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 
device.
4.  Inspect air intake and air outlets for obstructions. 
To prevent overheating make sure there 
is sufficient clearance to allow air to flow 
unobstructed into and out of the system.
5.   Verify whether system is functional.
Deep Dive
Check ResultAction Code
1.   Verify whether the source of 
the odor can be identified 
by visually inspecting  each 
module and its associated 
cables for signs of burned or 
damaged components,  smoke 
residue, burned traces, or 
melted or damaged wiring, Yes
Replace affected module(s). 
Go to step 2 P08
No Unable to locate source of 
odor. Go to step 3.
2.  Disconnect all third-party 
devices and cables. Power ON 
system and verify whether 
smoke or strong odor returns. Yes
Power down system 
immediately. Go to step 3.
No System functions correctly. 
Verify system functionality 
with third-party devices and 
cables and return system 
to user if problem has been 
resolved. Consult third-party 
companies as needed for 
issues with those products.  
						

							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 known-good 
outlet.
2.  Listen for boot chime, fan, optical drive, or hard 
drive noise which indicates system is powering 
up. If noise is heard, go to Won’t Start Up. If no 
noise is heard go to No Power, Dead Unit.
3.   Attempt to boot from Install DVD to isolate 
possible software issues.
Deep Dive
Check ResultAction Code
1.   Verify whether existing 
symptom code applies to the 
issue reported by the user. Yes
Jump to appropriate 
symptom code flow.
No
Document reported failure 
and send feedback to 
[email protected] 
stating that a suitable 
symptom code wasn’t found. 
Provide as much detail as 
possible. N99  
						

							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 
functioning. Go to No Video if no image is visible 
on external display.
Deep Dive
Check ResultAction Code
1.   Verify boot chime present and 
fans running when system 
powered ON. (Reset SMC and 
clear PRAM if necessary for 
proper boot up.)  Yes
Power ON self test OK. Boot 
sequence started. Go to step 
2.
No
Go to Won’t Start Up.
2.  Verify whether image is visible 
on LCD panel. Yes
Video present. Verify system 
functionality and return to 
user or jump to appropriate 
troubleshooting flow.
No Go to step 3.
3.   Connect supported external 
display. Verify whether image 
appears on external display 
when system is booted. Yes
External display detected by 
system. Video circuitry on 
logic board functional.  
Go to step 4.
No
Go to No Video.
4.  Verify if LCD backlight is ON 
by looking for faint glow 
from display when viewed in 
darkened room with brightness 
set at maximum. Yes
Internal LCD panel backlight 
is functioning.  Go to step 6.
No Go to step 5.  
						

							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 panel. Yes
Issue resolved by cable reseat. 
Return computer to user. M24
No Replace inverter. Retest. Go to 
step 7 if issue is still present. L03
7.   Remove screws securing LCD 
panel and inspect LVDS cable 
and connections for damage. 
Reinstall. Power ON system. 
Verify whether image is visible 
on LCD display. Yes
Issue cause by loose LVDS 
connection. Verify system 
functionality and return 
system to user. M24
No Connecting external display 
in earlier step confirmed that 
logic board video circuitry 
is functioning. Replace LVDS 
cable first, then LCD panel if 
the issue persists. Retest. L03  
						

							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 this software 
to monitor and control internal temperatures 
potentially causing higher fan speeds to generate 
higher than expected noise levels.
Deep Dive
Check ResultAction Code
1.   Verify if user issue is due to  
flickering or an unstable image 
on the LCD. Yes
Suspected flickering issue, go 
to step 2.
No For audible noise issues go to 
step 8. All other issues go to 
appropriate symptom flow.
2.  Connect a supported external 
display to the DisplayPort. 
Verify whether issue occurs 
with external display. Yes
Suspect issue with video 
circuitry. Go to Corrupted 
Video.
No Video circuitry OK. Go to step 
3.
3.   Disconnect and carefully 
inspect the LVDS and backlight 
bulb connections for signs of 
damage, corrosion, or pinched 
wires. Were any problems 
observed? Yes
Replace damaged cable(s) 
where needed, otherwise 
reattach connectors. Retest. L06
No Go to step 4.
4.  Power ON system and verify 
whether the issue still occurs. Yes
If connections are secure and 
the display is still flickering, 
go to step 5.
No Issue was caused by a poor 
connection between display 
and logic board or inverter. 
Return computer to user.  
						

