[quote=default]On Fri, 02 Dec 2005 21:10:59 GMT, "Dallas"
wrote:

In between most key pads and the circuit board below is a vinyl (rubber)
membrane pad that has an electrically conductive area that closes two
contact points on the circuit board below . (Like on the inside of a TV
remote under the push buttons)

I have a device on-off switch that is failing because the black conductive
surface is wearing off. What I am looking for is that conductive paint so I
can dab a bit back on to the contacting surface area to make the switch work
again.

Does anyone know where to get something like that?


Dallas


ANYONE FINDS THE ANSWER TO THIS ONE . . . pLEASE pOST.

I have two thoughts on this :
The first being that it might be posssible for contaminants to have gotten to the mating surfaces as mentioned. I sometimes also have to clean a pad of what seems to be have been a migration to its surface from within the "vinyl" body. It seems to be worse if environmentally exposed to a higher temp, naturally. I also do a cleaning with ethylene alcohol but only in a non agressive action, such as to permit a degreasing action only, with no further deteriortion of the conductive agent on the pad.
The other, and most common problem, actually is that there is no contaminant present, but merely a shiny surface / sheen present on a pad surface due to massive usage. If that proves to be the case I DO NOT clean the pad initially but get it out where it can be turned for observation .The idea is for the light from a lamp source in front of you to shine towards the shiny pads surface and then reflect off it towards your eyes. Then you use one of the pencil/stick style of typewriter erasers made by Eberhard Faber, (or others) and sharpen it to a quasi rounded point and buff it to a rounded dome shape on clean demin and then EVER so lightly, erase the shine from the conductive pads top surface, just enough to acquire a a matte surface. As when observed with the referenced, reflected light source. Then, lastly, you ever so slightly solvent clean that new surface.
I have also tried copper foil, aluminun foil, resurfacing with both their attached adhesives ....BAAAd..........as well as additional adhesive types...contact cement...gluper sue......RTV....Pliobond....the last, the best, but still not up to perfection. I will pass on all of their performances/ reliabilities.
The best thing used yet is some colloidial graphite solution that is used for making an aquadag grounding coating for picture tubes. It is good enough in its tenacity and sticking action as to be applied to a SLICK glass surface of a picture tube and stay with it for 20-30 years+. I just degrease the pads surfaces and use a Q-tip to put a drop topside and then let it dry hard. Then the fix is done.
Lastly, if perchance, your referenced "Dallas" is coincident with your location, I can provide you with a bit of same coating.
73's de Edd