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Random Black screen, Help please
I just got a iMac 20" 2.1GHz (2006) at first it ran well no problems, but now the screen randomly goes black, system still runs just black screen, if left alone it will go to sleep and can be awaken just fine as if nothing happened but later its black again. any advise would be Appreciated
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have you tried resetting PRAM?:
Shut down the computer.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time (I usually let it do this till it chimes 3 times).
Release the keys.
Thanks for the replies, I tried them all but the problem persists. I found a few other sites where others have the same issue, I’m finding a common theme the hardware seems to be ok but it looks like the drivers from apple for this specific ATI video card, in one thread they found that removing the divers help solve the problem but limited the video abilities of the system (not good). By following your advice I did notice that when the screen comes on it’s really bright (during boot and wake from sleep) and then it dims to normal settings, that’s when the blackout happens, if it goes to normal setting it runs fine, otherwise it will black out right at the time it goes to normal settings. So I’m wondering if it’s hardware and a new mother board is needed.
Gerald Thomas,
Well I think I solved the issue, tell me if I’m on the right track. I followed every thread on this site dealing with screen issues, and learned about a thing called an Inverter, it controls the backlight for this type of screen, I also found a couple of simple tests to diagnose problem. 1. Connect a second monitor if it stays on when the onboard screen goes out, it’s not the video card. 2. When the screen goes out hold a flashlight up to the screen on a slight angle and look real hard, if you can see the desktop (in the dark) then it’s your screens backlight. I performed these tests, secondary monitor worked when primary went out, and the flashlight test fail the first time because I was looking at a blank background so I opened some windows and there they were. I found and ordered the part, I have the removal/install
Gerald Thomas,
She lives,, I replaced the inverter and the power supply, not that hard of a job (I've done worst). I picked up the parts on a famous auction site both for well under $100 and with the Guides found on ifixit i brought new life to this Imac, after replacing the parts the screen seams brighter and stronger. I got this mac for the wife and now I think she'll love me long time (LOL). Thanks ifixit, your my heroes,
Gerald Thomas,