Apple iMac 27 late 2009 Service Manual

 Apple Technician Guide

iMac (27-inch, Late 2009)

2009-12-15

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

Apple
1 Innite 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 (27-inch, Late 2009)

Contents

About This Guide

Updates 10

15 December 2009 10
20 November 2009 10
11 November 2009 10
28 October 2009 11
27 October 2009 11
Apple Technician Guide introduced 20 October 2009 11

Feedback 11

Basics

Overview 13

Identifying Features 14
Product Congurations 14
Wireless Troubleshooting 14
Safety Precautions 15
Serial Number Location 16

Troubleshooting

General Troubleshooting 18

Wireless Troubleshooting 18
Update System Software & Firmware 18
Troubleshooting Theory 18
Hardware vs. Software 19
Power On Self Test (POST) 19
Resetting the System Management Controller (SMC) 19
Resetting Parameter RAM (PRAM) 20
Starting Up in Safe Mode 20
Diagnostics 21
Diagnostic LEDs 23
Location of Diagnostic LEDs 24
LED Startup Sequence 26
Logic Board Test Points 27
Sensor and Fan Connector Locations 28

Block Diagram 29

Symptom Charts 30

Startup and Power 30

No Power, Dead Unit 30
Won’t Start Up 32
Intermittent Shutdown 34
Kernel Panic, System Crashes 36
No Video 38
Corrupted Video 40
Burnt Smell/Odor 43
Uncategorized Symptoms 44

Display 45

Backlight Issue/No Backlight 45
Noise / Unstable Flickering 47
LCD Image Issues 49
Incorrect/Missing Colors 50
Distorted/Blurred Image 51
Pixel Anomalies 53
Vertical/Horizontal Lines 54
Non-Uniform Brightness 56
Cosmetic Defects 57
Uncategorized Symptoms 57

Mass Storage 58

Hard Drive Not Recognized 58
Hard Drive Noisy 61
Optical Drive Not Recognized 63
Optical Drive Won’t Accept/Eject Media 64
Optical Drive Read/Write Error 65
Optical Drive Not Performing to Specications 67
Optical Drive Noisy 68
SD Card Will Not Insert Into Slot 69
SD Card Not Recognized 70
Uncategorized Symptoms 71

Communications 72

AirPort/Bluetooth Issues 72
AirPort Card Kernel Panic 74
Ethernet Port/Device Issue 75
Wireless Input Device Doesn’t Pair 76
Wireless Input Device Loses Connection 78

Input/Output Devices 81

Apple Remote Inoperable 81
Audio: Microphone 83
Audio: Built-in Speakers Have Distorted Sound 84
Audio: Built-in Speakers Have No Audio 85
Camera Issues 87

FireWire Device Not Recognized 88
USB Device Not Recognized 90
Wired Keyboard Does Not Function Properly 92
Keyboard: Specic Keys Do Not Respond 94
Wired Keyboard/Mouse Not Recognized 94
Uncategorized Symptoms 96

Mechanical 97

Noise/Hum/Vibration 97
Fan Failures / Thermal Issues 100
Stand/Hinge Issues 101
Physical Damage 102
Uncategorized Symptoms 102

Take Apart

General Information 104

Opening the Unit 104
Required Tools 104
Cleaning & Handling the Glass Panel 106
Do’s and Don’ts 106
Handling a Broken Glass Panel 107
Safety 112
Logic Board Handling 113
Reassembly Steps 113
Note About Images in This Manual 113
Screw Sizes 113

Access Door 114

Memory 116

Removal 117
Reassembly 117

Glass Panel 118

Removal 119
Reassembly 120

Camera 123

LCD Panel 125

Removal 126
Reassembly 129

Vertical Sync Cable 131

LCD Temp Sensor Cable 132

DisplayPort Cable 133

Audio Ports and Cable 134

Bluetooth Antenna 136

AirPort Antenna 138

Bluetooth Board 140

AirPort Card 142

AirPort Cable 144

AirPort Carrier Board 146

LED Backlight Board 148

Power Supply 150

Removal 151
Reassembly 152

Backlight Pressure Wall 153

Power Supply/Hard drive Pressure Wall 155

Removal 156
Reassembly 15 6

Hard Drive 158

Removal 159
Reassembly 160

Hard Drive Sensor Cable 161

Removal 162
Reassembly 162

Optical Drive 163

Removal 164
Reassembly 166

Optical Sensor Cable 168

Optical Drive Fan 170

SD Board 172

SD Card Cable 174

IR Board 176

Removal 177

Logic Board 178

Removal 179

Reassembly 183

Video Card 187

Hard Drive Data Cable 190

Removal 191

Optical Drive Data Cable 193

Removal 194

Battery 195

Removal 196
Reassembly 196

Optical Pressure Wall 197

Right Speaker 199

CPU Fan 201

Removal 202
Reassembly 203

Ambient Temp Sensor 204

Removal 205
Reassembly 205

Left Speaker 206

Removal 207
Reassembly 207

Hard Drive Fan 209

Mechanism Cover 211

Mechanism 213

Bluetooth Cable 215

Cable, AC/DC Power/Backlight/SATA 217

Camera Cable 219

Microphone Cable 222

Rear Housing 223

Stand 224

Removal 225
Reassembly 226

Additional Procedures

Retrieving Mechanism 229

Views

Exploded Views 234

Exploded View #1 234
Exploded View #2 235
Exploded View #3 236

External Views 237

Rear View 237
Ports 238

Internal Views 239

Components Below LCD 239
Inside Rear Housing 239
Logic Board, Top Side 240
Logic Board, Bottom Side 240

Screw Chart 241

 Apple Technician Guide

About This Guide

iMac (27-inch, Late 2009)

© 2009 Apple Inc. All rights reserved.

Updates

15 December 2009

Troubleshooting:

General Troubleshooting: Updated Apple Service Diagnostic and Apple Hardware Test •
version numbers, updated Apple Hardware Test error code table.
Startup Power and Display chapters: Updated Flickering/No Video/ Backlight Issue/•
Corrupted Video topics to alert technicians to check:

Mac OS X version installed is the build version supported on the hardware. See • kBase

#TS3101: Mac (Late 2009): Using the correct Mac OS X system software.

Cable connections • on back of LCD panel; check for signs of damage, corrosion,
or pinched wires. Reseat/replace DisplayPort cable and Vertical sync cable when

instructed.

20 November 2009

Troubleshooting:•

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.

11 November 2009

Take Apart:

General Information: Added graphics to topic, “How to Remove a Broken Glass Panel.”•
Hard drive: Added information on the Western Digital drive and sensor cable. 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).

Views, Exploded Views:

Added AirPort (922-9286) and Bluetooth(922-9285) antennas•
Added parts unique to the iMac (27-inch, Quad Core, Late 2009) •

Skin temp sensor 922-9287•
SDRAM DIMMs, 661-5453 and 661-5454•
Power supply, 661-5468•
Logic boards, 661-5428 and 661-5429•
Optical drive,• 922-5284

2009-12-16

iMac (27-inch, Late 2009) About This Guide — Updates 10

28 October 2009

Take Apart: Added backlight cable to list of items included with replacement panel

27 October 2009

Formatting changes throughout manual•
Troubleshooting: added new LED Location graphic on page 22 •

Apple Technician Guide introduced 20 October 2009

Feedback

We want your feedback to help improve this and future Technician Guides! Please email any comments to smfeedback2@

apple.com

2009-12-16

iMac (27-inch, Late 2009) About This Guide — Feedback 11

 Apple Technician Guide

Basics

iMac (27-inch, Late 2009)

© 2009 Apple Inc. All rights reserved.

Overview

2009-12-16

Introducing the iMac (27-inch, Late 2009) with a new edge-to-edge glass design and seamless
all aluminum enclosure. The new iMac line is the fastest ever with Intel Core 2 Duo processors
starting at 3.06 GHz, and Core i5 and i7 quad-core processors for up to twice the performance.

iMac (27-inch, Late 2009) Basics — Overview 13

Identifying Features

The iMac (27-inch, Late 2009) computer features include:

LED-backlit 27-inch display•
Increased processor speeds: •

3.06GHz and 3.33GHz Intel Core 2 Duo•

2.66GHz quad-core Intel Core i5 •

2.8GHz quad-core Intel Core i7•
Four RAM slots, each of which can accept a 2 GB or 4 GB SO-DIMM up to 16GB•
SD card reader slot•
Mini DisplayPort output (DVI, VGA, and dual-link DVI) and supports input from external •
DisplayPort sources (adapters sold separately)
Graphics and video support: •

ATI Radeon HD 4670 graphics processor with 256MB of GDDR3 memory (dual-core)•
ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory (dual-core)•

ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory (quad-core)•
Hard drive: 1TB, 2TB (CTO only) •
New Apple Magic Mouse and Apple Wireless Keyboard (2009), standard with all •
congurations
Ships with and requires at least Mac OS 10.6.1 (Snow Leopard)•

Product Congurations

For product congurations, refer to Apple Support Tech Specs: http://support.apple.com/

specs/

Wireless Troubleshooting

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

Desktop computers: Troubleshooting wireless mouse and keyboard issues • http://support.

apple.com/kb/TS3048

AirPort and Bluetooth: Potential sources of interference • http://support.apple.com/kb/

HT1365

Apple Wireless Keyboard and Mouse: How to install batteries • http://support.apple.com/

kb/HT3903

2009-12-16

iMac (27-inch, Late 2009) Basics — Overview 14

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.

2009-12-16

iMac (27-inch, Late 2009) Basics — Overview 15

Serial Number Location

The iMac (27-inch, Late 2009) serial number is located on the base of the stand. When
replacing a stand, transfer the serial number to the new stand.

2009-12-16

iMac (27-inch, Late 2009) Basics — Overview 16

 Apple Technician Guide

Troubleshooting

iMac (27-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 the following
Knowledge Base articles:

Desktop computers: Troubleshooting wireless mouse and keyboard issues • http://support.

apple.com/kb/TS3048

AirPort and Bluetooth: Potential sources of interference • http://support.apple.com/kb/

HT1365

Apple Wireless Keyboard and Mouse: How to install batteries • http://support.apple.com/kb/

HT3903

Update System Software & Firmware

Important: Ensure the correct version Mac OS X and latest software and rmware updates have

been applied before you begin troubleshooting. Computers sometimes exhibit symptoms that
indicate the wrong Mac OS X system software is installed. Refer to the following article about
using the correct Mac OS X ystem software:

kBase # TS3101: iMac (Late 2009): Using the correct Mac OS X system software

Firmware is the name given to software that is written into memory circuits such as ash
memory, that will hold the software code indenitely, 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 rmware updates, refer to:

kBase # HT1557: About rmware updates for Intel-based Macs

Troubleshooting Theory

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

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 18

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

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-specication or no SDRAM, or if the RAM installed does not •
meet the appropriate specications, the screen will remain black but the computer will
beep This error condition may be due to physically damaged RAM, installing the incorrect
type of RAM, or not having RAM installed.
Some RAM may appear to pass the Power-On-Self-Test (POST) but still cannot be used by •
the operating system. In this case, the computer will display a gray screen, sound three
tones and repeat the tones until the computer is turned o.
The solution to both of these situations is to rst re-seat the memory and test the computer •
again. If the memory fails the POST test again, remove all installed memory and test by
installing one by one each memory that has been veried to work correctly on another
system (i.e., “known-good”) or order new memory.

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:

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

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

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

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

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

For more information, refer to:

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

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 19

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:

Shut down the computer.1.

Locate the following keys on keyboard: Command, Option, P, and R. You will need to hold 2.
these keys down simultaneously in Step 4.
Note: If the keyboard does not have an Option key, use the Alt key instead.

Press power button.3.

Immediately press and hold Command-Option-P-R keys. 4.
Important: You must press this key combination before the gray screen appears.

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

Release keys.6.

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

A Safe Boot is a special way to start Mac OS X when troubleshooting. To start up in Safe Mode:

Make sure computer is shut down.1.

Press power button.2.

Immediately after you hear the startup tone, press and hold Shift key. 3.
Note: The Shift key should be held as soon as possible after startup tone but not before.

Release Shift key when you see the screen with the gray Apple and progress indicator (looks 4.
like a spinning gear). During startup, ”Safe Boot” appears on the Mac OS X startup screen.

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

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

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 20

Diagnostics

Run Apple Service Diagnostic version 3S135 to determine if any thermal sensors or blowers are malfunctioning. If
ASD is not available, run Apple Hardware Test version 3A188 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, blower, logic
board, video card, or power supply). See Apple Hardware Error code chart below for correlation between error code,
aected sensor, sensor location, and additional checks to perform.

AHT Error code Suspected part and

Location

4SNS/1/C0000008:TA0P - xxx Ambient temp sensor

damaged or disconnected
from logic board.

4SNS/1/C0000008 T00p-xxx ODD temp sensor

damaged or disconnected
from logic board.

4SNS/1/C0000008 TH00--xxx HDD temp sensor

damaged or disconnected
from logic board. Use the
correct sensor cable, each
drive vendor has a unique
sensor cable.

Suggested Action Notes

Verify sensor cable is
securely connected to the
top edge of the logic board
and attached to the left
speaker housig. Replace
sensor cable if damaged.

Verify sensor cable is
securely connected to the
logic board and the sensor
is properly attached to the
ODD mechanism. Replace
sensor cable if damaged.

Verify sensor cable is
securely connected to top
left side of logic board and
it’s connected to hard drive.
Check for damaged cable
on logic board.

All fans ramp at full
speed if sensor is
disconnected.

The ODD fan will run
at full speed if sensor is
disconnected.

The HD fan may run at
full speed if the sensor
is disconnected.

2009-12-16

4SNS/1/C0000008 TL0p LCD temp sensor on LCD

is damaged or
disconnected from top of
logic board

4SNS/1/C0000008 TS2P-xxx Skin temp sensor (Quad-

core models only) is
damaged or disconnected
from top of logic board.

Verify that the LCD sensor
cable is securely connected
to the logic board and the
sensor is attached to the
LCD. Replace the sensor
cable if damaged

Verify that the skin temp
sensor cable is securely
connected to the top
of the logic board and
sensor is attached to rear
housing (near the camera).
Replace the sensor cable if
damaged.

iMac (27-inch, Late 2009) — General Troubleshooting 21

The CPU fan will run at
full speed if the sensor
is disconnected.

