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 effort has been made to ensure that the information in this document is accurate. Apple is not responsible for printing or clerical errors.

Apple

1 Infinite 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

Differences Between Models  9

Product Configuration  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 Specifications						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:Specific 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)					117
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 differences 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 first.

•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.

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

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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

Differences Between Models

The iMac (20-inch, Early 2009) and iMac (20-inch, Mid 2009) computers are very similar. The differences are that the Mid 2009 model does not have IR (Infrared) or Bluetooth, and has a smaller capacity hard drive (160GB).

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iMac (20-inch, Early/Mid 2009) Basics — Overview  9

Product Configuration

To confirm the configuration 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 configuration at introduction:

Feature	Specification
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

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.

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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 firmware updates have been applied.

Firmware Updates

Firmware is the name given to software that is written into memory circuits such as flash memory, that will hold the software code indefinitely, 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 firmware versions for Intel Macs can be found in the following Apple Knowledge Base article:

kBase #HT1237:EFI and SMC firmware 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

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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 fifth digits in the system serial number. See examples below.

•Apple Hardware Test 3A156 to be used on systems with the third, fourth, and fifth 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 fifth 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-specification or no SDRAM or the RAM installed does not meet the appropriate specifications, 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 off.

•The solution to both of these situations is to first re-seat the memory and test the computer again. If the memory fails the POST test again, try memory that has been verified to work correctly on another system (i.e.,“known-good”) or order new memory.

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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:

1.Make sure the computer is shut down.

2.Press the power button.

3.Immediately after you hear the startup tone, press and hold the Shift key.

Note:The Shift key should be held as soon as possible after the startup tone but not before.

4.Release the Shift key when you see the screen with the gray Apple and progress indicator (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)

1.If the computer is on, turn it off.

2.Locate the following keys on the keyboard:Command, Option, P, and R.You will need to hold these keys down simultaneously in Step 4.

Note: If the keyboard does not have an Option key, use the Alt key instead.

3.Turn on the computer.

4.Press and hold the Command-Option-P-R keys. A simple way to do this with one hand is to put your right pinky finger on P, your right index finger 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.

5.Hold the keys down until the computer restarts and you hear the startup sound for the second time.

6.Release the keys.

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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 off, 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 suffice. If your computer isn’t responding, perform these steps one at a time, in this order, until the issue has been resolved:

1.Force Quit (Option-Command-Escape)

2.Restart (Control-Command-Power)

3.Force Shut Down (press the power button for 10 seconds)

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

1.From the Apple menu, choose Shut Down (or if the computer is not responding, hold the power button for approximately ten seconds until it powers off).

2.Unplug all cables from the computer, including the power cord.

3.Wait at least 15 seconds.The SMC reset occurs automatically once the iMac has been unplugged from the AC power source for several seconds.

4.Plug power cord back in, making sure the power button is not being pressed at the time.

5.Reconnect keyboard and mouse to the computer.

6.Press power button on the back to start up the computer.

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).

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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 off 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 configurations 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.

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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.

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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.

			12V in 20”
AC Inlet
			AC/DC	Temperature	Optical Drive
					SATA II	Temperature
				Sensor
						Sensor
						Inverter
Camera	Microphone		Hard Drive		ODD Fan
USB 2.0			SATA II	Temperature
				Sensor
				HD Fan		Display
						Temperature
						Sensor
				MLB
		USB 2.0		PCIe x1		USB 2.0
					Antenna
Power Button		IR Sensor		802.11n		Bluetooth
		DDR3-1066		DDR3-1066	Antenna	Antenna
	Ambient
Temperature
CPU Fan	Sensor	SO-DIMM		SO-DIMM	Audio Board
Speaker						Speaker

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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		1.	Verify power source.
	•	No power	2.	Verify power cable.
	•	No fan spin
			3.	Listen closely for signs of activity from system
	•	No startup chime
				including:rotating fans, hard drive or optical drive
	• No image on external display
				activity, startup chime, etc.

•No hard drive or optical drive activity

•Caps Lock LED on wired keyboard doesn’t light when pressed.

Deep Dive

Check	Result	Action	Code
1. Power ON system.Verify if	Yes	The symptom is powering
there is any indication that the		up. Jump to Won’t Start Up
system has powered up (fan		symptom flow.
rotation, hard drive or optical
drive noise, backlight turns on).	No	Go to step 2.

