Hi,
I have a new iMac and was working properly. I changed the hard drive. It works without any issues. Afterwards, I put new cover and glass is back on, but wonder video is not visible. I removed the cover and videos are visible. I have checked whole thing. Everything is works fine. Please kindly help me to find the solution. Thanks in advance!
The problem is that when you put the cover back on, one of the video cables are being moved. (There is more than 1 video cable). This is causing you to lose signal. Verify that your logic board/Video Graphics Controller or your Graphics Processing Unit isn’t faulty. You can do this by connecting an external monitor – if it works, then normally the above are ok.
The problem could also be that the cable is shorting out as you screw the cover back on. Make sure that you are putting the correct screws in each place, if a too long screw is screwed in, it may be touching the logic board. This can cause it to warp or short out.
