Apple iMac 21 late 2009 Service Manual
Apple Technician Guide
iMac (21.5-inch, Late 2009)
Updated: 2009-11-24
Apple Inc.
© 2009 Apple Inc. All rights reserved.
Under the copyright laws, this document may not be copied, in whole or in part, without the
written consent of Apple.
Every eort has been made to ensure that the information in this document is accurate. Apple
is not responsible for printing or clerical errors.
Apple
1 Innite Loop
Cupertino, CA 95014-2084
USA
+ 1 408 996 1010
www.apple.com
Apple, the Apple logo, Mac, and Macintosh are trademarks of Apple Inc., registered in the U.S.
and other countries.
iMac (21.5-inch, Late 2009)
Contents
About This Guide
Updates 9
Updated 24 November 2009 9
Updated 28 October 2009 9
Introduced 20 October 2009 9
Feedback 9
Basics
Overview 11
Identifying Features 11
Product Congurations 12
Wireless Troubleshooting 12
Safety 12
Serial Number Location 13
Troubleshooting
General Troubleshooting 15
Wireless Troubleshooting 15
Update System Software & Firmware 15
Troubleshooting Theory 15
Hardware vs. Software 15
Common Reset Procedures 16
Power On Self Test (POST) 16
Resetting the System Management Controller (SMC) 16
Resetting Parameter RAM (PRAM) 17
Starting Up in Safe Mode 17
Apple Service Diagnostics 18
Diagnostic LEDs 19
LED Functions 20
LED Startup Sequence 21
Logic Board Test Points 22
Sensor and Fan Connector Locations 23
Block Diagram 24
Symptom Charts 25
Startup and Power 25
No Power, Dead Unit 25
Won’t Start Up 27
Intermittent Shutdown 29
Kernel Panic, System Crashes 31
No Video 33
Corrupted Video 34
Burnt Smell/Odor 37
Uncategorized Symptoms 38
Display 39
Backlight Issue/No Backlight 39
Noise / Unstable Flickering 41
LCD Image Issues 43
Incorrect/Missing Colors 44
Distorted/Blurred Image 45
Pixel Anomalies 47
Vertical/Horizontal Lines 48
Non-Uniform Brightness 50
Cosmetic Defects 51
Uncategorized Symptoms 51
Mass Storage 52
Hard Drive Not Recognized 52
Hard Drive Read/Write Errors 54
Hard Drive Noisy 55
Optical Drive Not Recognized 57
Optical Drive Won’t Accept/Eject Media 58
Optical Drive Read/Write Error 59
Optical Drive Not Performing to Specications 61
Optical Drive Noisy 62
SD Card Will Not Insert Into Slot 63
SD Card Not Recognized 64
Uncategorized Symptoms 65
Communications 66
AirPort/Bluetooth Issues 66
AirPort Card Kernel Panic 68
Ethernet Port/Device Issue 69
Wireless Input Device Doesn’t Pair 70
Wireless Input Device Loses Connection 72
Uncategorized Symptoms 74
Input/Output Devices 75
Apple Remote Inoperable 75
Audio: Microphone 77
Audio: Built-in Speakers Have Distorted Sound 78
Audio: Built-in Speakers Have No Audio 79
Camera Issues 81
FireWire Device Not Recognized 82
USB Device Not Recognized 84
Wired Keyboard Does Not Function Properly 86
Keyboard: Specic Keys Do Not Respond 88
Wired Keyboard/Mouse Not Recognized 88
Uncategorized Symptoms 90
Mechanical 91
Noise/Hum/Vibration 91
Fan Failures / Thermal Issues 94
Stand/Hinge Issues 95
Physical Damage 96
Uncategorized Symptoms 96
Take Apart
General Information 98
Opening the Unit 98
Required Tools 98
Required Special Tools for Glass Panel 99
Cleaning Tools Starter Kit 99
Cleaning Tool Resources 99
Cleaning & Handling the Glass Panel 100
Do’s and Don’ts 100
Handling a Broken Glass Panel 100
How to Remove a Broken Glass Panel 101
Safety 105
Logic Board Handling 106
Note About Images in This Guide 106
Access Door 107
Memory 109
Glass Panel 111
