Apple iMac 21 late 2009 Service Manual

Apple Technician Guide

iMac (21.5-inch, Late 2009)

Updated: 2009-11-24

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 (21.5-inch, Late 2009)

Contents

About This Guide

Updates  9

Updated 24 November 2009   9

Updated 28 October 2009   9

Introduced 20 October 2009   9

Feedback  9

Basics

Overview  11

Identifying Features  11

Product Configurations  12

Wireless Troubleshooting  12

Safety  12

Serial Number Location  13

Troubleshooting

General Troubleshooting			15
Wireless Troubleshooting			15
Update System Software & Firmware				15
Troubleshooting Theory		15
Hardware vs. Software		15
Common Reset Procedures  16
Power On Self Test (POST)			16
Resetting the System Management Controller (SMC)  16
Resetting Parameter RAM (PRAM)  17
Starting Up in Safe Mode			17
Apple Service Diagnostics			18
Diagnostic LEDs	19
LED Functions	20
LED Startup Sequence		21
Logic Board Test Points		22
Sensor and Fan Connector Locations				23
Block Diagram	24

Symptom Charts  25

Startup and Power  25

No Power, Dead Unit  25

Won’t Start Up  27

Intermittent Shutdown  29

Kernel Panic, System Crashes  31

No Video  33

Corrupted Video  34

Burnt Smell/Odor  37

Uncategorized Symptoms  38

Display  39

Backlight Issue/No Backlight  39

Noise / Unstable Flickering  41

LCD Image Issues  43

Incorrect/Missing Colors  44

Distorted/Blurred Image  45

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 Errors	54
Hard Drive Noisy  55
Optical Drive Not Recognized	57
Optical Drive Won’t Accept/Eject Media  58
Optical Drive Read/Write Error	59

Optical Drive Not Performing to Specifications  61 Optical Drive Noisy  62

SD Card Will Not Insert Into Slot  63

SD Card Not Recognized		64
Uncategorized Symptoms		65
Communications  66
AirPort/Bluetooth Issues		66
AirPort Card Kernel Panic		68
Ethernet Port/Device Issue  69
Wireless Input Device Doesn’t Pair  70
Wireless Input Device Loses Connection			72
Uncategorized Symptoms		74
Input/Output Devices	75
Apple Remote Inoperable		75
Audio:Microphone	77
Audio:Built-in Speakers Have Distorted Sound  78
Audio:Built-in Speakers Have No Audio			79

Camera Issues  81

FireWire Device Not Recognized  82

USB Device 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

Fan Failures / Thermal Issues  94

Stand/Hinge Issues  95

Physical Damage  96

Uncategorized Symptoms  96

Take Apart

General Information  98

Opening the Unit  98
Required Tools	98
Required Special Tools for Glass Panel			99
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
How to Remove a Broken Glass Panel			101
Safety  105

Logic Board Handling  106

Note About Images in This Guide  106

Access Door  107

Memory  109

Glass Panel  111

Removal  112

Reassembly  113

Camera  116

LCD Panel  118

Vertical Sync Cable  122

LCD Temp Sensor Cable  123

LVDS Cable  124

Bluetooth Antenna  125
Bluetooth Board				127
AirPort Antenna				129
AirPort Card			131
AirPort Cable			133
AirPort Carrier Board					135
LED Backlight Board					137
Power Supply			139
Backlight Pressure Wall						141
Power Supply Pressure Wall							143
Hard Drive		145
Hard Drive Sensor Cable						148
Bluetooth Cable				150
Camera Cable			153
Optical Drive			156
Optical Drive Sensor Cable							159
Optical Drive Fan				161
SD Board	163
SD Cable	165
Audio Cable			167
IR Board & Cable				169
Logic Board		171
Video Card		178
Battery  180
Hard Drive Data Cable  182
Optical Drive Data Cable						184

Cable, AC/DC Power/Backlight/SATA  186

CPU Fan  187

Ambient Temp Sensor  190

Left Speaker  192

Right Speaker  194

Hard Drive Fan  196

Mechanism Cover  198

Stand  200

Mechanism  202

Microphone Cable  204

Rear Housing  205

Views

Exploded Views		208
iMac (21.5-inch, Late 2009), Part 1			208
iMac (21.5-inch, Late 2009), Part 2			209
iMac (21.5-inch, Late 2009), Part 3			210
Screw Chart	211
External Views		213
Front View  213
Rear View	214
I/O Ports	215

Internal Views  216

Photo of Components below LCD  216 Photo of Components below Logic Board  217

Logic Board, Front Side	218
Logic Board, Back Side	218

Apple Technician Guide

About This Guide

iMac (21.5-inch, Late 2009)

© 2009 Apple Inc. All rights reserved.

