Thin horizontal lines: Screen or Motherboard issue?

[UbiCrea]

Hi,
I've a Macbook Pro Retina 13" late 2013 and I now have thin horizontal line all over the screen. I've seen many other people having this and also many similar photos on Google Images, but i cannot find any information if it's a screen fault or a motherboard / graphic card issue?
Any info about that?
Thanks

 

[1885507]

It can be one or more of the following...
a. Discrete GPU is failing.
b. Ribbon cable to LCD is failing/disconnected.
c. Main logic board itself is failing.

Run diagnostics to see if it spawns any error codes.

 

[UbiCrea]

Well, I've seen many people on Google having the same issue of the small thin horizontal lines all over the screen that I was hoping someone would have explain what it was... I know it must be hardware, but motherboard or screen... That's the question....

 

[UbiCrea]

I got another MacBook Pro 2014 fully working.
Verdict: It's the screen. If I switch the screen, everything works well. So it's not the motherboard or the graphic card (part of the motherboard).
Voila