Lines popping up all over the display

Do a search in these forums for vertical lines. There are many threads that deal with this topic.

lenn

Hi,

Have you tried running the Apple Hardware Test from your install disk?
http://support.apple.com/kb/HT2684

Might be a good idea to check the hard disk.
Insert Installer disk and Restart, holding down the "C" key until grey Apple appears.
Go to Installer menu (Panther and earlier) or Utilities menu (Tiger and later) and launch Disk Utility.
Select your HDD (manufacturer ID) in the left panel.
Select First Aid in the Main panel.
(*Check S.M.A.R.T Status of HDD at the bottom of right panel. It should say: Verified*)
Click Repair Disk on the bottom right.
If DU reports disk does not need repairs quit DU and restart.
If DU reports errors Repair again and again until DU reports disk is repaired.






Carolyn 🙂

The hardware disk? Do you mean you ran the Apple Hardware Test? Or you booted from your install disk and used Disk Utility?


Carolyn 🙂

Needs to go in for service 😟

Search forum for HORIZONTAL lines and iMac freezing subject. Welcome to the club!

try it w/ an external lcd screen.. if those lines keeps coming out, probably heat or logic board problem.

it the external display doesnt show those lines, then you need to bring to service center to have the lcd replaced

There are a couple of threads on this issue.

I have a late 2006 imac (24" screen) which was experiencing these problems -- lines which were contained to specific windows -- other graphic anomalies -- intermittent freezes as the lines increased. It got quite bad about 3 weeks ago and the computer became virtually unusable.

Genius bar was unhelpful after I shlepped the whole thing in -- suggested doing a clean reinstall of system and also (after my query) suggested replaced the Video Card -- which wasn't in stock anyway.

At any rate, I brought the computer home -- searched the forums and read threads. Based upon MANY suggestions, I downloaded smcfancontrol which increases fan speed and decreases the temperature of the computer. Fingers crossed my problem is solved -- no lines and no freezes since then.

I certainly would recommend trying it before doing anything more drastic. The problem seems to be particularly acute with NVIDIA GeForce 7300 GT graphic cards -- perhaps they are more heat sensitive -- perhaps as they age, they become more heat sensitive. That it is heat related (at least for me) is also supported since the computer "crisis" occurred during the first heat wave so the ambient temperature of my condo was higher than it's been in many months.

At any rate, it's a simple application -- if it doesn't work, you haven't invested much but it worked for me and a lot of other people with the identical issue.

In my opinion it's not only a problem for NVidia card, because I found many cases with X1600 card and even Mac Pro suffered from the same sympthoms with X1900 cars rev 1. What is interesting here only 20 and 24 inch iMacs late 2006 suffer from the issue. No single case with 17 iMacs.
There is another way to hide sympthoms and eliminate most of freezes which I described in another tread. And suprisely replacing of GPU and VRAM does nothing. It has to be another overheating chip.