Removal 112
Reassembly 113
Camera 116
LCD Panel 118
Vertical Sync Cable 122
LCD Temp Sensor Cable 123
LVDS Cable 124
Bluetooth Antenna 125
Bluetooth Board 127
AirPort Antenna 129
AirPort Card 131
AirPort Cable 133
AirPort Carrier Board 135
LED Backlight Board 137
Power Supply 139
Backlight Pressure Wall 141
Power Supply Pressure Wall 143
Hard Drive 145
Hard Drive Sensor Cable 148
Bluetooth Cable 150
Camera Cable 153
Optical Drive 156
Optical Drive Sensor Cable 159
Optical Drive Fan 161
SD Board 163
SD Cable 165
Audio Cable 167
IR Board & Cable 169
Logic Board 171
Video Card 178
Battery 180
Hard Drive Data Cable 182
Optical Drive Data Cable 184
Cable, AC/DC Power/Backlight/SATA 186
CPU Fan 187
Ambient Temp Sensor 190
Left Speaker 192
Right Speaker 194
Hard Drive Fan 196
Mechanism Cover 198
Stand 200
Mechanism 202
Microphone Cable 204
Rear Housing 205
Views
Exploded Views 208
iMac (21.5-inch, Late 2009), Part 1 208
iMac (21.5-inch, Late 2009), Part 2 209
iMac (21.5-inch, Late 2009), Part 3 210
Screw Chart 211
External Views 213
Front View 213
Rear View 214
I/O Ports 215
Internal Views 216
Photo of Components below LCD 216
Photo of Components below Logic Board 217
Logic Board, Front Side 218
Logic Board, Back Side 218
Apple Technician Guide
About This Guide
iMac (21.5-inch, Late 2009)
© 2009 Apple Inc. All rights reserved.
Updates
Updated 24 November 2009
Troubleshooting
General: Updated close-up image of diagnostic LEDs.•
Mechanical: Fan noise issues: updated two topics, “Noise/Hum/Vibration” and “Fan Failures/ •
Thermal Issues” with the following information:
Check: Verify if any tape, gasket, cable label, or cable is touching the fan blades and •
causing a ticking noise.
Actions: Secure the material so it doesn’t touch fan blades. If tape adhesive has lost its •
stickiness, replace that section of tape.
Take Apart
General Information: Added images to section “How to Remove a Broken Glass Panel.”•
Hard Drive and Hard Drive Sensor Cable: Added information about connecting sensor cables •
to Western Digital drives: Orient the drive with its circuit board facing up and connect the
sensor cable to the hard drive pins, leaving the 2 left pins unconnected (exposed).
Logic Board: Added note that logic board may be easier to remove if RAM is removed rst.•
Views
Exploded Views: Added part numbers for Power Supply Pressure Wall (922-9281), Backlight •
Pressure Wall (922-9282), Bluetooth Antenna (922-9283), and AirPort Antenna (922-9284).
Updated 28 October 2009
Basics: Added another kBase link to Wireless Troubleshooting section.•
Troubleshooting: General: Added another kBase link to Wireless Troubleshooting section.•
Take Apart: General: Added • section “How to Remove a Broken Glass Panel.”
Introduced 20 October 2009
Feedback
We want your feedback to help improve this and future Technician Guides!
Please email any comments to: smfeedback6@apple.com
2009-11-24
iMac (21.5-inch, Late 2009) — Updates 9
Apple Technician Guide
Basics
iMac (21.5-inch, Late 2009)
© 2009 Apple Inc. All rights reserved.
Overview
2009-11-24
Identifying Features
The iMac (21.5-inch, Late 2009) has an all-aluminum enclosure with a glass front. It can be
distinguished from the previous model by the glass extending all the way to the top, left and
right edges, rather than having an aluminum bezel that borders the glass. Also, the rear of the
computer is aluminum rather than black plastic.
