Grey Screen after Password
I’m trying to fix an old iMac that suffered from a regularly appearing black screen problem: after some hours the display would shut off.
So far, I diagnosed that one issue was a defect HDD fan, and I replaced it. After I took it apart and put it together, the iMac shortly worked , but then had the same problem again after a period of 1-2 hours.
Now, it completely fails to boot and just shows a grey screen after the password entry. The same happens when I try to enter the local or internet recovery modes. However, the hardware test is functioning normal and does not find any issues.
As the iMac had a black screen issue before, I’m inclined to think that the graphics card was the issue all along and now gives up entirely as soon as the iMac requires some more intensive work to be done (such as drawing the normal UI). Another option would be that I messed something up during my repair work of the HDD fan and now I’m looking at two hardware problems.
What is my best guess here? Could the grey issue arise from a defect graphics card? Or is a symptom for another well-known issue?
Questa è una buona domanda?