iPod Nano 6th Damaged display?

Hi all,

I provide exchange a power button unit of my iPod nano 6th but unfortunately after assemble back all parts and try to switch on, display starts to flashing and display seems like broken.

I am sure that when I disassemble the display so I was careful and all connection seems also good condition.

I want to make sure that there is really problem with display, not in motherboard or something different.

Before exchange display work fine.

Please check video below.

Many thanks for any advices!

VIDEO