Apple MD094LL/A manual Symptoms Quick Check Corrupted Video, Further

Corrupted Video

Unlikely cause: power supply, hard drive, optical drive, fans, speakers, camera, microphone

Quick Check

Symptoms	Quick Check
Corrupted Video	1.	Using the KBase article http://support.apple.com/
• Text and graphics appear fuzzy		kb/HT1159 , verify Mac OS X version installed is
• Image corrupted		the build number supported on the hardware.
		Make sure customer didn’t migrate over their old
		version of Mac OS.
	2.	Set System Preferences > Displays to native
		resolution of LCD. Non-native resolutions are
		unable to produce optimal clarity.
	3.	Clean outside surface of glass panel..
	4.	Make sure all relevant firmware and software
		updates have been applied. Graphics driver
		updates may be included with software updates.
	5.	Boot from install DVD or another known-good
		volume to determine whether a potential
		software/driver issue exists.
	6.	When issue occurs, take a screenshot of the
		display (Command-Shift-3). View screenshot file
		on a known-good computer. If image corruption
		can be seen in the screenshot then issue is with
		the video drivers, software, or video/logic board.
		If issue cannot be seen in the screenshot then
		LCD panel and DisplayPort cable should be tested
		further.

2010-09-09 iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power  48