On 2/23/21 6:58 PM, AvantGuard Systems wrote:
Well, I just discovered the W key doesn't work. Is there a trick to
pulling off the key caps? Pulled on it, but it doesn't want to budge.
Afraid there might be some locking mechanism on them. I realize I may
have to resolder.
Curtis
The keycaps pull straight off. Please use an actual keycap puller so
that you are pulling straight instead of prying it from one side.
Then, further, it depends on what model machine you're talking about.
For Model 100 and NEC
The keys don't come any further apart without desoldering, but, they are
metal to metal contacts inside, so they can usually be refreshed by just
pressing them a lot. Evenually the oxide layer gets worn away.
You can also spray DeoxIT on them and let it soak in through the seams,
then press the key a bunch of times, let it sit a few hours or a day,
press a bunch more times. It's ok for the deoxit to run all over. It's a
light oil that dries slowly but does dry completely within a day for
most areas, maybe several days or even a few weeks for really sealed up
areas. I have had the exceedingly sensitive LCD contrast circuit take a
couple weeks for the screen to go back to fully normal operation. (well,
better than normal, it DID do the job of cleaning up the pot and making
the display work perfect.
For 102 and 200
The keys can come further apart without having to desolder. After the
keycap is removed, there is a black top part that is just snapped on.
You can lift the latches away with a dental pick and pop the top cover
off. But the 102 keys are silicone domes with graphite pads and metal
contacts on the pcb.
https://youtu.be/n_oyDYRDYzs
In that video, the reason I did that swap, was the T key wasn't working.
I figured I would swap the carbon pads with a less-used key, and a key
that I could tolerate being dead. It worked even better than I hoped,
because in the end, both keys worked perfectly. I thought I was just
choosing which key had to be dead, instead now none are dead.
The keyboard was out of the machine in that case, but you can do all
this without taking the machine apart.
They do make carbon pad repair kits for remote controls, where you paint
some black stuff onto the old pad, but I don't know how well they
actually work, how well they hold up for the long term etc.
Bonus for Model 600
The keys are capacitive "foil & foam" type. No electrical contact and
nothing to clean and you probably do not want any kind of liquid in
there. If a key doesn't work on a 600, it's either a corroded trace on
the pcb, or the foam is degraded or something. There are ebay/amazon
sellers that have foil & foam repair kits, not specifically for the 600
of course but I think they are mostly all the same or close enough. I
haven't tried them, just seen them.
--
bkw
