Repair: Samsung ARM Chromebook Trackpad that Won’t Click

While most people seem to have a mixed relationship with Google’s Chromebooks, I’ve been a user of the Samsung ARM Chromebook for a while, and it serves quite a few specific purposes. For one, it’s a low-cost, thin, low-power consuming Linux machine that performs decently despite being a little flimsy. It’s ideal for small web tasks as well as working with the RTL-SDR, NFC dongles, testing and formatting USB keys and hard drives and SD cards (reading CID/CSD, partitioning). In short, I really could not fathom being without one.

Unfortunately, the other day, when I picked it up, it was very difficult to use. For some reason, the trackpad itself just wouldn’t behave itself. A reboot didn’t solve it, and a close visual inspection showed nothing out of the ordinary.

There wasn’t anything stuck around the perimeter, it didn’t look obviously depressed into the case, and there wasn’t any “abuse” of the unit at all, as it’s been used mostly in my room on flat desks. But the problem was that the pad felt very spongey to use. It didn’t depress far, but it stopped clicking altogether. While there was no tactile click, if you slammed your finger hard enough on it, the machine would eventually register a click, but often the wrong sort – i.e. a right click.

Given the build quality and price, I suppose failure and death are expected. It’s a disposable society after all. But I wasn’t ready to give up on it just yet.

(Disclaimer: Try anything and everything at your own risk. I will not be held responsible for any damages or successes, consequential or inconsequential, direct or indirect, of any nature. The information is provided on a good faith basis, you should consider your own circumstances before performing anything described.)

Taking it Apart

The first step to patching up the patient is to do an examination. Flipping the Chromebook over, the first thing you need to do is remove the four rubber feet (as they are labelled with > symbols to let you know there are screws underneath).

With the feet removed, a total of nine #0 philips screws hold the unit together. A small screwdriver from a precision screwdriver set is all that’s needed to remove them.

Now comes the part of removing the bottom shell. Start from the bottom left edge near the speaker and use your fingernail, or a spaula and lift part of the shell up until it unclicks from the body. Continue going around all sides except the rear port side.

The assembly at the rear port side is different, and you cannot just lift the lid off else you will risk cracking all the latches. Instead, you need to pry the port-strip fascia back far enough to release the clips, and then the whole rear can be taken off.

The Symptoms and Prognosis

The flimsy mostly-plastic build seems to have resulted in the trackpad not being mounted in anything metallic, as is often the case with regular laptops. The problem is not immediately obvious until you start playing with it.

The click action actually relies on a set of switches mounted in the plastic crossbar with a knob on it – centred in the picture above. By having pressure exerted between the pad and crossbar, the switches are closed and signal a “click” to the system.

The knob in the crossbar is important to support as it provides the “opposing pressure” to the pad to make the click happen. As a result, you can see the corresponding brace-bars and screw hole support on the rear of the case.

My hypothesis is that the plastic brace bar isn’t getting enough support due to the “flimsiness” of the all plastic body, and over time, the fatigue has resulted in insufficient pressure from the rear to actuate the switches.

My quick fix is just to increase the pressure, by using some thick self-adhesive tape (or multiple layers of thinner self-adhesive tape) on the knob itself to act as a shim and increase the pressure on the brace bar.

Unfortunately, there’s no simple way to know how much is enough until you’ve reassembled it – so go ahead and reverse the instructions to reassemble it and try it out.

I was pleasantly surprised after I did this, to find that it perfectly restored both left and right clicking performance with a pleasant tactile click – as it should be. The Chromebook is saved (from a life of remote administration or external mice, or death), and the cost entirely negligible. About 10 minutes of time was all that was needed.

Conclusion

If your Samsung ARM Chromebook no longer clicks and that’s driving you nuts, the fix (at least, temporarily) seems to be quite simple. All you need is a screwdriver, some sticky tape and some time.