View Full Version : Specific keyboard keys not working

20th February 2008, 04:36 PM
Namely, tab, space, delete and the left arrow keys on my MacBook. This problem is intermittent, which is the only reason I can type properly.

I've just downloaded the latest MB/MBP Apple keyboard update, to the same effect. The problem is still occurring as I type this message which means every so often I have to stop for a second to make sure my words aren't starting to run together.

I'm just wondering whether this is specifically the keyboard hardware mucking up or something else. It makes no sense that it is those four keys not working (if it was the remnants of the tea my sister spilled on the right side of the keyboard last year, the tab wouldn't be affected). I'm thinking of going and getting it fixed but if it can be fixed without the hassle that'd be fantastic.

Has anyone else had this problem or something related? Any ideas as to what it is and how to fix it? All comments will be greatly appreciated.

20th February 2008, 10:07 PM
It's a hardware problem -- part of the sensing matrix is not working as it should.

All keys on your keyboard are laid out electronically on a grid, and if one row or column of that grid fails (or in your case, becomes intermittent) then all keys on that row or grid will develop the same fault.

And I happen to know that the keys you mention all use the X2 row. Command, Alt/Option, Esc, PageUp and PageDn are also on this row ... you don't use them as much, so you wouldn't notice them being intermittent.

And I also happen to know that the lines from each row and column of the matrix all come together into a ribbon-connector that is at the right side of the keyboard.

So, the tea has finally corroded the connector on the X2 line just enough to be a problem, or worse, corrosion from leaked liquid on the motherboard around the keyboard matrix decoder chip is starting to become a problem (if this is the case, the only fix is a new motherboard).

There is no end-user fix, either the entire keyboard assembly must be replaced, or the motherboard must be replaced ... and because it is liquid damage, any such replacement would not be covered by warranty nor AppleCare.

20th February 2008, 10:37 PM
yep, agreed. in my experience, if ever i see a row of keys, typically diagonally, then it is the result of a liquid spill...
book it in to a service centre, & have it replaced

21st February 2008, 09:49 PM

I am having a similar problem with my macbook keyboard - the key between o and [ is not working or working intermittently.

I am temted to do a archive and install....

23rd February 2008, 10:42 AM
Ah, ok... bummer. Thanks for the info.