How to make remote control keys work again

Question

🖼️

The project:

Many of us have had remote controls get "sticky" keys where pressing them doesn't always (or never) work. and a suggestion on another post by  made me think of posting this.

I work/ed in Telecommunications and used to have to refurbish telephones in order to maintain customers and phones with membrane keyboards (rubbery keys) are the same as remote controls. The issue that stops the keys from working is as follows (you can skip ahead if you aren't intrested in the technicalities).

The rubberised keys have a point on the back of them that has carbon impregnated in it. compressed carbon is a good conductor that when it is pressed on the circuit board behind it shorts out the tracks on the circuit board and that is how the remote knows you have pressed the button. the issue is that the manufacturing process doesn't permanently lock in the carbon and over time molecules of carbon migrate to the surface. Thing is, uncompressed carbon is a very poor conductor of electricity and so creates a resistive coating on the back of the button and the surface of the circuit board stopping it from working correctly.

And so to Eric's trigger, he recently mentioned Isopropyl Alcohol for cleaning a tile surface before sticking a laminate to it and that is what I have always used when fixing keyboards. So if you feel confident dismantling a problem remote, you can clean both the circuit board and thoroughly clean the back of the membrane key pad (don't overdo it as you could rub all the carbon away with some of the cheaper remotes) then reassemble and see how well it works.

- Materials:

https://www.bunnings.com.au/diggers-125ml-isopropyl-alcohol-125ml_p1564443

- Tools:

Suitable sized screwdriver

lint free cleaning cloths

- Step 1:

Disassemble

Clean

Reassemble

Test

JacobZ · Answer

Hi @R4addZ,

Thanks for sharing this, really useful info. The explanation about how the contacts actually work makes a lot of sense, and the cleaning tip is something most people can easily try before tossing a remote. Always good to see practical experience like this being passed on.

Jacob

Noyade · Answer

A few years back the remote for my car stopped working, so I opened it up and found contact points had fatigued and fractured, which I assume is common with all the 'pressing' that goes on. I purchased a new one from a key place but within a few months it was erratic - however I left it alone as it was still under warranty. I returned it for repair.

"Repaired" they said.

But weeks later the problems reoccurred. So I opened it up and found a fractured contact point. What their repair entailed was placing a folded calling card between the board and the body - hoping the contact would reconnect and hopefully survive the remaining warranty period.

It was not easy - but I re-soldered it using a very fine tip. Yes, it's ugly and I used too much flux, but I could barely see what I was doing. You can even see where I scorched the card in the process. I kept the card there to reduce movement.

It has worked so well and for so long now - the symbols have rubbed off the function buttons.

Should i die tomorrow I would like this to be historically recorded on the Community for posterity, as the greatest electronic repair I ever undertook.

😁