lk201 question

Tony Duell ard at p850ug1.demon.co.uk
Mon Feb 28 17:06:15 CST 2005


> Then again, if it's a stuck key or something like that, the keyboard
> is beyond repair.  LK201 keyboards are cheesy low quality membrane
> switches that cannot be disassembled or cleaned or repaired.  If
> moisture ever gets in them, your only option is to scrap the board.  I
> found this out the hard way.

They can be dismantled... Getting them back together is the difficult bit :-)

What I would do is take off the casing (2 hex-head bolts under the feet, 
unlatch the plastic clip in the bottom section and slide the keyboard 
assembly out), then separate the PCB from the keyboard membranes. From 
what I remmeber there's a clip that holds a regulator to the chassis, one 
screwm and you then bend up the tabs on the metal clips over the membrane 
tails and take the whole lot apart.

With said clips removed, you cna conenct the PCB to the terminal with the 
normal modular cable. If it now gives no errors (very likely), you've got 
a matrix problem.

You can remove the keycaps -- slightly twist them to free the locking 
hooks. There's even a special DEC tool for this -- I have it somewere, it 
came as part of a custom blank keycap kit. 

Now, the thing is heat-stakeed together. There are plastic housings with 
metal springs under them, then a rubber sheet, then the mebrane, them a 
metal base. Pegs on the plastic housings go through the whole lot and are 
moulded over on the back.

It's triviel to take apart. The problem is leaving enough peg to be able 
to fix it all back again. I have wondered about making a hollow tubular 
cutter to remove the moulded-over bit from each peg, then putting said 
bits back on at the end and trying to melt the plastic together again. I 
am told this method has worked on HP handhelds with similar heat-staked 
assembiles

-tony



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