Intermittent display glitches (moving horizontal lines)

@jadonlyon - If the external is clear (as it is here) that’s a bad internal display assembly.

@danj - Yes, exactly. I cannot tell in the picture if it clear or not.

@jadonlyon - The two screens are showing the same image. the external on the left is offering a spotless image only the internal displays image is messed up.

@danj - Okay, I see that. Yes, the internal display is probably messed up.

@clemens29917 - I would suggest running Apple Diagnostics to see if you can diagnose the problem. (Apple Diagnostics doesn't always show exact issues, but it can gave you a head start!)

@jadonlyon - Apple diags won’t test the display only the graphics engine, which it’s clear is working on the external.

It fell around 40cm from the edge of the bed, then kept working for another ~4 days. Then the glitches started to happen.

As of now there is a period of ~2h where there were no glitches at all.

(Also, the external display is always fine.)

I am from Germany.

I still wonder why it only glitches sometimes. I was hoping that there is some part inside the display that could be brought back to life with a heat gun or something :(

@clemens29917 - Sadly, these older displays are getting hard to find in good condition. Even still people are having a hard time letting them go! Even I have a firm grasp on my two 2015 15” systems too!

The best source other than iFixit on your side of the pond is TheBookYard in the UK, the only one they have right now is this one MacBook Pro 13" Complete Display (15) - Staingate Removed : Grade-B

Issues like yours where it comes and goes is when micro fractures within the panels back plate occurs. The back side has all of the metal oxide traces which are invisible to the eye but are easy to damage when the glass encounters too much stress. Just like a loose light bulb in the ceiling will flicker when someone walks across about above.

Thanks for your help. PRAM and SMC reset did nothing, as expected. Yesterday everything was working without any glitch for hours. I go to bed, come back the next morning, activate the screen and the glitches are back. I don't see any reaction of the glitches to mechanical stress. It just seems to appear/go away completely random. It pressed everywhere on the screen, even twisted it. Bobbed the hinge. Banged the device on the desk. No reaction.

I will try the mechanical-stress-thing again next time when everything works fine.

Another interesting observation: Different glitches seem to appear: sometimes the scanning horizontal lines, sometimes a green glow that fades to the edges and over the course of half an hour slowly fades more and more until it is completely gone.

Anyways, 135€ for the used replacement seems like an okay deal.

@clemens29917 - Sounds like your on your way! Don’t forget to score the answer and accept it ir you’re set - Thanks!