Updates

Updated 24 November 2009

Troubleshooting

•General:Updated close-up image of diagnostic LEDs.

•Mechanical:Fan noise issues:updated two topics,“Noise/Hum/Vibration”and“Fan Failures/ Thermal Issues”with the following information:

•Check:Verify if any tape, gasket, cable label, or cable is touching the fan blades and causing a ticking noise.

•Actions:Secure the material so it doesn’t touch fan blades. If tape adhesive has lost its stickiness, replace that section of tape.

Take Apart

•General Information:Added images to section“How to Remove a Broken Glass Panel.”

•Hard Drive and Hard Drive Sensor Cable:Added information about connecting sensor cables to Western Digital drives:Orient the drive with its circuit board facing up and connect the sensor cable to the hard drive pins, leaving the 2 left pins unconnected (exposed).

•Logic Board:Added note that logic board may be easier to remove if RAM is removed first.

Views

•Exploded Views:Added part numbers for Power Supply Pressure Wall (922-9281), Backlight Pressure Wall (922-9282), Bluetooth Antenna (922-9283), and AirPort Antenna (922-9284).

Updated 28 October 2009

•Basics:Added another kBase link to Wireless Troubleshooting section.

•Troubleshooting:General:Added another kBase link to Wireless Troubleshooting section.

•Take Apart:General:Added section“How to Remove a Broken Glass Panel.”

Introduced 20 October 2009

Feedback

We want your feedback to help improve this and future Technician Guides! Please email any comments to: [e-mail]

2009-11-24

iMac (21.5-inch, Late 2009) — Updates  9

Apple Technician Guide

Basics

iMac (21.5-inch, Late 2009)

© 2009 Apple Inc. All rights reserved.

Overview

Identifying Features

The iMac (21.5-inch, Late 2009) has an all-aluminum enclosure with a glass front. It can be distinguished from the previous model by the glass extending all the way to the top, left and right edges, rather than having an aluminum bezel that borders the glass. Also, the rear of the computer is aluminum rather than black plastic.

This model’s other new features include:

•Larger and LED-backlit 21.5-inch 16:9 display with 1920x1080 native HD resolution

•Increased processor speeds:3.06 GHz or 3.33 GHz Intel Core 2 Duo

•Integrated NVIDIA GeForce 9400M or ATI Radeon HD 4670 graphics

•Four RAM memory slots:two slots are filled with at least 2GB each, for a total of 4GB; maximum RAM is 16GB

•Larger hard drive options:500GB, 1TB, 2TB (CTO only)

•SD card reader

•New Apple Wireless Keyboard and wireless Magic Mouse, standard with all configurations

•Ships with and requires at least Mac OS 10.6.1 (Snow Leopard)

2009-11-24

iMac (21.5-inch, Late 2009) Basics — Overview  11

Product Configurations

For product configurations, refer to AppleCare Tech Specs:http://support.apple.com/specs/

Wireless Troubleshooting

If you’re having issues with Bluetooth and wireless connectivity issues, refer to the following Apple Knowledge Base articles:

kBase #TS3048: Desktop computers:Troubleshooting wireless mouse and keyboard issues kBase #HT1365: AirPort and Bluetooth: Potential source of interference

kBase #HT3903: Apple Wireless Keyboard and Mouse: How to install batteries

Safety

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

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

2009-11-24

iMac (21.5-inch, Late 2009) Basics — Overview  12

Serial Number Location

The iMac (21.5-inch, Late 2009)’s serial number is located on the bottom of the stand.When replacing a stand, transfer the serial number to the new stand.

2009-11-24

iMac (21.5-inch, Late 2009) Basics — Overview  13

Apple Technician Guide

Troubleshooting

iMac (21.5-inch, Late 2009)

© 2009 Apple Inc. All rights reserved.

General Troubleshooting

Wireless Troubleshooting

If you’re having issues with Bluetooth and wireless connectivity issues, refer to:

kBase #TS3048: Desktop computers:Troubleshooting wireless mouse and keyboard issues kBase #HT1365: AirPort and Bluetooth: Potential source of interference

kBase #HT3903: Apple Wireless Keyboard and Mouse: How to install batteries

Update System Software & Firmware

Important: Whenever possible before beginning troubleshooting, ensure the latest software and firmware updates have been applied.

