Chosen Solution
Hi, my late 2009 iMac 27" is killing me. Display goes black 10 times a day. When I hold a flashlight to the screen I can see stuff on the screen. External Monitor works fine. Regarding to some other articles on ifixit, the backlightboard should be damaged. So i ordered one from the US (I´m in germany) and replaced the old one… same failure crying loud. Do you think i should change the backlight cable also? I can only find one on the internet and thats &##* expensive (more expensive then the board itself). Where do you guys get those cables? Does anyone know why the display is turning off in such irregular intervals? Is it a heatproblem?? Maybe i should plug out the display-thermal-sensor-cable an see if it is still turning off?! Thank you!
Check your display settings. Turn off the Ambient Light setting. Also check your Desktop & Screen Saver settings make sure the Start Screen Saver is put to never. Restart your system and see what happens.
looks like the GPU, i had similar problem - check here: http://forums.macrumors.com/showthread.p…
I had the same problem with a 27-inch iMac 2009 i7, I changed the inverter board several times without success. Then removed the flat cable between inverter board and display, which I had previously renewed and curiously, the backlight is now permanently on. Although the temperature sensor cable of the LCD was also defective, but had the consequence that the backlight did not even concern. The temperature sensor is a standard component, a 2N3904 transistor and easy to replace.
You guys mean the vsync cable right? I just ran into the same issue on a mid 2011 27". Inverter board was faulty, so i’ve changed it, now if i turn the brightness control over 5, it starts to black out. The only way to wake it is the ctrl+shift+eject then a mouse click, but then it does it again. I have to mention though, that the broken inverter board is the Sumida 612-0094 and i could only replace it with the V267-604HF…dunno if that could be a problem, because it’s used inside the same iMac with probably the same LCD display… If the problem can be the board, please tell me, I can return it today or in a few days if it’s not ok!
