✏ How to test your touchscreen for abberant behaviour (is it a hardware or software failure?)

This is a #wiki. Everybody can edit it.

:information_source: This post describes how you perform a Touchscreen Test on the FP1. On the FP2 you simply have to go to Settings > Maintenance > Checkup to test your screen.


Hi everyone,

on @Stefan’s request, I’ll post this as a new topic, to be easier found, wikified and extended by everyone who has more infos to share:.

Continuing the discussion from Buttons pressed randomly:

How to test your touch screen for abberant behaviour.

  • We will now boot to testing (or factory) mode:
  • Turn your FP off. (Wait a moment until it is properly turned off.)
  • Press volume down and hold it, then press and hold the power button.
  • The screen turns blue. (Wait.)
  • The screen shows “factory mode”. (Wait)
  • The screen shows a menu with mandarin characters, and (in brackets)
    the english translation.

In factory mode, you can navigate ONLY with volume down. The power button is going to select. In some (not all) menus, volume up is going to take you one menu back.

  • On we go:
  • Press volume down twice to go to “Item test”.
  • Press power to select “Item test”.
  • Press volume down again to go to “Touch panel”.
  • Press power to select “Touch panel”.
  • Press power to select CTP Test.

You can now test your display. Play with it. Single touches should show single white dots, multitouches should show straight lines between the touched spots, touching the squares in the corners should turn them from red to green.

If you are not charging your device at the moment, and are not being charged with a lot of static electric energy yourself (you should
‘ground’ yourself, e.g. by touching a central heating radiator), and if you can now still reproduce “ghost” touches and other aberrant touch screen behaviour, there is quite probably something wrong with the hardware, and you should document the issue with a photo and/or video and attach it to a support ticket.

  • To get out of factory mode from the CTC test:
  • To leave the touch screen test, press volume up.
  • To go back to the “Item Test” menu, press volume up.
  • To go back to the main “Factory mode” menu, press volume up.
  • Press volume down five times to go to “Reboot”.
  • select Reboot by pressing the power button.

Done. Your FP should power up as usual.