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 by

running the Mac OS X Software Update check (available in the Apple menu) while computer is connected to the Internet. For more information about firmware updates, refer to:

kBase # HT1557: About firmware updates for Intel-based Macs

Troubleshooting Theory

For general information on troubleshooting theory, go to GSX and fiind the Service Training course menu link. From there you can access the Troubleshooting Theory self-paced course.

Hardware vs. Software

For information on how to isolate a hardware issue from a software issue, refer to: kBase #TS1388: Isolating issues in Mac OS X

For information on how to troubleshoot a software issue, refer to: kBase #HT1199: Mac OS X: How to troubleshoot a software issue

kBase #TS1394: Mac OS X:Troubleshooting installation and software updates kBase #HT2956:Troubleshooting Mac OS X installation from CD or DVD

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 15

Common Reset Procedures

Power On Self Test (POST)

Intel-based Mac computers such as the iMac rely on a combination of tones to indicate Power On Self Test (POST) error codes.

•If the computer detects out-of-specification or no SDRAM, the screen will remain black but the computer will beep. This error condition may be due to physically damaged RAM, installing 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 tones until computer is turned off.

•The solution to both situations is to first re-seat memory and test computer again. If memory fails POST again, remove all installed memory and test by installing one by one each memory that has been verified to work correctly on another system (i.e.,“knowngood”) or order new memory.

For more information, refer to:

kBase #HT2538: iMac (Mid 2007) and later models: About new startup tones

Resetting the System Management Controller (SMC)

The System Management Controller (SMC) is a chip on logic board that controls all power functions. If computer is experiencing any power issue, such as not starting up, not displaying video, sleep issues, or fan noise issues, resetting SMC may resolve it.To reset SMC on an iMac:

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

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

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

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

5.Press power button on back to start up computer.

For more information, refer to:

kBase #HT1543: Intel-based iMac: How to reset the System Management Controller

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iMac (21.5-inch, Late 2009) — General Troubleshooting 16

Resetting Parameter RAM (PRAM)

PRAM stores certain system and device settings in a location that Mac OS X can access quickly. Exactly which settings are stored in the computer’s PRAM varies depending on the type of computer as well as the types of devices and drives connected.To reset PRAM:

1.Shut down the computer.

2.Locate the following keys on 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.Press power button.

4.Immediately press and hold Command-Option-P-R keys.

Important: You must press this key combination before the gray screen appears.

5.Hold down keys until the computer restarts, and you hear the startup chime a second time.

6.Release keys.

For more information, refer to:

kBase #HT1242: Mac OS X:What’s stored in PRAM kBase #HT1379: Resetting your Mac’s PRAM and NVRAM

Starting Up in Safe Mode

Starting up into Safe Mode does several things that can help resolve software or directory issues that may exist on the startup volume.To start up in Safe Mode:

1.Shut down the computer.

2.Press power button.

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

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

4.Release Shift key when you see the screen with a gray Apple and progress indicator (looks like a spinning gear). Note that booting into Safe Mode will take longer than a normal startup. During startup, the words ”Safe Boot”will appear on Mac OS X startup screen.

5.To leave Safe Mode, restart computer normally, without holding down any keys during startup.

For more information, refer to:

kBase #HT1564: Mac OS X:What is Safe Boot, Safe Mode? kBase #TS1884: Safe Boot takes longer than normal startup

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 17

Apple Service Diagnostics

Run Apple Service Diagnostic version 3S133 to determine if any thermal sensors or blowers are malfunctioning. If ASD is not available, run Apple Hardware Test by holding down the D key during startup.When a test reports an error, reseat appropriate connections. If issue persists, replace the corresponding part (sensor, fan, logic board, video card, or power supply). See chart below for correlation between error code, affected sensor, sensor location (stand-alone, or part of a sub-assembly), and additional checks to perform.

