29 May
2000
29 May
'00
12:04 p.m.
5) Capacitive matrix (Keytronics, e.g. PERQ 2, Apricot, Sirius, etc).
These are not really switches. The keyboard works by the increase in
capacitance when a plastic disk coated with metal on the back bridges 2
electrodes on the PCB. These are actually very reliable, but you can take
off the PCB and clean it with propan-2-ol. The only common failure is
loss of the metalisation from the disks, for which the only cure is
replacement. The good news is that all such keyboards that I've seen use
the _same_ disks, so spares are not hard to come by.
A common failure for capacitive keyboards is age/ozone/whatnot which
causes the foam between the plastic disks to break down. I havent seen
the problem where the metal wears off the disk. Either way, you can
still buy brand new capacitive pads from Keytronic Corporation, about
10 cents per pad, or 9 cents if you buy at least 1000, plus 6.50
shipping of course. Just what the doctor ordered if you have Terak's.
It really helps out when playing videogames like Asteroids on my
Terak as well ;) For a while there, I thought I was losing my
skills.
-Lawrence LeMay