AHT Error code Suspected part and

Location

Suggested Action Notes

4SNS/1/40000000 TC0H CPU temp sensor located

on back side of logic
board; this sensor is not
available as a service part

4SNS/1/40000000:TG0H GPU temp sensor is

disconnected or faulty
(located on back side of
logic board)

Check CPU sensor cable
connection to logic board.
It requires removal of the
logic board.

Check GPU sensor cable
connection to logic board.
It requires removal of the
logic board.

4MOT/4/40000002 :ODD-xxx Optical fan/blower Verify that the ODD

blower/fan cable is securely
connected to the right side
of the logic board and that
there are no obstructions
that would prevent the
blower/fan from rotating.
Replace fan if the error
continues.

4MOT/4/40000002 :HDD-xxx Hard drive fan/blower,

located below logic board,
near hard drive

Verify that the HDD
blower/fan cable is securely
connected to the top of the
logic board and that there
are no obstructions that
would prevent the blower/
fan from rotating. Replace
fan if the error continues.

4MOT/4/40000002 :CPU-xxx CPU fan/blower, located

next to left speaker (logic
board has to be removed
to replace CPU blower)

Verify that the CPUblower/
fan cable is securely
connected to the left side
of the logic board and that
there are no obstructions
that would prevent the
blower/fan from rotating.
Replace fan if the error
continues.

If the sensor is
disconnected, the
CPU fan will run at full
speed.

If sensor is
disconnected the CPU
fan will run at full
speed.

Normal fan operation,
except the ODD blower

Normal fan operation,
except the HDD blower

Normal fan operation,
except the CPU blower

Note: Make sure black
mylar tape along the
bottom of LCD panel
is not obstructing fan
blades, if so, cut tape
and re-stick to LCD.

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 22

Diagnostic LEDs

The iMac (27-inch, Late 2009) computer has four built-in diagnostic LEDs on the main logic
board that can help you to troubleshoot the computer. The LEDs are located on the bottom left
edge of the logic board (under a piece of black mylar tape) and can only be seen when looking
through the lower vents of the enclosure. Refer to the next page for a close up graphic of the
troubleshooting LEDs.

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 23

Location of Diagnostic LEDs

The LEDs are located under the mylar tape, on the bottom, left corner of the logic board. They
can only be seen when looking through lower vents of rear housing.

LED Functions

2009-12-16

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 o only if the AC power source is disconnected or the power
supply is faulty.

iMac (27-inch, Late 2009) — General Troubleshooting 24

LED #2

Indicates that the main logic board has detected proper power from the power supply •
when the computer is turned on and that logic board voltage regulators are functioning
properly. 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.

LED #4

Indicates that the computer and the LCD 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 display, then the LCD panel, the LED backlight board, or the cables
between might be installed incorrectly or need replacement.

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 25

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 the 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 the LED backlight board

-If external display works then verify/replace the LCD panel

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

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 26

Logic Board Test Points

Some test points are accessible on the logic board when the LCD panel is removed. The test
points are dened below.

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
o); 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

Pin12 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

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 27

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.

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 28

Block Diagram

SO-DIMM

Antenna

Antenna

Antenna

SO-DIMM

Temperature

Sensor

Temperature

Sensor

Fan

MLB

SO-DIMM

Display

AC/DC

Power
Button

Bluetooth

Speakers

Hard Drive

Optical Drive

AC Inlet

Temp

Sensor

Camera

Microphone

Speakers

Backlight

Controller

Fan

Fan

MXM

802.11n

Ambient

Temperature

Sensor

K22/K23 System Block Diagram

09/01/2009

David Cox

Apple Confidential

IR Sensor

SD Card

Reader

SO-DIMM

Refer to this diagram to see how modules are interrelated.

2009-12-16

iMac (27-inch, Late 2009) — General Troubleshooting 29

Symptom Charts

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

Startup and Power

No Power, Dead Unit

Unlikely cause: speakers

Quick Check

Symptoms Quick Check

No Power, Dead Unit

No power•
No fan spin•
No startup chime•
No image on external display•
No hard drive or optical drive •
activity
Caps Lock LED on wired •
keyboard doesn’t light when
pressed.

Verify power source.1.
Verify power cable.2.
Listen closely for signs of activity from system 3.

including: rotating fans, hard drive or optical drive
activity, startup chime, etc.

Deep Dive

Check Result Action Code

Power ON system. Verify if 1.
there is any indication that the
system has powered up (fan
rotation, hard drive or optical
drive noise, backlight turns on).

Locate diagnostic LEDs in 2.
bottom case vents. Plug AC
cord into system. Verify if
diagnostic LED #1 turns ON.
You may alternately check for
presence of a 12V DC signal
between pin 4 and pin 1 of
logic board.

Yes The symptom is powering

up. Go to Won’t Start Up
symptom ow.

No Go to step 2.

Yes Standby power voltage being

supplied by power supply.
Go to step 3.

No Replace power supply.

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 30

Press power button while 3.
monitoring diagnostic LEDs.
Verify if LED #2 turns ON and
remain ON after pressing
the power button. You may
alternately check for a power
request signal between pin 12
and pin 1 of logic board.

Yes Power supply functioning and

logic board detects supply
voltages. Go to Won’t Start

Up symptom ow.

No Go to step 4.

Disconnect AC cable then 4.
remove power supply and
carefully inspect connectors
between AC inlet and power
supply, then DC connectors and
cables between power supply
and logic board, for damage or
poor connections.

Inspect power button and 5.
verify if it is properly connected
to the logic board.

Disconnect power button from 6.
logic board. Inspect cable and
connector for damage. Verify
continuity between the two
pins of power button when it is
pressed.

Press power button and Verify 7.
if system turns ON. You may
alternately check for presence
of a 12V DC signal between
pin 11 and pin 1 of logic board
when power button is pressed.

Yes Replace damaged part. P16

No Go to step 5.

Yes Go to step 6.

No Reconnect power button.

Yes Power button is functioning

correctly. Reconnect power
button to logic board and
go to step 7.

No Power button faulty. Replace

X14

rear housing (which includes
power button).

Yes Power supply functioning. If

system still won’t boot, go
to Won’t Start Up symptom
ow.

No Replace DC power cable.

X03

Go to step 8.

2009-12-16

Press power button and verify if 8.
system turns ON.

Yes Issue solved with replaced DC

power cable.

No Replace power supply.

P01

Go to step 9.

Press power button and verify if 9.
system turns ON.

Yes Issue solved with replaced

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
conguration 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.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 31

Won’t Start Up

Quick Check

Symptoms Quick Check

Won’t Start Up

No startup chime.•
Error tones during startup.•
Grey screen with fan noise, or •
other noise.
Will not progress beyond •
Apple logo or spinning gear.

Isolate OS by starting up from original install 1.
media for 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.

Reset SMC and PRAM to clear any stored, 2.
corrupted information.

Start up in Safe Mode by holding shift key down 3.
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?

If system generates error tones there may be an 4.
issue with the SDRAM. See kBase #HT2341: Intel-

based Mac: Power On Self Test RAM error codes

Identifying when in the startup process the 5.
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.

2009-12-16

Deep Dive

Check Result Action Code

Boot computer to Apple 1.
Hardware Test on the internal
hard drive or an inserted Install
DVD by holding down the D
key at startup. Verify if system
boots up from any of these
volumes.

Remove installed SDRAM, and 2.
test with known-good SDRAM.
Verify if computer starts up
properly now.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 32

Yes Run the extended tests

and proceed with results. If
AHT passes or boots with a
memory error, go to step 2.

No Go to step 2.

Yes SDRAM issue. Reinstall one

of user’s SDRAM modules
and retest. Proceed one by
one to nd the faulty SDRAM
module, and replace it.

No Go to step 3.

X02

Wait 15 seconds after computer 3.
was powered down and
disconnect AirPort cable from
logic board. Verify if computer
starts up properly now.

Yes Go to AirPort Card Kernel

Panic symptom ow.

No Go to step 4.

Disconnect hard drive SATA 4.
cable and startup from Install
DVD in the optical drive, or
from an external bootable
volume. Verify if computer
starts up properly now.

Reconnect hard drive, 5.
disconnect optical drive cable
and retest. Verify if computer
starts up properly now.

Remove coin battery on back 6.
of logic board (you will need to
completely remove logic board
to do this), and leave out for
approximately 1 minute. Then
reinstall battery. This will reset
logic board. Verify if computer
starts up properly now.

Yes Go to Hard Drive Not

Recognized symptom ow.

No Go to step 5.

Yes Go to Optical Drive Not

Recognized symptom ow.

No Go to step 6.

Yes Issue resolved by logic board

reset. Measure DC voltage on
battery touching battery with
red probe, and grounding
with black probe. If voltage is

2.7v or less, replace battery.

For multimeter help, see

kBase #HT3250: Diagnostics:
Using a digital multimeter.

No Replace logic board. M02

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 33

Intermittent Shutdown

Quick Check

Symptoms Quick Check

Intermittent Shutdown

Powers o during startup.•
Powers o during desktop use.•
Computer restarts •
spontaneously.
Powers o when waking from •
sleep.

Make sure that power cord is securely attached 1.
to the back of computer, and is not hindered by a
desk or other furniture.

Plug computer directly into an AC outlet to test if 2.
a surge protector or UPS is causing issue.

Open System Preferences > Energy Saver > 3.
Schedule and make sure that a “Shut Down”
event is not scheduled.

Isolate OS by starting up from original install 4.
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.

Reset SMC and PRAM to clear any stored, 5.
corrupted information.

Start up in Safe Mode by holding shift key down 6.
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?

2009-12-16

Deep Dive

Check Result Action Code

Verify improper shutdown 1.
by opening the system.log
located in /var/log. Filter log
for “shutdown cause”. Entries
of value “0” or a negative
value indicate an improper
shutdown. Verify if you nd
recent entries of an improper
shutdown in log le.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 34

Yes Determine if user caused

improper shutdown. Use
known-good AC power cord
and AC outlet. Go to step 2.

No Revisit Quick Check examples

for possible software issues.
Check if user is running
other automating software
that may be shutting down
system. Verify issue and jump
to appropriate symptom
ow. No repair needed under
current symptom ow.

With known-good AC power 2.
cord and AC outlet, Verify if
system continues to restart or
shutdown

Yes Go to step 3.

No AC power cord / outlet issue.

Issue resolved.

X03

Disconnect hard drive power 3.
cable from hard drive and
startup the computer from
other bootable media (like
Install DVD, a same model
computer in Target Disk Mode,
or a compatible known-good
OS on an external drive). Verify
if system continues to restart or
shutdown.

Inspect and reseat AC inlet 4.
connection to power supply
(the smaller of the 2 cables
connected to power supply),
and DC power cable from
power supply to logic board.
Verify if damage is observed on
the cables or connectors.

Install known-good power 5.
supply. Verify if system
continues to restart or
shutdown.

Yes Go to step 4.

No Possible bad software or hard

drive. Go to Hard Drive Not

Recognized symptom ow.

Yes Replace damaged cable.

Retest. Return to step 1 if
problem continues.

No Go to step 5.

Yes Reinstall original power

supply. Go to step 6.

No Issue resolved with power

supply replacement.

X03

P02

Replace DC power cable, 6.
which supplies power to
logic board, hard drive, and
LED backlight board. Verify if
system continues to restart or
shutdown.

Replace logic board. 7. Verify if
system continues to restart or
shutdown.

Yes Go to step 7.

No Issue resolved with DC power

cable replacement.

Yes Use Minimum Conguration

troubleshooting to isolate
failed module.

No Issue resolved with logic

board replacement.

X03

M08

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 35

Kernel Panic, System Crashes

Quick Check

Symptoms Quick Check

Kernel Panic, System Crashes

Kernel Panic on startup or •
desktop use.
System freeze during use.•
System freeze upon wake from •
sleep.

Isolate OS by starting up from original install 1.
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.

Ensure that all software and rmware updates for 2.
this model have been installed to take advantage
of any available bug xes.

Reset SMC and PRAM to clear any stored, 3.
corrupted information.

Start up in Safe Mode by holding shift key down 4.
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?

Check the panic.log, located /Library/Logs/5.
Panicreporter, for information in the back trace
that may give clues about the kernel panic.

For more information, see 6. kBase #HT1392:

About “You need to restart your computer”
(kernel panic) messages.

2009-12-16

Deep Dive

Check Result Action Code

Boot the computer to Apple 1.
Hardware Test on internal hard
drive or an inserted Install DVD
by holding down the D key at
startup. Verify if system boots
up from any of these volumes.

Remove all peripheral devices 2.
including keyboard and mouse.
Verify if system starts without
kernel panic.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 36

Yes Run extended tests and

proceed with results. If AHT
passes or boots with a kernel
panic, go to step 2.

No Go to step 2.

Yes Add peripheral devices one

at a time until kernel panic
repeats. Replace device
causing issue.

No Go to step 3.

Use known-good SDRAM in the 3.
system. Verify if system start
without kernel panic now.

Yes Install user’s SDRAM one by

one and test. If kernel panic
repeats, replace aected
SDRAM. Verify if correct
SDRAM specication is being
used.

No Go to step 4.

X01

Wait for 20 seconds after 4.
shutdown and disconnect
AirPort cable on logic board.
Verify if system starts without
kernel panic now.

Disconnect SATA cable from 5.
hard drive and startup to the
Install DVD in the optical drive
or from an external volume.
Verify if system starts without
kernel panic now.

Disconnect camera and 6.
microphone cables from logic
board. Verify if system starts
without kernel panic now.

Disconnect Bluetooth cable 7.
on logic board. Verify if system
starts without kernel panic
now.

Disconnect SD board on logic 8.
board. Verify if system starts
without kernel panic now.

Yes Go to AirPort Card Kernel

Panic symptom ow.

No Go to step 5.

Yes Go to Hard Drive Not

Recognized symptom ow.

No Go to step 6.

Yes Go to Camera Issues or

Audio: Microphone symptom

ow as appropriate.

No Go to step 7.

Yes Go to AirPort/Bluetooth

Issues symptom ow.

No Go to step 8.

Yes Go to SD Card Not

Recognized symptom ow.

No Go to step 9.

X99

2009-12-16

Disconnect optical drive and 9.
test. Verify if system starts
without kernel panic now.

Yes Go to Optical Drive Not

Recognized symptom ow.

No Replace logic board.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 37

No Video

Unlikely cause: hard drive, optical drive, speakers, camera, microphone

Quick Check

Symptoms Quick Check

No Video

No image.•
Backlight failure.•

Check brightness setting.1.
For no-video issues, connect an external display 2.

to Verify if iMac video circuitry is functioning.
If image appears on external display go to
Backlight Issue/No Backlight symptom ow.

