Model M doesn't work - not sure why

[Special K]

I bought a model M on ebay awhile back and the first thing I did was take it apart and clean it (the inside and the sides/bottoms of the keycaps were filthy).  I took all the keycaps off, washed them, dried them, and also cleaned the plastic backplate using a q-tip and some water.  I waited for everything to dry and put the keyboard back together.  I didn't test the keyboard before washing it (although I probably should have).

Now it doesn't work.  It isn't recognized in my new system, even though the numlock light comes on at bootup.  When I plugged it into an older Dell machine (2004) and boot up the computer, I get a black screen that says "keyboard failure" and I hear a constant stream of rapid beeps coming from the system speaker.  The computer then goes into a screen that says "Hardware Profile/Configuration Recovery Menu" and allows me to choose "Profile 1", which then causes Windows XP to load.  At this screen, I can turn the keyboard LEDs on and off using the num/caps/scroll lock buttons.  It also recognizes my Enter key press when I select Profile 1.  Windows never loads though.

What could be the problem here?  Other keyboards work just fine with the PC's that the model M failed on.  The ebay seller offers returns, but if there is an easy fix for this then I'd rather not go through the hassle.

[timw4mail]

Your motherboard is probably not supplying enough power through the PS/2 port on your motherboard, and the keyboard should work with a suitable USB adapter.

[Special K]

Your motherboard is probably not supplying enough power through the PS/2 port on your motherboard, and the keyboard should work with a suitable USB adapter.

I tried a blue cube with it but then I get odd errors in windows.  For example, the Esc key behaves as a windows key, and the spacebar isn't registered at all.  If I press the spacebar down many times quickly in succession, then the cursor will behave as if I was holding the spacebar down, and it won't stop until I press the backspace key.

[timw4mail]

I tried a blue cube with it but then I get odd errors in windows.  For example, the Esc key behaves as a windows key, and the spacebar isn't registered at all.  If I press the spacebar down many times quickly in succession, then the cursor will behave as if I was holding the spacebar down, and it won't stop until I press the backspace key.

Hmm...that's kind of strange. It's possible that a capacitor on the controller has dried out, and that's making it take more power than would otherwise be needed, but you'd have to check that yourself.

[Special K]

Hmm...that's kind of strange. It's possible that a capacitor on the controller has dried out, and that's making it take more power than would otherwise be needed, but you'd have to check that yourself.

How would I check that?  I did notice that there appears to be something on two of the capacitors found on the control board:





Is that permanent marker or damage to the capacitors?

[Special K]

Alright, here's another update: I tried the Model M with an older computer (2001).  I get the same behavior as the Dell - a constant beeping of the system speaker, and then it takes me to that "Hardware Profile/Configuration Recovery Menu" screen.  I select "Profile 1", and then it takes me to the logon screen.  

At this point the PC must be registering a stuck key on the keyboard, because the "Password" field of the logon screen immediately starts to fill up with characters.  A backspace stops this behavior.

I am able to input my password and enter windows.  Once in windows, the keyboard seems to work fine except for the spacebar key, which exhibits the behavior I described earlier - you can't enter single spaces when typing, but if you press the spacebar several times in quick succession, it acts as though you are holding the spacebar down until you hit another key.

[timw4mail]

Alright, here's another update: I tried the Model M with an older computer (2001).  I get the same behavior as the Dell - a constant beeping of the system speaker, and then it takes me to that "Hardware Profile/Configuration Recovery Menu" screen.  I select "Profile 1", and then it takes me to the logon screen.  

At this point the PC must be registering a stuck key on the keyboard, because the "Password" field of the logon screen immediately starts to fill up with characters.  A backspace stops this behavior.

I am able to input my password and enter windows.  Once in windows, the keyboard seems to work fine except for the spacebar key, which exhibits the behavior I described earlier - you can't enter single spaces when typing, but if you press the spacebar several times in quick succession, it acts as though you are holding the spacebar down until you hit another key.

Well, that definitely sounds like a controller issue. (No, the marks are just permanent marker, that's normal) I guess if you know how to solder, it would be best to try replacing the capacitors. I'm not an expert on electronics, though, so I don't guarantee it will work if you do change the capacitors.