Error	Sensor and Location	Check
TA0P	Ambient temp sensor	Check sensor cable connection
	stand-alone part, located near CPU fan	to logic board, run CPU fan test,
		check air flow.
TC0H	CPU heatsink sensor	Check CPU sensor cable
	part of logic board	connection to logic board, run
		CPU fan test, check air flow.
TG0D	MXM GPU die sensor	Run ODD fan test, check air
	part of MXM video card	flow.
TG0H	MXM GPU heatsink sensor	Check video card sensor cable
	part of MXM video card	connection to logic board, run
		ODD fan test, check air flow.
TH0O	HDD sensor	Check sensor cable connection
	stand-alone part, located on hard drive	to logic board, run HDD fan
		test, check air flow.
TL0p	LCD temp sensor	Check sensor cable connection
	stand-alone part, located on back of LCD panel	to logic board, run all fans tests,
		check air flow.
TN0H	MCP79 heatsink	Check sensor cable connection
	part of logic board, located on heatsink	to logic board, run HDD fan
		test, check air flow.
TO0p	ODD sensor	Check sensor cable connection
	stand-alone part, located on optical drive	to logic board, run ODD fan
		test, check air flow.
Tp1P	PS1 T1 proximity sensor	Check logic board to power
	part of power supply	supply cable connections, run
Tp2H	PS1 T2 secondary heatsink sensor	CPU fan test, check air flow.
	part of power supply
Tp3H	PS1 T1 primary heatsink sensor
	part of power supply

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 18

Diagnostic LEDs

Depending on iMac model, there are either three or four built-in diagnostic LEDs on the logic board that can help troubleshoot the computer. LEDs are located on bottom right edge of logic board (under a piece of black mylar tape) and can only be seen when looking through lower vents of rear housing.

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 19

LED Functions

LED #1

•Indicates that trickle voltage from power supply has been detected by 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 computer has been shut down or put to sleep.The LED will turn off only if AC power source is disconnected or power supply is faulty.

LED #2

•Indicates that logic board has detected power from power supply when computer is turned on.This LED will be ON when computer is turned on and power supply and voltage regulators are working correctly.

LED #3

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

LED #4

•Indicates that computer and LCD panel are communicating.This LED will be ON when computer is turned on and video signal is being generated. If LED 4 is ON and there is no image on display, then LCD panel, LED backlight board, or cables between might be installed incorrectly or need replacement.

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 20

LED Startup Sequence

LED #1 = Power available.

If no LED is visible:

•Verify AC source

•Verify known-good AC cable is connected

•Verify cable connection between AC inlet and power supply

•Verify cable connection between power supply and logic board

•Verify power supply

LED #1 + LED #2 = Power available, and system is powered on.

If second LED is not visible when power button is pressed:

•Verify power button connection to logic board

•Verify power button functionality

•Verify cable connection between power supply and logic board

•Verify power supply

•Verify logic board

LED #1 + LED #2 + LED #3 = Power available, system is powered on, and video card found.

If third LED is not visible after power on:

•Verify that MXM video card is seated properly

•Verify logic board

LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card found, and internal LCD found.

If fourth LED is not visible after power on:

•Verify cable connections between LCD panel and logic board

•Inspect LCD display cables for cable damage

•Verify external video functionality, and according to result check the following items: -If external display works then verify/replace LED backlight board

-If external display works then verify/replace LCD panel

-If external display does not work verify/replace logic board

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 21

Logic Board Test Points

Test points, which can be used to verify proper power flow, are accessible on logic board when LCD panel is removed. All voltages given in Troubleshooting Symptom Charts assume that computer is plugged into a known-good power outlet with a known-good AC cable. Some guidelines for using test points:

•Warning: HIGH VOLTAGE: Use extreme caution when live testing!

•Do NOT lean over or touch the power supply area during live testing.

•Keep your fingers behind finger guards on test probes when measuring.

•Turn dial of voltmeter/multimeter to measure DC (direct current, usually indicated by a solid horizontal line over dashes). If your voltmeter requires a set voltage range, choose a DC range that includes the voltage you are measuring.

•Connect black probe to ground. Connect red probe to test point and verify voltage.

For more info, see kBase #HT3250: Diagnostics: Using a digital multimeter

Logic Board Test Point	Function
Pin 1	Ground
Pin 4	Standby 12V power (permanent power coming from power supply
	and present as long as AC cable is connected, even if computer is
	off); corresponds to LED #1
Pin 6	Backlight Control pulse width modulated signal (from logic board
	to LED backlight board, to adjust the backlight level setting
	according to user setup)
Pin 11	12V Run-Mode power to logic board (coming from power supply,
	present as long as system is on or asleep); corresponds to LED #2
Pin 12	Power On Request signal (from logic board to power supply when
	power button is pressed)
Pin 13	Backlight Enable (signal from logic board to Backlight Controller
	board, to enable backlight

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 22

Sensor and Fan Connector Locations

Ambient temp sensors and fans connectors 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 and Apple Service Diagnostic will generate an error code.