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  19

2.	Remove front bezel and locate	Yes	Trickle voltage being supplied
	diagnostic LED’s on logic board.		by power supply. Go to step 3.
	Plug power cord into system.
		No	Replace power supply.
	Verify whether diagnostic LED
	#1 turns ON.
3.	Press power button while	Yes	Power supply functioning and
	monitoring diagnostic LED’s.		logic board detects supply
	Does diagnostic LED #2 turn		voltages. Jump to Won’t Start
	ON and remain ON after		Up symptom flow.
	pressing the power button?
		No	Go to step 5.
4.	Disconnect power then remove	Yes	Replace damaged part.	P16
	power supply and carefully
	inspect AC inlet and DC output
	connectors and cables for	No	Go to step 5.
	damage or poor connections.
	Were any problems identified?
5.	Inspect power button and	Yes	Visual inspection OK.
	verify that it is properly		Go to step 6.
	connected to the logic board.
		No	Reconnect power button.	X14
			Replace rear housing (which
			includes power button) or
			logic board if damage is
			present.
6.	Disconnect power button	Yes	Power button is functioning
	from logic board and verify		correctly. Go to step 6.
	continuity between two pins
	when power button is pressed.	No	Power button faulty. Replace	X16
			rear housing which includes
			power button.
7.	Press power button and verify	Yes	Power supply is functioning.
	whether system turns ON.		If system still does not boot
			jump to Won’t Start Up
			symptom flow.
		No	Replace power supply. Retest.	P01

Note:If No Power symptom persists after all steps have been followed use Minimum Configuration 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.

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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	1.	Isolate OS by starting up from original install
	• No startup chime.		media for the computer, the same make and
	• Error tones during startup.		model computer in Target Disk Mode, or
			compatible known-good OS on an external drive.
	• Grey screen with fan noise, or
			Both AirPort and Bluetooth services are available
	other noise.
			when booted from the Install disk.
	• Will not progress beyond
		2.	Reset SMC and PRAM to clear any stored,
	Apple logo or spinning gear.
			corrupted information.
		3.	Start up in Safe Mode by holding the shift key
			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
		4.	If system generates error tones there may be an
			issue with the SDRAM. See KBase article
			http://support.apple.com/kb/HT2341
		5.	Identifying when in the startup process the
			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.

Deep Dive

Check		Result	Action	Code
1.	Boot the computer to Apple	Yes	Run the extended tests
	Hardware Test on the Install		and proceed with results. If
	DVD. Does the computer boot		AHT passes or boots with a
	up to this volume?		memory error, go to step 2.
		No	Go to step 2.
2.	Remove the installed SDRAM,	Yes	SDRAM issue. Replace SDRAM.	X02
	and test with known-good		Issue resolved.
	SDRAM. Does the computer
		No	Go to step 3.
	startup properly now?

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  21

3. Remove the coin battery on	Yes	Issue resolved by logic board
the logic board, and leave out		reset. Measure DC voltage
for approximately 1 minute.		on the battery touching the
Then reinstall the battery.This		battery with the red probe,
will reset the logic board. Does		and grounding with the black
the computer startup properly		probe. If voltage is 2.7v or less,
now?		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.
4. Remove AirPort card and test.	Yes	Go to AirPort Card Kernel
Does the computer startup		Panic symptom flow.
properly now?
	No	Go to step 5.
5. Disconnect the hard drive SATA	Yes	Go to Hard Drive Not
cable and startup to the Install		Recognized symptom flow.
DVD on the optical drive, or
an external volume. Does the
	No	Go to step 6.
computer startup properly
now?
6. Disconnect the optical drive	Yes	Go to Optical Drive Not
and test. Does the computer		Recognized symptom flow.
start without kernel panic now?
	No	Replace logic board.	M02