[keyb_gr]

Try reseating the membrane connections. You can also whip out the multimeter and do a continuity test of each row vs. each column (there should never by any connection).

Were there any signs of a previous spill inside?

[ch_123]

To be honest, I wouldn't bother with soldering stuff when you're dealing with one of the most common keyboard types out there. Return it to the seller and buy another one.

[Special K]

Update - the Model M now seems to work just fine using both the PS/2 port and the blue cube on the 2001 PC I was testing with.

Update 2 - the Model M also works just fine with the blue cube on my primary PC.

All I did was reseat the spacebar.  That seems kind of quirky.  Should I keep the board now?

[ch_123]

Use it for two/three days and see if the problem comes back. If it does, send it back. They're not worth the hassle considering how easy it is to get a working one.

[timw4mail]

Update - the Model M now seems to work just fine using both the PS/2 port and the blue cube on the 2001 PC I was testing with.

Update 2 - the Model M also works just fine with the blue cube on my primary PC.

All I did was reseat the spacebar.  That seems kind of quirky.  Should I keep the board now?

Considering the extent of your issues, that doesn't seem too unlikely. It's possible you just had the spring at the wrong angle...these things are complex.

Oh, and a similar issue happens when I remove a keycap on the Model F, it does weird things like your spacebar issue.

[ch_123]

Yeah, the Model F seems particularly sensitive to the way you reinsert the keycaps. Remember to hold the keyboard upside down when you're putting the keycaps back in, it makes it easier for the springs to notch into the correct position.

[Special K]

Disregard my previous updates.  This board is really quirky.  Sometimes I will plug it in and it will work fine, and other times no keypresses will be recognized, but the PC speaker will emit a beep every time I press a key.  This is at the windows logon screen.

On an unrelated note, the plastic rivets that hold the metal backplate to the plastic plate seem to be ridiculously fragile.  I have been very careful with this board since I bought it, yet 2 rivets have already fallen out.  Would it do any good to glue these back on?

[Special K]

Just  to double check - you only washed keycaps and shell so nothing else got wet??

I also used a damp Q-tip to wash the black plastic plate, but I was very careful to make sure no water leaked into the spring holes.

[Special K]

Try reseating the membrane connections. You can also whip out the multimeter and do a continuity test of each row vs. each column (there should never by any connection).

Were there any signs of a previous spill inside?

There were no signs of a previous spill that I could tell.

[ch_123]

Just send it back and get a new one.

[Special K]

OMG this is very weird - the backspace and spacebar keys produce a dot in the password field when I press it, and the H key behaves like a backspace.  All other keys beep (with no keypress being registered) or do nothing.  The Z key pastes several characters into the password field and hilights them.

WTF?

[wellington1869]

OMG this is very weird - the backspace and spacebar keys produce a dot in the password field when I press it, and the H key behaves like a backspace.  All other keys beep (with no keypress being registered) or do nothing.  The Z key pastes several characters into the password field and hilights them.

WTF?

on some systems control-H is backspace. So is the control key stuck in the down position?

[Special K]

on some systems control-H is backspace. So is the control key stuck in the down position?

You might be onto something here.  When I had notepad open earlier, pressing S would pull up the "Save As" dialog box.  I'll try reseating the CTRL keys.

EDIT: you were correct - the CTRL key was somehow stuck in the ON state.  I reseated it and the problem disappeared.  Just to make sure, I held down the CTRL key once I was back at the logon screen and duplicated the behavior I saw earlier, confirming that the CTRL key was somehow stuck in the ON state.

I like typing on this thing, but what a finicky piece of hardware it is.

[wellington1869]

EDIT: you were correct - the CTRL key was somehow stuck in the ON state.  

cool  

This happens from time to time on all my keyboards, tho I usually chalk it up to my huge autohotkey file misfiring.  I just rapidly toggle the "stuck" control key a few times and  the problem goes away.

If its a physical problem with the key's mechanism, try some grease on the plunger/brace/slider of the key. On older model M's I do find that they sometimes need a touch of grease on the sliders/plungers.