Apple imac 24 early 09 Service Manual

Apple Technician Guide

iMac (24-inch, Early 2009)

2009-03-03

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 (24-inch, Early 2009)

Contents

Manual Updates  8

Basics

Overview  10

Product Features  10

Product Configurations  11

Safety Precautions  12

Serial Number Location  13

Troubleshooting

General Troubleshooting		15
Diagnostic LEDs  15
Sensor and Fan Connector Locations  18
Troubleshooting Theory	19
Hardware vs. Software	19
Power On Self Test (POST)		19
Firmware Updates  19
How to Reset the System Management Controller (SMC)  20
To reset the SMC on an iMac  20
Block Diagram  21

Symptom Charts	22
Startup and Power		22
No Power, Dead Unit  22
Won’t Start Up	24
Intermittent Shutdown  26
Kernel Panic, System Crashes				28
No Video  30
Corrupted Video		32
Burnt Smell/Odor		34
Uncategorized Symptoms			35
Display  36
Backlight Issue/No Backlight				36
Noise / Unstable Flickering			39
LCD Image Issues		42
Incorrect/Missing Colors  43

Distorted/Blurred Image			44
Pixel Anomalies	47
Vertical/Horizontal Lines			48
Non-Uniform Brightness			50
Cosmetic Defects  51
Uncategorized Symptoms				51
Mass Storage  52
Hard Drive Not Recognized				52
Hard Drive Read/Write Error				54
Hard Drive Noisy	55
Optical Drive Not Recognized  57
Optical Drive Won’t Accept/Eject Media					58
Optical Drive Read/Write Error  60
Optical Drive Not Performing to Specifications						61
Optical Drive Noisy		62
Uncategorized Symptoms				64
Communications	65
AirPort/Bluetooth Issues			65
AirPort Card Kernel Panic			67
Ethernet Port/Device Issue				68
Wireless Input Device Doesn’t Pair  69
Wireless Input Device Loses Connection					71
Uncategorized Symptoms				73
Input/Output Devices		74
Apple Remote Inoperable			74
Audio:Microphone		76
Audio:Built-in Speakers Have Distorted Sound						77
Audio:Built-in Speakers Have No Audio					79
Camera Issues  81
FireWire Devices Not Recognized  82
USB Devices Not Recognized  84
Wired Keyboard Does Not Function Properly						86
Keyboard:Specific Keys Do Not Respond					88
Wired Keyboard/Mouse Not Recognized					88
Uncategorized Symptoms				90
Mechanical  91
Noise/Hum/Vibration  91
System Runs Hot	94
Stand/Hinge Issues		95
Physical Damage	96
Uncategorized Symptoms				96

Take Apart

General Information  98

General Tools  98
Opening the Unit	98
Required Special Tools for Glass Panel			98
Cleaning Tools Starter Kit		99
Cleaning Tool Resources		99
Cleaning & Handling the Glass Panel			100
Do’s and Don’ts  100
Handling a Broken Glass Panel  100
Safety  101
Logic Board Handling  102
Serial Number Location		103
Reassembly Steps	103
Screw Sizes  103

Access Door  104

Memory  106

Removal  107

Reassembly  107

Glass Panel  108

Removal  109

Reassembly  110

Front Bezel  114

Removal  115

Reassembly  117

Camera  118

Battery  120

Removal  121

Reassembly  121

IR Board  122

AirPort Extreme Card  124

Bluetooth Board  126

LCD Display Panel  128

Ambient Temp Sensor  132

Left Speaker  134

LVDS Display Cable  136

Right Speaker  138

Inverter Cable  140

Optical Drive Fan  142

CPU Fan  144

Power Supply  146

Hard Drive  149

Removal  150

Reassembly  152

Hard Drive Sensor Cable  154

Optical Drive  156

Optical Data Cable  159

Optical Sensor Cable  161

Logic Board  163

Removal  164

Reassembly  166

Handling Logic Boards  167

Video Card  168

Hard Drive Fan  171

Audio Board  173

Hard Drive Data Cable  175

Mechanism Cover  177

Stand  179

Removal  180

Reassembly  181

Mechanism  183

Chassis  185

Camera Cable  187

Microphone Cable  189

Cable, DC,Power Supply/SATA  191

Rear Housing  194

Views

Exploded View  197

Screw Chart  199

Internal Views   202

I/O Ports  204

Manual Updates

Manual introduced 3 March 2009.

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iMac (24-inch, Early 2009) Basics — Manual Updates  8

Apple Technician Guide

Basics

iMac (24-inch, Early 2009)

© 2008 Apple Inc. All rights reserved.

