HP Chromebook 14 G5 Trackpad Failure

I have a fleet of about 200 HP Chromebook 14 G5’s that I manage at my job (among other models of machines) and I’ve been having this common fault with the trackpads where they will stop working or stutter around. I thought it was an interesting problem so I’ve decided to document it a bit more in detail here.

Update (2022) – There’s a fix! (see bottom of post)

The Problem

After 1-2 years, the machines start to have problems with the trackpad where the mouse will stutter around the screen or stop moving altogether.
It seems to happen in batches, I can go for months with no problems then suddenly 5+ machines end up on my desk needing replacements. I’ve been talking with my HP Tech about this and we believe it’s weather related, either due to static electricity or moisture.
I have seen this problem on some HP430g3 and HP430g4 machines as well, but with a much lower rate.

Frequency

My 200 machines were purchased between 2018 and 2019, I always buy 3 year onsite extended warranty on them, so a good portion of them are now out of warranty.
Of my 200 machines, I’ve had 100 of them fail so far and with a 50% failure rate, I’m expecting that more will die.

The Fix

For all the machines under warranty, I contact HP and usually within a day a tech is on site to replace the trackpad. An interesting thing to note is that the replacement trackpad is very slightly different in that the chip on the board has some black stuff around the chip covering the pins. After a machine has had the trackpad replaced, I’ve never seen the problem again. So I believe HP is aware of the issue and has implemented a fix for the failing part.

 

The old faulty part

The new working part

For the out of warranty machines, there’s not much you can do. I contacted HP and managed to get escalated up to some higher ups who agreed to give me an extra 6 months of warranty (of which I got many of the machines repaired), but that has now expired. So any machines that die now are just going to have to either go to my spare parts pile, or have a mouse connected at all times.

I really do like HP, especially their warranty guys. The local repair guy is an absolute legend and the higher up guys in Australia were really nice to me and negotiated with HP on my behalf.
I am a bit saddened though that any machines (~100 of them) are likely to show the fault out of warranty and be uneconomical to repair, and I was hoping to get 5 years out of these ones (besides the trackpad issue they’ve been really solid machines).

For those curious, the HP Part number for the trackpad is: L14356-001
A quick search on ebay shows the part to be ~$55AUD or so – but you can’t be sure if you’re getting the version 1 with the fault or the fixed version 2.

Update (Oct 2022)

I’ve worked out a way to fix them!  As I figured it was related to static or moisture, I figured I could try shield the contacts on the chip with hot glue and.. it works (with about 95% success rate)!

So to fix them:  Pull the machine apart, don’t worry about removing the trackpad from the top case.

Peel back the protection sticker about half way, hot glue around the contacts on the chip, then put the sticker back and use it to smooth any air bubbles out of the hot glue.  Slap it back together and you’re good!

Note: Your mileage may vary, don’t blame me if it goes really wrong!  Here’s one I prepared earlier:

I hope this helps!

6 comments

Do you have any idea what the black stuff is on the new version of the trackpads? I’d like to perhaps do some preventative maintenance on some of the older (but still perfectly fine) G5 trackpads…

Ahoy!
Thanks for reminding me to update this post – I worked out you can use hot glue to protect the chips.
I don’t do it on any that haven’t failed yet, I wait until they start showing problems and then I’ll hot glue the chip (you don’t want to accidentally break a perfectly fine one!)
I’ve put instructions and pictures in the post 🙂

This actually worked. Thanks!

blazeafj

Hot glued 3x and the 3rd time worked

Tips:
1. the blob must be clear and covering the whole chip (my first two times the blobs were fuzzy because I was spreading the glue with the machine)
2. also check for broken wire with a multimeter (mine was good)

Um, this is awesome.
My first try at this worked great!
I have a bunch of G5s that I was going to get rid of this upcoming summer. Their initial Google AUE was May of 2024. Google extended that to May of 2027. If this works this could save me a bunch so……Thanks!

Greg Kennedy

Working on a similar HP Chromebook today. @Zack: the material surrounding the chip on newer models is epoxy glue, common in electronics to hold chips onto circuit boards without conducting electricity.

Trackpads are a menace – for certain Samsung models, there’s a ground connection that goes bad over time, and a bit of copper tape can restore the machine to full health again (https://issuetracker.google.com/issues/176638009#comment42).

Moisture and/or static is a good theory – the epoxy may well be providing a barrier, which could help with its sensitive capacitative touchpad area by reducing line noise. Hot glue would provide a similar function, keeping moisture out from under there.

But I actually have a different theory: because the chip is soldered directly to a PCB on the back of the touchpad, then each press may cause flexing of the PCB, and over time may lead to a cracking of a solder joint holding the two together. This could manifest as intermittent failure. In this way the epoxy is rather providing strain relief, spreading the forces of flexing out around the chip instead of concentrated on the solder joints only. Hot glue may provide similar assistance; it’s also possible doing anything to the little chip may improve the connection somewhat and make the problem less likely or go away entirely (for now).

In my case, the chip already has the epoxy and still shows issues. By pressing a bit on the back of the chip I can get intermittent functioning, but I suspect that a joint is broken underneath and will need to replace the whole assembly in order to restore it to usability.

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