Red line across iMac screens

Question

Both my sons have the 2006 white 24" iMacs and for the last few months the screens are showing an intermittent red thin horizontal line, not always all the way across the screen.
It can cause flickering when showing movies.
Also both have a tendency to lock up at odd intervals and require a hard restart.
Anyone else with the problem?
Peter

Answer 1

Louise,
If you go to the "Using your Intel-based iMac" discussion, you can find numerous posts about freezing/crashing 2006, 2007 vintage iMacs. My late-2006 iMac started to have these problems 3-4 months ago, and the problems increased in frequency over time. My 20" display also started to show partial horizontal lines at different times during this period. In my case my iMac eventually became so unstable it wouldn't run even 1 hour before freezing, and then would not re-boot successfully until I shut it off and waited for several hours.
I became convinced that heat was a major contributing factor for these problems even though the internal temperature sensors in my iMac were well within advertised tolerances. Rather than repeat what has been documented in the other forum, I suggest you read the recent thread:
http://discussions.apple.com/thread.jspa?messageID=10893244#10893244
The good news is that by taking the steps described in the referenced thread, my iMac appears to now be stable (knock on wood), and has run without a crash/freeze in 6+ days.
Good luck,
Dave