Apologies in advance for relatively sub-par pictures. Credits and inspirations, in no particular order:
dfj (for general advice)
Soarer (for the adapter, of course)
kishy (for case advice and general advocacy)
fohat.digs (for
http://geekhack.org/showwiki.php?title=Island:24615)
So, motivated by Soarer's adapter project, and having my curiosity peaked by the multitude of Model F advocates (did someone say NKRO, metal construction, and compatibility with modern stuff?), I decided to snag an F 122 on the cheap to try out:
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It appears to be a fairly early model, with one piece keys having reinforced corners. A key or two were of the two-piece construction, indicating that they were replaced at some point. In addition, a stabilizer was missing on the numpad enter key and the reset key was missing a spring. Front plate was remarkably clean, with a few minor rust spots, and one small rust spot on the bottom metal case. Most notably, the top case is cracked almost entirely through to the function key rows. Overall, not bad for what I paid for it.
After disassembling it further, I noted that the foam was in a fairly crumbly condition. While the sticky backing was keeping the bulk of it intact, I decided to replace it outright. It was creating quite a disgusting mess.
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The glue and the remains of the mat can be cleaned with denatured or rubbing alcohol. Once I pried off all of the barrels, I put them in some tupperware, doused with denatured alcohol, and gave it a good shake. Cleans the gunk quite nicely.
Tools used:
5/8 arch punch
Krylon industrial latex paint
Rubber mallet
Old plastic cutting board
1/32" EPDM 60a rubber sheet
I roughly cut the rubber mat to shape using scissors, and secured it from the rear to the front plate (which should be sanded to remove rust). Then I proceeded to spray paint the plate which simultaneously marks the hole locations:
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Yep, I'm using the rear of an M 122 just to take photos of other stuff. Anyway, not too bad of a result for two coats. The back also got a coat. My goal here was more to stop the rust process and prevent further rust, rather than making it look pretty. Next up, punching the holes:
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The paint is not designed to stick to rubber, so I needed to be a bit careful with it, otherwise it would have flaked off. The rubber, although thin, is also fairly hard so it sometimes took a few hits per hole. Placing the cutting board on a hard surface helped a lot here.
Putting the mat on:
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The 5/8 punch does give a comfortable margin of error, as long as I was careful to include the cutout notch in the area that I was punching out. The barrels:
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And the hammers - this is where one needs to be careful and make sure to place them according to the desired layout. Being used to ANSI, that's what I went with:
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I did not feel that I really needed a bolt mod, but at this point the plates refused to slide back together, even though I used the thinnest rubber sheet that I could find. After a lot of swearing, sweating, and perhaps overzealous clamping and hammering (which is discouraged in this case), they eventually slid back together:
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In retrospect, I think that if I used something like 30a hardness rubber instead of 60a, it would have had just slightly more give to make this process easier.
Add a breadboard with a teensy:
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One of my unexpected finds is that the dip switch block had to be connected in order for the converter to work, which is apparently not normal. Might have something to do with the keyboard being an early one. For the usb cable, I used a short one with a slim usb-b connector in order for it to fit in the cable opening. I like having quick disconnects as well, so with the short cable I simply use a female to male usb extension. Mmmm, laziness.
Final result:
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By coincidence, a coworker gave me for free a Model M a few days prior, which provided the source for all of the keys and in-barrel stabilizers needed for an ANSI layout. And the crack in the case? Well, I actually had two F 122s, and for the time being I just cleaned and used the case from the second one. Laziness strikes again.
For that second F 122, once I have some more time, I will fix the case, paint it, and test out softer rubber for the mat replacement. I'll add that here once I get that going.. eventually.
As for this board here, I can say that I'm a new convert, after never using buckling springs before. The feel is great, I'm enjoying the hardware remapping and NKRO advantages of the converter, and this historical piece of hardware will probably outlast me.