Two model m keyboards with identical problems

[MissileMike]

Hi guys, I used the search and couldn't find anything on this.

Two of my model M keyboards, one a 1997 Greenlock 42H1292 and the other a 1992 usa 1391401, both have the exact same problem:

When I press space, it sends a carriage return/enter press.  And both enable numlock when I press the down arrow key.

-I am typing this on a model m that's fine, so I know it isn't my pc. (besides I tried it on two different computers anyway)

-The problem happens whether I go through a usb dongle or straight to ps2.

Is there something simple I am missing here?

Thanks!

[ch_123]

I'd still try using them on another computer. The odds that two Model Ms of different ages, and quite different electronics would both fail in the same way is waaay too much of a coincidence.

[MissileMike]

3 computers, all the same problem...  Whether USB or PS2...  Now on the 1391401, the spacebar sometimes works, sometimes doesn't....  Argh!

[MissileMike]

Hrm there is one common element: I cleaned both of them before using.  I wonder if something got down in the membrane?

[MissileMike]

I definitely didn't douse them, correct.  Just a good vacuuming and wipedown with Clorox Cleanup...  The Greenlock has no broken rivets, but the 1391401 had about 8...  But they're plastic, what difference would that make?  No stuck keys btw...  I might actually try dousing them, now though....

[ch_123]

Broken plastic rivets mean that stuff could come loose, which can lead to the sort of problems described above.

[MissileMike]

Update: I put both keyboard innards in the dishwasher and let them dry out in my hot car for 6 days.  Both have the exact same problem they did before, across 4 different computers...  The newer one is the really weird one: I press space and it sends a space and a carriage return.  I press the down arrow and it sends a down arrow and a numlock.  I wish I could restore this one because it has every single rivet intact

[Daniel Beaver]

I would be curious to know if this sort of problem is related to the membrane, or if this is a problem with the controller. And, most importantly, whether it is fixable. I have a Lexmark model M that sends ghost keys when I press the arrow keys, and which fails to send various other keys (g, h, t, etc.).

[MissileMike]

When you say keyboard innards you mean you put this part in the dishwasher?

Show Image

Yes, exactly.  I didn't know what term to use for it :)

[MissileMike]

Well..... that's not good then.  Capillary action  alone means some water soaked into the membrane.

At some point here I'm afraid you'll need to open up the keyboard and do a nut/bolt mod if you want to save it.  Wipe down the sheets with 99% Isopropyl - I've found that's safe on the Model M membranes.

But before you do that try reseating the key LOTS of times.  If that  works you may not need to go through the nut/bolt hassle.

It's having the same exact problem as before i dishwashered it, so I think it's safe to say it isn't a water that's the issue.

By reseating, I assume you mean popping off the key, and putting it back on multiple times?  Will try that now.

If that doesn't work, it's totalled, because the boltmod is so time consuming.  Would be a shame too, as all the rivets are intact

[rantenki]

Update: I put both keyboard innards in the dishwasher and let them dry out in my hot car for 6 days.  Both have the exact same problem they did before, across 4 different computers...  The newer one is the really weird one: I press space and it sends a space and a carriage return.  I press the down arrow and it sends a down arrow and a numlock.  I wish I could restore this one because it has every single rivet intact

Do _not_ dishwasher the keyboard plate assembly. Too late I know, but the membrane doesn't like the chemicals in dishwasher detergent (or anything else left over in the dishwasher).

I had a very similar problem as you a little while ago: http://armyofevilrobots.com/model_m_refurb

Disassembly and rebuilding the plate/membrane is the only way, but likely to work.

[MissileMike]

Yeah this has to be the membrane.  Space and enter always show together on aquakeytest, whether it's space that's pushed or enter.  Same with down arrow and numlock, and a few others.

At this point, I am going to call them totalled and be happy I still have 15 others.

EDIT: I won't dishwasher again, it was an act of lazy desperation.

[itlnstln]

If you have 15 others, I wouldn't waste my time with them.

[MissileMike]

Hah I just counted, I actually still have 17.  Time to update the sig!

[Mental Hobbit]

If you have 17 other Ms, you could test swap a controller. Then we'd know for sure if it's a membrane or controller issue. Two Ms with an identical problem that nobody else here had before pose an interesting puzzle that needs a definite solution.

[rantenki]

Hey Ranteki, nice web page and mod!

Another happy USB enabled nut/bolt modded Model M user!

Thanks! I'll be happier once I put a board in with a proper usb-B connector, but I was running out of time after fixing up the backing plate.

Anyhow, the wife is getting tired of listening to it anyhow, so I'll probably just swap back to the (quieter, but crappy) M$ natural until I can pick up a Kinesis or a TrulyErgonomic (hoping those are real, but I live right by their mailing address; nice neighborhood).

[MissileMike]

If you have 17 other Ms, you could test swap a controller. Then we'd know for sure if it's a membrane or controller issue. Two Ms with an identical problem that nobody else here had before pose an interesting puzzle that needs a definite solution.

You're absolutely right.  I will do that tomorrow morning.