Hi there,
I recently bought a RPi touchscreen (my second) and the input is erratic: very gentle touches register (finger hasn't even always made contact yet), and sometimes the touches register somewhere else on the screen entirely. Additionally, any 'drag' or 'slide' motions don't work at all, sending touch inputs scattered all over the screen.
I'm currently running it with PiCorePlayer and Jivelite (https://www.picoreplayer.org/ ) but also tried it on a fresh install of Raspi OS and experienced the same input problems.
I have pulled it apart and re-seated every ribbon cable and it didn't help. I even ran the calibration app, but the inputs are so erratic (a single touch often registers multiple times, machine gun style) that I couldn't finish it correctly (the touches would fire off, quickly progressing through all the steps and registering the touches in the wrong places).
It's attached to a Raspberry Pi 3 Model B Rev 1.2 housed in a SmartiPi Touch 2 Case and using an official Raspberry Pi 3 power supply (5.1V 2.5A). I've tried several different SD cards, and even bought a new Kingston Endurance card and tried it with that.
Let me know if anyone has any ideas for a software solution, or how to confirm if it's a hardware fault (and if Farnell/Element14 offer warranty service).
Many thanks.