No image displayed on screen
My mid 2011 21.5” iMac has been acting very weird.
So there is no image displayed on the screen, but If I shine a torch on the screen I can see everything. This leads to the conclusion that the backlight has failed. I also know that it is not the LCD that is the issue as I have another iMac of the same model which I plugged the LCD into and it worked fine. I replaced the LED Backlight driver board and still I get the same result.. The Image is only visible under a torch light.
I am open to any suggestions/ideas of what the problem would be.
Some other info:
1. The image is also visible on an external screen using the Mini display port.
2. I also managed to get to the recovery window just by using a torch so its not the HDD
3. All indicator lights light up, including LCD one which means the computer is communicating with the LCD
If it is needed i can upload photos.
Could you please give me some more in-depth information so I can let the person I got the backlight driver from know? Also below are images of the connectors on the screen.
@danj Here are some photos of the wires
I hope this is what you meant.
Is this a good question?
@danj Thanks for the response.
i have checked multiple times so I’m not to sure what it is. I also bought a replacement LED backlight driver but still got the same result. A technician said that if the LED backlight driver was faulty you wouldn’t even see the icons under a torch light.
So what do you think it could be?
Your friend is mistaken! The a bad backlight cable or LED driver board won't effect the LCD's data signals and the image on the display, so shining a flashlight in confirms the issue is within the back light cable or the LED driver. As all you are doing is substituting one light source for another.
Isn’t the image being displayed on the screen via the display data cable and it’s not using the LED backlight driver at all?
Can you please give me some more in-depth information
You are correct, you have two independent pathways! The Backlight and the screens data (LVDS ribbon). The connectors look OK.
But just looking is not what's needed here, you need to check the pathway of each wires connection of the backlight power lines (4 heavy black wires).
@quinn218 - You'll need an ohm meter to test the lines.