SUMMARY: how to fix malfunctioning shift key?

From: John Interrante (interran@uluru.stanford.edu)
Date: Sat Jul 03 1993 - 07:37:23 CDT


Many people told me that one can disassemble a SPARCstation Type 4 or
5 keyboard quite easily to clean the etched contact underneath a key
which has stopped working. The only tools you need are a small-head
Phillips screwdriver, the patience to remove and replace over 20
screws, and a gauze pad dipped in an alcohol solution like 70%
isopropyl rubbing alcohol. Someone thought there were springs within
the casing that upon opening would go everywhere, but this kind of
keyboard contains no nasty surprises like that. HOWEVER, check with
somebody knowledgeable before you dismantle a different kind of
keyboard or getting it back together may be as hard as re-assembling
an engine without instructions.

When you disassemble the keyboard, you can disconnect both cables from
the keyboard without a problem. You don't have to shut down and power
off the SPARCstation. When you reconnect the cables, connect the
mouse cable first and then the CPU cable. When you connect the CPU
cable, the SPARCstation will stop as if you had just typed L1-a and
print "Type go to resume" or something similar on the console. Type
`c' if the prompt is ">" or `go' if the prompt is "ok" and the
SPARCstation'll resume where it left off.

To disassemble the plastic case, turn the keyboard upside down and use
the Phillips screwdriver to remove the seven small screws on the back.
You will have to disconnect a narrow ribbon connector (it's a press on
the protruding latch while sliding type of plastic connector) before
you can lift the keys and circuit board out of the plastic case. Now,
remove yet another set of 15-20 screws holding the printed circuit
board down. Clean the etched copper contacts on the board with a
gauze pad dipped in rubbing alcohol and press the keys so you can
clean the foil contacts on them too. Wipe down or blow on the inside
of the plastic case to remove any crumbs or hair there as well.
Replace the screws on the back of the circuit board, remember to
re-connect the ribbon connector when reassembling the parts, and
replace the screws on the back of the keyboard.

You can also pop the key off with a key-puller (the key snaps right
back on when you're finished) and use forced air or a cleaner spray to
try and dislodge the crud. Popping the key off and blowing underneath
it cleared up the shift key for me, but I couldn't be sure it was
fixed permanently (it failed only intermittently even before I popped
the key off) so I disassembled the keyboard anyway and wiped down the
contacts on the circuit board and keys. Now my left shift key is
working fine again and all of the other keys should keep working for a
long time, too.

I'm very grateful to the following people who responded to my
question. Give them a big round of applause!

Bill Morrow <morrow@cns.ucalgary.ca>
Andrew Scarman <andrews@erin.gov.au>
Allen Talbot <a.talbot@lsi-logic.co.uk>
Michael J. Maciolek <mikem@ll.mit.edu>
J. Matt Landrum <mdl@cypress.com>
Steven D. Ims <sdi@sun-valley.Stanford.EDU>
Jim Wills <jwills@deltam.com>
Mark Cain <mcain@mcs.drexel.edu>

> From: interran@uluru.stanford.edu (John Interrante)
> Newsgroups: info.sun-managers
> Subject: how to fix malfunctioning shift key?
> Date: 30 Jun 93 18:30:37 GMT
>
> Lately the left shift key on my SPARCstation 1's old Type 4 keyboard
> has started to go. It works only intermittently, as if it's not
> making electrical contact reliably when I press the key. Does anyone
> know how I could try to clean the electrical switch so that it makes
> contact better, or is this a problem that only a keyboard swap or a
> repair shop with the right tools can fix?
>
> John Interrante / interran@uluru.stanford.edu



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