All of the 4 Logic Board lights are green but screen does not turn on.
Hi, I wonder if you can help me.
I have a iMac 2011 21.5" and I have recently replaced the thermal paste on the CPU & GPU as it needed to be replaced.
All of the cables are attached properly as the 4 LED lights on the logic board are green when the iMac powers on.
The only problem is the screen is black and even when the computer chimes the screen never turns on, BUT the 4th LED on the logic board is green indicating the screen is connected properly.
What can I do? What does it mean?
Here is my GPU I can see a tiny amount of thermal paste in-between some of the SMD devises. Does it need to be isopropyl alcohol to clean effectively the GPU as don’t have that in stock?.
Is this a good question?
The little paste that dribbled can easily get cleaned up. You'll need to carefully clean the GPU chip of its paste and being careful not to touch the gapping paste or best yet I would clean it off and replace it with thermal pads. The gapping paste is not as good as the the pads.
I'm more concerned on when you apply the fresh paste you don't over do it.
Hi Dan, I have put new thermal paste on the GPU making sure I didn't over do it and still a black screen.
Sadly, its looking like your GPU board has failed.
Oh no, I have had the iMac powered on for 2 hours and the heat pipe is warm that connects to the GPU I don't know if it shows it's still working? It's a bit strange that the GPU has died when I opened the iMac, what might have caused that?
ESD is one possibility. In the winter early spring the air is quite dry in the northern hemisphere with the cold.
You could have damages something in the process. It's also possible just kismet.
Show 2 more comments