This model’s other new features include:
Larger and LED-backlit 21.5-inch 16:9 display with 1920x1080 native HD resolution•
Increased processor speeds: 3.06 GHz or 3.33 GHz Intel Core 2 Duo•
Integrated NVIDIA GeForce 9400M or ATI Radeon HD 4670 graphics•
Four RAM memory slots: two slots are lled with at least 2GB each, for a total of 4GB; •
maximum RAM is 16GB
Larger hard drive options: 500GB, 1TB, 2TB (CTO only)•
SD card reader•
New Apple Wireless Keyboard and wireless Magic Mouse, standard with all congurations•
Ships with and requires at least Mac OS 10.6.1 (Snow Leopard)•
iMac (21.5-inch, Late 2009) Basics — Overview 11
Product Congurations
For product congurations, refer to AppleCare Tech Specs: http://support.apple.com/specs/
Wireless Troubleshooting
If you’re having issues with Bluetooth and wireless connectivity issues, refer to the following
Apple Knowledge Base articles:
kBase #TS3048: Desktop computers: Troubleshooting wireless mouse and keyboard issues
kBase #HT1365: AirPort and Bluetooth: Potential source of interference
kBase #HT3903: Apple Wireless Keyboard and Mouse: How to install batteries
Safety
Warning: HIGH VOLTAGE: The AC/DC power supply PCB remains powered up whenever
system is plugged in, whether or not system has been turned on. Use extreme caution
when troubleshooting system with glass panel and LCD panel removed.
Important: If computer is shut down by removing power cord, allow power supply a good 2-3
minutes to discharge capacitors before handling it. However, if you select “Shut Down” via the
Apple menu, the computer will discharge power supply capacitor almost immediately.
2009-11-24
iMac (21.5-inch, Late 2009) Basics — Overview 12
Serial Number Location
The iMac (21.5-inch, Late 2009)’s serial number is located on the bottom of the stand. When
replacing a stand, transfer the serial number to the new stand.
2009-11-24
iMac (21.5-inch, Late 2009) Basics — Overview 13
Apple Technician Guide
Troubleshooting
iMac (21.5-inch, Late 2009)
© 2009 Apple Inc. All rights reserved.
General Troubleshooting
Wireless Troubleshooting
If you’re having issues with Bluetooth and wireless connectivity issues, refer to:
kBase #TS3048: Desktop computers: Troubleshooting wireless mouse and keyboard issues
kBase #HT1365: AirPort and Bluetooth: Potential source of interference
kBase #HT3903: Apple Wireless Keyboard and Mouse: How to install batteries
Update System Software & Firmware
Important: Whenever possible before beginning troubleshooting, ensure the latest software
and rmware updates have been applied.
Firmware is the name given to software that is written into memory circuits such as ash
memory, that will hold the software code indenitely, even when power is removed from
the hardware. Firmware on Intel Mac computers is designed to be updated if necessary 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
For information on how to isolate a hardware issue from a software issue, refer to:
kBase #TS1388: Isolating issues in Mac OS X
For information on how to troubleshoot a software issue, refer to:
kBase #HT1199: Mac OS X: How to troubleshoot a software issue
kBase #TS1394: Mac OS X: Troubleshooting installation and software updates
kBase #HT2956: Troubleshooting Mac OS X installation from CD or DVD
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 15
Common Reset Procedures
Power On Self Test (POST)
Intel-based Mac computers such as the iMac rely on a combination of tones to indicate Power
On Self Test (POST) error codes.
If the computer detects out-of-specication or no SDRAM, the screen will remain black •
but the computer will beep. This error condition may be due to physically damaged RAM,
installing incorrect type of RAM, or not having RAM installed.
Some RAM may appear to pass the Power-On-Self-Test (POST) but still cannot be used by •
the operating system. In this case, the computer will display a gray screen, sound three
tones and repeat tones until computer is turned o.
The solution to both situations is to rst re-seat memory and test computer again. If •
memory fails POST again, remove all installed memory and test by installing one by one
each memory that has been veried to work correctly on another system (i.e., “knowngood”) or order new memory.
For more information, refer to:
kBase #HT2538: iMac (Mid 2007) and later models: About new startup tones
Resetting the System Management Controller (SMC)
The System Management Controller (SMC) is a chip on logic board that controls all power
functions. If computer is experiencing any power issue, such as not starting up, not displaying
video, sleep issues, or fan noise issues, resetting SMC may resolve it. To reset SMC on an iMac:
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
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 16
Resetting Parameter RAM (PRAM)
PRAM stores certain system and device settings in a location that Mac OS X can access quickly.