							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 7.
No
Noise is from another source. 
Go to Noise/Hum/Vibration.
7.   Verify whether noise can be 
heard when computer is set 
up with user seated in normal 
user position. Adjusting the 
brightness level up and down 
may be necessary to recreate 
the issue.  Yes
Replace inverter. Go to step 8. L06
No Noises that are not audible 
from the normal user position 
are considered acceptable. 
Return computer to user.
8.  Verify whether noise is still 
present.  Yes
Replace LCD display. Retest. L06
No Noise issue resolved. Return 
computer to user. L06  
						

							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 for use of custom 
display profile.
3.   Check brightness setting.
4.  Clean glass panel while checking for dust/debris.
Deep Dive: General
Check ResultAction Code
1.   Verify if issue is incorrect/
missing colors. Yes
Go to incorrect/missing 
colors.
No Go to step 2.
2.  Verify if issue is distorted/
blurred image. Yes
Go to distorted/blurred 
image.
No Go to step 3.
3.   Verify if issue is bright or dark 
pixel anomalies. Yes
Go to pixel anomalies
.
No Go to step 4.
4.  Verify if issue is vertical or 
horizontal lines.  Yes
Go to vertical/horizontal 
lines.
No Go to step 5.
5.   Verify if issue is non-uniform 
brightness.  Yes
Go to non-uniform 
brightness.
No LCD functioning OK.  Return 
to appropriate symptom chart 
if user issue is still present.  
						

							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 display profile. 
3.   Verify System Preferences/Universal Access/ 
Display “Enhance contrast”, “Use grayscale”, and 
“Black on White/White on Black” settings are set 
to defaults.
Deep Dive
Check ResultAction Code
1.   Verify system has been warmed 
up for ~15 minutes to stabilize 
backlight before continuing. Yes
Go to step 2.
No Allow system to warm up for 
approximately 15 minutes 
then go to step 2.
2.  Verify that the LVDS and 
backlight connections between 
the logic board and LCD are 
secure.  Yes
Go to step 3.
No Reseat connections, replace 
damaged cable(s) if needed. 
Retest. L14
3.   Set desktop pattern in system 
preferences to ‘Solid Gray Light’. 
Verify if incorrect/missing color 
issue affects entire display. Yes
Suspect poor video 
connection. Replace LVDS 
cable. L14
No Go to step 4.
4.  Set up display under test side 
by side with another known-
good display showing the 
same image. Verify if issue is 
noticeably worse on the display 
being tested.  Yes
Replace LCD panel. L02
No Small variations in color 
uniformity across display are 
normal and do not warrant 
replacement or repair of the 
display. Return computer to 
user.  
						

							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.   Boot from install DVD to determine whether 
potential software issue exists.
Deep Dive
Check ResultAction Code
1.   Boot from Install DVD and 
verify whether issue is still 
visible. Yes
Go to step 2.
No Issue likely caused by 
software or driver issue. 
Troubleshoot for software 
issues. Make sure all software 
updates have been installed.
2.  Verify whether issue is visible 
on an external display attached 
to the DisplayPort. Yes
Issue is NOT caused by 
internal LCD panel.  
Go to step 3.
No Go to step 5.
3.   Remove logic board, inspect 
connectors for damage or 
corrosion then reinstall. Verify 
whether issue still occurs. Yes
Replace logic board.  
Go to step 4. M04
No Issue likely caused by poor 
connection. Return computer 
to user. M04
4.  Verify whether issue is still 
present with replacement logic 
board installed. Yes
Return to step 1 and retest. X04
No Issue resolved with 
replacement logic board. 
Return computer to user. M04  
						

							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 replacement LCD 
panel installed. Yes
Return to step 1 and retest.
No Issue resolved with 
replacement LCD panel. 
Return computer to user. L04