Reset SMC.3.

Deep Dive

Check Result Action Code

Verify boot chime present and 1.
fans running when system
powered ON. (Reset SMC and
clear PRAM if necessary for
proper boot up.)

Verify if image is visible on 2.
built-in LCD panel.

Yes Power ON self test OK. Boot

sequence started.
Go to step 2.

No Go to Won’t Start Up

symptom ow.

Yes Video present. Verify system

functionality and return to
user or jump to appropriate
troubleshooting ow.

No Go to step 3.

2009-12-16

Connect supported external 3.
display. Verify if image appears
on external display when
system is booted.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 38

Yes External display detected by

system. Video circuitry on
logic board functional.

Inspect DisplayPort cable to
back of panel connection.
Reseat and test again. If you
continue to have problems
go to Backlight Issue/No

Backlight symptom ow.

No Go to step 4.

Pivot enclosure to access 4.
lower intake vent, and locate

diagnostic LEDs on edge of

logic board. Verify if LED #3
turns on shortly after system
powers on.

Yes Logic board communicating

with video card. Go to step 5.

No If LED #3 does not turn ON

reseat video card and retest,
then replace video card and
repeat step 4. If issue persists,
replace logic board.

M03

Locate 5. diagnostic LEDs on
logic board. Verify if LED #4
turns on shortly after system
powers on.

Locate 6. diagnostic LEDs on
the logic board. Verify if LED #4
turns on shortly after system
powers on.

Yes Logic board communicating

with LCD panel. Go to

Backlight Issue/No Backlight

symptom ow.

No Replace DisplayPort cable. Go

to step 6.

Yes Video controller functional

and communicating with LCD
panel. Go to Backlight Issue/

No Backlight symptom ow.

No Video controller unable to

communicate with LCD panel.
Reseat cables rst. If issue
persists, replace LCD panel.
Retest.

M03

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 39

Corrupted Video

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

Quick Check

Symptoms Quick Check

Corrupted Video

Text and graphics appear fuzzy•
Image corrupted•

Verify Mac OS X version installed is the build 1.
number supported on the hardware. Make sure
customer didn’t migrate over their old version of
Mac OS. See kBase #TS3101: Mac (Late 2009):

Using the correct Mac OS X system software.

Set System Preferences > Displays to native 2.
resolution of LCD. Non-native resolutions are
unable to produce optimal clarity.

Clean outside surface of glass panel.3.
Make sure all relevant software updates have 4.

been applied. Graphics driver updates may be
included with software updates.

Boot from install DVD or another known-good 5.
volume to determine whether a potential
software/driver issue exists.

When issue occurs, take a screenshot of the 6.
display (Command-Shift-3). View screenshot le
on a known-good computer. If image corruption
can be seen in the screenshot then issue is with
the video drivers, software, or video/logic board.
If issue cannot be seen in the screenshot then
LCD panel and DisplayPort cable should be tested
further.

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 40

Deep Dive

Check Result Action Code

Boot from Install DVD and 1.
Verify if issue is still visible.

Verify if issue is visible on an 2.
external display.

For systems without a separate 3.
video card, go to step 4. If a
video card is present, remove
video card, inspect connector
for damage or corrosion.
Reinstall video card and retest.
Verify if issue still occurs.

Verify if video corruption issue 4.
is still present.

Yes Go to step 2.

No Issue likely caused by

software or driver issue.
Troubleshoot for software
issues. Make sure all software
updates have been installed.

Yes Issue is NOT caused by

internal LCD display.
Go to step 3.

No Go to step 6.

Yes Replace video card.

Go to step 4.

No Issue resolved by reseating

video card.

Yes Replace logic board. If a video

card was replaced, reinstall
the user’s original video card.
Go to step 5.

M04

M04

Verify if video corruption issue 5.
is still present with replacement
logic board installed.

Inspect glass panel. Verify if 6.
issue is caused by condensation
or contaminants on inside/
outside surface of glass panel,
or on surface of LCD panel.

No Issue resolved with

replacement video card.

Yes Return to step 1 and retest. X04

No Issue resolved with

replacement logic board.

Yes Clean glass and/or LCD using

procedures in Glass Panel
take-apart chapter.

Identify possible sources
of contamination (nearby
cigarette/cooking smoke,
heavy airborne dust, etc.)
to prevent recurrence.
Condensation should
dissipate after computer has
been running a few hours.

No Go to step 7.

M04

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 41

Disconnect DisplayPort cable 7.
between LCD display and logic
board, and verify if there is
damage to cable or connectors.
Repeat with vertical sync cable
connected between LCD panel
and LED backlight board.

Yes Replace DisplayPort cable

or any other damaged part/
module.

No Reinstall DisplayPort cable

and vertical sync cable.
Go to step 8.

X03

Verify if issue is still visible 8.
after reinstalling/replacing
DisplayPort cable and vertical
sync cable.

Verify if issue is still present 9.
with replacement LCD panel
installed.

Yes Replace DisplayPort cable and

LCD panel. Go to step 9.

No Issue resolved with reseating

cables.

Yes Return to step 1 and retest.

No Issue resolved with

replacement of LCD panel.

L04

L04

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 42

Burnt Smell/Odor

Unlikely cause: speakers, microphone, rear housing

Quick Check

Symptoms Quick Check

Burnt Smell/Odor

Burning smell•
Unusual odor•

Verify that computer is the source of the odor.1.
If system is new, see 2. kBase #TA22044: New

Equipment: Odors May Be Present Short-Term.

Disconnect all third-party devices and check to 3.
see if any external device is the source of odor.

Inspect air intake and air outlets for obstructions. 4.
To prevent overheating make sure there
is sucient clearance to allow air to ow
unobstructed into and out of the system.

Verify if system is functional.5.

Deep Dive

Check Result Action Code

Verify if source of the odor 1.
can be identied by visually
inspecting each module
and its associated cables for
signs of burned or damaged
components, smoke residue,
burned traces, or melted or
damaged wiring,

Yes Replace aected module(s).

Go to step 2

No Unable to locate source of

odor. Go to step 3.

P08

2009-12-16

Disconnect all third-party 2.
devices and cables. Power ON
system and verify if smoke or
strong odor returns.

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 43

Yes Power down system

immediately. Go to step 3.

No System functions correctly.

Verify system functionality
with third-party devices and
cables and return system
to user if problem has been
resolved. Consult third-party
companies as needed for
issues with those products.

Verify if source of odor can be 3.
located using your nose.

Yes Replace aected module(s)

No Contact Apple for assistance

Uncategorized Symptoms

Quick Check

Symptoms Quick Check

P08

and retest system.

if you feel that there is a
possible safety issue with
computer that has not been
resolved in previous steps.

Uncategorized Symptoms

Unable to locate appropriate •
symptom code.

Make sure system is plugged into a known-good 1.
outlet.

Listen for boot chime, fan, optical drive, or hard 2.
drive noise which indicates system is powering
up. If noise is heard, go to Won’t Start Up
symptom ow. If no noise is heard go to

No Power, Dead Unit symptom ow.

Attempt to boot from Install DVD to isolate 3.
possible software issues.

Deep Dive

Check Result Action Code

Verify if existing symptom code 1.
applies to issue reported by
user.

Yes Jump to appropriate

symptom code ow.

No Document reported failure

and send feedback to

[e-mail]

stating that a suitable
symptom code wasn’t found.
Provide as much detail as
possible.

N99

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 44

Display

Backlight Issue/No Backlight

Unlikely cause: hard drive, optical drive, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Backlight Issue/No Backlight

No image•
Partial backlight failure•
Backlight ickers•
Display dim•

Check for Software Update.1.
Verify that System Preferences > Displays > 2.

Brightness control setting is above minimum.
If no image on built-in display, connect external 3.

display to verify if iMac video circuitry is
functioning. If no image visible on external
display, go to No Video symptom ow under
Startup and Power troubleshooting.

Deep Dive

Check Result Action Code

Verify boot chime present and 1.
fans running when computer
powered ON. (Reset SMC and
clear PRAM if necessary for
proper boot up.)

Verify if image is visible on 2.
built-in LCD panel, with
adjustable backlight level.

Yes Power on self test OK.

Go to step 2.

No Go to Won’t Start Up

symptom ow.

Yes Video present. Verify system

functionality and return to
user or go to appropriate
troubleshooting ow.

2009-12-16

Connect supported external 3.
display. Verify if image appears
on external display when
system is booted.

Verify if LCD backlight is ON 4.
by looking for faint glow
from display when viewed in
darkened room with brightness
set at maximum.

No Go to step 3.

Yes External display detected by

system. Video circuitry on
logic board functional.
Go to step 4.

No Go to No Video symptom

ow.

Yes LED backlight is functioning.

Go to step 7.

No Go to step 5.

iMac (27-inch, Late 2009) Symptom Charts — Display 45

Shine bright (low heat) 5.
ashlight onto front of LCD.
With computer powered ON
verify if a faint image is visible.

Yes LCD panel functional but

backlight is missing or
dim. Remove LCD panel
and inspect and reseat the
following cable connections:

-Backlight power cable
between backlight board and
LCD panel.

-Vertical sync cable between
backlight board and LCD
panel.

-DC power cable to backlight
board and power supply.

Replace any damaged cable.
Reinstall LCD panel and go to
step 6.

No No image or backlight.

Go to step 7.

X03

Power ON system. Verify if 6.
image is now visible on LCD
panel with correct backlight
level.

Inspect and reseat 7. internal
DisplayPort cable (between
logic board and LCD panel).
Power ON system. Verify if
image is visible on built-in LCD
display.

Yes Issue resolved.

No Replace LED backlight board.

Retest. If issue persists, go to
step 7.

Yes Issue resolved.

No Replace internal DisplayPort

cable.

If issue persists, replace LCD
panel. Retest.

M04

X03

L03

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Display 46

Noise / Unstable Flickering

Unlikely cause: camera, microphone

Quick Check

Symptoms Quick Check

Noise / Unstable Flickering

Unstable image•
Flickering image•
Humming noise from display•
High frequency noise from •
display

Check for Software Update.1.
Verify Mac OS X version installed is the build 2.

version supported on the hardware. Make sure
customer didn’t migrate over their old version of
Mac OS. See kBase #TS3101: Mac (Late 2009):

Using the correct Mac OS X system software.

Verify that intake vent on bottom of computer is 3.
not obstructed.

Inspect system for third party software that is 4.
being used to set fan speeds to a higher than
normal RPM. Some users may install this software
to monitor and control internal temperatures,
potentially causing higher fan speeds to generate
higher than expected noise levels.

Deep Dive

Check Result Action Code

Verify if user issue is due to 1.
ickering, or to an unstable
video image on the LCD.

Yes Suspected ickering issue, go

to step 2

No For audible noise issues go to

step 8. All other issues go to
appropriate symptom ow.

2009-12-16

Connect a supported external 2.
display to the mini DisplayPort
on rear of computer. Verify
if issue occurs with external
display.

Disconnect and carefully 3.
inspect all four cables on
back of LCD panel for signs of
damage, corrosion, or pinched
wires.

Power ON computer and verify 4.
if issue still occurs.

Yes Suspect issue with video

circuitry. Go to Corrupted

Video symptom ow.

No Video circuitry OK.

Go to step 3.

Yes Replace damaged cable(s)

where needed, otherwise
reattach connectors. Retest.

No Go to step 4.

Yes If connections are secure and

display is still ickering, go to
step 5.

No Issue resolved.

iMac (27-inch, Late 2009) Symptom Charts — Display 47

X03

Shine bright (low heat) 5.
ashlight into front of LCD.
Verify if an image is being
displayed when ickering issue
is occurring.

Yes Image present but backlight

is ickering. Replace vertical
sync cable (between LCD
panel and backlight board)
and retest.

X03

No Replace internal DisplayPort

cable (between logic board
and LCD panel), and retest.

Verify if high pitch noise varies 6.
when adjusting brightness level
up and down.

Yes Noise seems to be generated

by vertical sync cable. Inspect
and replace.

No Noise is from another source.

Go to step 7.

Verify if noise can be heard 7.
when computer is set up with

Yes Replace LED backlight board.

Go to step 8.
user seated in normal user
position. Adjusting brightness
level up and down may be
necessary to recreate issue.

No Noises that are not audible

from the normal user position

are considered acceptable.

Verify if noise is still present.8. Yes Replace LCD panel. If noise

still present, go to Noise/

Hum/Vibration symptom

ow.

No Issue resolved.

X03

X03

M04

L06

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Display 48

LCD Image Issues

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

Quick Check

Symptom Quick Check

LCD Issues

Incorrect/missing colors•
Distorted/blurred image•
Pixel anomalies•
Vertical/horizontal lines•
Non-uniform brightness•
Flickering•

Check for Software Update.1.
Verify Mac OS X version installed is the build 2.

version supported on the hardware. Make sure
customer didn’t migrate over their old version of
Mac OS. See kBase #TS3101: Mac (Late 2009):

Using the correct Mac OS X system software.

Allow display to reach normal operating 3.
temperature for about 15 minutes before
evaluating front-of-screen performance.

Check display preferences for use of custom 4.
display prole.

Check brightness setting.5.
Clean glass panel while checking for dust/debris.6.

Deep Dive: General

Check Result Action Code

Verify if issue is incorrect/1.
missing colors.

Yes Go to incorrect/missing

colors.

2009-12-16

Verify if issue is distorted/2.
blurred image.

Verify if issue is bright or dark 3.
pixel anomalies.

Verify if issue is vertical or 4.
horizontal lines.

Verify if issue is non-uniform 5.
brightness.

No Go to step 2.

Yes Go to distorted/blurred

image.

No Go to step 3.

Yes Go to pixel anomalies.

No Go to step 4.

Yes Go to vertical/horizontal

lines.

No Go to step 5.

Yes Go to non-uniform

brightness.

No LCD functioning OK. Return to

appropriate symptom ow if

user issue is still present.

iMac (27-inch, Late 2009) Symptom Charts — Display 49

Incorrect/Missing Colors

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

Quick Check

Symptoms Quick Check

Incorrect/Missing Colors

Wrong color display•
Color/contrast issues•

Allow display to reach normal operating 1.
temperature for about 15 minutes before
evaluating front-of-screen performance.

Verify if System Preferences > Display settings are 2.
congured to use default display prole.

