iMac late 2012

[Weemansb]

Right where to start, I had a failing hard drive on my iMac so decided to fix it myself and I replaced the hard drive but when I went to turn it back on the screen was black and don't know why this is? I have tried putting the old hard drive back in but a still a black screen. I have tried the control-Option-p-r as I still get the start up noise so wondering what to do next

Many Thanks
Matt

 

[ApfelKuchen]

Resetting NVRAM (which is Command-Option-P-R) was a good try. But after that, I wouldn't suspect the HD (old or new). To confirm that, try booting to Internet Recovery (Command-Option-R) - that bypasses the HD. If the display doesn't wake for that, it's not the HD.

My first suspect would not be the hard drive, but the display cables (power and data).

In a darkened room, is there any hint of display backlight?

 

[elf69]

I too would think screen cables not seated correctly.

See this with laptops sometimes when screens get replaced.

less so with led backlight though.

 

[Weemansb]

There is no ghost display, but I have made progress today, I connected it to my tv and started it in recovery mode which has got it working but nothing from the screen when connected

 

[nambuccaheadsau]

Open her up, and go back and double check everything. using the TV proves there is a cable not fitted correctly, or some fitting fractured. Go to ifixit and download the reardown if you have another Mac. By the way if this is a 27" model, did you use a heat sensor kit from OWC?

 

[zoomos]

Same thing happened to me, It's probably the center connection, mine is a 2011 so I don't know yours might be different but the center connection wasn't seated and locked properly, make sure their is slight pressure when you locked it down.

No worse feeling when you do repairs to your computer and it doesn't load up lol.

 

[Weemansb]

It's a 21.5 model

 

[zoomos]

It's a 21.5 model

Did you get it fixed?