Apple iMac 20 mid 2009 Service Manual
Apple Technician Guide
iMac (20-inch, Early/Mid 2009)
iMac (20-inch, Early 2009), iMac (20-inch, Mid 2009)
Updated: 2009-05-01
Apple Inc.
© 2009 Apple Inc. All rights reserved.
Under the copyright laws, this document may not be copied, in whole or in part, without the
written consent of Apple.
Every eort has been made to ensure that the information in this document is accurate. Apple
is not responsible for printing or clerical errors.
Apple
1 Innite Loop
Cupertino, CA 95014-2084
USA
+ 1 408 996 1010
www.apple.com
Apple, the Apple logo, Mac, and Macintosh are trademarks of Apple Inc., registered in the U.S.
and other countries.
iMac (20-inch, Early/Mid 2009)
Manual Updates 7
Updated 28 April 2009 7
Manual introduced 3 March 2009 7
Basics
Overview 9
Product Features 9
Dierences Between Models 9
Product Conguration 10
Serial Number Location 10
Troubleshooting
General Troubleshooting 12
Update System Software 12
Firmware Updates 12
Troubleshooting Theory 12
Hardware vs. Software 12
Apple Hardware Test 13
Apple Service Diagnostic 13
Power On Self Test (POST) 13
Starting Up in Safe Mode 14
Resetting the Parameter RAM (PRAM) 14
Resetting the System Management Controller (SMC) 15
Diagnostic LEDs 16
Sensor and Fan Connector Locations 17
Block Diagram 18
Symptom Charts 19
Startup and Power 19
No Power, Dead Unit 19
Won’t Start Up 21
Intermittent Shutdown 23
Kernel Panic, System Crashes 25
No Video 27
Corrupted Video 28
Burnt Smell/Odor 30
Uncategorized Symptoms 31
Display 32
Backlight Issue/No Backlight 32
Incorrect/Missing Colors 37
Distorted/Blurred Image 38
Pixel Anomalies 40
Vertical/Horizontal Lines 41
Non-Uniform Brightness 43
Cosmetic Defects 44
Uncategorized Symptoms 44
Mass Storage 45
Hard Drive Not Recognized 45
Hard Drive Read/Write Error 47
Hard Drive Noisy 48
Optical Drive Not Recognized 50
Optical Drive Won’t Accept/Eject Media 51
Optical Drive Read/Write Error 53
Optical Drive Not Performing to Specications 54
Optical Drive Noisy 55
Uncategorized Symptoms 57
Communications 58
AirPort/Bluetooth Issues 58
AirPort Card Kernel Panic 60
Ethernet Port/Device Issue 61
Wireless Input Device Doesn’t Pair 62
Wireless Input Device Loses Connection 64
Uncategorized Symptoms 66
Input/Output Devices 67
Apple Remote Inoperable 67
Audio: Microphone 68
Audio: Built-in Speakers Have Distorted Sound 70
Audio: Built-in Speakers Have No Audio 71
Camera Issues 73
FireWire Devices Not Recognized 74
USB Devices Not Recognized 76
Wired Keyboard Does Not Function Properly 78
Keyboard: Specic Keys Do Not Respond 80
Wired Keyboard/Mouse Not Recognized 80
Uncategorized Symptoms 82
Mechanical 83
Noise/Hum/Vibration 83
Fan Failures / Thermal Issues 86
Stand/Hinge Issues 87
Physical Damage 87
Uncategorized Symptoms 88
Take Apart
General Information 90
General Tools 90
Opening the Unit 90
Required Special Tools for Glass Panel 90
Cleaning Tools Starter Kit 91
Cleaning Tool Resources 91
Cleaning & Handling the Glass Panel 92
Do’s and Don’ts 92
Handling a Broken Glass Panel 92
Safety 93
Logic Board Handling 94
ESD Precautions 95
ESD Guidelines 95
Reassembly Steps 96
Images in This Guide 96
Screw Sizes 96
Access Door 97
Memory 98
Glass Panel 100
Removal 101
Reassembly 102
Front Bezel 106
Camera 109
