best method to restore conductive keypads? - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 01:09:11 am
content: My wavetek 399 has a rubber keypad with the carbon stuff on it.I need to press very hard with a implement to get it to register. I cleaned them before and it did not really help.I see there are a whole bunch of methods to repair them, from gluing on conductive plates, to putting conductive glue on, etc. What works the best and is most durable?

author: Psi
author_rank: Super Contributor
timestamp: February 24, 2023, 01:15:53 am
content: Check with a DMM using a very light touch to see which side is the problem (higher resistance).Either the carbon pads inside the rubber buttons or the pcb carbon tracks.(It's probably the carbon pads on the rubber buttons)If that's correct, then you can probably order some carbon sheet or carbon pads and cut them out to stick pieces inside the buttons to restore them.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 01:32:19 am
content: what should a good resistance be to light probing? ANd they are over gold tracks, those are fine.I am gonna stick it in a hot ultrasonic for a while incase it got contaminated, maybe that will help.How about silver paint? Silver epoxy?

author: Psi
author_rank: Super Contributor
timestamp: February 24, 2023, 01:44:06 am
content: The rubber buttons are usually covered in carbon and this can wear away/crack because the buttons move.You could try some silver paint/silver epoxy however i feel that it will crack under the flex of pressing the buttons.I would try to find a sheet of carbon intended for button use.Or you could probably find some junk electronic device with carbon buttons and pry out the pads using a knife and then glue them into your defective keypad buttons.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 01:45:38 am
content: do they have high flex paint or coating that is conductive? Like silicone? Mix silver powder in 2 component silicone?The idea of... cutting all that crap is really awful

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 01:46:42 am
content: And while the coating can crack, so can the adhesive. I have a feeling adhesion to those rubber membrane is gonna be dodgy at best.

author: Psi
author_rank: Super Contributor
timestamp: February 24, 2023, 01:52:34 am
content: if you search aliexpress for "Rubber Conductive Buttons" there's lots of things you could order for couple of dollars to pry out the conductive pads from.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 04:38:18 am
content: I am going to try this, I did not realize major electronics retailers sell ithttps://www.chemtronics.com/circuitworks-rubber-keypad-repair-kitI see a few brands of this kinda stuff.. I am sure someone here has experiance with these products?I am basically irate at this wavetek 399, I literarly started a few small repair jobs 2 weeks ago because I thought I could clear out some of the simple repairs but it has been nothing but completely annoying and I keep running into bizzare problems like this one not involving electronics. Plastic panels, keypads, clasps, rubber feet, etc

author: floobydust
author_rank: Super Contributor
timestamp: February 24, 2023, 04:46:42 am
content: First I do a wash of the keypad in dish soapy water. Use IPA and Q-tip on the PC board. Modern keypads are just conductive paint for a pad, older gear it's a conductive pad bonded to the silicone.I now use the conductive rubber repair kits. More here:https://www.eevblog.com/forum/repair/carbon-contact-pad-repair/msg4032652/#msg4032652My buddy just used thatCircuitWorks Rubber Keypad Repair KitI'll check how it worked for him.I did not have success with MG Chemicals (discontinued) keypad repair kit, it used cyanoacrylate which cures hard so flexing made it crumble and fall off.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 05:14:23 am
content: Yeah I tried clean, fader lube, and even deoxit gold on the gold parts. None of them really work too well, if anything the fader lube grease made it work worse, with deoxit gold being neutral or close to it. But I cleaned it up in 20 min of ultrasonic followed by a spray down with IPA and then wipe with IPA q-tips on the carbon.I ordered the circuitworks one, hopefully this fixes it. I bet there is some surface condition going on from age, that panel was totally disintegrated too, I need to fill that up with flowable epoxy maybe as a reinforcement where I can... but wow I am sick of this thing, total fucking menace, they packed the fail real hard into that interface panel.Good lord people go with metal panels and metal mechanical switches, that key pad stuff is not worth it!500,000 cycles seems quite nice! Might be able to program a handful arb wave with that amount from the front panel before it needs a recoat

author: Psi
author_rank: Super Contributor
timestamp: February 24, 2023, 05:50:50 am
content: Sometimes the carbon coating is very thin on top of black rubber.It gets worn off completely and no amount of cleaning will get it to work, obviously.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 05:51:55 am
content: ah, I thought it was a poured layer. Like why would you have 2 things to pour instead of one if you are gonna paint it? I guess unless they need different softness materials to get the right feel. Like a brace

author: xavier60
author_rank: Super Contributor
timestamp: February 24, 2023, 11:15:56 am
content: A while back I tried to remove the conductive layer from the underside of the buttons on a keypad using Dremel with a rounded burr.The burr didn't seem to remove any material, but I found that low resistance was restored.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 11:30:15 am
content: you mean like sand paper or like a carbide burr?