Exactly which settings are stored in the computer’s PRAM varies depending on the type of
computer as well as the types of devices and drives connected. To reset PRAM:
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
Starting up into Safe Mode does several things that can help resolve software or directory
issues that may exist on the startup volume. To start up in Safe Mode:
Shut down the computer.1.
Press power button.2.
Immediately after you hear 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 a gray Apple and progress indicator (looks 4.
like a spinning gear). Note that booting into Safe Mode will take longer than a normal
startup. During startup, the words ”Safe Boot” will appear on Mac OS X startup screen.
To leave Safe Mode, restart computer normally, without holding down any keys during 5.
startup.
For more information, refer to:
kBase #HT1564: Mac OS X: What is Safe Boot, Safe Mode?
kBase #TS1884: Safe Boot takes longer than normal startup
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 17
Apple Service Diagnostics
Run Apple Service Diagnostic version 3S133 to determine if any thermal sensors or blowers are
malfunctioning. If ASD is not available, run Apple Hardware Test by holding down the D key
during startup. When a test reports an error, reseat appropriate connections. If issue persists,
replace the corresponding part (sensor, fan, logic board, video card, or power supply). See chart
below for correlation between error code, aected sensor, sensor location (stand-alone, or part
of a sub-assembly), and additional checks to perform.
Error Sensor and Location Check
TA0P Ambient temp sensor
stand-alone part, located near CPU fan
TC0H CPU heatsink sensor
part of logic board
Check sensor cable connection
to logic board, run CPU fan test,
check air ow.
Check CPU sensor cable
connection to logic board, run
CPU fan test, check air ow.
TG0D MXM GPU die sensor
part of MXM video card
TG0H MXM GPU heatsink sensor
part of MXM video card
TH0O HDD sensor
stand-alone part, located on hard drive
TL0p LCD temp sensor
stand-alone part, located on back of LCD panel
TN0H MCP79 heatsink
part of logic board, located on heatsink
TO0p ODD sensor
stand-alone part, located on optical drive
Tp1P PS1 T1 proximity sensor
part of power supply
Tp2H PS1 T2 secondary heatsink sensor
part of power supply
Tp3H PS1 T1 primary heatsink sensor
part of power supply
Run ODD fan test, check air
ow.
Check video card sensor cable
connection to logic board, run
ODD fan test, check air ow.
Check sensor cable connection
to logic board, run HDD fan
test, check air ow.
Check sensor cable connection
to logic board, run all fans tests,
check air ow.
Check sensor cable connection
to logic board, run HDD fan
test, check air ow.
Check sensor cable connection
to logic board, run ODD fan
test, check air ow.
Check logic board to power
supply cable connections, run
CPU fan test, check air ow.
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 18
Diagnostic LEDs
Depending on iMac model, there are either three or four built-in diagnostic LEDs on the logic
board that can help troubleshoot the computer. LEDs are located on bottom right edge of logic
board (under a piece of black mylar tape) and can only be seen when looking through lower
vents of rear housing.
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 19
LED Functions
LED #1
Indicates that trickle voltage from power supply has been detected by logic board. This LED •
will remain ON whenever the iMac is connected to a working AC power source. The LED will
remain on even when computer has been shut down or put to sleep. The LED will turn o
only if AC power source is disconnected or power supply is faulty.
LED #2
Indicates that logic board has detected power from power supply when computer is •
turned on. This LED will be ON when computer is turned on and power supply and voltage
regulators are working correctly.
LED #3
Indicates that computer and video card are communicating. This LED will be ON when •
computer is communicating properly with video card. If LEDs 1 and 2 are ON and you heard
the startup sound, but LED 3 is OFF, then video card might be installed incorrectly or need
replacement. Note: LED #3 is not present on models with integrated graphics.
LED #4
Indicates that computer and LCD panel are communicating. This LED will be ON when •
computer is turned on and video signal is being generated. If LED 4 is ON and there is
no image on display, then LCD panel, LED backlight board, or cables between might be
installed incorrectly or need replacement.
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 20
LED Startup Sequence
LED #1 = Power available.
