With no moving parts, you might think a remote control would last forever. But all that pushing and poking eventually takes its toll. One day, you may find your remote stops working: the buttons you press no longer do anything, no matter how hard you prod them.
This can be a real nuisance, because chances are your TV is now obsolete and the remote you need is no longer manufactured. Fortunately, it's often possible to repair a defunct remote. If the entire remote stops working, most likely the batteries have gone. That's the first, most obvious thing to test before you go any further.
If only a couple of buttons have gone—typically the volume up/down or channel buttons, or other buttons you use most often—you have a different problem. Remotes are built around a rubber membrane keypad
. Each key is part of a single, large piece of rubbery plastic. Under each one, there's a thin strip of conducting paint or plastic. When you press the key down, the conducting material bridges contacts on the printed circuit board directly underneath, completing a switch and activating the circuit. In the top photo here, you can see the membrane keypad (second from the right) and the circuit board it sits on (second from the left). Over time, a thin greasy film builds up between the bottom of the keys and the top of the circuit board. I'm not sure what causes this, and it doesn't really matter (probably as the current flows through the conducting material on the base of the key it warms up slightly and that gradually degrades the material). This film acts as a barrier between the base of the key and the circuit board and stops the keys from completing the circuit.
How to fix it? First, remove the batteries. Next, carefully open the case of your remote. You'll either have to undo some screws or, with a remote like the one shown here, separate the top of the case from the bottom with a thin, flat screwdriver. Generally, if there are no screws, there are several plastic clips holding the two parts together and you need to find them and push them gently to open the case. Go carefully! Once you've taken the case apart, separate out the layers as I've done here. Inspect the circuit board, particularly the bits of the board that are directly underneath the buttons that aren't working. See a film there or a dirty deposit? Put a small amount of detergent and water on a cloth and carefully wipe it away. Don't use anything abrasive. Gently wipe the bottom of the rubber membrane keys to remove any film from there too. Do this very carefully so you don't damage or degrade the conducting layer. Make sure the whole thing is completely dry, reassemble it, and you may well find it works again.
If it still doesn't work, the conducting layer on the base of the non-functioning keys has probably worn away. (If you have a multimeter, you can test the bottom of the keys to see if any current flows, and establish that this is the fault beyond doubt.) You can buy repair kits and conducting paint pens to touch up the damaged layers, but they're quite expensive and it might not be worth the bother. In theory, you could use a soft graphite pencil to make a temporary repair, but that's unlikely to last very long. Another option might be to transplant one of the working keys to replace the broken ones, but since these keypads are built from a single piece of material, that's going to be a slightly tricky operation involving rubber surgery!
A simpler alternative is simply to find the model number from your remote and type it into eBay or your favorite auction site. You might well find a replacement someone no longer wants.