My Solution

This guide takes off at the stage where you have completely removed the LCD panel from the iMac, and disassembled it. The glass pane which actually holds the electronics (the IPS LCD) is very fragile. Be very careful when removing the side brackets from the screen, there are electronic components on two sides of the glass pane! Store the glass pane in a safe place while working on the backlight system.

 

After removing the glass pane (with hopefully the electronics still attached to it) you'll be left with the assembly just containing the backlight (and backlight cable). Disassemble further by removing the black plastic bezel (one side contains screws) and removing the layers of filters. Be careful with the filters and remember in which order they where stacked!

 

This leaves you with an empty panel just containing the backlight leds in a strip near the bottom. It really surprised me that these leds where all you need to illuminate the screen. They must be incredibly bright and that might be the cause of this problem.. Show us some pictures!


These LED's seem to have created burned spots on the reflective tape behind them.. Either this tape is not suitable for the job or the LED's are getting to hot.
These LED's seem to have created burned spots on the reflective tape behind them.. Either this tape is not suitable for the job or the LED's are getting to hot.
The strip is easy to remove.. Will this be the source of the annoying yellow tinge? It can't be good..
The strip is easy to remove.. Will this be the source of the annoying yellow tinge? It can't be good..
I've tried to clean the reflective foil, however that did't work. I then thought of self-adhesive-reflective-aluminium-foil I once bought to fix some tubing in the house. It was very cheap (bought it here in The Netherlands at a store called 'Action').
I've tried to clean the reflective foil, however that did't work. I then thought of self-adhesive-reflective-aluminium-foil I once bought to fix some tubing in the house. It was very cheap (bought it here in The Netherlands at a store called 'Action').
It was really easy to stick on! It's not as smooth as the original tape but it sure has no yellow spots (yet?)
It was really easy to stick on! It's not as smooth as the original tape but it sure has no yellow spots (yet?)
Why is the strip even there? The housing itself is pretty reflective as well!
Why is the strip even there? The housing itself is pretty reflective as well!
Installed strip with the fist mask in place, this mask already hides half of the strip. Was this the real problem?? Maybe there is more to explore!
Installed strip with the fist mask in place, this mask already hides half of the strip. Was this the real problem?? Maybe there is more to explore!
There is! The black plastic bezel also holds the cursed reflective strip.
There is! The black plastic bezel also holds the cursed reflective strip.
Let's fix this too while we're at it! Same treatment applies.
Let's fix this too while we're at it! Same treatment applies.
The aluminium foil is really thin and very sticky. I think this solution will hold for a while!
The aluminium foil is really thin and very sticky. I think this solution will hold for a while!
You can use the foil to seal the screen after the repair as well. I first checked the screen off course..
You can use the foil to seal the screen after the repair as well. I first checked the screen off course..

And now for some results:

It might still look like crap on this particular picture, but is is way better than before! The whites are even from top to bottom!
It might still look like crap on this particular picture, but is is way better than before! The whites are even from top to bottom!
Hard to see, but the grey bars show the same grey. Before the fix I had to trim the white level of the display because the bottom part was very yellow, now I'm running on the default white point again!
Hard to see, but the grey bars show the same grey. Before the fix I had to trim the white level of the display because the bottom part was very yellow, now I'm running on the default white point again!

I'm very happy so far. This fix cost me a couple of hours but that's all! A replacement screen is hard to find and costly, this was practically free. I'd recommend this procedure to anyone experiencing yellow tinge and who is comfortable working on the inside of the iMac.  

 

iMac 2010 LCD screen repairability : 9/10