Strange screen artefacts on MacBook Pro 2013

nouman161 wrote:

I have MacBook Pro 15" 2013 late, and I have problem with screen artefacts for longer time. It appears randomly, even tough I don't do anything with notebook. It appears and after few moments dissapears but sometimes I have to only move with mouse and all artefacts immediately dissapear.

If I have connected notebook to external display, this problem occurs only on MacBook display, external display is without this problem. I have tried almost everything reinstall, reset SMC and PRAM. My MacBook has display changed for 2 times (1. antireflective coating problem, 2. changed display has a problem with brightness), and I am affraid, that someone during repairing damaged some piece of HW. Could someone help me, where could be a problem?

https://discussions.apple.com/content/attachment/f569bb19-d6c4-41e5-a814-0ca3faf3f8a4

I would suspect either GPU, memory, or Display assembly—

external display is fine rules out GPU.

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"—

https://www.apple.com/retail/geniusbar/

Outside the USA

https://locate.apple.com/country

you can try run the user Diagnostic...not as definitive as Apple's own AST2 (Apple Service Toolkit) back bench diagnostic, but may kick out an error code.

Use Apple Diagnostics to test your Mac

https://support.apple.com/en-us/HT202731