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 23

Block Diagram

Refer to this diagram to see how modules are interrelated.

Optical Drive

Temperature

Sensor

Display

Microphone

AC Inlet

	Backlight	Hard Drive	AC/DC
	Controller
		Temperature
		Sensor

MXM	Camera	IR Sensor
Temperature
Sensor

			SD Card
			Reader
		MLB
			Fan
			Fan
			Fan
		SO-DIMM
	Bluetooth	SO-DIMM
	Antenna		Power
		SO-DIMM	Button
		SO-DIMM

		Ambient
Speakers	802.11n	Temperature	Speakers
		Sensor
	Antenna
	Antenna

2009-11-24

iMac (21.5-inch, Late 2009) — General Troubleshooting 24

Symptom Charts

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

Deep Dive

Check		Result	Action	Code
1.	Power ON system.Verify if	Yes	The symptom is powering
	there is any indication that the		up. Go 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.
2.	Locate diagnostic LEDs in	Yes	Standby power voltage being
	bottom case vents. Plug AC		supplied by power supply.
	cord into system.Verify if		Go to step 3.
	diagnostic LED #1 turns ON.
	You may alternately check for	No	Replace power supply.
	presence of a 12V DC signal
	between pin 4 and pin 1 of
	logic board.

2009-11-24

iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power  25

3.	Press power button while	Yes	Power supply functioning and
	monitoring diagnostic LEDs.		logic board detects supply
	Verify if LED #2 turns ON and		voltages. Go to Won’t Start
	remain ON after pressing		Up symptom flow.
	the power button.You may
	alternately check for a power
		No	Go to step 4.
	request signal between pin 12
	and pin 1 of logic board.
4.	Disconnect AC cable then	Yes	Replace damaged part.	P16
	remove power supply and
	carefully inspect connectors
	between AC inlet and power
	supply, then DC connectors and	No	Go to step 5.
	cables between power supply
	and logic board, for damage or
	poor connections.
5.	Inspect power button and	Yes	Go to step 6.
	verify if it is properly connected
		No	Reconnect power button.
	to the logic board.
6.	Disconnect power button from	Yes	Power button is functioning
	logic board. Inspect cable and		correctly. Reconnect power
	connector for damage.Verify		button to logic board and
	continuity between the two		go to step 7.
	pins of power button when it is
		No	Power button faulty. Replace	X14
	pressed.
			rear housing (which includes
			power button).
7.	Press power button and Verify	Yes	Power supply functioning. If
	if system turns ON.You may		system still won’t boot, go
	alternately check for presence		to Won’t Start Up symptom
	of a 12V DC signal between		flow.
	pin 11 and pin 1 of logic board
		No	Replace DC power cable.	X03
	when power button is pressed.
			Go to step 8.
8.	Press power button and verify if	Yes	Issue solved with replaced DC
	system turns ON.		power cable.
		No	Replace power supply.	P01
			Go to step 9.
9.	Press power button and verify if	Yes	Issue solved with replaced
	system turns ON.		power supply.
		No	Reinstall power supply and	M01
			replace logic board.

Note:If No Power symptom persists after all steps have been followed use minimum configuration troubleshooting to proceed.Try disconnecting hard drive, optical drive, AirPort, Bluetooth, and SD card modules to determine if one of them is preventing the power supply from functioning.

2009-11-24

iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power  26

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 this computer, from a same-model
	• Error tones during startup.		computer in Target Disk Mode, or from a
			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 shift key down
			during startup to load only required kernel
			extensions and disable all startup and login
			items. See kBase #HT1564: Mac OS X:What is
			Safe Boot, Safe Mode?
		4.	If system generates error tones there may be an
			issue with the SDRAM. See kBase #HT2341: Intel-
			based Mac: Power On Self Test RAM error codes
		5.	Identifying when in the startup process the
			computer hangs can help isolate the issue.
			See kBase #HT2674: Intel-based Mac: Startup
			sequence and error codes, symbols for
			information on the Macintosh startup sequence,
			and error codes and symbols used.

Deep Dive

Check		Result	Action	Code
1.	Boot computer to Apple	Yes	Run the extended tests
	Hardware Test on the internal		and proceed with results. If
	hard drive or an inserted Install		AHT passes or boots with a
	DVD by holding down the D		memory error, go to step 2.
	key at startup.Verify if system
		No	Go to step 2.
	boots up from any of these
	volumes.
2.	Remove installed SDRAM, and	Yes	SDRAM issue. Reinstall one	X02
	test with known-good SDRAM.		of user’s SDRAM modules
	Verify if computer starts up		and retest. Proceed one by
	properly now.		one to find the faulty SDRAM
			module, and replace it.
		No	Go to step 3.