author: xavier60
author_rank: Super Contributor
timestamp: February 24, 2023, 11:42:35 am
content: Quote from: coppercone2 on February 24, 2023, 11:30:15 amTungsten carbide Burr like this one,https://www.hobbytools.com.au/dremel-max-life-9903hp-1-8-3.2mm-tungsten-carbideMy original intention was to remove the black conductive layer to see if an adhesive would work better at sticking on some aluminum foil.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 12:04:14 pm
content: ok, those are not the ones you would use for soft material (maybe 2 flute or even 1 flute for mill cutting ) I think. I have that, but I am a little scared that I will rip up the keypad. Maybe I can try it very carefully. People usually sand very soft materials, they don't have a good reputation for being burred with a burr made for ferrous metal, but in this case it helped. But I am also wondering if you just sand it a little... with a sanding stick. I bought a bunch of sanding sticks.

author: xavier60
author_rank: Super Contributor
timestamp: February 24, 2023, 12:25:17 pm
content: I have just tried doing the same to a working TV remote. The burr removed the black conductive material at a slow controlled rate. I think a stone burr would be safer though.Take care, your results may differ.

author: rfengg
author_rank: Regular Contributor
timestamp: February 24, 2023, 02:30:53 pm
content: Cleaning either the pcb pads or the carbon on the keypads is a very temporary fix.....in cases where I have to tried to do this on remote controls, the fix lasts for a month or two even if you are very careful with using the remote.......it looks like once the deterioration has started , it's a very hard to prevent its worsening.My last resort was to get some copper tapes with conductive glue, cut them into tiny circles and place them over the keypad carbon......works better than the temporary cleaning fix.

author: TERRA Operative
author_rank: Super Contributor
timestamp: February 24, 2023, 05:08:10 pm
content: I have used this stuff to good effect.I'm not sure about the long-term durability, but it's not a hard repair to repeat.https://www.bareconductive.com/collections/all/products/electric-paint

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: February 24, 2023, 05:19:24 pm
content: Hi coppercone2,You might use somegraphite paintThis one dries in minutes.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 24, 2023, 05:58:34 pm
content: I used aluminum conductive tape. Cut dots with a paper punch. Worked pretty well.This worked for a while. I think it wears out the traces on PCB.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: February 24, 2023, 07:43:02 pm
content: I've had good results with this conductive paint. I apply it with a q-tip.https://www.amazon.com/gp/product/B01MQ4F1T5/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2023, 09:54:05 pm
content: anyone want to hazard a guess about how much silver powder you need to add to two component silicone to make it conductive enough to work with these pads? I do have 10 grams of silver powder for those sintering experiments that I strayed away from. I would prefer to not waste silver and I have no clue what a mix ratio might be. I noticed conductive silver epoxy does not register conductivity until it cures (with dmm probes), and the cure time of the silicone mix is very long (24 hours IIRC), so its kind of expensive and time consuming to guess.I bought the repair kit already, but I could try the silicone silver mix if someone has a reasonable answer

author: eurgenca
author_rank: Regular Contributor
timestamp: February 25, 2023, 08:40:10 am
content: Isn't copper powder cheaper?I always use conductive rubber pads with super glue and no problems.

author: wraper
author_rank: Unknown
timestamp: February 25, 2023, 08:51:21 am
content: Clean it with dishwashing liquid first, measure resistance of conductive rubber by multimeter. Resistance should be up to a few hundred ohms on good buttons when pushing probes a few millimeters apart. If on bad buttons it's much higher than on working buttons, use fine sandpaper to remove a thin layer of conductive rubber. To do so, push the button so conductive part protrudes outside, then make a few light passes with sandpaper, measure resistance. Repeat until resistance drops <2x of good buttons, then stop sanding. You should remove just a few microns at a time. Be careful to not sand the membrane around the button as it's very thin. Clean PCB with some sort of alcohol too. Use additive repair like gluing conductive part only if conductive rubber is totally destroyed and cannot be rejuvenated by removing outer layer.

