Chosen Solution
My parents Macbook Pro A1502 recently developed some heavy screen glitching / colorful flickering all over. Here’s what I checked so far: Issue starts right after boot to full UI, more present where there is (mouse) movement.Rarely there are a few seconds where everything looks fine, fullscreen videos on YT weirdly seem to be ok.Still glitches in red/green/blue if I set MacOS UI to grayscaleScreen also looks mostly fine during startup or diagnostics but sometimes shows the issue during the software update screenThe problem is not present on an external display (HDMI) or in screenshotsIf an external screen is connected via HDMI, the flickering/glitching on the internal screen and the external display stops (HDMI cable w/o a device connected on the other end does nothing, though)elementary OS does not show the same problemsDiagnostics additionally show NDC001, “CPU System Agent Core” in iStat Menus sometimes reads 0˚ (which I believe the machine might have already shown when I gave it to them 3 years ago, so probably unrelated) Any ideas what the problem might be and how it could be fixed? And what worse symptoms could come next, if any?
It’s more of a hack/workaround than a fix but costs 1% of a display and doesn’t even require tools: I ended up getting one of these $5 virtual HDMI dummy plugs that we now just keep attached to the Macbook permanently. This 100% solved my flickering problem and the machine is perfectly usable again.
What you are seeing is signal issue between the main logic board and the displays T-CON likely within the display lid. What I often encounter on systems like this is excessive screen cleaner dripping down wetting the T-CON board corroding up the display cable connector. Sadly, it would take someone with micro-soldering skills with a delicate touch as you can damage the display very easily. To get a good idea on what’s involved review this MacBook Pro Retina Display Teardown Here’s the area of concern
You might be able to clean the connector and its solder joints. Otherwise its time for a new display assembly MacBook Pro 13" Retina (Early 2015) Display Assembly and here’s the guide MacBook Pro 13" Retina Display Early 2015 Display Assembly Replacement
