Resolved M0110 Keyboard Disassembly

[defjam]

I have an old M0110 keyboard for which the spacebar is non-functional. I believe the issue is the result of some water damage the keyboard has sustained (it shows signs of rust) and I suspect the spacebar contacts have become corroded. I have attempted to clean the contacts with electrical cleaner but that didn't resolve the issue.

So....I have decided the corrective action is to remove the circuit board for the keyboard and clean the contacts. However I am unable to separate the metal cover from the circuit board. I have removed the four screws from the back of the circuit board and all of the key caps. Unfortunately the metal piece is not separating from the circuit board. I am wondering if each individual key is retaining the metal cover to the circuit board.

Does anyone have any experience with disassembly of the metal cover from the circuit board? If not are there any suggestions as to how I can go about cleaning the space bar key contact (I'd prefer to clean them all as would be possible by separating these two pieces plus this would allow me to better clean the metal piece)?

As an FYI every other key works, it's is just the space bar which is failing. None of the space bar mechanics are damaged so it's not a matter of misalignment or broken pieces.

 

[MacTech68]

Each keyswitch is soldered to the circuit board. You de-solder the two pins directly underneath, then squeeze the grey clips to release the individual keyswitch from the metal frame.

To do what you request, would require desoldering every key's two pins. Unnecessary unless they're all faulty.

Once you get the keyswitch out, you can disassemble it very carefully, clean the contacts, sometimes bend the copper switch contacts and re-assemble.

However, you just MIGHT be able to get the keyswitch working by squirting contact cleaner down the white shaft to fill the keyswitch body with contact cleaner, then work the keyswitch continuously to clean it. Sometimes it works.

NOTE: you may want to clean the area between the keyswitches BEFORE you spray the contact cleaner. You want to avoid 'washing' dust into the keyswitch.

This page may be of assistance:
http://www.harrowalsh.de/APPLEBOX/APPLE2/appleboxkeypage.htm

 

[defjam]

Thanks MT. I'll give the cleaning you've described a try, should be easier now that I have the spacebar off. If that doesn't work I can just remove the one switch to repair it?

 

[MacTech68]

Thanks MT. I'll give the cleaning you've described a try, should be easier now that I have the spacebar off. If that doesn't work I can just remove the one switch to repair it?

Correct - one switch can be removed without disturbing others.

 

[defjam]

The electrical contact cleaner didn't work so it appears as if removal of the switch is in order. Before doing so, given all the other keys work fine, it's highly likely the switch itself is the problem and not something else?

 

[defjam]

UPDATE: I removed the spacebar switch and measured it with an OHM meter. Open resistance was > 6M ohms, closed resistance was ~ 5.5M ohms. It's almost definitely the issue with the spacebar.

Now on to see if I can repair it.

EDIT: Repair completed. The switch assembly is easy to disassemble. The issue ended up being a lack of tension on what is referred to as the "Steele Spring Plate" in the diagram MT's reference referred to. Interestingly it had nothing to do with corrosion, everything was nice and clean inside the switch assembly.