Battery 111
IR (Infrared) Board (Early 2009 only) 113
AirPort Extreme Card 115
Bluetooth Board (Early 2009 only) 11 7
LCD Panel 119
LVDS Cable 123
Hard Drive 125
Hard Drive Sensor Cable 129
Optical Drive 131
Optical Drive Sensor Cable 134
Optical Drive Fan 136
Optical Drive Data Cable 138
Inverter 140
Power Supply 142
Left Speaker 145
Ambient Temp Sensor Cable 147
CPU Fan 149
Right Speaker 151
Audio Board 153
Logic Board 156
Removal 157
Reassembly 158
Handling Logic Boards 160
Hard Drive Fan 161
Hard Drive Data Cable 163
Mechanism Cover 164
Stand 165
Mechanism 167
Chassis 169
Cable, DC, Power Supply/SATA/Inverter 172
Removal 173
Reassembly 175
Camera Cable 178
Microphone Cable 180
Rear Housing 182
Views
Exploded Views 184
iMac (20-inch Early 2009), Part 1 184
iMac (20-inch, Early 2009), Part 2 185
iMac (20-inch, Mid 2009), Part 1 186
iMac (20-inch, Mid 2009), Part 2 187
Screw Chart 188
Internal Views 190
I/O Ports 192
Feedback 193
Manual Updates
Updated 1 May 2009
Views:
Exploded Views: Corrected rear housing information for Mid 2009 model.•
Updated 28 April 2009
Basics:
Added section about dierences between Early 2009 and Mid 2009 models.•
Troubleshooting:
General Troubleshooting: Added sections about Apple Hardware Test and Apple Service •
Diagnostic, how to determine which version to use.
Block Diagram: Added note that Mid 2009 model does not have IR or Bluetooth.•
Take Apart:
Front Bezel: Added reassembly note to install bottom of bezel rst.•
Camera Board: Corrected screw size and part number.•
IR Board: Added note that Mid 2009 model does not have an IR Board.•
Bluetooth Board: Added note that Mid 2009 model does not have a Bluetooth Board.•
Optical Drive: Added reassembly note to avoid trapped inverter cables.•
Hard Drive Sensor Cable, Optical Drive Sensor Cable, Hard Drive Fan: Added details about •
connector pin sizes.
Logic Board: Added note that Mid 2009 model does not have IR or Bluetooth boards. Added •
note to route camera cable over, not under, the logic board. Removed note to transfer black
plastic airdam from old board to new board, as it should be included with new board.
2009-05-01
Views:
Exploded Views: Added 1 logic board part number for Early 2009 model. Added new •
exploded views for Mid 2009 model.
Screw Chart: Corrected camera screw size and part number.•
Manual introduced 3 March 2009
iMac (20-inch, Early/Mid 2009) — Manual Updates 7
Apple Technician Guide
Basics
iMac (20-inch, Early/Mid 2009)
© 2009 Apple Inc. All rights reserved.
Overview
Product Features
The iMac (20-inch, Early 2009) and iMac (20-inch, Mid 2009) computers have the same overall
look as the previous generation aluminum iMac. Distinguishing exterior features are Mini
DisplayPort (instead of mini DVI port) and 4 USB ports (instead of 3) on the rear, and a tapered
front edge on the stand.
New features:
Increased processor speed: 2.66GHz•
Mini DisplayPort•
4 USB 2.0 ports•
Increased RAM capacity: 2GB min, 8GB max•
Increased hard drive capacity in Early 2009 model: 320/640/1TB•
Dierences Between Models
The iMac (20-inch, Early 2009) and iMac (20-inch, Mid 2009) computers are very similar. The
dierences are that the Mid 2009 model does not have IR (Infrared) or Bluetooth, and has a
smaller capacity hard drive (160GB).
