PDA

View Full Version : IBM Model M Keyboard repair



ssussman
August 11th, 2008, 01:21 PM
Hello all

Forgive a noob question here...

I have a wonderful vintage 1987 IBM Model M keyboard (1391401, dated 7-27-87) which has been beautifully restored and works great except for a lone problem...

The left shift key sticks when pushed down... will only come back up if you jostle it or push a nearby key like CapsLock or left Ctrl.

Any advice on the best way to rectify this? Would a new left-shift keycap do the trick? I can't figure out what is causing it to stay down!

It would be a crime to not get this one fully working... it is otherwise a flawless vintage keyboard (typing on it now in fact)

Thanks in advance
SS

Trixter
August 11th, 2008, 01:23 PM
It just sounds like it's stuck with gunk or something. The Model M is very easy to clean and repair; you can just pull the keycaps off (NOT the spacebar, but everything else) and clean what you need to. Try pulling a few off, using an airduster, etc.

ssussman
August 11th, 2008, 01:29 PM
It just sounds like it's stuck with gunk or something. The Model M is very easy to clean and repair; you can just pull the keycaps off (NOT the spacebar, but everything else) and clean what you need to. Try pulling a few off, using an airduster, etc.

Thanks trixter, that would be my first guess, except this is a total rebuild, everything has been cleaned meticulously before it was reassembled. So I don't see any gunk...

When you depress it, you get the click from the spring buckling and the shift is enabled (i can tell by typing something else out) so i don't think it's the switch at all... seems like the key is catching somewhere...

Any other ideas?

SS

dongfeng
August 11th, 2008, 01:54 PM
You might find a VERY VERY LIGHT DROP of lubrication will work.

Remove the key cap, use some LIGHT oil on a cotton tip, very lightly rubbed on the moving parts of the shaft.

That will work :)

paul
August 11th, 2008, 02:01 PM
I believe these would have been lightly lubricated from new but non-the-less I would be loath to put anything petroleum based on plastic parts. I would try a straight silicone spray instead (not CRC or WD40.)

Erik
August 11th, 2008, 02:09 PM
Pull out the key and one or more of the others to see if you notice anything about the shape of the bottom that might be amiss. Try putting another key into the shift-key position to see if it sticks. If so then the problem is in the key hole or with the spring. If not then it's the key itself. . .

Good luck!

ssussman
August 11th, 2008, 02:42 PM
Pull out the key and one or more of the others to see if you notice anything about the shape of the bottom that might be amiss. Try putting another key into the shift-key position to see if it sticks. If so then the problem is in the key hole or with the spring. If not then it's the key itself. . .

Good luck!

Hi Erik and all

Thanks for the tips... wow that was quick.

I think I can see the problem now... the spring is curled up inside the mechanism, it is not standing up straight. Tried to get at it with tweezers but it's too tight.

Can anyone recommend a place/person that could fix this thing? I'm a little scared to take this thing apart myself - not to mention I have no idea what kind of screws those are holding it together (hex? torx?)

I am in the LA area.

Thanks a million
SS

Erik
August 12th, 2008, 01:33 PM
I don't think you'll find a repair shop willing to do the work. It's not that hard to take them apart to the point where you can get better access. . . usually.

Failing that, Model M keyboards usually sell for around $40 +/- depending on condition, etc.

Vardigon
October 21st, 2008, 09:17 PM
I'm having a similar problem with my IBM Model M with the Enter key. (Not the one on the numpad.) I put the Ctrl key's stem into the slot and it depressed fine. It seems to be acting a bit lazy for some reason. If I push on the right side of the key (where the actual spring is) the key will depress finely, but on the left side (where there's a "stabilizer" I guess), it'll just stay depressed when I push down. I wonder if the spring is just weak for some reason. I can identify no source for the problem visually.

Edit: I think oiling the stabilizer might have fixed the problem for the most part. I'm still testing the enter key in an OCD manner to make sure that there's nothing else wrong. Hehe.

andy
October 23rd, 2008, 07:26 AM
I was just having this problem with the enter, and shift keys on a model M, and cleaning the guide pin and hole with a Q-tip and alcohol fixed it. I think it's just caused by dust and dirt. Oil may help, but shouldn't be needed.

I've never seen a bad spring unless it was bent. It is possible to replace the springs without disassembling the keyboard, but it's difficult to do. Don't disassemble the keyboard, because that will make it 10 times harder! The springs are just held on by friction, and pull off easily. Pushing them back on is the hard part. I have a whole bag of springs I saved from a broken model M just in case I need to replace one.