Hello I have a question.
thanks you for your time.

I have old generation nspire cx cas.

https://youtu.be/BfDmG3XfRg8

Ive recorded one video.
as you see you can check the periodic scan line kind of noise. (especially in black colour)
is it normal situation ?

when my eyeball is moving, i can see some horizental line vibration on the screen in OS mode always. but my eyeball is not hurt.