2009-05-01
iMac (20-inch, Early/Mid 2009) Basics — Overview 9
Product Conguration
To conrm the conguration from the Apple menu, choose About This Mac. The processor
listing will show the speed of the processor followed by the processor type. The following table
shows the conguration at introduction:
Feature Specication
Processor 2.66 GHz Intel Core 2 Duo
6MB shared L2 cache, 1066MHz frontside bus
Memory 2GB (2 x 1GB) 1066MHz DDR3 (optional 4GB, 8GB CTO)
Hard Drive Early 2009: 320GB Serial ATA 7200-rpm (optional 640GB, 1TB)
Mid 2009: 160GB Serial ATA 7200-rpm
Optical Drive 8x SATA SuperDrive
Display 20-inch, 1680x1050 resolution, 800:1 contrast ratio, 290 cd/m brightness,
160-degree viewing angle, glossy
Graphics NVIDIA GeForce 9400M with 256MB shared memory
Wireless AirPort Extreme 802.11a/b/g/n, Bluetooth 2.1 + EDR (only in Early 2009)
Input Devices wired keyboard, wired mouse, no remote, no modem
I/O Gigabit Ethernet, (4) USB 2.0, (1) FireWire 800
Audio I/O iPhone headset connector, microphone, stereo speakers, combo digital in
Video I/O Mini-DisplayPort (HDCP, dual-link, dual display; simultaneously supports
full native resolution on built-in display and up to 2560x1600 on an
external 30-inch display), iSight camera
Power Supply 180W universal
2009-05-01
Serial Number Location
The iMac (20-inch, Early/Mid 2009)’s serial number is located on the base of the stand. When
replacing a stand, transfer the serial number to the new stand.
iMac (20-inch, Early/Mid 2009) Basics — Overview 10
Apple Technician Guide
Troubleshooting
iMac (20-inch, Early/Mid 2009)
© 2009 Apple Inc. All rights reserved.
General Troubleshooting
Update System Software
Important: Whenever possible before beginning troubleshooting, ensure the latest software
and rmware updates have been applied.
Firmware Updates
Firmware is the name given to software that is written into memory circuits such as ash
memory, that will hold the software code indenitely, even when power is removed from the
hardware. Firmware on Intel Mac computers is designed to be updated if necessary through a
software update.
Information about rmware versions for Intel Macs can be found in the following Apple
Knowledge Base article:
kBase #HT1237: EFI and SMC rmware updates for Intel-based Macs
Troubleshooting Theory
For a review of basic troubleshooting theory, refer to:
http://service.info.apple.com/service_training/en/006/troubleshoot/
Hardware vs. Software
For information on how to isolate a hardware issue from a software issue, refer to the following
Apple Knowledge Base article:
kBase #TS1388: Isolating issues in Mac OS X
For information on how to troubleshoot a software issue, refer to the following Apple
Knowledge Base articles:
kBase #HT1199: Mac OS X: How to troubleshoot a software issue
kBase #HT2956: Troubleshooting Mac OS X installation from CD or DVD
kBase #TS1394: Mac OS X: Troubleshooting installation and software updates
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 12
Apple Hardware Test
There are two versions of Apple Hardware Test (AHT) for the iMac (20-inch, Early 2009). To
identify which version of AHT to use, check the third, fourth, and fth digits in the system serial
number. See examples below.
Apple Hardware Test 3A156• to be used on systems with the third, fourth, and fth serial
number digits below 913. Example: Serial number W 8 9 1 0 S M R D W K
Apple Hardware Test 3A168• to be used on systems with the third, fourth, and fth serial
number digits equal to or higher than 913. Example: Serial number W 8 9 1 3 8 M T 0 T F
The iMac (20-inch, Mid 2009) uses Apple Hardware Test 3A168.
Apple Service Diagnostic
The correct version of ASD for all iMac (20-inch, Early 2009) and iMac (20-inch, Mid 2009) is
Apple Service Diagnostic 3S131.
Power On Self Test (POST)
Intel-based Mac computers such as the iMac rely on a combination of tones and blinking LEDs
to display Power On Self Test (POST) error codes.
If the computer detects out-of-specication or no SDRAM or the RAM installed does not •
meet the appropriate specications, the screen will remain black but the computer will
beep. This error condition may be due to physically damaged RAM, installing the incorrect
type of RAM, or not having RAM installed.
Some RAM may appear to pass the Power-On-Self-Test (POST) but still cannot be used by •
the operating system. In this case, the computer will display a gray screen, sound three
tones and repeat the tones until the computer is turned o.
The solution to both of these situations is to rst re-seat the memory and test the computer •
again. If the memory fails the POST test again, try memory that has been veried to work
correctly on another system (i.e., “known-good”) or order new memory.
