Apple MD094LL/A Non-Uniform Brightness / Color, Symptoms Quick Check Non-Uniform Brightness/Color

Non-Uniform Brightness / Color

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

Quick Check

Symptoms		Quick Check
Non-Uniform Brightness/Color		1.	Verify System Preferences > Displays > Brightness
•	Brightness not uniform		slider is set above minimum.
•	Color not uniform	2.	Allow a minute for backlight to reach normal
•	Yellow tint		operating temperature and output before
			evaluating display.
		3.	Visually inspect glass panel for presence of dust,
			cigarette smoke, or other contaminants. Clean
			glass panel if needed.

Deep Dive

Check		Result	Action	Code
1.	Determine if color/brightness	Yes	Go to step 2.
	uniformity issue is visible after
		No	Display backlight can take a
	display has warmed up for
			minute to stabilize. Retest. If
	about a minute.
			issue still not visible return
			computer to user.
2.	Look at user-provided	Yes	Go to step 3.
	examples showing brightness
	uniformity issue. Determine if	No	Demonstrate to user that LCD
	variation in uniformity appears
			performs similarly to another
	excessive when compared to
			computer of the same model.
	another same-model computer.
3.	Remove glass panel and	Yes	Inspect for mechanical
	loosen screws securing LCD		interference with screws
	panel. Determine if brightness		or cables making contact
	uniformity improves.		with back of LCD. Reseat
			components & cables, retest.
		No	Go to step 4.
4.	Remove LCD panel, then	Yes	One or more backlight cables
	inspect and reseat backlight		were loose.
	cables. Determine if brightness
		No	Replace LCD panel. Run Apple	L07
	uniformity improves.
			Service Display Utility. To
			verify the resolution of issue.
			Enter the resulting verification
			code into the “Notes” field
			of GSX and return system to
			customer if repair is complete

2010-09-09 iMac (27-inch, Mid 2010) Symptom Charts — Display  68