An odd touchpad failure

da na · December 1, 2022

Got a HP Elitebook 8470p in for repair yesterday with the note "Touchpad not working". The pointstick works fine, but at first try the touchpad did indeed appear to not be functioning. Checked and it did appear in Device Manager, I uninstalled and reinstalled the Synaptics driver, reset the Windows mouse settings, still nothing. Then I tried two fingers and sure enough it did work. It's odd, the touchpad doesn't respond at all to one finger but two, three, whole fist, or elbow it will respond to and work as intended. Seems to require an unusually large area of skin touching it to respond at all.

Took a similar Synaptics touchpad from my older Probook and plugged it into the internal PS/2 port, and it didn't display the same behavior. At this point I'm sure it's a hardware failure with the touchpad itself, and I assume it can only be fixed with a new touchpad - but I'm bewildered how this happened in the first place.

Anyone have any ideas? Any help would be appreciated!

Kid.Lazer · December 1, 2022

I'm guessing this would be similar to joycon drift, where the default resistance has shifted, and a single finger doesn't provide enough of a change to register the "touch," basically increasing the deadzone. I'd bet a month's pay there's no consumer software available, but I wonder if the pad could be calibrated to fix this issue (aside from replacement, that is).

da na · December 1, 2022

1 minute ago, Kid.Lazer said:

I'm guessing this would be similar to joycon drift, where the default resistance has shifted, and a single finger doesn't provide enough of a change to register the "touch," basically increasing the deadzone. I'd bet a month's pay there's no consumer software available, but I wonder if the pad could be calibrated to fix this issue (aside from replacement, that is).

That's a bit along the lines of what I was thinking too. I've been looking through the Synaptics driver (which is quite good) for such an option, there are a few sensitivity settings but none seem to affect it meaningfully (besides requiring a little less pressure.)