montana 700 time out problem

Hello
I'm having problems with my montana 700
when I set the time out for my screen it no longer falls completely out in the past the screen became black now it remains a bit illuminated.
If I have the screen automatically locked, the lighting will be completely off and I will get a black screen.
I also get notifications like 'price error' and 'on course' every time
Do you have any idea what could be wrong?