PDA

View Full Version : Conductive Material for Keyboard Membrane Repair



SkydivinGirl
31st August 2012, 13:35
Hey everyone,

I'm trying to find a conductive material to repair an SX-64 keyboard membrane. For those of you who have not seen an SX-64 keyboard membrane, it's basically a large rubber membrane that connects to the control board via a row of contacts on both the rubber membrane and the board itself.

The problem I'm having is that the row of connectors is not getting a good connection. If I put pressure on that row then the keyboard works perfectly. I've already tried cleaning all the contacts but the problem persists. If there is some sort of material that I could use to re-coat the contacts on the membrane then I think the problem would be solved. Is there anything like that available?

Thanks guys!

Heather

Bryce
31st August 2012, 13:47
You could try using conductive silver paint. This is great for repairing keyboard foils and would probably be fine for fixing the contacts too.

Bryce.

thecellartroll
31st August 2012, 14:01
I haven't tried this but I think it would work...
http://www.ebay.co.uk/itm/Electrical-Conductive-Glue-Connect-Bus-Tabbing-Wire-Solar-Cell-No-Soldering-iron-/330780002133?pt=BI_Welding_Supplies&hash=item4d04064755

SpeedGeek
31st August 2012, 14:51
@Heather

The conductive silver paint is good for repairing PCBs but will likely wear down to quickly for a keyboard application. So the conductive rubber is a better (or longer lasting choice). Digi-Key sells this but you can usually find better price on other-bay.

Kevin

Bryce
31st August 2012, 15:08
I understood that tha problem is with the connector tags (ie: the edge connector on the foil) and not the actual buttons themselves. If it's the buttons, then yes, conductive rubber is definitely a better choice, but for the connector tags, which will only be re-connected once, silver paint should be fine.

Bryce.

Justin
31st August 2012, 16:00
i have used car heat screen heater element repair stuff before with great success (silver conductive paint:))

SkydivinGirl
31st August 2012, 17:47
Bryce is correct, I'm looking to repair the conductors for attaching the membrane to the board so it won't be moving. I may opt for the conductive rubber. Any chance someone could send me a link to it on Digi-Key? I searched but couldn't find it. :)

If I can't find something suitable then I might try the conductive paint. :)

Thanks guys!

Heather

protek
31st August 2012, 18:08
Graphite from pencil would do the trick. I fixed a broken trace of a Spectrum membrane ribbon with a pencil.

SkydivinGirl
31st August 2012, 19:20
Might have to try that for a quick fix. :)

Thanks!

Heather

SpeedGeek
31st August 2012, 19:25
@Heather

Thanks for clarifying that. In that case, the conductive silver is a better choice for an edge connector because it has lower electrical resistance than conductive rubber. Digi-Key no longer stocked the conductive silver the last time I checked but a search on other-bay should turn something up at a reasonably good price.

Kevin

rkauer
31st August 2012, 19:57
A home-made and cheaper solution is using half a vial of clear nail varnish and graffiti powder mixed up.

The mixed result is a conductive paint and will work in places where a large quantity can be applied.

SkydivinGirl
31st August 2012, 21:07
Some great ideas everyone. :) I think I have a few things to try now. I'll give the graphite pencil a try first since it's the least permanent option and I'd hate to ruin an SX-64 keyboard.

Heather

protek
31st August 2012, 21:33
Keep us posted how it turns out. :)

ShambleS1980
31st August 2012, 23:59
Graphite from pencil would do the trick. I fixed a broken trace of a Spectrum membrane ribbon with a pencil.

we used to do this on gfx cards to allow more power through for over clocking.. the more graphite you put down on the pcb the more conductive it was. but it is prety resistive.

rkauer
1st September 2012, 00:16
Just remember to use a soft pencil, like a 2B.