When I wake up my computer the display comes on and goes to full brightness. However, after a couple seconds the top half of the screen dims a little bit. I tried adjusting brightness, rebooting, etc. but cannot figure out how to fix it.
Any help is much appreciated, thank you!
iMac, Mac OS X (10.5.8)
How old is your computer? What you describe is not user adjustable, it is a sign that the display is failing. Since you have an iMac, an all in one computer, if it is an older model it is not easy to get spare parts to repair or replace these units, and the parts that are obtained are often from similar worn out units. If this uneven screen bothers you enough or gets worse, I think a new computer will be the only long term solution.
My computer is 3 1/2 years old. Yesterday the screen was flickering a little and then this uneven appearance in brightness showed up. Any ideas on how long display might last? I use the computer for work and entertainment, it is on around 4-5 hours a day. Thank you for your help.
3-1/2 years is not very old, you should not be experiencing this. I thought maybe your computer was 7 or 8 years old. The flickering and uneven illumination is indicative of a hardware issue. Unfortunately, 3-1/2 years is just past the extended warranty (assuming you have one).
A repair shop might be able to check connections and do a local repair, say a solder joint that was weak. Does the appearance improve at all as the computer warms up and has been on for a while? Is it better or worse when first started up versus having been on for several hours?
I'm not so sure that the number of hours/day determines how much longer the display will be usable. It might be that thermal cycles (on/off cycles) have more of a degrading impact than just running at a stable temperature.
I have two suggestions for you:
(1) Start in Safe Mode, http://support.apple.com/kb/HT1455 . This will disable some features, including some of the advanced graphics chip functions. If your screen looks good when you Safe Boot, that means the advanced graphics chip is failing or has failed, in which case you will need a new computer (although what you have may function acceptably for a while, maybe a long while) to fix the issue.
(2) If Safe Mode boot looks the same as before, then it's most likely the display itself. In that case, you might be able to get a low cost display ($100 or so) and "mirror" your primary display to that second display. I believe newer iMacs like yours can drive a second display through a display out port. You might need an adaptor also and a cable for this. Some stores like Best Buy let you get such items like these displays and return them within 14 days or so for a full refund if you save all the packaging. That protects you in case somehow the external display does not work out for your issue. (e.g. maybe the external display will also show the same problem ...)
One more thing -- it is possible that you have a simple to fix problem, such as one of the backlights going out. That might be straightforward to fix at an Apple authorized service provider.
Thank you for your help, I am very grateful and will try your suggestions. It would be great if it's a simple matter of a backlight needing to be replaced and/or running a second display to solve the problem.
Top half of display is darker than the bottom
