Sometimes my S4 Mini displays artefacts and some parts are hot. I can't turn off display.

[AC Question]

Hello
I have Galaxy S4 Mini GT-I9195. Every day it freezes. It displays artefacts, I have stock wallpaper and I can recognize blue background.
Some parts inside phone are usually hot. I can't turn off the display.
Hard reset works but then I won't turn my phone. I have to remove battery.

I noticed that my phone probably works without rear flap. When I try to put on when it's working it starts displays artefacts.

I flashed phone via Odin with stock firmware but it didn't help.
Maybe lcd tape inside causes this problem?
I'm looking for any help and suggestions.

 

[Tim1954]

And it works well with the rear cover off you say? Seems it may be pushing on something causing it to malfunction... Crack on (circuit) board, loose fitting, wiring harness..
Take the back off again and gently press on things watching the display and you may narrow down the location. It will likely be repair shop job if that's the cause...

 

[dever3]

Thanks for your reply.
It worked without rear cover, but at this moment I can't turn on my smartphone.
It's probably motherboard failure, but I will measure also battery voltage.
@Edit Probably discharged battery. It turned itself.
So it has just turned on. I guess It will happen again. Then I will check battery or micro USB.