Verify System Preferences > Universal Access > 3.
Display “Enhance contrast”, “Use grayscale”, and
“Black on White/White on Black” settings are set
to defaults.

Deep Dive

Check Result Action Code

Verify computer has been 1.
warmed up for about 15
minutes to stabilize backlight
before continuing.

Verify if all four cables on back 2.
of LCD panel are secure at both
ends.

Yes Go to step 2.

No Warm up computer for about

15 minutes. Go to step 2.

Yes Go to step 3.

No Reseat connections, replace

damaged cable(s) if needed.

Retest.

L14

2009-12-16

Go to System Preferences > 3.
Desktop & Screen Saver >
Desktop and set color to Solid
Gray Light. Verify if incorrect/
missing color issue aects
entire display.

Set up computer side-by-side 4.
with a known-good, same­model computer showing
same image. Verify if issue is
noticeably worse on display
being tested.

Yes Suspect poor video

connection. Replace internal

DisplayPort cable between

logic board and LCD panel.

No Go to step 4.

Yes Replace LCD panel. L02

No Small variations in color

uniformity across display are

normal and do not warrant

replacement of LCD.

iMac (27-inch, Late 2009) Symptom Charts — Display 50

L14

Distorted/Blurred Image

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

Quick Check

Symptoms Quick Check

Distorted/Blurred Image

Text and graphics appear fuzzy•
Image corrupted•

Check for Software Update.1.
Verify Mac OS X version installed is the build 2.

version supported on the hardware. Make sure
customer didn’t migrate over their old version of
Mac OS. See kBase #TS3101: Mac (Late 2009):

Using the correct Mac OS X system software.

Set System Preferences > Displays to native 3.
resolution of LCD. Non-native resolutions are
unable to produce optimal clarity.

Clean outside of glass panel.4.
Boot from install DVD to determine if a potential 5.

software issue exists.

Deep Dive

Check Result Action Code

Boot from Install DVD and 1.
verify if issue is still visible.

Yes Go to step 2.

No Issue likely caused by

software or driver issue.

Troubleshoot for software

issues. Make sure all software

updates have been installed.

2009-12-16

Verify if issue is visible on an 2.
external display attached to
mini DisplayPort.

Disconnect DisplayPort cable 3.
between LCD display and logic
board, and verify if there is
damage to cable or connectors.

Repeat with vertical sync cable
connected between LCD panel
and LED backlight board.

Yes Issue NOT caused by internal

LCD panel. Go to step 3.

No Go to step 8.

Yes Replace DisplayPort cable

and vertical sync cable or any

other damaged part/module.

No Reinstall DisplayPort cable

and vertical sync cable.

Go to step 4.

iMac (27-inch, Late 2009) Symptom Charts — Display 51

X03

Verify if issue is still visible after 4.
reinstalling internal DisplayPort
cable and vertical sync cable.

Yes Replace LCD panel.

If issue still present go to step

5.

No Issue resolved.

L04

Remove video card, inspect 5.
connector for damage or
corrosion then reinstall. Verify if
issue still occurs.

Verify if distorted/blurred 6.
image issue is still present.

Verify if issue is still present 7.
with replacement logic board
installed.

Inspect glass panel. Verify if 8.
issue is caused by condensation
or contaminants on inside
surface of glass panel.

Yes Replace video card.

Go to step 6.

No Issue likely caused by poor

video card connection.

Yes Replace logic board. Go to

step 7.

No Issue resolved.

Yes Return to step 1 and retest.

No Issue resolved.

Yes Clean glass and/or LCD using

procedures in Glass Panel

take-apart chapter.

Identify possible sources

of contamination (nearby

cigarette/cooking smoke,

heavy airborne dust, etc.)

to prevent recurrence.

Condensation should

dissipate after computer has

been running a few hours.

M04

2009-12-16

Verify if issue is still present 9.
with replacement LCD panel
installed.

No Go to step 9.

Yes Return to step 1 and retest.

No Issue resolved.

iMac (27-inch, Late 2009) Symptom Charts — Display 52

Pixel Anomalies

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

Quick Check

Symptoms Quick Check

Pixel Anomalies

Dark dot anomalies•
Bright dot anomalies•
Debris on inside surface of •
glass panel
Debris on surface of LCD panel•

Clean outside surface of glass panel.1.
See 2. kBase #HT1721: About LCD display pixel

anomalies.

Deep Dive

Check Result Action Code

Determine if “defects” are dust/1.
debris on surface of glass panel
or LCD.

Determine if bright pixel 2.
defects exceed acceptable
number. See kBase #HT1721:

About LCD display pixel
anomalies.

Determine if dark pixel defects 3.
exceed acceptable number. See

kBase #HT1721: About LCD
display pixel anomalies.

Yes Clean glass and/or LCD using

procedures in Glass Panel

take-apart chapter.

No Go to step 2.

Yes Replace LCD panel. L08

No LCD panel meets bright pixel

defect specications.

Go to step 3.

Yes Replace LCD panel. L08

No LCD panel meets dark pixel

defect specications.

Go to step 4.

2009-12-16

Determine if combination 4.
of bright/dark pixel defects
exceed acceptable number. See

kBase #HT1721: About LCD
display pixel anomalies.

Yes Replace LCD panel. L08

No Explain to user that LCD

panel is operating within

specications for pixel defects.

Do NOT replace LCD panel.

iMac (27-inch, Late 2009) Symptom Charts — Display 53

Vertical/Horizontal Lines

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

Quick Check

Symptoms Quick Check

Vertical/Horizontal Lines

Vertical lines•
Horizontal lines•

Boot from install DVD to determine if potential 1.
software issue exists.

Verify if issue is visible on an external display.2.

Deep Dive

Check Result Action Code

Boot from Install DVD and 1.
verify if issue is still visible.

Verify if issue is visible on an 2.
external display attached to
mini DisplayPort.

Yes Go to step 2.

No Issue likely caused by

software or driver issue.

Troubleshoot for software

issues. Make sure all software

updates have been installed.

Yes Issue NOT caused by internal

LCD. For systems with a video

card, go to step 3. For systems

without a video card, go to

step 4.

No Go to step 6.

2009-12-16

If a video card is present, 3.
remove video card and inspect
connector for damage or
corrosion then reinstall. Verify if
issue still occurs.

For systems without video card, 4.
horizontal lines may be related
to a failing RAM module. Verify
if video issue only happens
AFTER Apple logo and spinning
wheel appear.

Start with shift key down 5.
(safe mode) to disable system
extensions. Verify if issue still
happens when booting in safe
mode.

Yes Replace video card.

Go to step 8.

No Issue likely caused by poor

video card connection.

Yes Issue only happens AFTER

Apple logo and spinning

wheel appear. Go to step 5.

No Issue present before Apple

logo and spinning wheel

appear. Go to step 8.

Yes Go to step 8.

No No video issue when booting

in safe mode. Go to step 6.

iMac (27-inch, Late 2009) Symptom Charts — Display 54

M24

Isolate with only one memory 6.
module installed, then with the
other one. Test with known­good memory. Verify if issue
only happens with specic
RAM module(s).

Yes Replace aected RAM

module.

No Go to step 7.

X02

Isolate with one known-good 7.
memory module installed in
one memory slot. Repeat by
testing in other memory slots
Verify if issue only happens
with specic memory slot of
logic board.

Disconnect DisplayPort cable 8.
between LCD display and logic
board, and verify if there is
damage to cable or connectors.

Repeat with vertical sync cable
connected between LCD panel
and LED backlight board.

Verify if issue is still present 9.
after reinstalling internal
DisplayPort cable and vertical
sync cable.

Verify if issue is still present 10.
with replacement logic board
installed.

Yes Replace logic board and

retest.

No Go to step 8.

Yes Replace DisplayPort cable

and vertical sync cable or any

other damaged part/module.

Go to step 9.

No Reinstall DisplayPort cable

and vertical sync cable.

Go to step 9.

Yes Replace logic board. If video

card was present, reinstall

original video card.

Go to step 10.

No Issue resolved.

Yes Go to step 11.

No Issue resolved.

M07

X04

M04

2009-12-16

Reinstall original logic board 11.
and verify if issue is still present
with original logic board
reinstalled.

Yes Replace LCD panel. L04

No Issue resolved. If a video card

was present, reinstall original

video card.

iMac (27-inch, Late 2009) Symptom Charts — Display 55

Non-Uniform Brightness

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

Quick Check

Symptoms Quick Check

Non-Uniform Brightness

Brightness not uniform•
Color not-uniform•

Verify System Preferences > Displays > Brightness 1.
slider is set above minimum.

Allow 15 minutes for backlight to reach normal 2.
operating temperature and output before
evaluating display.

Visually inspect glass panel for presence of dust, 3.
cigarette smoke, or other contaminants. Clean
glass panel if needed.

Deep Dive

Check Result Action Code

Determine if brightness 1.
uniformity issue is visible after
display has warmed up for
about 15 minutes.

Look at user-provided 2.
examples showing brightness
uniformity issue. Determine if
variation in uniformity appears
excessive when compared to
another same-model computer.

Yes Go to step 2.

No Display backlight can take

several minutes to stabilize.

Retest. If issue still not visible

return computer to user.

Yes Go to step 3.

No Demonstrate to user that LCD

performs similarly to another

computer of the same model.

2009-12-16

Remove glass panel and 3.
loosen screws securing LCD
panel. Determine if brightness
uniformity improves.

Remove LCD panel, then 4.
inspect and reseat backlight
cables. Determine if brightness
uniformity improves.

Yes Inspect for mechanical

interference with screws

or cables making contact

with back of LCD. Reseat

components & cables, retest.

No Go to step 4.

Yes One or more backlight cables

were loose.

No Replace LCD panel. L07

iMac (27-inch, Late 2009) Symptom Charts — Display 56

Cosmetic Defects

Symptoms Quick Check

Cosmetic Defects to LCD

Cracked glass panel•
Cracked LCD•
Scratched LCD polarizer•
Scorched or melted LCD•
LCD impact damage•
Foreign material on LCD or •
back side of glass panel.

Replace glass panel. Refer to Take Apart/General 1.
Information/How to Remove a Broken Glass Panel

Determine if damage was caused by user 2.
environment, accidental damage, or abuse. If
applicable, inform user that Apple does not
warrant damage caused by accident, abuse,
misuse, ood, re, earthquake, or other external
causes. For more information refer to: http://

www.apple.com/legal/warranty

For dark and bright pixel anomalies see 3. Pixel

Anomalies symptom ow.

Uncategorized Symptoms

Quick Check

Symptoms Quick Check

Uncategorized Symptoms

Unable to locate appropriate •
symptom code.

Make sure brightness level is set above minimum.1.
Clean glass panel to make sure external 2.

contaminants are removed prior to evaluating
display performance.

2009-12-16

Allow LCD display to warm up approximately 3.
15 minutes before evaluating display color and
brightness uniformity performance.

Deep Dive

Check Result Action Code

Verify if existing symptom code 1.
applies to issue reported by
user.

Yes Jump to appropriate

symptom code ow.

No Document reported failure

and send feedback to

[e-mail]

stating that a suitable

symptom code wasn’t found.

Provide as much detail as

possible.

iMac (27-inch, Late 2009) Symptom Charts — Display 57

N99

Mass Storage

Hard Drive Not Recognized

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Drive Not Recognized
Drive No Boot

Flashing Question Mark•
Boots to Grey Screen•
Boots to Blue Screen•
Boots to Prohibitory Symbol •
(Review kBase #HT2674: Intel-

based Mac: Startup sequence
and error codes, symbols)

Use a known-good mouse. A stuck mouse button 1.
will not allow boot.

Boot from Install DVD. Use Disk Utility to verify 2.
S.M.A.R.T. status of hard drive.

Use Disk Utility to repair disk.3.
Verify that user’s data is backed up and that user 4.

authorizes erasing disk and reinstalling software.
Use Target Disk Mode to mount user’s hard drive 5.

on a known-good computer. Use Disk Utility on
host computer for Quick Checks 2 through 4.

Deep Dive

Check Result Action Code

Boot from Install DVD and run 1.
Disk Utility. Verify if user’s hard
drive is available for Disk Utility
to repair.

Run Disk Utility’s “Repair 2.
Disk” function and verify if it
completes successfully.

Yes Go to step 2.

No Go to step 5.

Yes Go to step 3.

No Go to step 4.

2009-12-16

Reboot computer. Verify if 3.
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

With user’s permission, erase 4.
hard drive and reinstall Mac
OS. Verify if installation process
completes.

Inspect hard drive SATA and 5.
power cables and connectors
for bent pins, or other damage
to the cable.

Yes Data error. Issue resolved. H07

No Go to step 4.

Yes Go to step 8.

No Go to step 5.

Yes Replace damaged SATA cable

or DC power cable.

Go to step 8.

No Go to step 6.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 58

X03

Reseat hard drive SATA cable 6.
at logic board and hard drive
connections, and verify if
computer starts up.

Yes Go to step 8.

No Replace SATA cable.

Go to step 8.

X03

Test with known-good 7.
bootable hard drive. Verify if
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

Reboot computer. Verify if 8.
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

Reboot computer. Verify if 9.
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

Replace hard drive. Boot from 10.
system-specic Install DVD
and reinstall Mac OS X with
drive format option. Verify if
drive is formatted correctly
(GUID partition table) and that
software restore was successful.

Yes Install user’s hard drive.

Go to step 9.

No SATA cable veried or

replaced and known-good

hard drive installed. Replace

logic board. Go to step 1.

Yes Issue resolved. Return system

to user.

No Go to step 7.

Yes Issue resolved.

No User’s hard drive appears to

be defective. Go to step 10.

Yes Issue resolved by replacing

hard drive.

No SATA cable veried/replaced

and new hard drive installed,

Check with known-good

restore DVD. If restore failure

still happens, go to step 11.

H01

If restore is unsuccessful, 11 .
startup a known-good system
in Target Disk Mode and
connect it to the user’s system
with a FireWire cable. Once
set up, insert the iMac Install
Disc in its optical drive. Startup
user’s system while holding
Option key, select and boot
from the Install Disc DVD
and restore system software.
Verify if software restore was
successful.

Yes Restore failure seems to be

due to internal optical drive

or media issue. Go to Optical

Drive Read/Write Error

symptom ow.

No Restore failure seems to be

due to internal SATA bus

issue. Replace logic board.

M19

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 59

Hard Drive Read/Write Errors

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Drive Read/Write Error
Drive Bad Sector/Defective
Drive Formatting Issues

Cannot save documents•
Read/write error message•
Hang when accessing or saving •
data

Boot from Install DVD. Use Disk Utility to verify 1.
S.M.A.R.T. status of hard drive.

