DeoxIt made by Caig Labs is the best performing product I've found for
switch contacts. I don't know where you're located, but these products can
be purchased from many of the larger parts/supplies dstributors in the U.S.,
even that Shack store sells it, I think.

The big problem with some push switches (and others like microswitches) is
that there isn't any sliding action to keep oxidants wiped clear from the
contact area.
Cleaning with many type of conact cleaners leaves no protection to eliminate
or reduce the reformation of the oxidants.
The DeoxIt products work most effectively when the contacts can be accessed,
and applied with a rubbing action with something such as a cotton swab tip.
You'll see the oxidants on the swab and when the contacts are clean, they're
also protected.
Heavy/stubborn oxidation can be scrubbed with a hardwood swab stick dipped
in DeoxIt.

Just flooding push/snap switches with spray isn't as effective as manually
cleaning them. I spray the aerosol DeoxIt into a small needle-tipped bottle
for applying it to switches and swabs, and this provides a more controlled
application.

The only application where I've found that contact wasn't improved was a
test I tried on the resistive compound contact pads in an IR remote control.
For all other metal contacts, the product has always provided excellent,
lasting results.

In power switching applications, badly burnt or pitted contacts should be
replaced. Applying a treatment of DeoxIt to new contacts will insure that
they're clean and protected.

WB
...................


"mike" wrote in message ...
Recurrent Keyboard Failure on GE clock radio

My favorite old GE clock radio has metal membrane
keys for the direct-set alarm.
Looks like this:
http://nm7u.tripod.com/homepage/keys.jpg

Every six months or so, they quit working.
Starts at the bottom row and works it's way up
over a period of months.
I take it apart and run a strip of paper soaked
in alcohol between
the contacts and it's all good for another six months.

I'm wearing out the screw holes that mount it together.

Is there anything I can put on the contacts to retard
oxidation or whatever's happening?
I thought it was dirt, but sealing the whole thing in
packing tape didn't help a bit.

The radio isn't worth nothin' but it sure is easy to set
the alarm time...when the keys work. I have two of these and
they both have the same problem.

Ideas?
mike
--
Bunch of stuff For Sale and Wanted at the link below.
laptops and parts Test Equipment
4in/400Wout ham linear amp.
Honda CB-125S
400cc Dirt Bike 2003 miles $550
Police Scanner, Color LCD overhead projector
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/