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iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power  27

3. Wait 15 seconds after computer	Yes	Go to AirPort Card Kernel
was powered down and		Panic symptom flow.
disconnect AirPort cable from
logic board.Verify if computer	No	Go to step 4.
starts up properly now.
4. Disconnect hard drive SATA	Yes	Go to Hard Drive Not
cable and startup from Install		Recognized symptom flow.
DVD in the optical drive, or
from an external bootable
	No	Go to step 5.
volume.Verify if computer
starts up properly now.
5. Reconnect hard drive,	Yes	Go to Optical Drive Not
disconnect optical drive cable		Recognized symptom flow.
and retest.Verify if computer
	No	Go to step 6.
starts up properly now.
6. Remove coin battery on back	Yes	Issue resolved by logic board
of logic board (you will need to		reset. Measure DC voltage on
completely remove logic board		battery touching battery with
to do this), and leave out for		red probe, and grounding
approximately 1 minute.Then		with black probe. If voltage is
reinstall battery.This will reset		2.7v or less, replace battery.
logic board.Verify if computer		For multimeter help, see
starts up properly now.
		kBase #HT3250: Diagnostics:
		Using a digital multimeter.
	No	Replace logic board.	M02

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iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power  28

Intermittent Shutdown

Quick Check

Symptoms		Quick Check
Intermittent Shutdown		1.	Make sure that power cord is securely attached
•	Powers off during startup.		to the back of computer, and is not hindered by a
• Powers off during desktop use.			desk or other furniture.
•	Computer restarts	2.	Plug computer directly into an AC outlet to test if
	spontaneously.		a surge protector or UPS is causing issue.
• Powers off when waking from		3.	Open System Preferences > Energy Saver >
	sleep.		Schedule and make sure that a“Shut Down”
			event is not scheduled.
		4.	Isolate OS by starting up from original install
			media for this computer, from a same-model
			computer in Target Disk Mode, or from a
			compatible known-good OS on an external drive.
			Both AirPort and Bluetooth services are available
			when booted from the Install disk.
		5.	Reset SMC and PRAM to clear any stored,
			corrupted information.
		6.	Start up in Safe Mode by holding shift key down
			during startup to load only required kernel
			extensions and disable all startup and login
			items. See kBase #HT1564: Mac OS X:What is
			Safe Boot, Safe Mode?

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 log		known-good AC power cord
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
		for possible software issues.
shutdown.Verify if you find
		Check if user is running
recent entries of an improper
		other automating software
shutdown in log file.
		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 (21.5-inch, Late 2009) Symptom Charts — Startup and Power  29

2.	With known-good AC power	Yes	Go to step 3.
	cord and AC outlet,Verify if
		No	AC power cord / outlet issue.	X03
	system continues to restart or
	shutdown		Issue resolved.
3.	Disconnect hard drive power	Yes	Go to step 4.
	cable from hard drive and
	startup the computer from
	other bootable media (like
	Install DVD, a same model
		No	Possible bad software or hard
	computer in Target Disk Mode,
	or a compatible known-good		drive. Go to Hard Drive Not
	OS on an external drive).Verify		Recognized symptom flow.
	if system continues to restart or
	shutdown.
4.	Inspect and reseat AC inlet	Yes	Replace damaged cable.	X03
	connection to power supply		Retest. Return to step 1 if
	(the smaller of the 2 cables		problem continues.
	connected to power supply),
	and DC power cable from	No	Go to step 5.
	power supply to logic board.
	Verify if damage is observed on
	the cables or connectors.
5.	Install known-good power	Yes	Reinstall original power
	supply.Verify if system		supply. Go to step 6.
	continues to restart or
		No	Issue resolved with power	P02
	shutdown.
			supply replacement.
6.	Replace DC power cable,	Yes	Go to step 7.
	which supplies power to
	logic board, hard drive, and
	LED backlight board.Verify if	No	Issue resolved with DC power	X03
	system continues to restart or		cable replacement.
	shutdown.
7.	Replace logic board.Verify if	Yes	Use Minimum Configuration
	system continues to restart or		troubleshooting to isolate
	shutdown.		failed module.
		No	Issue resolved with logic	M08
			board replacement.

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iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power  30