24 Jan
2008
24 Jan
'08
12:33 a.m.
First of all, a giant thank-you to Tony for getting it all right (from
memory, no less). Unfortunately, I still need advice:
Tony Duell wrote:
If you get the right 'feel' and normal keyclick, then you've got it
together properly. If a key feels odd, make sure you've got the spring
correctly postioned in the keycap's stem.
Odd keys not working doesn't sound like an electronic fault (it's a
matrix of sensors, after all). So if the flaps are OK, the problem could
be :
Defective keycap (spring not located properly, can't locate properly)
Problems with the keyboard frame (flaps not moving freely)
PSB trouble?
9) Fit the flaps, taking care to ket the space
bar one correctly
positioned. Fit the base/PCB and slide it over to lock it. Don't bend the
tab yet. Prese the space bar down so it clicks in place, and check it
clicks and returns properly. If not, you need to take the baseplate off
again and have another go.
While this fixed the spacebar, it has rendered other keys unusable. I
have taken it completely apart and reassembled it three times now and no
matter what I do, the return key is dodgy (doesn't always register, or
registers twice) and the numeric "-" is dead. I have looked at the On a side note, how does this mechanism work? I
understand how the
buckling spring mechanism works, but it looks like a piece of plastic is
hitting two metal pads -- since plastic doesn't conduct electricity, how
is this working at all?
Sinve the flaps come down onto soldermasked areas of the PCB anyway, it
pretty much can't be conductive. I've always assumed it's a capacitive
sensor. When the flap comes doewn it increases the capacitance between
PCB pads, this is detected by that IBM sense amplifier chip (the square
metal thing)
-tony