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 13
Starting Up in Safe Mode
A Safe Boot is a special way to start Mac OS X when troubleshooting. Safe Mode is the state
Mac OS X is in after a Safe Boot:
Make sure the computer is shut down. 1.
Press the power button. 2.
Immediately after you hear the startup tone, press and hold the Shift key. 3.
Note: The Shift key should be held as soon as possible after the startup tone but not
before.
Release the Shift key when you see the screen with the gray Apple and progress indicator 4.
(looks like a spinning gear). During startup, ”Safe Boot” appears on the Mac OS X startup
screen. To leave Safe Mode, restart the computer normally, without holding down any keys
during startup.
For more information about Safe Mode, refer to the following Apple Knowledge Base articles:
kBase #HT1564: What is Safe Boot, Safe Mode? (Mac OS X)
kBase #TS1884: Safe Boot takes longer than normal startup
Resetting the Parameter RAM (PRAM)
If the computer is on, turn it o.1.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to 2.
hold these keys down simultaneously in Step 4.
Note: If the keyboard does not have an Option key, use the Alt key instead.
Turn on the computer.3.
Press and hold the Command-Option-P-R keys. A simple way to do this with one hand is 4.
to put your right pinky nger on P, your right index nger on R, and your right thumb over
both the Command and Option keys.
Important: You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the 5.
second time.
Release the keys.6.
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 14
Resetting the System Management Controller (SMC)
The System Management Controller (SMC) is a chip on the logic board that controls all power
functions for your computer. If your computer is experiencing any power issue, resetting the
SMC may resolve it. The SMC controls several functions, including:
telling the computer when to turn on, turn o, sleep, wake, idle, and so forth;•
handling system resets from various commands; and•
controlling the fans.•
Note that resetting the SMC does not reset the PRAM. Resetting the SMC will not resolve issues
in which your computer is unresponsive—in these situations, restarting your computer will
generally suce. If your computer isn’t responding, perform these steps one at a time, in this
order, until the issue has been resolved:
Force Quit (Option-Command-Escape)1.
Restart (Control-Command-Power)2.
Force Shut Down (press the power button for 10 seconds)3.
Resetting the SMC can resolve some computer issues such as not starting up, not displaying
video, sleep issues, fan noise issues, and so forth. If your computer still exhibits these types of
issues after you’ve restarted the computer, try resetting the SMC.
How to Reset the SMC on an iMac
From the Apple menu, choose Shut Down (or if the computer is not responding, hold the 1.
power button for approximately ten seconds until it powers o).
Unplug all cables from the computer, including the power cord. 2.
Wait at least 15 seconds. The SMC reset occurs automatically once the iMac has been 3.
unplugged from the AC power source for several seconds.
Plug power cord back in, making sure the power button is not being pressed at the time. 4.
Reconnect keyboard and mouse to the computer. 5.
Press power button on the back to start up the computer. 6.
Note: The iMac does not have a button on the logic board for resetting the SMC, which
eliminates the need to open the computer to reset it (as is required for some other models).
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 15
Diagnostic LEDs
The iMac has built-in diagnostic LEDs on the main logic board that can help you to
troubleshoot the computer. The LEDs are located to the right of the battery (see photo below).
LED #1
Indicates the trickle voltage from the power supply has been detected by the logic board.
This LED will remain ON whenever the iMac is connected to a working AC power source.
The LED will remain on even when the computer has been shut down or put to sleep. The
LED will turn o only if the AC power source is disconnected or the power supply is faulty.
LED #2
Indicates the main logic board has detected proper power from the power supply when
the computer is turned on. This LED will be ON when the computer is turned on and the
power supply is working correctly.
LED #3
Note: This LED is not used on systems that have integrated graphics, which includes all
congurations of the iMac (20-inch, Early/Mid 2009).
LED #4
Indicates the computer and the LCD display panel are communicating. This LED will be ON
when the computer is turned on and video signal is being generated. If the LED is ON and
there is no image on the LCD display panel, the LCD display panel or inverter might be
installed incorrectly or need replacement.