Use Disk Utility to repair disk.2.
Verify that user’s data is backed up and that user 3.

authorizes erasing disk and reinstalling software.
Use Target Disk Mode to mount user’s hard drive 4.

on a known-good computer. Use Disk Utility on
host computer for Quick Checks 2 through 3.

Deep Dive

Check Result Action Code

Run Disk Utility ‘Repair Disk’ 1.
function and verify if it
completes successfully.

Reboot computer. Verify if 2.
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

With user’s permission, erase 3.
hard drive and reinstall Mac
OS. Verify if installation process
completes.

Yes Go to step 2.

No Go to step 3.

Yes Data error. Issue resolved. H07

No Go to step 3.

Yes Go to step 6.

No Go to step 4.

2009-12-16

Inspect hard drive SATA, power 4.
cables and connectors for bent
pins, or other damage to the
cable.

Reseat SATA cable on hard 5.
drive and logic board. Verify if
computer starts up.

Reboot computer. Verify if 6.
system boots successfully and
Disk Utility “Verify” function
reports no errors.

Yes Replace damaged cable.

Go to step 6.

No Go to step 5.

Yes Go to step 6.

No Replace hard drive data cable.

Go to step 6.

Yes Issue resolved.

No Go to step 7.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 60

H04

H04

Test with known-good hard 7.
drive. Verify if system boots
successfully and Disk Utility
“Verify” function reports no
errors.

Yes Reinstall user’s hard drive, go

to step 8.

No SATA cable veried or

replaced and known-good

hard drive installed. Replace

logic board.

Reboot computer. Verify if 8.
system boots successfully and
that Disk Utility “Verify” function
reports no errors.

Replace user’s hard drive. Verify 9.
if drive formats correctly with a
GUID partition map and installs
Mac OS without errors.

Yes Issue resolved.

No User’s hard drive appears to

be defective. Go to step 9.

Yes Issue resolved by replacing

user’s hard drive.

No SATA cable veried or

replaced and new hard drive

did not resolve issue. Replace

logic board.

Hard Drive Noisy

Unlikely cause: LCD panel, logic board, power supply, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Hard Drive Noisy

Noise during start up•
Noise during operation•
Noise when drive is copying or •
saving data

Boot from Install DVD. Use Disk Utility to verify 1.
S.M.A.R.T. status of hard drive.

Use Disk Utility to repair disk.2.
Determine if noise is comparable to another 3.

machine of the same model.

H03

M19

2009-12-16

Deep Dive

Check Result Action Code

Boot from the Install DVD and 1.
run Disk Utility. Verify if user
hard drive is available for Disk
Utility to repair.

Run Disk Utility ‘Repair Disk’ 2.
function and verify if it
completes successfully.

Yes Go to step 2.

No Go to Hard Drive Not

Recognized symptom ow.

Yes Go to step 3.

No Go to step 4.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 61

Restart the computer. Verify if 3.
the noise is still present.

Yes Go to step 4.

No Issue resolved. Return system

to user.

H06

With user’s permission, erase 4.
hard drive and reinstall Mac
OS. Verify if installation process
completes.

With replacement hard drive 5.
installed, reboot computer.
Verify if noise is still present.

With hard drive removed verify 6.
if rubber vibration isolation
grommets are properly
installed in hard drive bracket
(attached to hard drive) and
to mechanism in rear housing
(where hard drive pins insert).

Reboot computer. Verify if noise 7.
is still present.

Disconnect hard drive SATA and 8.
power connections then boot
from the Install DVD. Verify if
noise is caused by fans.

Yes Go to step 3.

No Replace hard drive.

Go to step 5.

Yes Replacement hard drive did

not resolve issue. Go to step 6.

No Issue resolved by replacing

hard drive.

Yes Go to step 8.

No If grommets are missing or

damaged, replace hard drive

bracket or mechanism as

appropriate. Go to step 7.

Yes Go to step 8.

No Issue resolved by replacing

hard drive bracket. Return

system to user.

Yes Go to Fan Failures/Thermal

Issues symptom ow.

No Go to step 9.

H06

H06

2009-12-16

Disconnect hard drive and 9.
optical drive then boot from an
external volume. Verify if noise
disappears when optical drive
has been disconnected.

Yes Possible optical drive or

media issue. Go to Optical

Drive Noisy symptom ow.

No Noise issue still present, but

does not appear to be caused

by hard drive. Go to Noise/

Hum/Vibration symptom

ow.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 62

Optical Drive Not Recognized

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Drive Not Recognized/Mount

Discs inject and eject, but do •
not appear in Finder

Use System Proler Serial-ATA section to see if 1.
optical drive appears.

System Proler Serial-ATA section will show any 2.
media inserted.

Check Finder Preferences and make sure “CD’s, 3.
DVD’s and iPods” is checked under “Show these
items on the desktop” in the General section.

Deep Dive

Check Result Action Code

Verify if optical drive is listed 1.
in Serial-ATA section of System
Proler.

Test both CD and DVD media. 2.
Verify if optical drive can read
both CD and DVD media.

Yes Go to step 2.

No Go to step 3.

Yes No issue, or possible

intermittent issue. Gather

more information from user.

No If both types of media fail,

check that Finder Preferences

are set to “show CD’s and

DVD’s”, then go to step 3.

J03

2009-12-16

Connect known-good optical 3.
drive to SATA cable. Verify if
both CD and DVD media are
read reliably.

Reseat SATA cable connections 4.
at optical drive and logic board
(cable connects to back of logic
board). Verify if both CD and
DVD media are read reliably.

If only one type of media fails,

drive has a laser pickup issue.

Replace optical drive.

Yes SATA cable and port on logic

board good. Go to step 5.

No Go to step 4.

Yes Go to step 6.

No Replace SATA cable and test.

If issue persists, replace logic

board.

Go to step 6.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 63

X03

M19

Connect original optical drive 5.
to known-good SATA cable.
Verify if both CD and DVD
media are read reliably.

Yes SATA cable issue. Replace

SATA cable. Go to step 6.

No Replace optical drive. J03

X03

Test read compatible known-6.
good CD and DVD media
(Install DVD). Verify if media is
recognized and reads reliably.

Yes Issue resolved.

No Replace optical drive. J03

Optical Drive Won’t Accept/Eject Media

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Drive Won’t Accept Media
Drive Won’t Eject Media

Cannot insert a disc into drive•
Cannot eject a disc from drive•

Use System Proler Serial-ATA section to see if 1.
optical drive appears. If not, go to Optical Drive

Not Recognized symptom ow.

Restart computer and hold down mouse button 2.
or keyboard eject key to cycle optical drive.

Inspect optical drive slot for obstructions3.

Deep Dive

Check Result Action Code

Verify if optical drive is listed in 1.
System Proler device tree for
Serial-ATA devices.

Verify SATA cable connections 2.
between optical drive and logic
board. Visually inspect cables
and connectors for any debris,
damage or bent pins. Verify if
optical drive is listed in System
Proler device tree.

Connect known-good optical 3.
drive to SATA cable. Verify if
known-good optical drive is
listed in the System Proler
device tree.

Yes Optical drive communicating

with logic board. Go to step 5.

No Go to step 2.

Yes Optical drive communicating

with logic board. Go to step 5.

No Replace damaged cables

and retest. If connections are

good and no visible cable

damage, go to step 3.

Yes Go to step 4.

No Suspect bad SATA cable.

Go to step 7.

X03

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 64

With known-good optical drive 4.
installed, test for media inject/
eject. Verify if drive accepts and
ejects known-good media.

Yes Known-good optical drive

resolved inject/eject issue.

Replace optical drive.

No Go to step 7.

J03

Inspect optical drive slot during 5.
disc insert/eject. Verify if discs
can be inserted easily.

With known-good optical 6.
media (Install DVD), test for
media inject/eject. Verify
if drive accepts and ejects
known-good media.

Replace SATA cable then test 7.
for media inject/eject. Verify if
drive injects and ejects known­good media.

Yes Go to step 6.

No Verify correct optical drive

bezel alignment with

enclosure. Reseat optical drive

then retest. If issue persists,

replace optical drive.

Yes Media issue. No repair

necessary. Suggest user

investigate use of dierent

media.

No Go to step 3.

Yes SATA cable resolved issue.

Return system to user.

No SATA cable veried or

replaced, and optical drive

veried or replaced. Replace

logic board and retest.

J03

X03

M19

Optical Drive Read/Write Error

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Drive Read/Write Data Error

Errors when writing optical •
media.
Errors when reading optical •
media.
Hang when accessing or •
preparing to write data.

Test optical media in a known-good optical drive 1.
in the same type of computer to rule out media
issue.

Check with known-good discs like the Install DVD 2.
that came with the computer.

For write issues, check with known-good media 3.
that performs well in a known-good optical drive
in the same type of computer.

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 65

Deep Dive

Check Result Action Code

Verify if media is free to spin 1.
without optical drive scraping
edge or surface of media.

Test both CD and DVD media. 2.
Verify if drive can read both CD
and DVD media.

Connect known-good optical 3.
drive to SATA cable. Verify if
both CD and DVD media are
read reliably.

Reseat SATA cable connections 4.
at optical drive and logic board
(cable connects to back of logic
board). Verify if both CD and
DVD media are read reliably.

Yes Go to step 2.

No Replace optical drive. J05

Yes Go to step 6.

No If both types of media fail,

check that Finder Preferences

are set to “show CD’s and

DVD’s”, then go to step 3.

If only one type of media fails,

drive has a laser pickup issue.

Replace optical drive.

Yes SATA cable and port on logic

board good. Go to step 5.

No Go to step 4.

Yes Go to step 6.

No Replace SATA cable and test.

If issue persists, replace logic

board.

J03

X03

M19

Connect original optical drive 5.
to known-good SATA cable.
Verify if both CD and DVD
media are read reliably.

Test write data to compatible 6.
CD and DVD media. Verify if
burned media is recognized
and read reliably.

Go to step 6.

Yes SATA cable issue. Replace

SATA cable. Go to step 6.

No Replace optical drive. J03

Yes Issue resolved.

No Run ODD sensor and ODD fan

tests in ASD:

If errors found check

ODD sensor and ODD fan

connections to logic board

(read/write errors may be due

to drive being too hot).

If no errors are found while

running diagnostics, replace

optical drive.

X03

J03

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 66

Optical Drive Not Performing to Specications

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

Optical Drive Not Performing to
Specications

Read or write speeds slower •
than expected

Test optical media in another computer of the 1.
same type to rule out media issue.

For write issues, check with known-good media 2.
that performs well in another computer and drive
of the same type.

Deep Dive

Check Result Action Code

Test both CD and DVD media. 1.
Verify if optical drive can read
both CD and DVD media.

Connect known-good optical 2.
drive to SATA cable. Verify if
both CD and DVD media are
read reliably.

Yes Go to step 5.

No If both types of media fail,

check that Finder Preferences

are set to “show CD’s and

DVD’s”, then go to step 2.

If only one type of media fails,

drive has a laser pickup issue.

Replace optical drive.

Yes SATA cable and port on logic

board good. Go to step 4.

No Go to step 3.

J03

2009-12-16

Reseat SATA cable connections 3.
at optical drive and logic board
(cable connects to back of logic
board). Verify if both CD and
DVD media are read reliably.

Connect original optical drive 4.
to known-good SATA cable.
Verify if both CD and DVD
media are read reliably.

Test write data to compatible 5.
CD and DVD media. Verify if
burned media is recognized
and read reliably.

Yes Go to step 5.

No Replace SATA cable and test.

If issue persists, replace logic

board.

Go to step 5.

Yes SATA cable issue. Replace

SATA cable. Go to step 5.

No Replace optical drive. J03

Yes Issue resolved.

No Go to step 6.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 67

X03

M19

X03

Media that is out of balance 6.
may not perform well at higher
speeds even though higher
speeds may be supported
by the optical drive. Verify if
slowing requested burn speed
allows discs to be written
reliably.

Yes Media issue. No repair

necessary.

No Go to step 7.

Test write data to compatible 7.
CD and DVD media. Verify
burned media is recognized
and reads reliably.

Yes Issue resolved.

No Run ODD sensor and ODD fan

tests in ASD:

If errors found check

ODD sensor and ODD fan

connections to logic board

(read/write errors may be due

to drive being too hot).

If no errors are found while

running diagnostics, replace

optical drive.

Optical Drive Noisy

Unlikely cause: LCD panel, power supply, fans, speakers, camera, microphone

Quick Check

Symptoms Quick Check

J03

2009-12-16

Optical Drive Noisy (J04)

Noise during boot•
Noise during operation•
Noise when drive is copying or •
writing data

Test optical media in another computer of the 1.
same type to rule out media issue.

Check with known-good discs like the Install DVD 2.
that came with the computer.

Verify if noise occurs without media in optical 3.
drive. If so, verify if noise made by hard drive or
fans.

Deep Dive

Check Result Action Code

Test optical drive with dierent 1.
source of media. Does the noise
issue remain?

Yes Go to step 2.

No Issue due to unbalanced

media. Recommend using

dierent media.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 68

Reseat optical drive in 2.
enclosure. Does noise issue
remain?

Yes Go to step 3.

No Issue resolved by reseating

drive in enclosure.

Install known-good optical 3.
drive in enclosure. Does noise
issue remain?

Compare system with similar 4.
model for optical drive noise in
operation and verify that noise
level is similar.

Yes Go to step 4.

No Replace optical drive. J04

Yes Noise level of optical

drive appears to be within

specication. Return system

to user.

No Check for other causes of

noise in the system.

SD Card Will Not Insert Into Slot

Unlikely cause: LCD panel, logic board, optical drive, hard drive

Quick Check

Symptom Quick Check

SD Card will not insert into slot

SD Memory Card does not fully •
seat into slot
Card slot does not align with •
enclosure.

The SD card must be a 32 mm by 24 mm by 2.1 1.
mm. You can also use thinner cards, such as Multi
Media Cards (MMC).

Clear any obstruction in SD card slot.2.

2009-12-16

Deep Dive

Check Result Action Code

Verify if known-good SD card 1.
ts in slot.

Verify if known-good SD card 2.
now ts in slot.

Yes Ask user to replace defective

or out-of-spec SD card.

No Loosen the SD board screws,

then insert known-good SD
card again. Go to step 2.

Yes Tighten SD board screws.

Go to step 3.