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  22

Intermittent Shutdown

Quick Check

Symptoms		Quick Check
Intermittent Shutdown		1.	Isolate OS by starting up from original Install
•	Powers off during startup.		media for the computer, the same model
• Powers off during desktop use.			computer in Target Disk Mode, or compatible
			known-good OS on an external drive. Both
•	Computer restarts
			AirPort and Bluetooth services are available when
	spontaneously.
			booted from the Install disc.
• Powers off when waking from
		2.	Reset SMC and PRAM to clear any stored,
	sleep.
			corrupted information.
		3.	Start up in Safe Mode by holding the shift key
			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
		4.	Open System Preferences > Energy Saver >
			Schedule and make sure that a‘Shut Down’event
			is not scheduled.
		5.	Make sure that power cord is securely attached to
			the back of the computer, and is not hindered by
			a desk or other furniture.
		6.	Plug the computer directly into an AC outlet to
			test whether a surge protector, outlet strip, or UPS
			is causing the issue.
Deep Dive
Check		Result		Action		Code
1.	Verify improper shutdown		Yes	Determine if user caused
	by opening the system.log			improper shutdown. Use
	located in /var/log. Filter the			known-good AC power cord
	log for“shutdown cause”.Entries			and AC outlet. Go to step 2.
	of value“0”or a negative
			No	Revisit Quick Check examples
	value indicate an improper
	shutdown. Did you find entries			for possible software issues.
	of improper shutdown?			Check if user is running
				other automating software
				that may be shutting down
				system.Verify issue and jump
				to appropriate symptom
				flow. No repair needed under
				current symptom flow.

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	2. With known-good AC power	Yes	Go to step 3.
	cord and AC outlet, does the
		No	AC power cord/ outlet issue.	X03
	unit continue to shutdown?
			Issue resolved.
	3. Disconnect the hard drive	Yes	Go to step 4.
	power cable from the hard
	drive and start the machine
	from the Install DVD, the same
	make and model computer	No	Possible bad software or hard
	in Target Disk Mode, or		drive. Go to Hard Drive Not
	compatible known-good OS		Recognized symptom flow.
	on an external drive. Does
	the computer continue to
	shutdown?
	4. Inspect and reseat DC power	Yes	Replace damaged cable.	X03
	cable and AC inlet connections		Retest. Return to step 1 if
	to power supply and logic		problem continues.
	board.Was damage observed
		No	Go to step 5.
	on the cables or connectors.
	5. Install known-good power	Yes	Reinstall original power
	supply. Does system continue		supply. Replace logic board.
	to restart or shutdown?		Go to step 6.
		No	Power supply issue.	P02
			Issue resolved.
	6. After logic board replacement.	Yes	Use Minimum Configuration
	does the computer continue to		troubleshooting to isolate
	shutdown?		failed module.
		No	Logic board issue.	M08
			Issue resolved.

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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	1.	Isolate OS by starting up system from original
	• Kernel panic on startup or		Install media for the computer, the same make
	desktop use.		and model computer in Target Disk Mode, or
			compatible known-good OS on an external drive.
	• System freeze during use.
			Both AirPort and Bluetooth services are available
	• System freeze upon wake from
			when booted from the Install disc.
	sleep.
		2.	Ensure that all software and firmware updates for
			the computer have been installed.
		3.	Reset SMC and PRAM to clear any stored,
			corrupted information.
		4.	Start up in Safe Mode by holding the shift key
			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
		5.	Check the panic.log, located /Library/Logs/
			Panicreporter, for information in the backtrace
			that may give clues about the kernel panic.
		6.	For more information on kernel panics refer to
			KBase article
			http://support.apple.com/kb/HT1392

Deep Dive

Check		Result	Action	Code
1.	Boot the machine to Apple	Yes	Run the extended tests and
	Hardware Test on the Install		proceed with results. If AHT
	DVD. Does the computer boot		passes or boots with a kernel
	up to this volume?		panic, go to step 2.
		No	Go to step 2.
2.	Remove all peripheral devices	Yes	Add peripheral devices one at
	including the keyboard and		a time until the kernel panic
	mouse. Does computer start		repeats. Replace the device
	without kernel panic?		causing the issue.
		No	Go to step 3.

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  25

3.	Use known-good SDRAM in	Yes	Install user’s SDRAM and test.	X01
	the system. Does the computer		If kernel panic repeats, replace
	start without kernel panic now?		SDRAM.Verify that the correct
			SDRAM is being used.
		No	Go to step 4.
4.	Remove AirPort card and	Yes	Go to AirPort Card Kernel
	test. Does the computer start		Panic symptom flow.
	without kernel panic now?
		No	Go to step 5.
5.	Disconnect the hard drive SATA	Yes	Go to Hard Drive Not
	cable and startup to the Install		Recognized symptom flow.
	DVD on the optical drive, or
	an external volume. Does the	No	Go to step 6.
	computer start without kernel
	panic now?
6.	Disconnect the camera/	Yes	Go to Camera Issues
	microphone cable. Does the		symptom flow.
	computer start without kernel
		No	Go to step 7.
	panic now?
7.	Disconnect the audio board	Yes	Replace audio board.	X99
	and test. Does the computer
	start without kernel panic now?	No	Go to step 8.
8.	Disconnect the optical drive	Yes	Go to Optical Drive Not
	and test. Does the computer		Recognized symptom flow
	start without kernel panic now?
		No	Replace logic board.