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 16
Sensor and Fan Connector Locations
Ambient temp sensor and fan connector locations are shown below. Ensure cables are
correctly routed and the sensors and fans are properly connected. If a sensor or fan is faulty or
not connected, Apple Hardware Test will generate an error code.
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 17
MLB
Ambient
Temperature
Sensor
802.11n
Antenna
Bluetooth
Antenna
Display
Temperature
Sensor
AC/DC
Temperature
Sensor
Hard Drive
Temperature
Sensor
Optical Drive
HD Fan
ODD Fan
CPU Fan
SO-DIMM SO-DIMM
SpeakerSpeaker
IR Sensor
Audio Board
Power Button
AC Inlet
Camera
Microphone
Inverter
Temperature
Sensor
PCIe x1
DDR3-1066 DDR3-1066
USB 2.0USB 2.0
USB 2.0
SATA II
SATA II
12V in 20”
Antenna
Block Diagram
Refer to this diagram to see how modules are interrelated. Note the iMac (20-inch, Mid 2009)
does not have IR or Bluetooth.
2009-05-01
iMac (20-inch, Early/Mid 2009) Troubleshooting — General Troubleshooting 18
Symptom Charts
Follow the steps in the order indicated below. If an action resolves the issue, retest the system
to verify.
Note: A compilation of Quick Check tables is available at:
http://service.info.apple.com/QRS/en/quickreference.pdf
Startup and Power
No Power, Dead Unit
Unlikely cause: speakers
Quick Check
Symptoms Quick Check
No Power, Dead Unit
No power•
No fan spin•
No startup chime•
No image on external display•
No hard drive or optical drive •
activity
Caps Lock LED on wired •
keyboard doesn’t light when
pressed.
Verify power source.1.
Verify power cable.2.
Listen closely for signs of activity from system 3.
including: rotating fans, hard drive or optical drive
activity, startup chime, etc.
Deep Dive
Check Result Action Code
Power ON system. Verify if 1.
there is any indication that the
system has powered up (fan
rotation, hard drive or optical
drive noise, backlight turns on).
Yes
No Go to step 2.
The symptom is powering
up. Jump to Won’t Start Up
symptom ow.
2009-05-01
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 19
Remove front bezel and locate 2.
diagnostic LED’s on logic board.
Plug power cord into system.
Verify whether diagnostic LED
#1 turns ON.
Yes Trickle voltage being supplied
by power supply. Go to step 3.
No Replace power supply.
Press power button while 3.
monitoring diagnostic LED’s.
Does diagnostic LED #2 turn
ON and remain ON after
pressing the power button?
Disconnect power then remove 4.
power supply and carefully
inspect AC inlet and DC output
connectors and cables for
damage or poor connections.
Were any problems identied?
Inspect power button and 5.
verify that it is properly
connected to the logic board.
Disconnect power button 6.
from logic board and verify
continuity between two pins
when power button is pressed.
Yes
Power supply functioning and
logic board detects supply
voltages. Jump to Won’t Start
Up symptom ow.
No Go to step 5.
Yes Replace damaged part. P16
No Go to step 5.
Yes Visual inspection OK.
Go to step 6.
No Reconnect power button.
X14
Replace rear housing (which
includes power button) or
logic board if damage is
present.
Yes Power button is functioning
correctly. Go to step 6.
No Power button faulty. Replace
X16
rear housing which includes
power button.
2009-05-01
Press power button and verify 7.
whether system turns ON.
Yes
Power supply is functioning.
If system still does not boot
jump to Won’t Start Up
symptom ow.
No Replace power supply. Retest. P01
Note: If No Power symptom persists after all steps have been followed use Minimum
Conguration troubleshooting to proceed. Try disconnecting the hard drive, optical drive,
AirPort, and Bluetooth modules to determine if one of them is preventing the power supply
from functioning.
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 20
Won’t Start Up
Quick Check
Symptoms Quick Check
Won’t Start Up
No startup chime.•
Error tones during startup.•
Grey screen with fan noise, or •
other noise.
Will not progress beyond •
Apple logo or spinning gear.
Isolate OS by starting up from original install 1.
media for the computer, the same make and
model computer in Target Disk Mode, or
compatible known-good OS on an external drive.
