11 Jul
2005
11 Jul
'05
7:13 p.m.
Hi
That sounds similar to the keyboard on my Sun at work
( the one I'm typing on now ). About 3 years ago, I spilt
Dr. Pepper on it. It immediately stopped working.
I took it apart and washed the layers one at a time and
dried them. It is still working today.
I can imagine that replacing missing traces would be
a little more difficult. I'd think that the current
through most of the wires is quite low and one might
try using some of the repair stuff for windshield
heaters. If that didn't work, a last resort might
be to use some small wire wrap wire and melt a channel
into the plastic layer to keep from deforming the stack
of sheets to much.
Just some thoughts.
Dwight
From: "Ethan Dicks" <ethan.dicks at
gmail.com>
On 7/11/05, Louis Florit <florit at gmail.com> wrote:
Hi, I pulled out my 64-sx out of the box it's
been stored with in
anticipation of getting my JiffyDos upgrade installed into it. To my
dismay, when I plugged it all in and powered it on, the keyboard
wouldn't work properly. Any of the keys have to be pressed multiple
times (3 to 10 times) in order to get the character to show up on
screen.
Any suggested remedies? I'm wondering if the keyboard contacts are
just a little dirty and need a little cleaning, but I wanted to check
with the gurus before prying it apart.
Unfortunately, the SX-64 keyboard is made entirely differently than
PET and C-64 keyboards... the SX keyboard is layers of mylar with
printed traces. The traces have been known to oxidize over time,
rendering the keyboard inert. You can try to be as careful as you
can, but I have seen plenty of dead keyboards from attempts to repair,
and have never seen a successfully repaired keyboard. If you manage
to work out a successful technique, please share it with us. I myself
have two SX-64s, two good keyboards and two dead keyboards (neither by
my hand).
One possible solution would be to wire up an appropriate switch matrix
to a the correct DB25 pinout and completely replace the native SX-64
keyboard. It would be functional, but not as portable. I don't want
to say there's zero chance of repairing the original keyboard, but it
would be an accomplishment to do so.
-ethan
11 Jul
11 Jul
9:18 p.m.
On 7/11/05, Dwight K. Elvey <dwight.elvey at amd.com> wrote:
If that didn't work, a last resort might
be to use some small wire wrap wire and melt a channel
into the plastic layer to keep from deforming the stack
too much
I've seen the results of attempts at that. Let me put it this way -
try it right before you are ready to pitch the whole mess.
there's not enough pressure to make contact between oxidized traces
printed on mylar and any kind of wire. The mylar sheeting is thin
enough that you are more likely to perforate the mylar than "melt a
channel" _Perhaps_ some kind of foil overlay might work, but it would
have to be akin to gold leaf, and you'd need a solder alloy that
melted below the temp of the plastic to get any sort of joint. For
that matter, if you had an uber-low-temp solder (200F? 300F?), you
might be able to overlay entire traces with WW wire, but not if the
plastic develops holes.
-ethan
12 Jul
12 Jul
12:53 p.m.
On 11 Jul, 2005, at 21:18, Ethan Dicks wrote:
On 7/11/05, Dwight K. Elvey <dwight.elvey at
amd.com> wrote:
There is a kind of silver paste used for thick-film circuits which
might be usable for this type of repair.
--
-bv
If that didn't work, a last resort might
be to use some small wire wrap wire and melt a channel
into the plastic layer to keep from deforming the stack
too much
I've seen the results of attempts at that. Let me put it this way -
try it right before you are ready to pitch the whole mess.
there's not enough pressure to make contact between oxidized traces
printed on mylar and any kind of wire. The mylar sheeting is thin
enough that you are more likely to perforate the mylar than "melt a
channel" _Perhaps_ some kind of foil overlay might work, but it would
have to be akin to gold leaf, and you'd need a solder alloy that
melted below the temp of the plastic to get any sort of joint. For
that matter, if you had an uber-low-temp solder (200F? 300F?), you
might be able to overlay entire traces with WW wire, but not if the
plastic develops holes.
6:05 p.m.
On 7/12/05, Bj?rn Vermo <bv at norbionics.com> wrote:
There is a kind of silver paste used for thick-film
circuits which
might be usable for this type of repair.
If you can get electrical contact from trace to trace and get the
paste to not migrate, that might be a workable solution.
-ethan
6944
days inactive
6946
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4 comments
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bv＠norbionics.com -
dwight.elvey＠amd.com -
ethan.dicks＠gmail.com -
gordon＠gjcp.net