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Screen with lines  



Hi there! My iMac is 10 years old, and a few days ago I shut it on and the screen is white with some vertical lines. I wanted to plug it to my tv with an HDMI but I don’t know how to command it to the tv screen. I need some help!! please. what can I do in this case? thanks in advance!!

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2 Answers

Command-F1 should cause your iMac's display to mirror on the external display (which in this case would be your TV).

But just plugging in an external display should give you a 2nd monitor which should so something.

But if your iMac is just giving you a white screen, there may be more happening.

You might try the following:

try an SMC reset and an NVRAM reset 
Reset the System Management Controller (SMC) on your Mac - Apple Support
How to reset NVRAM on your Mac - Apple Support
Try booting into Safe mode
This will not load any 3rd party additions, it will load some more conservative Apple drivers (may cause screen flicker), and it will clear some kernel caches (a cache is saved data in a form that can speed up a program, but is totally redundant to the original source, and thus can be safely cleared).  Booting into Safe mode is just an experiment, but can frequently eliminate any 3rd party interference, or a cached item out-of-sync with the world.  (Verify Safe mode via Applications -> Utilities -> System Information -> Software -> Boot Mode -> Safe vs Normal)

There are only two "fixes" for the vertical lines . . . replace the LCD panel or get the mini-DVI video adapter and attach an external monitor. Guess which is cheaper/easier?