Fixing Faulty Controller Buttons

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March 15, 2022

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Repairs
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controller faulty repair
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TV remotes, along with other types of controllers, use silicone for the main body of the buttons. There are many reasons to use silicone – it is waterproof, easy to clean, soft to the touch, and can be produced in a variety of colours.

Beneath the buttons will lie a set of contacts, with each button having one contact on either side. Sometimes, these contacts are simple pads, with a break in between. Often, they form more complex swirls, but the function is still the same.

When the button is pressed, the centre of the button is pushed down, and bridges the contact points. The device is able to detect a connection between the two points, and registers a button press.

The contact points are often routed together – computer keyboards, for example, will often use a grid-style electrical layout. This reduces the number of connections needed, while still ensuring each key can be uniquely identified.

If you want to see some button issues being diagnosed, and fixes attempted, take a look at my video here.

Cause

There are a few reasons a button will stop working,

Remember how we said that the silicone buttons are non-conductive? Well, to bridge the pads (and create an electrical connection, each button will contain a pad, usually coated in graphite. When the button is pressed, this graphite pad makes contact with the PCB, creating a connection across the button pads.

If this graphite wears off, becomes contaminated, or otherwise loses its ability to conduct electricity, the button will stop working.

opened remote
TV remote with a non-functional ‘Home’ button (the large 3-pad button connected to the blue patch) and coloured buttons.

For old remotes, the silicone itself could have deteriorated, preventing the middle section from pressing down correctly. I’ve seen this in a few old game controllers, where the button contact has become completely detached from the outer edge. This is more likely on single buttons, rather than the larger silicone membrane seen above.

It is also possible for the fault to be on the PCB side. A potentially easy way to test this is to use the silicone button from a known working button, which could be as simple as rotating the pad 90 degrees (such as in a PS4 controller). You can also make the connection using another conductive material, such as a strip of foil.

If several keys stop functioning at the same time, it is likely they share a connection. For example, the PS4 controller that originally contained the following flexible button PCB had a set of non-functional face buttons on the right-hand side, along with faulty R2 and L2 buttons.

ds4 pcb
Flexible PCB from a Dualshock 4. Note the failed contacts on the curled-up connector in the centre.

The obvious failure of a couple of connections has caused a large portion of the controller to stop working. In this case, the fix is to replace the flexible PCB, to restore the connections.

Fixes

If the issue seems to be on the PCB side, the easiest fix is to replace the PCB. The flex PCBs that are often used are, in my experience, not the most durable, and seem much more sensitive to contamination than a rigid board.

If the issue is on the button side, the first think to check is whether there is any contamination on the button. Try cleaning the underside of the pad, preferably using IPA (though general wipes should be enough). Be careful when doing this, as it will potentially remove some of the graphite coating as well.

It’s also a good idea to do this on the board as well, to ensure a clean contact surface.

remote board
This TV remote clearly has some contamination on the contacts – cleaning might not fix it, but it certainly won’t hurt.

Again replacement is usually the easiest option. But for some products, such as an old TV remote, this isn’t a viable solution. And this costs money – there are a few things to try using equipment you should have at home.

The goal of this fix is to restore conductivity to a failed pad. Using a conductive ink/paint on the button pad, or rubbing pencil lead over the surface, is often enough to restore the original layer of graphite, though this is likely to need repeating down the line.

My favoured fix is to glue a small piece of foil over the button pad, just large enough to cover the important part in the centre.

Fixed silicone buttons
Silicone buttons, with foil added to fix the ones that have stopped working.

This should give a more permanent fix, at least until the device itself ceases to be useful.

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