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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		1.	Check brightness setting.
•	No image.	2. For no-video issues, connect an external
•	Backlight failure.
			display to verify whether iMac video circuitry is
			functioning. If image appears on external display
			go to Backlight Issue/No Backlight symptom
			flow.
		3.	Reset SMC.
Deep Dive
Check		Result		Action	Code
1.	Verify boot chime present and		Yes	Power ON self test OK. Boot
	fans running when system			sequence started.
	powered ON. (Reset SMC and			Go to step 2.
	clear PRAM if necessary for
			No	Go to Won’t Start Up
	proper boot up.)
				symptom flow.
2.	Verify whether image is visible		Yes	Video present.Verify system
	on LCD panel.			functionality and return to
				user or jump to appropriate
				troubleshooting flow.
			No	Go to step 3.
3.	Connect supported external		Yes	External display detected by
	display.Verify whether image			system. Video circuitry on
	appears on external display			logic board functional. Go to
	when system is booted.			Backlight Issue/No Backlight
				symptom flow.
			No	Go to step 4.
4.	Remove glass panel and front		Yes	Internal video circuitry
	bezel. Do all three diagnostic			functional and
	LED’s turn ON shortly after the			communicating with LCD
	system is powered ON?			panel. Go to Backlight Issue/
				No Backlight symptom flow.
			No	Replace logic board. Retest.	M03

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  27

Corrupted Video

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

Quick Check

Symptoms	Quick Check
Corrupted Video	1.	Set System Preferences/Display LCD panel to
• Text and graphics appear fuzzy		native resolution. Non-native resolutions are
• Image corrupted		unable to produce optimal clarity.
	2.	Make sure all relevant software updates have
		been applied. Graphics driver updates may be
		included with software updates.
	3.	When the issue occurs take a screenshot of the
		display (Command-Shift-3).View the screen shot
		file 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.
	4.	Clean the outside surface of glass panel using
		provided cleaning cloth.
	5.	Boot from install DVD or another known-good
		volume to determine whether a potential
		software/driver issue exists.
Deep Dive
Check	Result		Action		Code
1. Boot from Install DVD and		Yes	Go to step 2.
verify whether issue is still
		No	Issue likely caused by
visible.
			software or driver issue.
			Troubleshoot for software
			issues. Make sure all software
			updates have been installed.
2. Verify whether issue is visible		Yes	Issue is NOT caused by
on an external display attached			internal LCD panel.
to the DisplayPort.			Go to step 3.
		No	Go to step 5.

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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  28

3.	Remove logic board, inspect	Yes	Replace logic board.	M04
	connectors for damage or		Go to step 4.
	corrosion then reinstall.Verify
		No	Issue likely caused by poor	M04
	whether issue still occurs.
			connection. Return computer
			to user.
4.	Verify whether issue is still	Yes	Return to step 1 and retest.	X04
	present with replacement logic
	board installed.	No	Issue resolved with	M04
			replacement logic board.
			Return computer to user.
5.	Remove LVDS cable from LCD	Yes	Replace LVDS cable.
	panel and logic board and
		No	Reinstall LVDS cable.
	carefully verify whether there
	is damage to the cable or		Go to step 6.
	connectors.
6.	Verify whether issue is still	Yes	Replace LCD panel.
	visible after reinstalling LVDS		Go to step 7.
	cable.
		No	Issue resolved with	M04
			replacement logic board.
			Return computer to user.
7.	Verify whether issue is still	Yes	Return to step 1 and retest.
	present with replacement LCD
		No	Issue resolved with	L04
	panel installed.
			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		1.	Verify source of smell/odor is emanating from the
•	Burning smell		system.
•	Unusual odor	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		Result	Action	Code
1.	Verify whether the source of	Yes	Replace affected module(s).	P08
	the odor can be identified		Go to step 2
	by visually inspecting each
		No	Unable to locate source of
	module and its associated
			odor. Go to step 3.
	cables for signs of burned or
	damaged components, smoke
	residue, burned traces, or
	melted or damaged wiring,
2.	Disconnect all third-party	Yes	Power down system
	devices and cables. Power ON		immediately. Go to step 3.
	system and verify whether
		No	System functions correctly.
	smoke or strong odor returns.
			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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iMac (20-inch, Early/Mid 2009) Symptom Charts — Startup and Power  30