Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.

"Tom Gardner" wrote in message
...
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote
commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.


Given any thought to roughing up the deposit with one of your wire brushes?
Something with .030" heat treated wire running at high speed should do it.

Harold

Tom Gardner wrote:
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.

My Commodore 32 used to have those conductive rubber pad switches on the
keyboard. If I didn't use it for a while (which was usually the case as
it was so old), it seemed like dust built up under the contacts and the
keys wouldn't work. To fix the problem I took apart the keyboard and
wiped the PCB using a rag dipped in methylated spirit. I think sometimes
I wiped the rubber pads, too. This always worked for me.

Best wishes,

Chris

"Harold and Susan Vordos" wrote in message
...
Given any thought to roughing up the deposit with one of your wire
brushes?
Something with .030" heat treated wire running at high speed should do it.

Harold


The brush to use would be a 15" knot-type but it might leave ferrous
deposits on the PCB that would soon oxidize.






Funny man...

"Tom Gardner" wrote in message
.. .

"Harold and Susan Vordos" wrote in message
...
Given any thought to roughing up the deposit with one of your wire
brushes?
Something with .030" heat treated wire running at high speed should do
it.

Harold


The brush to use would be a 15" knot-type but it might leave ferrous
deposits on the PCB that would soon oxidize.






Funny man...



No problem. Pickle the board in sulfuric acid afterwards. It'll dissolve
any traces of iron.



Funny man? Me?

H

Depends on how much you want your remote. CaiKote44 is what you need but it
cost about $25 for 3.5g from CMH chemicals or Newark.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Tom Gardner" wrote in message
...
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote
commandeered due to a faulty remote in somebody else's possession. It
seems that there is a deposit on the PCB that is also affected and the
button seems to be non-conductive anymore.

Hardly worth the trouble. A new universal remote can be found on sale
for under $10.
Bugs

"Bugs" wrote in message
ups.com...
Hardly worth the trouble. A new universal remote can be found on sale
for under $10.
Bugs

Youbetcha! My time limit includes 10 minutes of attempted repair and 10
minutes of NG wisdom then it's off to the dollar store. Most things that
are throw-always can be repaired in that 20 minutes, so it's worth the
attempt as long as one doesn't become obsessive.

"Tom Gardner" wrote in message
...
| Is there any way to repair those membrane keyboard switches with the
| carbon-like button that makes contact on a PCB? Sometimes cleaning them
| works but not always and now I'm in danger of getting MY remote
commandeered
| due to a faulty remote in somebody else's possession. It seems that there
| is a deposit on the PCB that is also affected and the button seems to be
| non-conductive anymore.

There are special eraser looking things for cleaning contacts and
copper, but for most uses, a plain old red eraser will do the job. I doubt
your switch contacts are copper anyway, most likely carbon deposits that are
crudding over.
That's my first trick, and when electronics repair was my job, that
unsharpened pencil with the worn eraser wasn't for writing!

Tom Gardner wrote:
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.


Try lightly sanding the conductive rubber buttons fine abrasive paper to
expose some fresh material?

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Jeff Wisnia wrote:
Tom Gardner wrote:

Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning
them works but not always and now I'm in danger of getting MY remote
commandeered due to a faulty remote in somebody else's possession. It
seems that there is a deposit on the PCB that is also affected and the
button seems to be non-conductive anymore.

Try lightly sanding the conductive rubber buttons fine abrasive paper to
expose some fresh material?

I'd be a bit cautious using abrasive paper. I've screwed up some
contacts by trying to clean them with emery paper in the past. If
methylated spirit and a rag doesn't work, try one of those
oil-impregnated fibre contact burnishing strips. Search online for
"contact burnisher".

Best wishes,

Chris

Christopher Tidy wrote:
Jeff Wisnia wrote:

Tom Gardner wrote:

Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning
them works but not always and now I'm in danger of getting MY remote
commandeered due to a faulty remote in somebody else's possession.
It seems that there is a deposit on the PCB that is also affected and
the button seems to be non-conductive anymore.

Try lightly sanding the conductive rubber buttons fine abrasive paper
to expose some fresh material?


I'd be a bit cautious using abrasive paper. I've screwed up some
contacts by trying to clean them with emery paper in the past. If
methylated spirit and a rag doesn't work, try one of those
oil-impregnated fibre contact burnishing strips. Search online for
"contact burnisher".

Best wishes,

Chris


I hear what you say Chris, and I wouldn't use abrasives on a metal
contact because I've heard tell that particles of the abrasive can lodge
in soft metal (like silver) contacts and act like little "insulated hold
offs" which keep the metals from touching as well as they should.

However, we're talking conductive rubber (or some elastomer) here, and I
don't think the same holds true there because of the soft nature of the
material, plus you don't need milliohm contact resistance in those TV
remotes and similar gadgets.

An oil impregnated strip is the *last* thing I'd use on that kind of
contact, because I'm convinced the greenish guck you find inside the
keyboards of TV remotes and other devices with "rubber buttons" is your
own body's skin oil which migrates down through the rubber, and maybe
also plasticisers which leach out, so I'd say oil of any kind is a no-no
there.