No Replace SD board and retest. M17

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 69

Verify if SD card now ejects 3.
and inserts without issue.

Yes Issue resolved by SD board

alignment.

No Replace SD board. M17

SD Card Not Recognized

Unlikely cause: LCD panel, logic board, optical drive, hard drive

Quick Check

Symptom Quick Check

SD Card Not Recognized

Card does not show up on •
desktop or in System Proler

Insert user’s SD card into a known-good system 1.
and verify that it functions properly. If card
cannot be read, contact card manufacturer for
support options.

Verify SD card slot with known-good SD card.2.
Check correct drivers are installed for user’s SD 3.

card type. Standard SD cards are supported by
Mac OS X, but others may require specic driver
software to be used.

Deep Dive

Check Result Action Code

Verify if SD card inserts 1.
correctly in SD slot.

Unlock and insert user’s SD 2.
card and verify it shows up on
desktop or in System Proler.

Insert a known-good unlocked 3.
SD card and verify if read/write
capabilities are working.

Yes Go to step 2.

No Go to SD Card Will Not Insert

Into Slot symptom ow.

Yes Go to step 6.

No Go to step 3.

Yes User’s SD card not functioning

properly. Contact card
manufacturer for support.

2009-12-16

No Go to step 4.

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 70

Run System Proler and verify 4.
if SD card reader is now listed
in USB devices.

Yes Go to step 5.

No Reseat SD cable at SD board

and logic board

If issue persists, replace
SD cable.

If issue persists, replace
SD board.

If issue persists, replace
logic board.

M17
M17
M17

Verify if a known-good 5.
unlocked SD card can now be
correctly read and written.

Lock the user’s SD card and 6.
verify if it can’t be written.

Yes Go to step 6.

No Replace SD board. M17

Yes Issue resolved.

No Replace SD board. M17

Uncategorized Symptoms

Check Result Action Code

Verify if existing symptom code 1.
applies to issue reported by
user.

Yes Jump to appropriate

symptom code ow.

No Document reported failure

and send feedback to

[e-mail]

stating that a suitable

symptom code wasn’t found.

Provide as much detail as

possible.

N99

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mass Storage 71

Communications

AirPort/Bluetooth Issues

Quick Check

Symptoms Quick Check

AirPort/Bluetooth Issues

Unable to join networks or pair •
devices
AirPort card not available•
Intermittent device or •
connection dropouts
Limited wireless range•

Deep Dive

Verify that AirPort or Bluetooth is turned ON, and 1.
for AirPort issues make sure that a network is
selected.

For AirPort, check if the wireless access point 2.
requires special connection and encryption
protocols.

Check for nearby sources of interference such 3.
as microwave ovens or cordless phones. See

kBase #HT1365: AirPort: Potential source of
interference.

Check the number of users trying to use AirPort 4.
in the area for possible network congestion
(available bandwidth).

Isolate potential OS issues by starting up 5.
from original Install media for the computer, a
same-model computer in Target Disk Mode, or
compatible known-good OS on an external drive.
Both AirPort and Bluetooth services are available
when booted from Install disc.

2009-12-16

Check Result Action Code

Open System Proler. AirPort 1.
is listed under Network, while
Bluetooth is listed under USB.
Verify if both AirPort and
Bluetooth cards are recognized.

Reseat both AirPort cable 2.
connection on logic board and
on AirPort card carrier ends.
Verify if AirPort card is now
listed in Apple System Proler.

iMac (27-inch, Late 2009) Symptom Charts — Communications 72

Yes Install all software updates

for AirPort/Bluetooth and

re-test. If issue persists after

software update, go to step 4

for AirPort, or go to step 6 for

Bluetooth.

No Go to step 2 for AirPort.

Go to step 6 for Bluetooth.

Yes Issue resolved by reaseating

AirPort cable.

No Replace AirPort cable and re-

test. Go to step 3.

M11

After cable has been replaced, 3.
verify if AirPort card is now
listed in Apple System Proler.

Yes Issue resolved by replacing

AirPort cable.

No Replace AirPort card carrier

board and re-test. If issue

persists (card not seen on

bus), replace AirPort card.

X03

M11

Enable AirPort and verify if 4.
known local AirPort networks
are available, or create a
computer-to-computer
network with another
Macintosh computer using
AirPort. See http://docs.

info.apple.com/article.
html?path=AirPort/5.0/en/
ap2110.html. Verify if you

connect successfully.

Check and reseat the two 5.
antennas to the AirPort card.
Verify if you can connect to
known AirPort network.

Verify that computer and 6.
Bluetooth device are both in
discoverable mode. Verify if
you can now successfully and
reliably pair the device.

Yes Issue resolved.

No Go to step 5.

Yes Issue resolved.

No Replace AirPort card. If issue

persists, replace AirPort

antenna(s). If damaged

antenna is the one embedded

in rear housing behind Apple

logo, replace rear housing.

Yes Issue resolved.

No Replace Bluetooth antenna.

Go to step 7.

N04

M11

2009-12-16

Re-test with new Bluetooth 7.
antenna and verify if Bluetooth
issues are resolved.

iMac (27-inch, Late 2009) Symptom Charts — Communications 73

Yes Issue resolved.

No Replace Bluetooth card. M11

AirPort Card Kernel Panic

Quick Check

Symptoms Quick Check

AirPort Card Kernel Panic

Kernel Panic on startup•
Kernel Panic or freezing while •
attempting to connect to WiFi
networks
Kernel Panic while transferring •
data on WiFi networks

Isolate OS by starting up from original Install 1.
media for this computer, a same-model computer
in Target Disk Mode, or compatible known-good
OS on an external drive. AirPort and Bluetooth
services are available when booted from the
Install disk.

Ensure that all software and rmware updates for 2.
the computer and AirPort been installed.

Deep Dive

Check Result Action Code

Disconnect AirPort card cable 1.
end from logic board. Verify if
computer starts now without
kernel panic.

Yes Reseat AirPort card cable and

retest. If problem continues

replace cable. Go to step 2.

No Kernel panic not related

to AirPort. Restart from

Install DVD or known-good

bootable external drive and

check Panic.Log le on user’s

hard drive to nd out which

is the crashing I/O interface.

Also troubleshoot installed

Mac OS X software..

2009-12-16

With replacement AirPort 2.
card cable installed, verify if
computer starts now without
kernel panic.

With replacement AirPort 3.
carrier or card installed, verify
if computer starts now without
kernel panic.

iMac (27-inch, Late 2009) Symptom Charts — Communications 74

Yes AirPort cable issue. Issue

resolved.

No Replace AirPort card carrier

board and re-test. If issue

remains, replace AirPort card.

Go to step 3.

Yes AirPort carrier or card issue.

Issue resolved.

No Replace logic board. M11

N13

N13

Ethernet Port/Device Issue

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Ethernet Port/Device Issue

No Ethernet device present•
Unable to access network •
resources
Ethernet device shows no •
connection
Ethernet device unable to an IP •
address
Slow network performance•

Check Ethernet cable for damage. Try a 1.
known good Ethernet cable – CAT5 or better
recommended for 100Mbps+ connections.

Check Ethernet ports on the computer and wall/2.
switch for dust, debris, damage or bent pins.

Ensure distance from networking infrastructure is 3.
less than 300 feet/ 105 meters.

Verify port, cable and network hardware with a 4.
known good system. Isolate rewall, MAC address
ltering or hardware access control devices.

Isolate OS by starting up from original Install 5.
media for this computer, a same-model computer
in Target Disk Mode, or compatible known-good
OS on an external drive.

Deep Dive

Check Result Action Code

Visually inspect Ethernet port 1.
of computer and ensure that all
pins will make physical contact
with the Ethernet cable.

Yes Go to step 2.

No Pins are damaged, bent at or

missing. Replace logic board.

M24

2009-12-16

Boot from original Install media. 2.
Verify Network Link status is
active by using Network Utility
under the “Info” tab. Verify if the
Link Status is “Active”.

Connect computer to another 3.
Mac using CAT5 Ethernet
cable. See article http://

docs.info.apple.com/article.
html?path=Mac/10.5/en/8429.
html. Verify if you connect

successfully.

iMac (27-inch, Late 2009) Symptom Charts — Communications 75

Yes Go to step 3.

No If same Ethernet cable gives

an “Active” link status on a

known-good, same-model

computer, replace logic board.

Yes Ethernet communication

good. Go to step 4.

No If same Ethernet cable and

computer connects to a

known-good, same-model

computer, replace logic board.

M10

M10

Check for speed and duplex 4.
issues on network. Open
System Preference > Network;
click the Advanced button,
then the Ethernet tab. Verify if
the speed and duplex reported
are what is expected.

Yes Go to step 5.

No Change speed and duplex

settings. See article http://

docs.info.apple.com/article.

html?path=Mac/10.5/

en/8711.html. Go to step 6.

Check for MTU (Maximum 5.
Transmission Unit) issues. See

kBase #HT2532: Mac OS X:
How to change the MTU for
troubleshooting purposes.

Verify if changing MTU settings
on computer resolves issue.

If changing speed, duplex 6.
or MTU settings allows
connectivity, check with a
known-good, same-model
computer. Verify if known-good
computer produces the same
results.

Yes Go to step 6.

No Ethernet controller damaged.

Yes Check with ISP or Network

No Verify with known good OS.

Wireless Input Device Doesn’t Pair

Quick Check

Symptoms Quick Check

M10

Replace logic board.

Administrator concerning

speed, duplex & MTU settings.

M10

If issue persists, replace logic

board.

2009-12-16

Wireless Input Device Doesn’t
Pair

Can’t get system to recognize •
the Bluetooth keyboard or
mouse

Remove and reinstall batteries for device.1.
Check that device is powering on.2.
Use known-good batteries with device.3.
Ensure that device is being used within 30-foot 4.

range for Bluetooth devices.
Ensure that the latest Software Updates have 5.

been applied.

iMac (27-inch, Late 2009) Symptom Charts — Communications 76

Deep Dive

Check Result Action Code

Without any wired input 1.
devices connected, and with a
wireless mouse in discoverable
mode, startup the computer.
Verify if computer shows
the Bluetooth Mouse Setup
Assistant.

Connect a wired mouse and 2.
run Apple System Proler. Verify
if Bluetooth interface is listed
under USB in System Proler.

Use an external monitor. Run 3.
Apple System Proler. Verify
if Bluetooth interface is listed
under USB in System Proler.

Run Apple System Proler. 4.
Verify if Bluetooth interface
is listed under USB in System
Proler.

Yes Bluetooth hardware is active.

Go to step 6.

No Go to step 2.

Yes Bluetooth hardware is

present. Go to step 6.

No Remove glass and LCD panel,

reseat both ends of cable

between Bluetooth board and

logic board. Go to step 3.

Yes Bluetooth hardware is now

present. Go to step 6.

No Replace Bluetooth cable.

Go to step 4.

Yes Bluetooth hardware is now

present. Go to step 6.

No Replace Bluetooth board.

Go to step 5.

X03

M11

Run Apple System Proler. 5.
Verify if Bluetooth interface
is listed under USB in System
Proler.

Run Software Update and 6.
apply any available Bluetooth
updates. Activate Bluetooth
in System Preferences (or
Apple menu icon) then select
“Congure a new Bluetooth
device” (or run Bluetooth
Mouse Setup Assistant). Verify if
Bluetooth mouse is seen.

With a wireless mouse on, and 7.
in discoverable mode, verify if
you can successfully pair the
mouse with the assistant.

Yes Bluetooth hardware is now

present. Go to step 6.

No Replace logic board. M11

Yes Bluetooth discovery is now

active. Go to step 7.

No Replace Bluetooth antenna. X03

Yes Check for stability.

Go to step 8.

No Go to Wireless Input Device

Loses Connection symptom

ow.

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Communications 77

With wireless mouse paired, 8.
verify if the mouse stays
connected.

Yes Issue resolved.

No Inspect and reseat Bluetooth

antenna cable. Replace a
damaged antenna cable, or
Bluetooth board if its antenna
connector is damaged.
Go to step 9.

With wireless mouse paired, 9.
verify if the mouse stays
connected.

Yes Antenna issue. Issue resolved.

No Go to Wireless Input Device

Loses Connection symptom

ow.

Wireless Input Device Loses Connection

Quick Check

Symptoms Quick Check

Wireless Input Device Loses
Connection

Wireless keyboard, mouse, or •
other wireless input device
loses connection.

Remove and reinstall batteries for device.1.
Check that device is powering on.2.
Use known-good batteries with device.3.
Ensure other devices pair and keep connection 4.

without issue. If not, see AirPort/Bluetooth

Issues symptom ow.

Ensure that device is being used within 30-foot 5.
range for Bluetooth devices.

2009-12-16

Ensure that the latest Software Updates have 6.
been applied.

Deep Dive

Check Result Action Code

Open System Preferences > 1.
Bluetooth. Paired items and
their connection status are
shown. Verify if device is listed.

iMac (27-inch, Late 2009) Symptom Charts — Communications 78

Yes Device has been paired.

Go to step 2.

No Device is not paired. Make

device discoverable and open
Bluetooth Setup Assistant.
Go to step 3.

Make sure device is on. 2.
In System Preferences >
Bluetooth, select device and
from the Action menu (gear)
choose “Connect”. Verify if
device connects successfully.

Yes Go to step 7.

No Delete pairing in System

Preferences. Go to step 3.

With the device on, run 3.
Bluetooth Setup Assistant.
Verify if you can successfully
pair the device.

With device on, run Bluetooth 4.
Setup Assistant. Verify if you
can successfully pair device.

Log into new Admin User 5.
account. With device on, run
Bluetooth Setup Assistant.
Verify if you can successfully
pair device with new user
account.

Restart computer, With device 6.
on, run Bluetooth Setup
Assistant. Verify if you can
successfully pair device.

With device paired and 7.
connected, verify if device
connection is stable if used
normally.

Yes Go to step 7.

No Restart computer.

Go to step 4.

Yes Go to step 7.

No Create a new Admin User.

Go to step 5.

Yes User account issue.

Troubleshoot software on

User account. No hardware

repair needed.

No Remove the following le: /

Library/Preferences/com.

apple.Bluetooth.plist

Go to step 6.

Yes Go to step 7.

No Go to AirPort/Bluetooth

Issues symptom ow.

Yes Issue resolved.

No Check wireless device manual

to verify if device is being

used in accordance with

manufacturer’s specications

(range, OS support, battery

types). Go to step 8.