author: elecdonia
author_rank: Frequent Contributor
timestamp: February 27, 2023, 03:44:43 am
content: I use these:ButtonWorx Rubber Keypad Repair KitSold on Amazon. Copy and paste the line above into Amazon search.These are self-adhesive conductive pads which you stick onto the PC board. The original rubber button presses on the new self-adhesive pad. These are easy to apply. The adhesive is strong enough. Performance is excellent.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 27, 2023, 04:36:08 am
content: There seem to be lots of slightly different but similar processes in these buttons. In some I have found there is a large volume of conductive material on the back of the button. The failure mode on these seems to be degradation of the surface layer (oxidation, lost of softener, who knows) and removal of the surface layer is an effective and long lasting cure. One others the problem is too much material transferred from the button to the PC board, lowering the resistance between the traces constantly. How high it needs to be varies depending on their readout strategy and the deposits causing the problem may be a long ways from the contact point.Some of these buttons allow very little travel so adding a new pad on top of the existing ones is problematic.Another suggestion that can sometimes work is installing a carefully placed and insulated snap disk from that style of switch. I like the idea of electrons flowing through continuous metal instead of depending on the contact between thousands of tiny particles, but the geometry on this approach is fiddly and doesn't often work.For those putting foil or other toppers on contact cement (used to install laminate countertops) is strong and remains pliable. I can't speak to its adhesion to the "rubber" used in these buttons, but with proper cleaning it probably works. Surface prep is everything with any adhesive.

author: Greybeard
author_rank: Frequent Contributor
timestamp: February 27, 2023, 12:03:30 pm
content: I used a repair kit containing thin conductible rubber pads, that must glued on the rubber foil with CA glue. Sometimes you have to grind off (Dremel) the old rubber pad to make place for the new one. Found on AliExpress or similar source.

author: artag
author_rank: Super Contributor
timestamp: February 27, 2023, 12:22:01 pm
content: I got some kits from {amazon, ebay, can't remember} -https://termopasty.pl/en/kategorie/electroconductive-materials/Haven't tried them yet but the company looks like they're knowledgable and they come with a tube of silicone glue which should be better than CA

author: coppercone2
author_rank: Super Contributor
timestamp: March 01, 2023, 02:49:53 am
content: I got and applied the keypad repair kit, It works wonderfully now.My process was to1) file all the keys down with a 400 grit sanding stick2) spray wash with alcohol3) q-tip with alcohol clean4) paint on conductive coating with fine paintbrush5) after 1 hour room temp cure, bake at 80C for 1 hour.Other then being tedious to apply, and also slightly expensive, since the kit is 1 use, it seems to work great. Only time will tell I guess.

author: DarkAngel
author_rank: Newbie
timestamp: October 13, 2024, 09:17:47 am
content: .FAILURE IS THAT IN MANY REMOTES, OVER TIME THE CONDUCTIVE RUBBER MATERIAL UNDER THE KEYPAD BUTTON,ALWAYSTURNS INTO MIX OF CLEAR "GOOP" AND BLACK CARBON MATERIAL. One must "mash down" very hard and slide the button around with your finger to make a connection...which is unreliable. I've seen the degradation of the switch take anywhere from less than 1 year to over 10 years, depending on the brand. I have to replace my Cox remote every few years because of this repeating failure.The "rubber" keypad failures I run into are that over time the buttons degrade in some way and create some sort of clear GOOP on the entire contact interface consisting of the conductive rubber pad and the metal "interlocked fingers" kind of pattern on a metal side of the PCB board.I canusuallyclean off the "goop" and it MAY work again for some time, but this method usually also removes quite a lot of the black (assumed carbon) material that had been partially disolved and mixed into the "grown" goop, so this repair can't be performed more than a few times before there's ZERO carbon left to form any electrical connection.Is there a repair kit forthis specifictype of remote's keypad button's failure?

author: BILLPOD
author_rank: Frequent Contributor
timestamp: October 13, 2024, 01:41:42 pm
content: Good Morning DarkAngel, What works bestfor me, is the conductive paint. I clean the rubber contacts and the corresponding traces on the PCB with IPA and then dab some of the paint on the rubber pads. This paint is super fast drying and by the time I reassemble the remote it's ready to go.

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 13, 2024, 04:38:46 pm
content: You can buy kits of conductive pads from ebay/aliexpress/etc.https://www.ebay.com/sch/i.html?_nkw=conductive+pad+keypad+repair+kit

author: Dave Wise
author_rank: Regular Contributor
timestamp: October 15, 2024, 12:51:11 am
content: My old stereo remote slowly became unusable. Pen-applied nickel worked at first but quickly flaked off. Then I cut little disks of brass foil and attached them to the rubber pads with contact cement. I only did worn out pads like Mute, Volume+, Volume-, Power. Couple months of heavy use and still fine.