Both AirPort and Bluetooth services are available
when booted from the Install disk.
Reset SMC and PRAM to clear any stored, 2.
corrupted information.
Start up in Safe Mode by holding the shift key 3.
down during startup to load only required kernel
extensions and disable all startup and login
items. See KBase article
http://support.apple.com/kb/HT1564
If system generates error tones there may be an 4.
issue with the SDRAM. See KBase article
http://support.apple.com/kb/HT2341
Identifying when in the startup process the 5.
computer hangs can help isolate the issue.
See KBase article
http://support.apple.com/kb/HT2674
for information on the Macintosh startup
sequence, error codes and symbols used.
2009-05-01
Deep Dive
Check Result Action Code
Boot the computer to Apple 1.
Hardware Test on the Install
DVD. Does the computer boot
up to this volume?
Remove the installed SDRAM, 2.
and test with known-good
SDRAM. Does the computer
startup properly now?
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 21
Yes Run the extended tests
and proceed with results. If
AHT passes or boots with a
memory error, go to step 2.
No Go to step 2.
Yes SDRAM issue. Replace SDRAM.
Issue resolved.
No Go to step 3.
X02
Remove the coin battery on 3.
the logic board, and leave out
for approximately 1 minute.
Then reinstall the battery. This
will reset the logic board. Does
the computer startup properly
now?
Yes Issue resolved by logic board
reset. Measure DC voltage
on the battery touching the
battery with the red probe,
and grounding with the black
probe. If voltage is 2.7v or less,
replace the battery. See KBase
article http://support.apple.
com/kb/HT3250 for details
on using a digital multi-meter.
No Go to step 4.
Remove AirPort card and test. 4.
Does the computer startup
properly now?
Disconnect the hard drive SATA 5.
cable and startup to the Install
DVD on the optical drive, or
an external volume. Does the
computer startup properly
now?
Disconnect the optical drive 6.
and test. Does the computer
start without kernel panic now?
Yes
Go to AirPort Card Kernel
Panic symptom ow.
No Go to step 5.
Yes
Go to Hard Drive Not
Recognized symptom ow.
No Go to step 6.
Yes
Go to Optical Drive Not
Recognized symptom ow.
No Replace logic board. M02
2009-05-01
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 22
Intermittent Shutdown
Quick Check
Symptoms Quick Check
Intermittent Shutdown
Powers o during startup.•
Powers o during desktop use.•
Computer restarts •
spontaneously.
Powers o when waking from •
sleep.
Isolate OS by starting up from original Install 1.
media for the computer, the same model
computer in Target Disk Mode, or compatible
known-good OS on an external drive. Both
AirPort and Bluetooth services are available when
booted from the Install disc.
Reset SMC and PRAM to clear any stored, 2.
corrupted information.
Start up in Safe Mode by holding the shift key 3.
down during startup to load only required kernel
extensions and disable all startup and login
items. See KBase article
http://support.apple.com/kb/HT1564
Open System Preferences > Energy Saver > 4.
Schedule and make sure that a ‘Shut Down’ event
is not scheduled.
Make sure that power cord is securely attached to 5.
the back of the computer, and is not hindered by
a desk or other furniture.
Plug the computer directly into an AC outlet to 6.
test whether a surge protector, outlet strip, or UPS
is causing the issue.
2009-05-01
Deep Dive
Check Result Action Code
Verify improper shutdown 1.
by opening the system.log
located in /var/log. Filter the
log for “shutdown cause”. Entries
of value “0” or a negative
value indicate an improper
shutdown. Did you nd entries
of improper shutdown?
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 23
Yes Determine if user caused
improper shutdown. Use
known-good AC power cord
and AC outlet. Go to step 2.
No Revisit Quick Check examples
for possible software issues.
Check if user is running
other automating software
that may be shutting down
system. Verify issue and jump
to appropriate symptom
ow. No repair needed under
current symptom ow.
With known-good AC power 2.
cord and AC outlet, does the
unit continue to shutdown?
Yes Go to step 3.
No AC power cord/ outlet issue.
Issue resolved.
