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remote control keypad conductivity repair

For remote controls that have been properly cleaned out and still don't work like new, I understand some conductive material needs to be coated onto the circuit board contacts on the inside of the pad buttons. Reviewing web discussions of this I wonder if a good approach may be to mix graphite in silicone glue and lightly coat the surface of the pad's underside. Anyone tried this or have a thought on it? Others have used electrically conductive paint (e.g., that purchased at auto supply stores to reconduct broken rear window defrost circuits) but that would not seem to be as flexible as silicone glue with conductive material mixed in it. I did read where someone mixed finely shredded copper (from pipe) with thinly diluted white glue and it worked well (but for how long?). It would seem that the latter approach would be better if silicone glue was used, as it is more flexible. What ye think?

Reply to
Thomas Williams
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"Thomas Williams"

** Think the graphite might simply dissolve in the silicone adhesive and the surface remain non conducting.

Conductive glues are rare animals for this reason.

Why don't YOU try it ??

.... Phil

Reply to
Phil Allison

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Reply to
Jamie

I use conductive paste:

If available, I've also used Aquadag (water based graphite paste).

Before you attack, clean both the graphite button bottom and the gold contacts on the PCB with alcohol. It might just be grease on the contacts.

The problem with mixing your own conductive graphite concoction is that only a few formulations are actually conductive. If you don't add enough graphite, or the graphite particles are too small, they will not touch each other and therefore will not be conductive. I've tried to make my own conductive glue with powdered aluminum and epoxy. It failed badly and was mostly an insulator. I eventually got it to conduct by radically adjusting the aluminum to epoxy ratio, but with little epoxy to act as a binder, it was terminally brittle.

Anyway, try it. You might get lucky and find the right combination of grain size and graphite to glue ratio. Test with an ohms guesser. Your remote should work with anything less than about 1,000 ohms per square, but I'm guessing:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

One more:

I haven't tried these but they sure look plausible.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

I ran the abut in this problem a few years ago. Previously, disassembly and cleanout with detergent water worked to perk up a balking RC. But a few years later, that did not solve all dropouts. I took to scrubbing the little rubber conducting boots with lacquer thinner, but that still did not solve eve half the dropouts.

My last resort was to add an aluminum foil bits the size of the footprint to each contact. That perked up about half the dropouts, still not good enough for serious cassette and DVD watching where the program content was recorded off of standard broadcast with its weighty commercial content.

As a "last" resort (there is really always "just-one-more" to be found), I went to mother Radio Shack and bought a universal control. It included my VCR and TV codes, so now I'm back to 95% RC functioning (nothing's perfect).

Ange

Reply to
Angelo Campanella

Rob pairs (or more if same matrix dimensions) of buttons cut from the pad of some disused zapper that has much the same size and spacing of buttons.

Reply to
N_Cook

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thanks, Jeff. your post was quite helpful (unlike some of the others here, I won't mention any names ("Phil, Jamie and Angelo" (at least the latter made an attempt)) will try the window defog preparation first, then later explore the two articles on making your own . . .

Reply to
Thomas Williams

Y'er welcome. It's a common problem. Incidentally, if you're going to try making your own graphite conductive paste, don't get the bright idea of using graphite lock lube. To be a lube, the particles must be spherical, which will not touch each other, and therefore not conduct. What you want are graphite flakes, which will overlap, and therefore conduct. Good luck.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

Source for guaranteed "flakey" graphite ?

Reply to
N_Cook

The author of one of the links I previously mentioned uses AGS Extra Fine Graphite from:

I have a small 4 oz bottle of graphite in the office I got from an auto body shop. They use it for lubing window and lock mechanisms in the door. It seems like a lifetime supply.

Doing some more reading, it appears that only some lock lube uses spherical particles. Most of the cheap stuff is flake, so I guess it's probably acceptable to use.

Other sources:

More:

Spherical Graphite (used in lock lube and Li-Ion batteries:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

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Reply to
Ron D.

There is conductive paint for just this purpose at electronics stores. Ford Electronics in Fullerton, CA had some. I saw it there. I think they ship.

FWIW I tried the aluminum foil glued on, I didn't have 100% success. Since I wanted a 100% working remote control any less than 100% is failure. I haven't tried the paint.

Reply to
steevo

Please note that the original question was about making his own formulation.

I call your missing link and raise you 4 more:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

How about Aqua-dag? I wonder if it is still available? Used to apply a conductive coating inside and outside of CRT envelopes.

tm

Reply to
tm

Aqudag won't work, however the Chemtronics remote repair kit works great. Chuck

Reply to
Chuck

**There are some proprietory kits available for remote control repairs. They work. I've used them many times with great success. Use one. Alternatively, but a new remote, or find a suitable programmable one. 
--
Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson

Here is the link to a product specifically made for fixing conductive keypads.

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It works... I've used it.

--
David
dgminala at mediacombb dot net
Reply to
Dave M

keypads.http://www.mcmelectronics.com/product/CAIG-LABORATORIES-K-CK44-G-/200...

I tried it ( Caikote 44 ). It worked fine for a couple weeks, then several of the keys died. Disappointing.

Reply to
Thomas Williams

keypads.http://www.mcmelectronics.com/product/CAIG-LABORATORIES-K-CK44-G-/200...

Try Neolube.

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I'm most familiar with it for [redacted] the [redacted] in the [redacted] but it also works well for regenerating those conductive pads in remotes. Proper surface preparation is key, of course.

--
Rich Webb     Norfolk, VA
Reply to
Rich Webb

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