Just my .02,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Tom,

Stay from all the advice about using anything stronger than a pencil
eraser,.. Actually I'd stay away from that too.

My usual techneque is to use isopropyl alcohol to clean the PCB, many times
those PCB pads have a graphite like coating on the and the I.A. dosen't seem
harm that.... Clean the keys with it also... it's been my experiance that
it's the keys that go bad, I've had good luck cutting the keys from the
keypad I don't use and replacing the bad key with it...

Dave



"Tom Gardner" wrote in message
...
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote
commandeered due to a faulty remote in somebody else's possession. It
seems that there is a deposit on the PCB that is also affected and the
button seems to be non-conductive anymore.

It's an idiotic design to start with, made with expediency in mind.
Modify it by gluing a very thin piece of aluminum foil(cigarette pack
foil or such)to the bottom of the rubber key where the carbon contact
is/was. Shine up the copper traces, usually in a circular pattern
directly under the rubber key. Use an rubber erasor as others pointed
out. My remotes now work effortlessly...

Tom Gardner wrote:
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.

Jeff Wisnia wrote:
Christopher Tidy wrote:

Jeff Wisnia wrote:

Tom Gardner wrote:

Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning
them works but not always and now I'm in danger of getting MY remote
commandeered due to a faulty remote in somebody else's possession.
It seems that there is a deposit on the PCB that is also affected
and the button seems to be non-conductive anymore.

Try lightly sanding the conductive rubber buttons fine abrasive paper
to expose some fresh material?



I'd be a bit cautious using abrasive paper. I've screwed up some
contacts by trying to clean them with emery paper in the past. If
methylated spirit and a rag doesn't work, try one of those
oil-impregnated fibre contact burnishing strips. Search online for
"contact burnisher".

Best wishes,

Chris


I hear what you say Chris, and I wouldn't use abrasives on a metal
contact because I've heard tell that particles of the abrasive can lodge
in soft metal (like silver) contacts and act like little "insulated hold
offs" which keep the metals from touching as well as they should.

However, we're talking conductive rubber (or some elastomer) here, and I
don't think the same holds true there because of the soft nature of the
material, plus you don't need milliohm contact resistance in those TV
remotes and similar gadgets.

It's not so much the insulating particles I'm concerned about; it's the
fact that the metal layer is really thin. I'd be concerned about
destroying it completely. Really fine emery paper would probably be
okay, but personally I wouldn't want to use coarser than 800 grit.

An oil impregnated strip is the *last* thing I'd use on that kind of
contact, because I'm convinced the greenish guck you find inside the
keyboards of TV remotes and other devices with "rubber buttons" is your
own body's skin oil which migrates down through the rubber, and maybe
also plasticisers which leach out, so I'd say oil of any kind is a no-no
there.

I take your point about oil accumulating muck, but these strips are only
impregnated with a very small amount of oil. I think the idea is that
the oil softens and dissolves the muck. Even if they don't solve the
problem, I don't think oil impregnated strips will do any permanent damage.

Best wishes,

Chris

It's not so much the insulating particles I'm concerned about; it's the
fact that the metal layer is really thin. I'd be concerned about
destroying it completely. Really fine emery paper would probably be
okay, but personally I wouldn't want to use coarser than 800 grit.


The zig-zag pattern of tracks they normally put on the printed circuit board
is solid enough to take a gentle clean with an ink rubber. Preferably those
old grey and white style ink and pencil rubbers (or eraser depending on
which school you went to!).

The fine abrasive cleans off the copper track nicely and is gentle enough to
use many times on the remote over the years.

The rubber pad that forms the buttons is easily cleaned with dish washing
detergent and your fingers in the kitchen sink. Allow it to dry before
putting it back together. If the little conductive bit has fallen off, then
you can cut one from another old dead remote control and glue it in place
with superglue (CA).

Hope this helps,
Peter

Tom Gardner (nospam) wrote:
Is there any way to repair those membrane keyboard switches with the
carbon-like button that makes contact on a PCB? Sometimes cleaning them
works but not always and now I'm in danger of getting MY remote commandeered
due to a faulty remote in somebody else's possession. It seems that there
is a deposit on the PCB that is also affected and the button seems to be
non-conductive anymore.

Before the advent of cheap universal remotes, I did a fair amount of
this. One of the problems is that the carbon buttons tend to be a
little abrasive, I've seen remotes where the metal was entirely removed
from the circuit board on the more heavily used buttons. This can be
temporarily repaired with some metallic circuit board paint but it
isn't a real fix. A lot depends on what the pattern is under the
buttons. Some have a spot that has a split down the center, some have
a double spiral. Obviously, the split spot will be easier to paint
than a double spiral. They make a kit for repair of these, Chemtronics
has it. Last retail I saw on it was like $25, which would get you a
couple of universal remotes from wally world with change left over.
When remotes were like $80 for a factory replacement, they were worth
working on. For $10 or less, pick up a universal that glows in the
dark... If the isopropyl alchohol doesn't work, bin the thing.

Stan