author: eLuke
author_rank: Newbie
timestamp: May 09, 2025, 06:46:53 pm
content: I tried sticking aluminium tape to the pads of the rubber key mat on a dect phone, but it would not stick. So today I threaded a wire through the pads, twisted the ends and cut them short.It works, and I hope this holds. 'Painting' with graphite did not last long. At least this won't rub off, but I worry the copper might oxidize. It is a single strand / hair from a multistranded wire. The same method would work for silver wire though. (jewellery filigree wire? have not tried that, do not have that on hand).I don't know if this is the best method, probably not, but at least my phone responds to keypresses again now

author: nonius_
author_rank: Contributor
timestamp: May 09, 2025, 07:06:16 pm
content: QuoteDid you try to mix the graphite with PVA-glue (polyvinylacetate, white woodworking glue)? I understand that there are commercially available mixtures based on this. Have never tried it myself though so can't say from experience how well they work. (As I tried looking for this commercial goo now, which I couldn't find, I *did* come across these tabs:https://nl.aliexpress.com/item/1005005580739063.html?src=bing&aff_short_key=UneMJZVf&aff_platform=true&isdl=y&albch=shopping&acnt=135095331&isdl=y&albcp=555315016&albag=1296325401357761&slnk=&trgt=pla-2332820077116304&plac=&crea=81020396324624&netw=s&device=c&mtctp=e&utm_source=Bing&utm_medium=shopping&utm_campaign=PA_Bing_NL_PMAX_ALL_maxvalue_20250221_newstore&utm_content=ALL&utm_term=soft%20rubber%20keyboard%20repair&msclkid=fb911dff5f5f129b6d1075e10e40943d&gatewayAdapt=glo2nldMaybe those might work too, with a dab of contact adhesive ('Bison Kit').In the past I've also tried to glue small aluminium disks (made with a paper puncher / 'perforator') with contact adhesive, but that wasn't much of a succes either in the long run.The trick with sewing a copper wire had never crossed my mind - good one! Did you think of that yourself? If so, that's good out-of-the-box thinkingQuoteI doubt whether there are any truly good repair methods for these kinds of keyboards, apart from a complete new one. But this sewing-needle repair is one I'll definitely keep in the back of my mind for future use.

author: reodor
author_rank: Contributor
timestamp: May 10, 2025, 08:02:42 am
content: In my experience, the rubber is infused with conductive material, not coated. Just rub them on some ordinary paper to clean them. Paper is slightly abrasive, and will clean the rubber nicely. I swipe them about 10-20 cm in opposite directions. It leaves a light grey line on the paper.I have also tried using 400 grit sandpaper. It also worked, which proves that the "conductiveness" is not a coating.Of course, there may be different types, and I have been lucky to never encountered a coated one. I have tried old Commodore 64s, a cheap digital caliper and a few remote controls. All successful.If yours is indeed a coating which is already gone, you will still not lose anything by trying abrasion first. It may even be a good glue prep method.

author: eLuke
author_rank: Newbie
timestamp: May 10, 2025, 12:43:16 pm
content: Quote from: nonius_ on May 09, 2025, 07:06:16 pmI have not tried that. I used graphite from a aquarel graphite pencil: “Karisma graphite aquarelle” “England berol Karismacolor soft”. Literaly painted on: rubbed the pencil on paper, then disolved in water and painted the keypads. But after a week or so in use it turns out it sticks to the board much better then to the keys.Thanks for the compliment. The stitching with conductive wire method I have not seen elsewhere yet, but I have not been looking very hard. So I might not be the first to invent this.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: June 24, 2025, 05:33:28 am
content: I'll add my voice here. Recently had to refurbish a Sony/Tektronix AFG310 function generator (nice device) and the main issue was the carbon-infused buttons at the back of the membrane keypad. Best ones (which still worked well) were clocking in at like 10Kohms, worst were around 300+Kohms. After trying less severe methods without success (alcohol q-tip light dab method, pencil method, light abrasion method) I said screw it, washed the whole thing, scrubbed the pads down clean and manually cut tiny squares of adhesive conductive copper foil tape that I keep in stock for trace repair and contact repair material. I had first tried HVAC aluminium tape, but the adhesive didn't bond at all, then tried my copper tape and that bonded pretty well. Device restored, buttons work properly now. There is, of course, an open-ended question about how well this fix will work over the long term. I WANT my repairs to be good for 10 years, but this does involve moving parts, so not fully confident.Link to video where I go over what I did if anyone wants:

author: jason123
author_rank: Newbie
timestamp: July 30, 2025, 12:54:54 pm
content: Not sure if any of you have tried this, but I just placed an order for one. indicates it's specifically designed for remote buttons -https://www.amazon.com/dp/B0DW8Z5CZ2?smid=A2FSFUKDO61E5X&ref_=chk_typ_imgToDp&th=1

author: Dave Wise
author_rank: Regular Contributor
timestamp: September 15, 2025, 04:13:01 pm
content: Quote from: Dave Wise on October 15, 2024, 12:51:11 amUPDATE: This is still working great.