Chosen Solution
Hello, I have a 24" iMac 2007 2.4GHz which turns ON to a black display. I have done a lot of research and have looked at many guides to determine the exact issue and fix. I will explain everything i have done to troubleshoot but without a resolution. Below you will see my troubleshooting has confirmed that both the Video card is in working order and the LCD screen is in working order. I have hooked up an external display and turned ON the iMac and to my surprise I was able to see video on the external display. So this means my graphics card is in working order. I removed the glass and aluminum frame and looked at the 4 LED lights and when powered ON all of the 4 LED’s are solid green. So that means everything is communicating with each other like Power Supply, LCD Screen, Video card and Motherboard. I decided to swap the LCD screen out with another iMac that i own (same EXACT model, specs and year iMac & same model # LCD screen). To my surprise the LCD remained black when i turned ON the iMac. This is a known good working LCD screen since it was removed from a fully functional imac. So i decided to swap the original screen from the 1st imac that doesnt display to the fully functional imac and i was able to see video on that screen. So now i know the actual LCD is in working order too! At this point i am stuck and dont know what the issue is and what more i can do. I was able to determine the Video card to be in working order by using an external display and i was able to confirm the LCD works by swapping it into another iMac system. What else can i try to troubleshoot it in order to get this iMac to work again? Please help me Thank you
If you can see a faint image on the LCD then the backlight circuit is having problems. This problem won’t show up under the diagnostics LED’s on the logic board as it’s an independent circuit. Your system uses CFL’s so it needs a high voltage (250 volts) to drive the tubes. Here is the needed IFIXIT guide to replace the faulty Inverter: iMac Intel 24" EMC 2111 Inverter Board Replacement.
I have the same problem Same model can’t find a solution anywhere All these super smart people and nothing out there Did you ever find a solution?? Update (08/30/2017) Its the GPU gone bad despite getting for lights on the logic board I had the exact same problem Searched and searched for an answer (found nothing) Replaced the display, inverter cable, and then the logic board. When that didn’t do it I had an extra GPU that closely matched the GPU in the iMac and now I am using a fully functional (despite a yellow screen which is another story) to write this post
