If LEDs 1 and 2 are on and you hear the powering sound, but this LED is off, then the graphics card may not be installed properly or needs to be replaced. This LED will stay on if the computer communicates correctly with the graphics card. LED 3: Indicates that the computer and graphics card are communicating.This LED will stay on when the computer is too and the power supply is working properly. LED 2: Indicates that the motherboard has detected the correct voltage from the power supply when the computer is turned on.It will only turn off the power or if the power supply is defective. It will stay on even if your iMac is turned off or hibernated. This LED will remain on as long as the iMac is connected to the current. LED 1: Indicates that the motherboard has detected the holding voltage from the power supply.Attached few pictures showing the symptoms where after checking on some website, top level analysis mentions the four green LED's internal status as a possible guide: You get a 6-month warranty on this repair covering both parts and labour.Hello all, This Mac has been working fine for many years then few weeks ago, its display progressively failed.

We will fully test your iMac Retina 5K 27' 2020 after the repair before returning it to you.

We will professionally remove the damaged part from your iMac Retina 5K 27' 2020 and fix it or install a new one.

Your iMac Retina 5K 27' 2020 will be fully checked before the repair in order to detect any other problems it may have.

For the stores outside the city of Athens, the repair time might be different. If the spare part is not currently available in our stock it might take up to 8 working days to be delivered to our store.

We can install your new screen in just a few hours if the spare part is in stock. We work with Apple's diagnostics, tools, and procedures in order to ensure that the repair of your iMac will be performed successfully and securely. The spare parts we use for this repair are original and provided by Apple. If you have cracked or broken your iMac screen with standard glass, or if your iMac screen has another problem, we can replace them with the new ones in a few days. IMac Retina 5K 27' 2020 Apple Genuine Screen Standard Glass Replacement

Imac 27 late 2013 display replacement