Overview

Product Features

The iMac (24-inch, Early 2009) computer features include:

•Increased processor speeds:2.66, 2.93, 3.06GHz

•Ultrafast NVIDIA graphics

•Mini DisplayPort

•Four USB 2.0 ports

•One FireWire 800 port

•Increased hard drive capacity:640/1TB

•Double the memory, 4GB of memory standard

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iMac (24-inch, Early 2009) Basics — Overview  10

Product Configurations

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 iMac (24-inch, Early 2009) model configurations at introduction:

Feature	Better	Best			Ultimate
Intel Intel Core 2	2.66 GHz, 1066MHz frontside bus, 6MB	2.93GHz/3.06			3.06GHz
Duo processor	shared L2 cache	GHz (CTO)
Memory	4GB (2 x 2GB SO-DIMMs) 1066 MHz DDR3 (CTO:Up to 8GB)
Hard Drive, Serial	640GB , 7200 rpm, (CTO:Up to 1TB)			1TB (7200 rpm
ATA
Optical Drive	8x SATA SuperDrive
Display	24”wide 1920 x 1200 94.1 ppi:IPS 400 nits, 14 lamps, glossy
Graphics	NVIDIA GeForce 9400M with 256MB of	NVIDIA GeForce			NVIDIA
	shared DDR3 memory	GT 120 with			GeForce GT
		256MB of			130 with
		GDDR3 memory,			512MB of
		(CTO:NVDIA			GDDR3
		GeForce GT 130			memory,
		or ATI Radeon			(CTO:ATI
		HD 4850 with			Radeon
		512MB of GDDR3			HD 4850
		memory)			with 512MB
					of GDDR3
					memory)
Audio I/O	Combo digital/analog in, Combo digital/heaphone out, Mic, Stereo
	speakers, 4 channel audio
Wireless	Mini PCIe 802.11a/b/g/n, Bluetooth 2.1
Input Devices	Wired mouse, no remote, no modem	Wired keyboard			Wireless
		and mouse,			keyboard
		wireless (CTO)			and mouse
I/O	Four USB 2.0 ports, two USB 2.0 ports on keyboard, one FW 800, Mini
	DisplayPort
Video I/O	Built-in iSight camera, MiniDisplayPort output for DVI, dual-link DVI, and
	VGA video (requires adapters, sold separately)
Power Supply	250W universal supply

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iMac (24-inch, Early 2009) Basics — Overview  11

Safety Precautions

Warning:HIGH VOLTAGE:The AC/DC power supply PCB remains powered up whenever the system is plugged in, whether or not the system has been turned on. Use extreme caution when troubleshooting the system with the front bezel removed.

WARNING: If the computer is shut down by removing the power cord, allow the power supply a good 2-3 minutes to discharge the capacitors before handling it. However, if you select“Shut Down”via the Apple menu, the computer will discharge the power supply capacitor almost immediately.

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iMac (24-inch, Early 2009) Basics — Overview  12

Serial Number Location

The iMac (24-inch, Early 2009) 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 (24-inch, Early 2009) Basics — Overview  13

Apple Technician Guide

Troubleshooting

iMac (24-inch, Early 2009)

© 2008 Apple Inc. All rights reserved.

General Troubleshooting

Diagnostic LEDs

Depending on the iMac model, it has either three or four 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. Refer to the next two pages for close-up pictures of the troubleshooting LEDs.

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iMac (24-inch, Early 2009) — General Troubleshooting 15

LED #1

•Indicates that the trickle voltage from the power supply has been detected by the main 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 that 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

•Indicates that the computer and the video card are communicating.This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement. Note:this LED is not used on systems with the integrated graphics.

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iMac (24-inch, Early 2009) — General Troubleshooting 16

LED #4

•Indicates that 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 (24-inch, Early 2009) — General Troubleshooting 17

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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iMac (24-inch, Early 2009) — General Troubleshooting 18

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 article:

kBase #HT1199:Mac OS X:How to troubleshoot a software issue

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.

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 Knowledge Base article 303880 Mac OS X:Firmware Updates for Intel-based Macs.

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iMac (24-inch, Early 2009) — General Troubleshooting 19

How to Reset 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.

•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.

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

5.Reconnect your keyboard and mouse to the computer.

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

Note:The iMac does not have a button on the main logic board for resetting the SMC, which eliminates the need to remove the computer’s cover to reset it (as required for some other models).

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iMac (24-inch, Early 2009) — General Troubleshooting 20

Block Diagram

Refer to this diagram to see how modules are interrelated.

			24V
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
MXM	Temperature			HD Fan		Display
(optional in 24”)
	Sensor					Temperature
	(if MXM present)
						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 (24-inch, Early 2009) — General Troubleshooting 21

Symptom Charts

Follow the steps in the order indicated below. If an action resolves the issue, retest the system to verify.

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 (24-inch, Early 2009) Symptom Charts — Startup and Power  22

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 (24-inch, Early 2009) Symptom Charts — Startup and Power  23

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 (24-inch, Early 2009) Symptom Charts — Startup and Power  24

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 (24-inch, Early 2009) Symptom Charts — Startup and Power  25

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 make and
• Powers off during desktop use.			model computer in Target Disk Mode, or
			compatible known-good OS on an external drive.
•	Computer restarts
			Both AirPort and Bluetooth services are available
	spontaneously.
			when booted from the Install disk.
• 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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iMac (24-inch, Early 2009) Symptom Charts — Startup and Power  26

	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 (24-inch, Early 2009) Symptom Charts — Startup and Power  27

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 disk.
	sleep.
		2.	Ensure that all software and firmware updates
			for the computer have been installed to take
			advantage of any available bug fixes.
		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 (24-inch, Early 2009) Symptom Charts — Startup and Power  28

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 Defective Camera
	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 Disc Drive Not
	and test. Does the computer		Recognized symptom flow
	start without kernel panic now?
		No	Replace logic board.

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iMac (24-inch, Early 2009) Symptom Charts — Startup and Power  29

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.		No Video symptom flow.
		No	Go to step 4.

2009-03-03

iMac (24-inch, Early 2009) Symptom Charts — Startup and Power  30