2009-12-16

Verify if device is performing to 8.
stated specications.

Yes Educate user. Issue resolved.

No Replace wireless device.

iMac (27-inch, Late 2009) Symptom Charts — Communications 79

Uncategorized Symptoms

Quick Check

Symptoms Quick Check

Uncategorized Symptoms

Unable to locate appropriate •
symptom code.

Verify System Preferences/Network settings 1.
are congured appropriately to support
communication method.

For Ethernet connection issues verify that cable 2.
being used functions when used with another
known-good system.

For wireless connection issues review user 3.
environment to determine whether possible
interference from other 2.4GHz communications
devices might be contributing to issue. See

kBase #HT1365: AirPort: Potential sources of
interference

Deep Dive

Check Result Action Code

Verify if existing symptom code 1.
applies to issue reported by
user.

Yes Jump to appropriate

symptom code ow.

No Document reported failure

and send feedback to

[e-mail]

stating that a suitable

symptom code wasn’t found.

Provide as much detail as

possible.

N99

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Communications 80

Input/Output Devices

Apple Remote Inoperable

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Apple Remote Inoperable

Apple Remote doesn’t bring up •
Front Row
Apple Remote doesn’t control •
iTunes
Apple Remote doesn’t control •
computer volume

Make sure Apple Remote is within 30 ft. of 1.
computer, and has an unobstructed line-of-sight
to computer.

Make sure lens end of Apple Remote is pointing 2.
directly at front of computer.

Make sure “Disable remote control infrared 3.
receiver” checkbox in System Preferences >
Security is not checked.

Ensure that all software and rmware updates for 4.
this model have been installed to take advantage
of any available bug xes.

Deep Dive

Check Result Action Code

Open Photo Booth or iChat’s 1.
video preview window. Point
Apple Remote at built-in
camera and press any button
on Apple Remote. Verify if a
white, ashing light is visible in
video preview.

Yes Apple Remote is functioning.

Go to step 2.

No Replace Apple Remote

battery.

Go to step 3.

2009-12-16

Open System Preferences 2.
> Security. Verify if “Unpair”
setting is available in this
preference panel.

With replacement battery, 3.
verify if white ashing light
is visible coming from Apple
Remote in video preview
window.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 81

Yes Click “Unpair” button to

disable possible pairing with

another Apple Remote.

Go to step 4.

No Possible IR board issue.

Go to step 5.

Yes Battery issue. Issue resolved. X05

No Apple Remote defective.

Replace Apple Remote.

X04

After clicking “Unpair”, verify if 4.
the computer now responds to
the Apple Remote.

Yes Pairing issue. Issue resolved.

No Possible IR board issue.

Go to step 5.

Open Apple System Proler. 5.
Verify if “IR Receiver” is listed in
USB list of devices.

Check that IR board is correctly 6.
tted and aligned with Apple
window and that lens is not
blocked by any foreign material
and re-test. Verify if computer
responds to Apple Remote.

After reseating or replacing 7.
IR board, verify if “IR Receiver”
is listed under USB in Apple
System Proler, and that
computer now responds to
Apple Remote.

After replacing IR cable, verify if 8.
“IR Receiver” is listed under USB
in Apple System Proler, and
that computer now responds to
Apple Remote.

Yes IR board reporting on USB

bus. Check for lens block.

Go to step 6.

No Inspect and reseat IR cable

connection to logic board.

Go to step 7.

Yes Lens blocked or sensor not

aligned with window. Issue

resolved.

No Lens damaged or inoperable.

Replace IR board. Go to step 7.

Yes IR module reseated/replaced.

Issue resolved.

No If IR board was only reseated,

replace IR cable. Go to step 8.

Yes IR cable replaced. Issue

resolved.

No Replace IR board. Go to step 9.

X03

X03

X03

2009-12-16

After replacing IR board, verify 9.
if “IR Receiver” is listed under
USB in Apple System Proler,
and that computer now
responds to Apple Remote.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 82

Yes IR board replaced. Issue

X03

resolved.

No Replace logic board. M23

Audio: Microphone

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Audio: Microphone

Microphone not working•
Microphone audio garbled•
No sound•

Verify that no tape, sticky notes, or other objects 1.
are blocking microphone located on top of
computer near camera. Microscopic perforations
on top of computer must be free of obstructions
in order for microphone to function.

Go to System Preferences > Sound > Input. 2.
Verify that sound input device is set to internal
microphone.

Go to System Preferences > Sound > Input. 3.
Verify that “Input volume” setting is set above
minimum level.

Go to System Preferences > Sound > Input. 4.
Verify that “Input level” indicator moves when
speaking into microphone.

Deep Dive

Check Result Action Code

Verify if boot chime is present 1.
when system is powered
ON. Make sure audio output
preferences are not set to mute.

Yes Go to step 2.

No Reset PRAM and retest.

2009-12-16

Make sure no cables are 2.
connected to external sound
input/output ports. Go to
System Preferences > Sound >
Input and verify that “Internal
microphone” is an available
option.

Go to System Preferences > 3.
Sound > Input and verify if
“Input volume” is set above
minimum sensitivity.

Go to System Preferences 4.
> Sound > Input and verify
if “Input level” indicator
moves when speaking into
microphone.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 83

Yes Go to step 3.

No Replace audio cable. M09

Yes Go to step 4.

No Set “Input volume” slider to

middle position. Retest.

Yes Microphone and audio input

functioning. Go to step 6.

No Suspect bad microphone

connection. Reseat

microphone connector on

logic board. Go to step 5.

Inspect microphone cable 5.
routing and verify if cable is
pinched or damaged.

Yes Replace rear housing

(microphone cable not

available separately).

No Go to step 6.

L14

Record sound sample using 6.
GarageBand or iMovie. Verify if
sound quality of sound sample
is normal during playback.

Yes Microphone circuitry OK.

Return system to user.

No Replace logic board. M09

Audio: Built-in Speakers Have Distorted Sound

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Audio: Built-in Speakers Have
Distorted Sound

No audio from one or both •
speakers.
Audio from speakers distorted•

Go to System Preferences > Sound > Output. 1.
Verify that sound output device is set to internal
speakers and that balance control is set to the
center position.

Obtain known-good high-quality sound le or 2.
use iTunes Store sound samples to evaluate
sound quality. Verify suspect sound les on
another system to determine if distortion is
caused by computer or sound le.

2009-12-16

Set volume control to mid-range. Overdriving 3.
built-in speakers can cause distortion.

Deep Dive

Check Result Action Code

Go to System Preferences > 1.
Sound > Output. Set speaker
balance 100% to LEFT speaker
and play a known-good sound
le. Verify if sound is generated
by LEFT speaker and that sound
quality is acceptable.

Set speaker balance 100% 2.
to RIGHT speaker and play a
known-good sound le. Verify
if sound is generated by RIGHT
speaker and that sound quality
is acceptable.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 84

Yes LEFT speaker and amplier

circuitry OK. Go to step 2.

No Distortion detected in LEFT

speaker. Set Balance slider to

middle position. Go to step 3.

Yes RIGHT speaker and amplier

circuitry OK. Set Balance slider

to middle. Go to step 3.

No Distortion detected in RIGHT

speaker. Go to step 4.

Connect external speakers or 3.
headphones to audio-out port
and play a known-good sound
le. Verify if sound quality is
acceptable.

Yes Suspect bad speaker.

Go to step 4.

No Audio CODEC or amplier

issue suspected. Replace logic

board and retest.

M09

Inspect LEFT and RIGHT 4.
speaker cones and speaker
connection cable for damage.
Verify if speakers have visible
damage.

Install known-good speaker 5.
into location where distorted
sound was heard. Verify if
sound quality improves.

Yes Replace damaged speaker.

Retest.

No Go to step 5.

Yes Replace speaker. L11

No Speaker amplier issue

suspected. Replace logic

board.

Audio: Built-in Speakers Have No Audio

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Audio: Built-in Speakers Have No
Audio

No audio from one or both •
speakers.
Audio from speakers distorted•

Go to System Preferences > Sound > Output. 1.
Verify that sound output device is set to internal
speakers.

Go to System Preferences > Sound > Output. 2.
Verify that “Output volume” setting is set above
the minimum level and that “Mute” checkbox is
not selected.

L11

M09

2009-12-16

Go to System Preferences > Sound > Output. 3.
Verify that “Balance” slider is set to middle
position so left and right speakers are both used.

Deep Dive

Check Result Action Code

Verify if boot chime is present 1.
when system is powered
ON. Make sure audio output
preferences are not set to mute
and volume is set to mid-range.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 85

Yes Go to step 2.

No Reset PRAM and retest.

Make sure no cables are 2.
connected to external sound
input/output ports. Go to
System Preferences > Sound >
Output and verify that “Internal
speakers” is an available option.

Yes Go to step 3.

No If “Headphones” is the only

available sound output

device, replace audio cable.

If “Digital output” is the

only available sound output

device, reseat audio cable to

logic board. If issue persists,

replace audio cable.

If issue persists, replace logic

board.

L11

L11

M09

Go to System Preferences > 3.
Sound > Output. Set speaker
balance 100% to LEFT speaker
and play a known-good sound
le. Verify if sound is generated
by LEFT speaker and that sound
quality is acceptable.

Set speaker balance 100% 4.
to RIGHT speaker and play a
known-good sound le. Verify
if sound is generated by RIGHT
speaker and that sound quality
is acceptable.

Verify if user-reported audio 5.
issue has been resolved.

Boot system from Install 6.
DVD or another known-good
bootable volume. Verify if issue
still occurs.

Yes LEFT speaker and amplier

circuitry OK. Go to step 4.

No No audio in LEFT speaker.

Go to step 7.

Yes RIGHT speaker and amplier

circuitry OK. Set Balance slider

to middle. Go to step 5.

No No audio in RIGHT speaker.

Go to step 7.

Yes Issue no longer present.

Return system to user.

No Go to step 6.

Yes Go to step 7.

No Known-good boot volume

works OK. Troubleshoot for

software issue. Isolate if issue

is application-specic or a

possible OS conict.

2009-12-16

Connect external speakers or 7.
headphones to audio-out port
and play a known-good sound
le. Verify if sound quality is
acceptable.

Disconnect and carefully 8.
inspect audio cable and
connection to logic board for
damage such as bent pins or
pinched/cut wires.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 86

Yes Logic board, internal

speakers, and audio-out port

functioning correctly. Return

system to user.

No Go to step 8.

Yes Replace damaged audio

L14

cable. If issue persists, verify if

symptom has changed.

No Replace logic board. M09

Camera Issues

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

Quick Check

Symptoms Quick Check

Camera Issues

Camera not detected•
No green LED for camera•
Excessive blooming•
Poor White Balance•
Poor Focus•
Green image•
Image distortion•

Launch Apple System Proler and conrm that 1.
system’s USB hub and built-in camera are visible.

Verify camera lens and glass panel are clean and 2.
free of contaminants. Clean glass panel if needed.

Launch Photo Booth to verify that green indicator 3.
LED near camera lens turns on and image quality
is acceptable.

Deep Dive

Check Result Action Code

Launch Apple System Proler 1.
and verify built-in camera is
visible in USB list of devices.

Launch Photo Booth. Verify if 2.
green LED near camera lens
turns ON and image appears
normal.

Yes Camera recognized.

Go to step 2

No Inspect and reseat camera

cable connection on logic

board. Go to step 2.

Yes Camera functioning. Return

system to user.

No Remove glass and clean both

sides. Clean camera lens.

If issue persists, replace

camera cable.

If issue persists, replace

camera.

If issue persists, replace logic

board.

X07

X07

M13

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 87

FireWire Device Not Recognized

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

FireWire Device Not Recognized

FireWire hard drive not •
recognized
FireWire optical drive not •
recognized
FireWire camera not recognized•
FireWire printer not recognized•

For external FireWire drives, make sure any 1.
external power source is plugged in and
operating to isolate a power issue with the
device.

Test a known-good FireWire device to isolate a 2.
failed peripheral issue.

Test a known-good FireWire cable to isolate a 3.
FireWire cable issue.

Ensure that all software and rmware updates for 4.
this model have been installed to take advantage
of any available bug xes.

Launch Apple System Proler and verify if the 5.
aected FireWire device is visible on FireWire
bus. If yes, then FireWire port and cable are
functioning properly. Contact FireWire device
manufacturer to verify that device is supported.

Deep Dive

Check Result Action Code

Unplug all FireWire devices 1.
from computer. Reset PRAM.
Reconnect FireWire device
in question. Verify if FireWire
device is recognized.

Yes Issue resolved.

No Possible logic board failure.

Go to step 2.

2009-12-16

Use a known-good FireWire 2.
cable with a known-good
FireWire device (such as
another Mac in Target Disk
Mode). Verify if FireWire device
is recognized.

Verify if FireWire device is 3.
recognized on a known-good
same model computer.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 88

Yes Try FireWire device in question

with a known-good computer

of same model. Go to step 3.

No FireWire not recognized.

Replace logic board.

Yes Go to step 4.

No Device may need additional

power. Use a powered FireWire

hub. Go to step 5.

M12

Verify if FireWire device is 4.
recognized with a known­good FireWire cable on user’s
computer.

Yes FireWire cable issue. Issue

resolved.

No FireWire device may need

additional power. Go to step 5.

Using a powered FireWire 5.
hub, and having installed any
software or rmware updates
for the device, verify if FireWire
device is now recognized.

Create a new user in System 6.
Preferences > Accounts and
log out current user. Log in
on new user account and
verify if FireWire device is now
recognized.

Yes Device recognized. Required

additional power from hub or

update. Issue resolved.

No Device may require additional

software, or there may be a

conict in the Mac OS. Go to

step 6.

Yes Software Issue. Troubleshoot

software on User account. Issue

resolved.

No Apply all Mac OS and FireWire

specic updates. If issue

persists, contact device

manufacturer for support.

FireWire port and cable have

been veried.

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 89

USB Device Not Recognized

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

USB Device Not Recognized

USB wired keyboard/mouse not •
recognized
USB external drive not •
recognized
USB camera not recognized•
USB printer not recognized•

Deep Dive

Reset SMC.1.
For printers and external USB drives, make sure 2.

any external power source is plugged in and
operating to isolate a power issue with device.

The iMac has 4 USB ports on rear of computer. Try 3.
each port to isolate a particular port malfunction.

Test with a known-good wired keyboard or 4.
mouse to isolate a failed peripheral issue.

Test with a known-good USB cable when dealing 5.
with a printer or external USB drive, to isolate a
USB cable issue.

