crwdns2936637:0crwdne2936637:0 crwdns2853008:0crwdne2853008:0 crwdns2918746:0crwdne2918746:0

Model A1419 / EMC 2806 / Late 2014 or Mid 2015. 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (ID iMac15,1); EMC 2834 late 2015 / 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (iMac17,1) All with Retina 5K displays

crwdns2934591:020crwdne2934591:0 crwdns2934593:0crwdne2934593:0 | crwdns2947278:032crwdne2947278:0 crwdns2947270:0crwdne2947270:0

crwdns2933897:0crwdne2933897:0

Black screen on 2015 iMac 27" retina with loud fan

This question is asked for one of my friends.

He has a 2015 iMac 27" retina system, recently he got the screen replaced, however, when trying to power it on, he can hear the chime sound, but nothing showing on screen, screen is totally black, instead, the fan is very load.

He tried to connect it with an external monitor, it is running and OK, but nothing displays on internal screen. He tried to do SMC reset, no help.

Can any one advise what's could be wrong here?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 2

crwdns2944067:02crwdne2944067:0:

Thanks for all your reply and suggestions. One more thing to ask, is backlight, either backlight unit or backlight cable, easily damaged when opening the display unit? It looks to me that the adhesive is on all edges, it should be safe just cut off the adhesive itself. Correct me if I’m wrong.

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

You must follow the IFIXIT guide here iMac Intel 27" Retina 5K Display Display Replacement make sure you use the tool supplied in the adhesive strips which you'll need before you open the system crwdns2937315:0IF174-005crwdne2937315:0 and you'll need a few of these as well Plastic Cards I use four just to make sure I don't damage the display which is very easy to do!

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934285:0crwdne2934285:0

crwdns2933315:03crwdne2933315:0

crwdns2934221:0crwdne2934221:0
crwdns2931211:0crwdne2931211:0 crwdns2931215:0crwdne2931215:0 crwdns2934225:0crwdne2934225:0

crwdns2933897:0crwdne2933897:0

You stated the display was replaced, then what did get done? Was it working afterwards? If not then I would go back to the shop that fixed the system and either get it fixed again under their warranty or get your money back.

It sounds like the backlight has failed. Using a flashlight held on the screen at about 20 degrees see if you can see the faint image of your desktop and its icons. If you do thats the issue if not the display it self is bad.

crwdns2934105:0crwdne2934105:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 0

crwdns2944067:011crwdne2944067:0:

Thanks a lot! By the way, if it is from the backlight, why fan is so loud?

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

The display has two cables, one passes the video, the other power. The display has two thermal sensors each communicate through these cables. If the connector or the cable its self is damaged that can explain your failure. If the system was returned broken. Which was the first point.

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

What do you mean "if the system was returned broken"? Thanks again!

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

Hey Dan, one more thing, for those two cables with display, is the one with the metal retaining bracket (display data cable) connects with the backlight component?

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

No, thats the iDP signals the power cable is the other one. But both have thermal sensor data connection.

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934275:06crwdne2934275:0

crwdns2934285:0crwdne2934285:0

crwdns2933897:0crwdne2933897:0

Personally I have repaired the logic board on one of these before, and the backlight is easily damaged. It is very possible that it is just a bad backlight or a broken backlight cable. @danj said, take it back to the repair store and ask for a refund and have then repair it properly or take it somewhere else that is more qualified.

crwdns2934105:0crwdne2934105:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0

crwdns2933897:0crwdne2933897:0

If the fan is spinning loudly it may be the thermal sensor on the LCD screen on the rear was not replaced from the old unit. Without it, the CPU runs at 0.8ghz and the fan spins at full speed. As for the black screen, likely a cable was not properly connected. I’m thinking maybe the power connected was not seated well and if the thermal sensor WAS attached, it and the screen itself doesn’t receive any power hence, black screen, and full fan.

crwdns2934105:0crwdne2934105:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0

crwdns2934229:0crwdne2934229:0

Tom crwdns2934231:0crwdne2934231:0
crwdns2936625:0crwdne2936625:0:

crwdns2936751:024crwdne2936751:0 0

crwdns2936753:07crwdne2936753:0 1

crwdns2936753:030crwdne2936753:0 3

crwdns2942667:0crwdne2942667:0 1,509