Problem with stuck/unresponsive key on IBM Model M

ZHENYA

13 Sep 2021, 21:49

Hello,

Long time lurker, first time poster.

So I have a 1987 IBM Model M 1391401 that I've been using daily for over 10 years. I've always taken great care of it. It has recently developed 2 seemingly related problems on the numpad block.

The first trouble is that the minus - key often gets stuck. I checked the spring, everything seems to be in proper alignment. And the second problem which I believe is causing the first problem is that the flipper that holds the spring for the adjacent * key has somehow worked itself loose and it rattles around inside the barrel. I tried to resposition it with tweezers and then the key registers, but it ulimately gets out of alignment again causing the * key to not work and also I believe it's what causing the - key to act like it's stuck.

The keyboard has most of it's plastic rivets intact, but this issue is not only annoying but hampers the usefulness of this keyboard. Do I have to break off all the rivets and do a screw/bolt mod to fix this? I tried searching around online I've never found anyone talking about a loose flipper, could it be broken?

Photo included
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IMG_1752.jpg (738.56 KiB) Viewed 591 times
Thanks,

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Bitteneite

18 Sep 2021, 07:22

Unfortunately, I don't know if there's a way to take out the flipper itself without taking apart the whole board. That being said...
ZHENYA wrote:
13 Sep 2021, 21:49
I tried to resposition it with tweezers and then the key registers, but it ulimately gets out of alignment
I'm wondering if you could realign it, then do a "Partial Screw-mod" where you can restore the tension without taking the whole board apart. I have a guide with pictures here. The Partial Screw-mod part is right at the end!
ZHENYA wrote:
13 Sep 2021, 21:49
The keyboard has most of it's plastic rivets intact
For some odd reason, IBM always left out a rivet near the "-" key. Not sure if it's just my bad luck, but I never saw a rivet here, even on my mint-est of Model Ms.

This probably the reason why some of my rough Ms ran perfectly well, except for a dead - key.

Image

I usually drill it through, and then put a screw in it.

Image

All the sheets already have a hole ready to take a rivet here. What a mystery.

Limme know!

User avatar
Muirium
µ

18 Sep 2021, 11:37

I had a Model F with a similar problem. This guy was the culprit:

Image

Perhaps your M's flipper is broken in the same way?

Because mine was an F, all I had to do was tweeze open the tabs and go take a look. A Model M makes such repairs a hell of a lot more involved. Bitteneite's tip might be worth a shot. But if your flipper is snapped like mine was, then it will need replaced, and that means a full bolt mod.

Bolt mods are a lot of bother, I won't deny that! But they're not impossible or the realm of experts. Even I pulled one off! Plenty of folk swear by them as an essential long term maintenance technique for all Model Ms. I'm in no hurry to embark upon a second, however… :roll:

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Bitteneite

18 Sep 2021, 14:26

Muirium wrote:
18 Sep 2021, 11:37
Bolt mods are a lot of bother, I won't deny that! But they're not impossible or the realm of experts. Even I pulled one off! Plenty of folk swear by them as an essential long term maintenance technique for all Model Ms. I'm in no hurry to embark upon a second, however… :roll:
I'd agree with that. If it's the flipper that's broken, a full rebuild is probably the only way.
That being said, as long as OP has the right basic tools, it should be a walk in the park!

If OP wants to do it just once and forget about it, I'd actually suggest a screw-mod. It's much easier and faster. (Especially for beginners)
And as long as OP doesn't go crazy on the screw tension, the plastic threads should hold up surprisingly well!

cday7173

18 Sep 2021, 16:13

Bitteneite wrote:
18 Sep 2021, 14:26
That being said, as long as OP has the right basic tools, it should be a walk in the park!
As someone who just finished their second bolt mod in less than two weeks...it's a very long walk in the park. Well worth it, though.

To the OP, I've had this same issue with the R key on a model M and it resolved itself upon reassembly. The flipper wasn't broken, so I assume it became crooked or misaligned somehow.

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