25 May
2007
25 May
'07
7:02 p.m.
I've actually fixed one of the CIT-220+ keyboards. It's *not* a job for the
faint of heart. It requires desoldering all 130-odd keys (this REQUIRES
a GOOD
$250 desoldering iron, lacking this I paid someone $60 to do it for me),
Wh yis it significantly harder than on other keyboards? I've desoldered
complete keyboard assemblies from their PCBs using a Weller TCP iron and
a normal solder sucker.
For keyboards where there are separate keyswitches in a metal frame, I
find it easiest to desolder one switch at a time and unclip it from the
frame. And at the end to unscrew the PCB from the frame. When putting it
back together, I crew the PCB and frame together first, then insert the
switches one at a time and solder them. It's a lot easier to get 2 pins
into their holse than 200 pins :-)
IBM model M clicky keyboard used. I also strongly
suspect the real DEC
vt-220
and vt-330 used better technology but I've never seen a real DEC one. :( )
The LK201 (DEC VT220 etc keyboard) is a disgusting design!. It's uses
mebmrane contacts. There's a metal base plate, the membrane layers on top
of that, then a rubber sheet, then metal spring leaves under each key,
and finally plasic housings that hold the keys themselves. The whole lot
is held together by pegs on the housings going down through all the other
parts and being heat stakced on the bottom
You can remove the keys fairly easilrt (twist them slightly to frre the
locking barbs. But you cannot dismantle the rest of the assembly and have
any hope of getting it back together.
-tony