What's the black conductive stuff in Pioneer keyboards?

[Paul Brogger]

I'm attempting repair of a couple of Pioneer keyboards. (Taking 'em apart isn't so hard -- getting them stuck back together may be interesting!)

I've diagnosed at least one problem: the matte black conductive "dots" inside the mylar (or whatever) dimples on the bottom row have worn through under oft-used keys. It's deposited itself among the black interlaced "fingers" imprinted on the facing contact sheet.

Cleaning the contact sheet fingers with alcohol went nicely, and seems to have rejuvinated a formerly "dead" 32SII and a 42S. But the dimple dots have visible wear, with some areas lacking the black stuff entirely. Keypress detection for these keys is intermittent, at best.

An obvious solution is to replace the dimple sheet with a better one. But as you might imagine, these things are in rather short supply. Because the plastic itself seems in relatively good shape, I'm wondering whether I can re-coat the inside of the dimples with something adhesive, flexible, durable and conductive. (I assume all those properties are required, as well as perhaps some others I haven't come up with.)

Does anyone have any idea what the flat-black carbon-looking stuff is that is used to effect contact inside these Pioneer keyboard assemblies?

Any info or ideas re: substitutes will be appreciated!

Thanks.

[Renato]

Paul,

I have not tried, but I think Caig´s Gold Pen would be a good candidate for fixing the "dots" - Newark had it. I have also found a dark grey conductive ink here in Brazil - it is graphite based, and after dry it looks very similar to the dots in the 48G keyboard mylar.

Good luck,

Renato

[David Smith]

The Caig Gold Pen is just a contact cleaner/corroison inhibitor. It will not restore a missing conductive thingy.