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?