F122 spacebar slightly crooked?

cloudhax

28 Dec 2018, 05:07

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Loving this ansi-modded IBM Model F 122 I purchased. The only minor issue I have is the space bar is sort of crooked. On the left side of the space bar it seems 'pushed down' too far compared the right side, and thus pressing and activating the space bar is difficult if you try to do so on the far left side of it. Generally its not a huge issue because I tend to always use my right thumb to space bar, more towards the right side. But I still would like to fix it.

I'm not super comfortable (yet) taking apart and working on these old boards, especially one as expensive as this one. And as I understand it, the space bar with internal stabilizer is kind of a pain to deal with in general. I don't want to break it or make it worse, but is there maybe something I can do to fix this?
Last edited by cloudhax on 29 Dec 2018, 06:41, edited 2 times in total.

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fohat
Elder Messenger

28 Dec 2018, 15:04

You will have to take the space bar up as the first step in anything that you do. It is not unusual for a piece to sit slightly misaligned, but it should feel the same on both sides when you press it. If one side feels "right" and the other side feels "wrong" or if they feel significantly different, then there is an actual problem.

My guess is that the top leg of the plastic tab that holds down the wire has broken off.

Luckily, the big Model Fs have conventional stabilization and this can be done from the top, unlike the small ones that have the long space bar and clunky "under-carriage" that requires taking the plates apart to repair.

The easy fix is wcass's discovery that a 7/16" SAE washer fits over a barrel and holds down the wire. That would also allow you to substitute a Model M space bar (if you wanted to) with its much larger wire, but in that case you would have to pull out the plastic tabs first.

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y11971alex

29 Dec 2018, 05:38

I'm under the impression that the pictured degree of bending is within tolerances. IBM spacebars are made of PBT plastic, which can warp while forming.

cloudhax

29 Dec 2018, 06:40

y11971alex wrote: I'm under the impression that the pictured degree of bending is within tolerances. IBM spacebars are made of PBT plastic, which can warp while forming.
thanks, I guess that is why PBT space bars are rare. I think you are right, its pretty minor, and it does still function fully. It is just somewhat stiffer and quick to bottom out on the left side.
fohat wrote: If one side feels "right" and the other side feels "wrong" or if they feel significantly different, then there is an actual problem.

I think I am over-estimating the difference in feel. It is noticeable to me but it is minor and like y11971alex mentioned, probably within tolerances. Thanks for the info on the repair, I think I will leave it alone for now. If I ever need to get in there, now I know how

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y11971alex

29 Dec 2018, 06:50

cloudhax wrote:
y11971alex wrote: I'm under the impression that the pictured degree of bending is within tolerances. IBM spacebars are made of PBT plastic, which can warp while forming.
thanks, I guess that is why PBT space bars are rare. I think you are right, its pretty minor, and it does still function fully. It is just somewhat stiffer and quick to bottom out on the left side.
I do agree with fohat, though. If it results in a different feel, then a correction ought to be available. IBM was not known for aesthetically perfect products, but it wasn't known for wonky products either.

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Darkshado

29 Dec 2018, 20:41

Get a (wire) key puller, remove the two Alt keys and a couple of letters around the spacebar, pull gently (there's going to be slight resistance at first) and take a look at the stabilizer wires, it may be as simple as an improperly positioned wire or perhaps a broken plastic "insert" which keeps the wire down and stops twisting motions.

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