the ANSI conversion (main enter, left shift, etc.). So I went with a full new set from Unicomp. I heard they refreshed their tooling (at least with the single piece keycaps), and I can say that the alignment and sharpness is great. I don't feel bad using them at all over the original keycaps.

Also while the paint was drying, I went through and performed the USB conversion.

I used a Teensy++ and loaded it with Soarer's firmware.
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I ran a 9-inch USB mini to USB A cable from the Teensy to a USB A female to USB C female adapter. I had to grind the original opening in the bottom cover a little bit to get the adapter through the opening. The result is a nice tight fit. The adapter is not going anywhere.
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I put some Kapton tape over the Teensy for good measure and tested the fit with the back plate. Everything checks out.
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With the barrel plate dried, reassembly began.

Here's the foam on the barrel plate
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The barrels back in the barrel plate
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And the flippers back in the barrels
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It is here that I should note that I got the barrel and flipper configuration wrong multiple times and had to remove the barrel plate from the back plate at least 4 times before getting it right. As you can see in the above pictures, I missed one of the barrels for the space bar. I also configured the flipper and empty barrel wrong for the left shift (and maybe the vertical keys on the numpad, but I don't remember).

Getting the barrel plate snapped back onto the back plate was the hardest part. Although, it really wasn't that challenging after seeing pictures and videos of other people doing it.

Here's some clamps
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Here's some more clamps
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Here is even more clamps
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One tricky thing is that I still had to use one hand to press down on one of the corners to get it to latch correctly while using the other hand to tighten the clamp to push the plates together. I forgot to do this 1-2 times and had to pop the plates apart and redo it.

Plates reassembled
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Then I flossed the springs. This part wasn't hard, it was just tedious and time consuming. Well worth to me though.
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Here's the keycaps all installed. I had to use some of the original PF keycaps. I will eventually replace them with relegendable covers if I end up using it as a daily driver.
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Here is a shot of the back of the keyboard fully assembled. You can see the USB port sticking out the back. I had to enlarge the cutout in the cover for it.
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And the final product again
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This is where I found out that the switch column didn't work and had to disassemble the entire thing to troubleshoot it. In fact, I had to take the PCB off of the back plate and add some Kapton tape under the pads and trace of the switch column to get it to work. But everything works great now.

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digital_matthew

12 Nov 2021, 04:54

I remember that listing on eBay. Glad to see it wound up in good hands. These things sure do clean up nice. Great work!

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fohat
Elder Messenger

12 Nov 2021, 15:34

VERY nice work.

If the repair work on the case continues to nag at you, a first generation Model M 122-key terminal case can be modified very easily to fit. Case material is the single aspect of the M that is superior to the F.

edit - sorry, I completely missed the comment where you said that - I assumed that you had repaired the original
Last edited by fohat on 13 Nov 2021, 21:01, edited 1 time in total.

Lucid

12 Nov 2021, 16:24

fohat wrote:
12 Nov 2021, 15:34
A first generation Model M 122-key terminal case can be modified very easily to fit
Thanks! That's exactly what I used :)

kaleyoverton

06 Dec 2021, 08:32

Nice one!

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Jugostran

10 May 2022, 14:27

Really nice job!

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