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