X03
Disconnect the hard drive 3.
power cable from the hard
drive and start the machine
from the Install DVD, the same
make and model computer
in Target Disk Mode, or
compatible known-good OS
on an external drive. Does
the computer continue to
shutdown?
Inspect and reseat DC power 4.
cable and AC inlet connections
to power supply and logic
board. Was damage observed
on the cables or connectors.
Install known-good power 5.
supply. Does system continue
to restart or shutdown?
After logic board replacement. 6.
does the computer continue to
shutdown?
Yes Go to step 4.
No
Possible bad software or hard
drive. Go to Hard Drive Not
Recognized symptom ow.
Yes Replace damaged cable.
Retest. Return to step 1 if
problem continues.
No Go to step 5.
Yes Reinstall original power
supply. Replace logic board.
Go to step 6.
No Power supply issue.
Issue resolved.
Yes Use Minimum Conguration
troubleshooting to isolate
failed module.
X03
P02
2009-05-01
No Logic board issue.
M08
Issue resolved.
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 24
Kernel Panic, System Crashes
Quick Check
Symptoms Quick Check
Kernel Panic, System Crashes
Kernel panic on startup or •
desktop use.
System freeze during use.•
System freeze upon wake from •
sleep.
Isolate OS by starting up system from original 1.
Install media for the computer, the same make
and model computer in Target Disk Mode, or
compatible known-good OS on an external drive.
Both AirPort and Bluetooth services are available
when booted from the Install disc.
Ensure that all software and rmware updates for 2.
the computer have been installed.
Reset SMC and PRAM to clear any stored, 3.
corrupted information.
Start up in Safe Mode by holding the shift key 4.
down during startup to load only required kernel
extensions and disable all startup and login
items. See KBase article
http://support.apple.com/kb/HT1564
Check the panic.log, located /Library/Logs/5.
Panicreporter, for information in the backtrace
that may give clues about the kernel panic.
For more information on kernel panics refer to 6.
KBase article
http://support.apple.com/kb/HT1392
2009-05-01
Deep Dive
Check Result Action Code
Boot the machine to Apple 1.
Hardware Test on the Install
DVD. Does the computer boot
up to this volume?
Remove all peripheral devices 2.
including the keyboard and
mouse. Does computer start
without kernel panic?
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 25
Yes Run the extended tests and
proceed with results. If AHT
passes or boots with a kernel
panic, go to step 2.
No Go to step 2.
Yes Add peripheral devices one at
a time until the kernel panic
repeats. Replace the device
causing the issue.
No Go to step 3.
Use known-good SDRAM in 3.
the system. Does the computer
start without kernel panic now?
Yes Install user’s SDRAM and test.
If kernel panic repeats, replace
SDRAM. Verify that the correct
SDRAM is being used.
No Go to step 4.
X01
Remove AirPort card and 4.
test. Does the computer start
without kernel panic now?
Disconnect the hard drive SATA 5.
cable and startup to the Install
DVD on the optical drive, or
an external volume. Does the
computer start without kernel
panic now?
Disconnect the camera/6.
microphone cable. Does the
computer start without kernel
panic now?
Disconnect the audio board 7.
and test. Does the computer
start without kernel panic now?
Disconnect the optical drive 8.
and test. Does the computer
start without kernel panic now?
Yes
Go to AirPort Card Kernel
Panic symptom ow.
No Go to step 5.
Yes
Go to Hard Drive Not
Recognized symptom ow.
No Go to step 6.
Yes
Go to Camera Issues
symptom ow.
No Go to step 7.
Yes Replace audio board. X99
No Go to step 8.
Yes
Go to Optical Drive Not
Recognized symptom ow
No Replace logic board.
2009-05-01
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 26
No Video
Unlikely cause: hard drive, optical drive, speakers, camera, microphone
Quick Check
Symptoms Quick Check
No Video
No image.•
Backlight failure.•
Check brightness setting.1.
For no-video issues, connect an external 2.
display to verify whether iMac video circuitry is
functioning. If image appears on external display
go to Backlight Issue/No Backlight symptom
ow.
Reset SMC.3.
Deep Dive
Check Result Action Code
Verify boot chime present and 1.
fans running when system
powered ON. (Reset SMC and
clear PRAM if necessary for
proper boot up.)