If no LED is visible:
Verify AC source •
Verify known-good AC cable is connected•
Verify cable connection between AC inlet and power supply•
Verify cable connection between power supply and logic board•
Verify power supply•
LED #1 + LED #2 = Power available, and system is powered on.
If second LED is not visible when power button is pressed:
Verify power button connection to logic board•
Verify power button functionality•
Verify cable connection between power supply and logic board•
Verify power supply•
Verify logic board•
LED #1 + LED #2 + LED #3 = Power available, system is powered on, and video card found.
If third LED is not visible after power on:
Verify that MXM video card is seated properly•
Verify logic board•
LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card
found, and internal LCD found.
If fourth LED is not visible after power on:
Verify cable connections between LCD panel and logic board•
Inspect LCD display cables for cable damage •
Verify external video functionality, and according to result check the following items:•
-If external display works then verify/replace LED backlight board
-If external display works then verify/replace LCD panel
-If external display does not work verify/replace logic board
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 21
Logic Board Test Points
Test points, which can be used to verify proper power ow, are accessible on logic board when
LCD panel is removed. All voltages given in Troubleshooting Symptom Charts assume that
computer is plugged into a known-good power outlet with a known-good AC cable. Some
guidelines for using test points:
Warning: HIGH VOLTAGE:• Use extreme caution when live testing!
Do NOT lean over or touch the power supply area during live testing.•
Keep your ngers behind nger guards on test probes when measuring.•
Turn dial of voltmeter/multimeter to measure DC (direct current, usually indicated by a solid •
horizontal line over dashes). If your voltmeter requires a set voltage range, choose a DC
range that includes the voltage you are measuring.
Connect black probe to ground. Connect red probe to test point and verify voltage.•
For more info, see kBase #HT3250: Diagnostics: Using a digital multimeter
2009-11-24
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
Pin 12 Power On Request signal (from logic board to power supply when
power button is pressed)
Pin 13 Backlight Enable (signal from logic board to Backlight Controller
board, to enable backlight
iMac (21.5-inch, Late 2009) — General Troubleshooting 22
Sensor and Fan Connector Locations
Ambient temp sensors and fans connectors locations are shown below. Ensure cables are
correctly routed and the sensors and fans are properly connected. If a sensor or fan is faulty or
not connected, Apple Hardware Test and Apple Service Diagnostic will generate an error code.
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 23
Block Diagram
SO-DIMM
Antenna
Antenna
Antenna
SO-DIMM
Temperature
Sensor
Temperature
Sensor
Fan
MLB
SO-DIMM
Display
AC/DC
Power
Button
Bluetooth
Speakers
Hard DriveOptical Drive
AC Inlet
Temperature
Sensor
Camera
Microphone
Speakers
Backlight
Controller
Fan
Fan
MXM
802.11n
Ambient
Temperature
Sensor
IR Sensor
SD Card
Reader
SO-DIMM
Refer to this diagram to see how modules are interrelated.
2009-11-24
iMac (21.5-inch, Late 2009) — General Troubleshooting 24
Symptom Charts
Follow steps in the order indicated below. If an action resolves the issue, retest system to verify.
Note: A compilation of Quick Check tables is available at:
http://service.info.apple.com/QRS/en/quickreference.pdf
Startup and Power
No Power, Dead Unit
Unlikely cause: speakers
Quick Check
Symptoms Quick Check
No Power, Dead Unit
No power•
No fan spin•
No startup chime•
No image on external display•
No hard drive or optical drive •
activity
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
No Go to step 2.
Yes Standby power voltage being
No Replace power supply.
The symptom is powering
up. Go to Won’t Start Up
symptom ow.
supplied by power supply.
Go to step 3.
2009-11-24
iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power 25
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.
2009-11-24
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
conguration 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 (21.5-inch, Late 2009) Symptom Charts — Startup and Power 26
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.
2009-11-24
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 (21.5-inch, Late 2009) Symptom Charts — Startup and Power 27
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
2009-11-24
iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power 28
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?
2009-11-24
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 (21.5-inch, Late 2009) Symptom Charts — Startup and Power 29
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 Conguration
troubleshooting to isolate
failed module.
No Issue resolved with logic
board replacement.
X03
M08
2009-11-24
iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power 30
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