Chosen Solution
iMac 24" ECM 2134
Shows in all brightness and background settingsCapture screen does not show the brownMore pronounced discoloration on right side (maybe)May be “growing” Computer on all time unless away for extended time (rare)Use moving screen saver till it goes in sleep mode (3-5 min.)Cleaned screen - no differenceNo direct sunlight on computerRest of computer works fine Thanks for any help!
I had really hoped someone else would jump in on this question. I’m fairly sure of what the problem is but would like to get some confirmation. To eliminate a couple of possibilities, start up from your system installation disk by inserting the disk and holding down the “C” key. See if the screen stays the same. UPDATE - I personally have the 2009 2.66 24" iMac. Bring yours by tomorrow afternoon and I’ll see if I can switch out the LVDS cable and the inverter and maybe even the screen to isolate the problem. My first guess on this is the screen. We can probably get a used one for about $450 and a new one for $700. The used would carry a 90 day warranty. UPDATE The screen was successfully replaced and all is well.
Maybe I’m too late, but I have the same question and I gave myself this answer: if you open the iMac, you may notice that two coolers is exactly behind the LCD, in the “brown zone”. I think it’s a overheating caused by hot air flow; in fact, when the iMac is powered on by only few hours, the brown shading is absent, or far less visible.
You have to clean the inside of the screen. See iMac Intel 24" EMC 2267 Glass Panel Replacement. Good Luck!