Verify whether image is visible 2.
on LCD panel.
Yes Power ON self test OK. Boot
sequence started.
Go to step 2.
No
Yes Video present. Verify system
Go to Won’t Start Up
symptom ow.
functionality and return to
user or jump to appropriate
troubleshooting ow.
2009-05-01
Connect supported external 3.
display. Verify whether image
appears on external display
when system is booted.
Remove glass panel and front 4.
bezel. Do all three diagnostic
LED’s turn ON shortly after the
system is powered ON?
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 27
No Go to step 3.
Yes
No Go to step 4.
Yes
No Replace logic board. Retest. M03
External display detected by
system. Video circuitry on
logic board functional. Go to
Backlight Issue/No Backlight
symptom ow.
Internal video circuitry
functional and
communicating with LCD
panel. Go to Backlight Issue/
No Backlight symptom ow.
Corrupted Video
Unlikely cause: power supply, hard drive, optical drive, fans, speakers, camera, microphone
Quick Check
Symptoms Quick Check
Corrupted Video
Text and graphics appear fuzzy•
Image corrupted•
Deep Dive
Set System Preferences/Display LCD panel to 1.
native resolution. Non-native resolutions are
unable to produce optimal clarity.
Make sure all relevant software updates have 2.
been applied. Graphics driver updates may be
included with software updates.
When the issue occurs take a screenshot of the 3.
display (Command-Shift-3). View the screen shot
le on another known-good computer. If the
image corruption can be seen in the screenshot
then the issue is with the video drivers, software,
or video/logic board. If the issue cannot be seen
in the screenshot then the LCD panel and LVDS
cable should be tested further.
Clean the outside surface of glass panel using 4.
provided cleaning cloth.
Boot from install DVD or another known-good 5.
volume to determine whether a potential
software/driver issue exists.
2009-05-01
Check Result Action Code
Boot from Install DVD and 1.
verify whether issue is still
visible.
Verify whether issue is visible 2.
on an external display attached
to the DisplayPort.
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 28
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.
Yes Issue is NOT caused by
internal LCD panel.
Go to step 3.
No Go to step 5.
Remove logic board, inspect 3.
connectors for damage or
corrosion then reinstall. Verify
whether issue still occurs.
Yes Replace logic board.
Go to step 4.
No Issue likely caused by poor
connection. Return computer
to user.
M04
M04
Verify whether issue is still 4.
present with replacement logic
board installed.
Remove LVDS cable from LCD 5.
panel and logic board and
carefully verify whether there
is damage to the cable or
connectors.
Verify whether issue is still 6.
visible after reinstalling LVDS
cable.
Verify whether issue is still 7.
present with replacement LCD
panel installed.
Yes Return to step 1 and retest. X04
No Issue resolved with
M04
replacement logic board.
Return computer to user.
Yes Replace LVDS cable.
No Reinstall LVDS cable.
Go to step 6.
Yes Replace LCD panel.
Go to step 7.
No Issue resolved with
M04
replacement logic board.
Return computer to user.
Yes Return to step 1 and retest.
No Issue resolved with
L04
replacement LCD panel.
Return computer to user.
2009-05-01
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 29
Burnt Smell/Odor
Unlikely cause: speakers, microphone, enclosure
Quick Check
Symptoms Quick Check
Burnt Smell/Odor
Burning smell•
Unusual odor•
Verify source of smell/odor is emanating from the 1.
system.
If system is new refer to KBase article 2.
http://support.apple.com/kb/TA22044
for information on new computer odors.
Disconnect all third-party devices and conrm 3.
whether the odor is being generated by the
device.
Inspect air intake and air outlets for obstructions. 4.
To prevent overheating make sure there
is sucient clearance to allow air to ow
unobstructed into and out of the system.
Verify whether system is functional.5.
Deep Dive
Check Result Action Code
Verify whether the source of 1.
the odor can be identied
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 aected module(s).
Go to step 2
No Unable to locate source of
odor. Go to step 3.
P08
2009-05-01
Disconnect all third-party 2.
devices and cables. Power ON
system and verify whether
smoke or strong odor returns.
iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power 30
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.
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