Apple imac 20 inch mid 2009 User Manual

iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 31 2010-11-24
Burnt Smell/Odor
Unlikely cause:  speakers, microphone, enclosure
Quick Check
SymptomsQuick Check
Burnt Smell/Odor
•  Burning smell
•  Unusual odor
1.  Verify source of smell/odor is emanating from the 
system.
2.  If system is new refer to KBase article 
http://support.apple.com/kb/TA22044 
for information on new computer odors.
3.   Disconnect all third-party devices and confirm 
whether the odor is being generated by the...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 32 2010-11-24
3.  Can the source of the odor be 
located using nose?  Yes
Replace affect module(s) and 
retest system.  P08
No Contact Apple for assistance 
if you feel that there is a 
possible safety issue with the 
computer that has not been 
resolved in the previous steps.
Uncategorized Symptoms
Quick Check
Symptoms Quick Check
Uncategorized Symptoms
•  Unable to locate appropriate 
symptom code.
1.  Make sure system is plugged into a...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 33 2010-11-24
Display
Backlight Issue/No Backlight
Unlikely cause:  hard drive, optical drive, speakers, camera, microphone
Quick Check
SymptomsQuick Check
Backlight Issue/No Backlight
•  No image
•  Partial backlight failure
•  Backlight flickers
•  Display dim
1.  Check System Preferences > Displays > Brightness 
control setting is above minimum.
2.  For no-image issues connect an external 
display to verify whether iMac video circuitry is...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 34 2010-11-24
5.  Shine bright (low heat) 
flashlight onto the front of the 
LCD. With the system powered 
ON verify whether a faint image 
is visible. Yes
LCD panel functional but 
backlight is not ON.  Inspect 
and reseat four backlight bulb 
connectors connecting LCD 
panel to inverter, and inverter 
connection to logic board.  
Go to step 6.
No No image or backlight.  
Go to step 7.
6.  Power ON system. Verify 
whether image is visible on 
LCD...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 35 2010-11-24
Noise / Unstable Flickering
Unlikely cause:  camera, microphone
Quick Check
SymptomsQuick Check
Noise / Unstable Flickering
•  Unstable image
•  Flickering image
•  Humming noise from display
•  High frequency noise from 
display 1.
  Verify that intake vent on the bottom of the 
system is not obstructed.
2.  Inspect system for 3rd party software that is 
being used to set fan speeds to a higher than 
normal RPM. Some users may use...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 36 2010-11-24
5.  Shine bright (low heat) 
flashlight into the front of the 
LCD. Verify if an image is being 
displayed when flickering issue 
is occurring. Yes
Image present but backlight 
is flickering. Replace inverter 
then retest. L06
No Replace LCD panel then 
retest. L06
6.  Verify whether noise varies 
when adjusting the brightness 
level up and down. Yes
Noise appears to be 
generated by the LCD panel 
or backlight circuitry. Go to 
step...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 37 2010-11-24
LCD Image Issues
Unlikely cause:  power supply, hard drive, optical drive, fans, speakers, camera, microphone
Quick Check
SymptomQuick Check
LCD Issues
•  Incorrect/missing colors
•  Distorted/blurred image
•  Pixel anomalies
•  Vertical/horizontal lines 
•  Non-uniform brightness 1.
  Allow display to reach normal operating 
temperature for about 15 minutes before 
evaluating front-of-screen performance.
2.  Check display preferences...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 38 2010-11-24
Incorrect/Missing Colors
Unlikely cause:  power supply, hard drive, optical drive, fans, speakers, camera, microphone
Quick Check
SymptomsQuick Check
Incorrect/Missing Colors
•  Wrong color display
•  Color/contrast issues 1.
  Allow display to reach normal operating 
temperature for about 15 minutes before 
evaluating front-of-screen performance.
2.  Verify that System Preferences/Display settings 
are configured to use the default...

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 39 2010-11-24
Distorted/Blurred Image
Unlikely cause:  power supply, hard drive, optical drive, fans, speakers, camera, microphone
Quick Check
SymptomsQuick Check
Distorted/Blurred Image
•  Text and graphics appear fuzzy
•  Image corrupted 1.
  Set System Preferences/Display LCD panel to 
native resolution. Non-native resolutions are 
unable to produce optimal clarity.
2.  Clean outside surface of glass panel using 
provided cleaning cloth.
3....

iMac (20-inch, Early/Mid 2009) Symptom Charts — Display 40 2010-11-24
5.  Remove LVDS cable from LCD 
panel and logic board and 
carefully verify whether there 
is damage to the cable or 
connectors.  Yes
Replace LVDS cable.
No Reinstall LVDS cable.  
Go to step 6.
6.  Verify whether issue is still 
visible after reinstalling LVDS 
cable. Yes
Replace LCD panel.  
Go to step 7.
No Issue resolved with 
replacement logic board. 
Return computer to user. M04
7.   Verify whether issue is still 
present with...