Ensure that all software and rmware updates for 6.
this model have been installed to take advantage
of any available bug xes.

Launch Apple System Proler and verify if device 7.
is visible on USB bus. If yes, then the USB port and
cable are functioning properly. Contact device
manufacturer to verify that device is supported.

2009-12-16

Check Result Action Code

Unplug all USB devices from 1.
the computer except for USB
keyboard and mouse. Start
computer and reset PRAM.
Verify if USB keyboard and
mouse are recognized.

Verify if Bluetooth Mouse Setup 2.
assistant launches after startup.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 90

Yes Test with all USB ports to

ensure all USB ports working

as expected. Replace logic

board for any port failures.

No Reset SMC. Go to step 2.

Yes Bluetooth detected, but

external USB devices not

recognized. Go to step 3.

No Disconnect USB keyboard and

mouse. Go to step 4.

Verify if a known-good USB 3.
keyboard and mouse are
recognized.

Yes Test original USB mouse and

keyboard. Replace if still not

recognized. Go to step 5.

With no USB devices 4.
connected, restart computer.
Verify if Bluetooth Mouse Setup
assistant launches after startup.

With known-good USB 5.
keyboard and mouse working,
test USB peripheral in question
(USB hard drive or printer, etc.)
Verify if device is recognized
in Apple System Proler under
USB.

Verify if using a powered USB 6.
hub resolves the issue.

No External USB ports not

functioning. Replace logic

board.

Yes Bluetooth detected.

Go to step 3.

No Bluetooth not recognized.

Internal and external USB not

functioning. Replace logic

board.

Yes Device recognized. Test in all

USB ports to ensure all USB

ports working as expected.

Replace logic board for any

port failures.

No Device may require more

power than supplied by USB

ports. Test with a powered

USB hub. Go to step 6.

Yes Test device on same USB port

of a same-model computer.

If other computer does not

require a powered USB hub

to allow functionality, replace

logic board.

M15

M15

M15

M15

2009-12-16

No Ensure all software and

rmware updates have

been applied for computer

and device. If issue persists,

contact device manufacturer

for support. The computer’s

USB ports and cable have

been veried.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 91

Wired Keyboard Does Not Function Properly

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Wired Keyboard Does Not
Function Properly

Some or all keys on the •
keyboard don’t work
Eject key or Caps Lock key •
doesn’t seem to work
Some keys don’t work as •
expected

Reset SMC1.
Open System Preferences > Universal Access > 2.

Mouse & Trackpad and verify that Mouse Keys
is turned OFF. When enabled, Mouse Keys can
disable functionality of some or most keys,
depending on keyboard used.

The iMac has 4 USB ports on rear of computer. 3.
Make sure to try each port to isolate a particular
port malfunction.

Test with a known-good wired keyboard to 4.
isolate a failed peripheral issue.

Test wired keyboard on a known-good, same-5.
model computer. If it works on the other
computer, this may indicate a bad USB port if
keyboard doesn’t work at all on user’s computer,
or a software issue if keyboard is working but not
as expected on user’s computer.

Ensure that all software and rmware updates for 6.
this model have been installed to take advantage
of any available bug xes.

2009-12-16

Deep Dive

Check Result Action Code

Verify if all keys on keyboard 1.
work.

Verify if Caps Lock is working as 2.
expected.

Verify if media Eject key is 3.
working as expected. Note that
to prevent accidentally ejecting
media, Mac OS X adds a slight
delay to the media Eject key
before it takes eect.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 92

Yes Go to step 2.

No Go to USB Device Not

Recognized symptom ow.

Yes Go to step 3.

No Go to Keyboard: Specic

Keys Do Not Respond

symptom ow

Yes Go to step 4.

No Go to step 5.

Open System Preferences > 4.
Speech. Verify if the “Speak
selected text when the key is
pressed” checkbox is selected.

Yes The key combination to speak

text cannot be used for any

other purpose. Either disable,

or change to a more rare

key combination (including

Shift, Command, Option and

Control).

No Go to step 6. M15

With optical media in the drive, 5.
hold the media Eject key. Verify
if the eject symbol appears on
screen and that optical media
is ejected if present.

Open System Preferences > 6.
Language and Text > Input
Menu. Check “Keyboard Viewer”.
From the Input Menu (ag) in
the Menu Bar, choose “Show
Keyboard Viewer”. Verify if keys
pressed appear in Keyboard
Viewer.

Open TextEdit or another text 7.
application and try typing
something using the non­responding keys. Verify if
they are typed in this other
application.

Yes Normal media eject key delay.

No repair necessary.

No Go to Optical Drive Won’t

Accept/Eject Media

symptom ow.

Yes Keys recognized.

Go to step 9.

No Keys not recognized.

Replace keyboard.

Yes Application-specic issue.

Troubleshoot application.

No Create a new user account

in System Preferences >

Accounts, log out from

current user and log in with

new user to isolate a User

account related issue. If issue

persists, reinstall Mac OS X

from Install DVD.

K01

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 93

Keyboard: Specic Keys Do Not Respond

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

Quick Check

Symptoms Quick Check

Keyboard: Specic Keys Do Not
Respond

One or more keys do not •
respond when pressed
Key sticks•
Keycap missing•

If wireless keyboard is being used verify that it is 1.
properly paired with computer. Go to Wireless

Input Device Doesn’t Pair symptom ow to

resolve pairing issues.
The caps lock key has a built-in delay to reduce 2.

accidental activation and must be held for
approximately ½ second for it to be activated. See

kBase #TS1578: Apple Keyboard (2007): Caps
Lock modied to reduce accidental activation.

Inspect keyboard for signs of liquid spills or other 3.
contamination. Apple’s warranty does not cover
accidental damage.

If keycap is loose attempt to reattach it.4.
For other keyboard issues jump to appropriate 5.

symptom ow.

Wired Keyboard/Mouse Not Recognized

Unlikely cause: LCD display, power supply, hard drive, optical drive, fans

2009-12-16

Quick Check

Symptoms Quick Check

Wired Keyboard/Mouse Not
Recognized

USB wired keyboard/mouse not •
recognized when plugged in.
Mouse scroll ball not working •
or not working as expected.
Mouse buttons not working or •
not working as expected.

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 94

Reset SMC.1.
The iMac has 4 USB ports on rear of computer. 2.

Make sure to try each port to isolate a particular
port malfunction.

Test with a known-good wired keyboard or 3.
mouse to isolate a failed peripheral issue.

Test a mouse when connected directly to ports 4.
on the back of iMac to isolate a keyboard USB
port issue.

Ensure that all software and rmware updates for 5.
this model have been installed to take advantage
of any available bug xes.

Deep Dive

Check Result Action Code

Verify if computer recognizes 1.
keyboard or mouse when
plugged into rear USB ports on
back of iMac.

Verify if keyboard is working as 2.
expected.

Verify if Mighty Mouse has an 3.
issue with scroll ball.

Verify if mouse has an issue 4.
with buttons.

Yes Test device in all USB ports to

ensure all other USB ports are

working as expected.

Replace logic board if any

USB port on rear fails.

Replace keyboard if any USB

port on keyboard fails.

Go to step 2.

No Go to USB Device Not

Recognized symptom ow.

Yes Go to step 3.

No Go to Wired Keyboard Does

Not Function Properly

symptom ow.

Yes See kBase #HT1537: How to

clean your Mighty Mouse.

No Go to step 4.

Yes Go to step 7.

No Go to step 5.

M15

K11

Verify if mouse has an issue 5.
with tracking.

Try using mouse on another 6.
surface. Non-reective, opaque
surfaces without repetitive
patterns work best. The surface
should be clean but not shiny.
Verify if mouse tracks correctly
when used on another surface.

See 7. kBase #HT1581:

Troubleshooting Mighty
Mouse and determining
expected behavior. Verify if

this article resolves issue.

Yes Go to step 6.

No Go to step 7.

Yes Surface issue. Issue resolved.

No Go to step 7

Yes Issue resolved.

No Replace wired Mighty Mouse. K99

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 95

Uncategorized Symptoms

Quick Check

Symptoms Quick Check

Uncategorized Symptoms

Unable to locate appropriate •
symptom code.

Reset SMC.1.
Verify that external I/O device (where applicable) 2.

works on a known-good, same-model computer.
For third party I/O devices, make sure necessary 3.

software is installed and up-to-date, and that
device is supported with user’s system.

Deep Dive

Check Result Action Code

Verify if existing symptom code 1.
applies to issue reported by
user.

Yes Jump to appropriate

symptom code ow.

No Document reported failure

and send feedback to

[e-mail]

stating that a suitable

symptom code wasn’t found.

Provide as much detail as

possible.

N99

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Input/Output Devices 96

Mechanical

Noise/Hum/Vibration

Unlikely cause: LCD panel, glass panel, enclosure, cables

Quick Check

Symptoms Quick Check

Noise/Hum/Vibration

Buzzing noise•
Rattling noise•
Ticking noise•
Squeaking noise•

Verify that the vents on the bottom and 1.
back of the system are free of dust and other
obstructions that might inhibit proper airow
through the system.

Launch Applications/Utilities/Activity Monitor. 2.
Determine whether an application or process is
consuming a high percentage of CPU bandwidth.
CPU-intensive applications can cause the fans
to run fast in order to maintain the proper
internal system temperatures. If needed, quit the
application or restart the system to resolve the
issue.

Eject optical media from optical drive. Out-of-3.
balance optical media can generate audible
noise. To resolve try a dierent brand of media.
For additional information, go to Optical Drive

Noisy symptom ow.

Tilt display to hinge limits to determine if 4.
mechanical noise is generated by the hinge
mechanism. For additional information, go to

Stand/Hinge Issues symptom ow.

Play sound sample at loud and soft volume 5.
levels to determine if the noise is caused by the
left/right speakers or the amplier circuit. Plug
external headphones to identify whether the
noise comes from audio out or from other source.
For additional information, go to Audio: Built-in

Speakers Have Distorted Sound symptom ow.

2009-12-16

Adjust the display brightness to determine 6.
whether the noise is related to the brightness
level. For additional information, go to Noise/

Unstable Flickering symptom ow.

iMac (27-inch, Late 2009) Symptom Charts — Mechanical 97

Deep Dive

Check Result Action Code

Verify if any tape, gasket, cable 1.
label, or cable is touching
the fan blades and causing a
ticking noise.

Run Apple System Diagnostic. 2.
Verify if running ASD generates
one or more errors.

Verify if noise sounds like one 3.
or more fans are spinning faster
than expected.

Verify if noise changes when 4.
optical drive is being accessed
or media is inserted or ejected.

Yes Secure the material so it

doesn’t touch fan blades. If

tape adhesive has lost its

stickiness, replace that section

of tape.

No Go to step 2.

Yes Go to ASD Error Codes

table to decode error. Follow

instructions in table for

resolving error, then retest.

No Go to step 3.

Yes Reset SMC by disconnecting

power cord for ~15 seconds

then retest. If issue continues

go to step 3.

No Go to step 6.

Yes Suspect issue with optical

drive or media used.

Go to Optical Drive Noisy

symptom ow.

Mute the system volume. Verify 5.
if issue still occurs.

Adjust brightness on display 6.
between maximum and
minimum settings. Verify if
issue changes depending on
brightness level.

Remove fans and rotate 7.
blades. Verify if fan blades spin
smoothly without interference
from fan housing.

No Go to step 5.

Yes Go to step 6.

No Suspect issue with speakers

or audio amplier circuitry.

Go to Audio: Built-in

Speakers Have Distorted

Sound symptom ow.

Yes Suspect issue with LCD

display or backlight controller

board. Go to Noise/Unstable

Flickering symptom ow.

No Go to step 7.

Yes Go to step 8

No Replace aected fan. P04

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mechanical 98

Reinstall fans while carefully 8.
ensuring that there are no
cables routed under or near
fan assembly that might cause
interference with fan blades.
After reassembling system
verify if noise issue is resolved.

Yes Noise issue resolved. Suspect

issue caused by interference

from wiring or possible

distortion or fan housing

when installed in system.

No Go to step 9.

P04

Temporarily remove LCD 9.
display then power ON system.
Verify if source of noise can be
located. Caution: The exposed
power supply poses a serious
shock hazard. Take proper
precautions when working
around an energized system.

Disconnect these major 10.
modules/parts (hard drive,
optical drive, fans, LCD display)
one at a time then power ON
the system. Determine if noise
issue goes away when one of
the modules is disconnected.
Caution: The exposed power
supply poses a serious shock
hazard. Take proper precautions
when working around an
energized system.

Yes Identify, inspect, and if

necessary replace part that

caused noise issue.

No Go to step 10.

Yes Identify, inspect, and if

necessary replace part that

caused noise to disappear

when it was disconnected

from the system.

No All parts veried. Verify that

correct symptom ow is

being used.

P04

P04

2009-12-16

iMac (27-inch, Late 2009) Symptom Charts — Mechanical 99

Fan Failures / Thermal Issues

Unlikely cause: speakers

Quick Check

Symptoms Quick Check

Fan Failures / Thermal Issues

System feels very hot•
Fan(s) not operating•
Fan(s) running fast•
System is noisy•

Verify that vents on bottom and back of system 1.
are free of dust and other obstructions that might
inhibit proper airow through the system.

Verify that computer is not exposed to direct 2.
sunlight which may heat up enclosure, making it
feel hot to the touch.

Verify computer is not running hotter than 3.
expected for normal operation. If possible,
compare to a similarly congured system. Note:
Power supply is located in upper left corner
where highest temperatures can usually be felt.

Launch Applications/Utilities/Activity Monitor. 4.
Verify if an application or process is consuming
a high percentage of CPU bandwidth. CPU­intensive applications can cause fans to run
fast in order to maintain proper internal system
temperatures. If needed, quit the application or
restart the system to resolve issue.

Reset SMC by unplugging power cord for ~15 5.
seconds.

2009-12-16

Deep Dive

Check Result Action Code

Run Apple System Diagnostic. 1.
Verify if ASD generates one or
more errors.

Verify if noise sounds like one 2.
or more fans running faster
than expected.

Yes Suspect possible fan or sensor

error. Go to ASD Error Codes

table to decode error. Follow

instructions in table for

resolving error, then retest.

No Go to step 2.

Yes Fans running fast. Reset SMC

by disconnecting power cord

for ~15 seconds then retest. If

issue continues go to step 3.

No Go to step 3.

iMac (27-inch, Late 2009) Symptom Charts — Mechanical 100