Apple iMac 20 early 2008 Service Manual
Service Source
iMac (20-inch Early 2008)
20 June 2008
© 2008 Apple Inc. All rights reserved.
Apple Inc.
© 2008 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.
ii
iMac (20-inch Early 2008)
Contents
Manual Updates 7
Updated 20 June 2008 7
Product Introduction April 29, 2008 7
Take Apart
General Information 10
Product Features 10
Product Congurations 11
Opening the Computer 11
Note About Images in This Manual 11
Serial Number Location 12
General Tools 12
Required Special Tools 12
Cleaning Tools Starter Kit 13
Removing the Glass Panel 13
View Under the LCD Panel 14
View of the Main Modules 14
View of Inside the Rear Housing 15
Back View 15
I/O Ports 16
Cleaning and Handling the Glass Panel 17
Do’s and Don’ts 18
Handling a Broken Glass Panel 18
Safety 19
EMI Shielding 20
Access Door 22
Memory 24
Glass Panel 28
Cleaning and Handling of the Glass Panel 29
Isopropyl Alcohol (IPA) 30
Removing the Glass Panel 32
Replacing the Glass Panel 35
Installing a Replacement Glass Panel 40
Cleaning Tool Kit 43
iii
Cleaning Tool Resources 43
LENSPEN Screen Cleaning Device 44
Front Bezel 46
Camera Board 52
Battery 56
IR (Infrared) Board 59
AirPort Extreme Card 62
Bluetooth Board 65
LCD Display Panel 68
LCD Temp Sensor Cable 76
LVDS Cable 82
Inverter 87
Speaker, Right 93
Speaker, Left 96
Ambient Temperature Sensor Cable 101
Ambient Temperature Sensor 104
Optical Drive Fan 108
CPU Fan 113
Power Supply, AC/DC 116
Hard Drive 124
Hard Drive Sensor Cable 130
Optical Drive 133
Optical Drive Flex Cable 138
Optical Sensor Cable 141
Logic Board 144
Video Card 153
Hard Drive Fan 158
Audio Board 162
iMac (20-inch Early 2008) Take Apart iv
Camera Cable 165
Microphone Cable 172
Hard Drive Data Cable 179
Mechanism Cover 182
Clutch Mechanism 185
Cable, DC, Power Supply/SATA/Inverter 189
Rear Cover 206
Stand 209
Chassis 213
Troubleshooting
General Information 224
Serial Number 224
Power On Self Test (POST) 225
Firmware Updates 225
DDR Memory 225
How to Reset the System Management Controller (SMC) 226
Diagnostic LEDs 227
Apple Hardware Test (AHT) Error Codes 228
Logic Board Sensor and Fan Connector Locations, Top Side 230
Logic Board Sensor Locations, Back Side 231
Cleaning Tools for the LCD and Glass 231
LensPen Cleaning Tool 232
Ionizing Air Gun 233
Symptom Charts 234
How to Use the Symptom Charts 234
Diagnostics 234
Apple Hardware Test (AHT) Error Codes 235
Power Issues 237
System Shuts Down 242
Display 242
Hard Drive 244
Optical Drive 246
Fan Sound 253
AirPort 258
Bluetooth (also see Wireless Issues topic) 259
IR Remote 260
IR Sensor/Receiver 261
v
Built-in iSight Camera 262
Speakers 264
Mouse (also see Wireless Issues topic) 265
Keyboard (also see Wireless Issues topic) 266
Wireless Issues (also see Additional Wireless Topics) 268
Additional Wireless Topics 272
Error Beep(s) 274
USB 275
Views
iMac (20-inch Early 2008)—Upper Exploded View 278
iMac (20-inch Early 2008)—Lower Exploded View 279
Screw Chart 280
iMac (20-inch Early 2008) Take Apart vi
Manual Updates
Updated 20 June 2008
Troubleshooting
Symptom Charts:•
Added new troubleshooting symptom: Optical Drive-->• Optical drive won’t eject
media. Verify that two or three black clips (on the bezel) are positioned on top of the
optical drive mechanism. Refer to the topic for images and more information.
Added a new troubleshooting symptom: Error Beeps-->• iMac display is black and the
system beeps nine times (3 short, 3 long, 3 short), then repeats. Remove the small
coin battery located on the logic board near the right speaker. Wait 30 seconds, reinstall
the battery.
Product Introduction April 29, 2008
New images, screws, and updated text were added to the following sections:
Take Apart
Battery•
AirPort•
Bluetooth•
LCD Display•
LCD temp sensor cable•
LVDS display cable •
Right speaker•
Optical drive fan•
Optical ex cable•
DC, power supply/SATA/inverter cable•
Logic board•
Audio board•
Troubleshooting
General Information: •
Apple Hardware Test (AHT) error code tabl• e was added that lists the code and the
suspect part
Logic Board Sensor and Fan Locators photo•
Diagnostic LEDs: new photo of LEDs•
Added Cleaning Tools for the LCD and Glass section•
Added LensPen Cleaning Tool information•
iMac (20-inch Early 2008) — Manual Updates 7
Symptom Charts:•
Added new troubleshooting sections called • Wireless Issues and Additional Wireless
Topics to help troubleshoot wireless keyboards and mice
Added a new symptom: Power Issues-->• System that intermittently shuts down or
restarts unexpectedly
Updated symptoms throughout for clarity, removed irrelevant links •
Exploded View
New part numbers were added to reference this iMac model•
iMac (20-inch Early 2008) — Manual Updates 8
Service Source
Take Apart
iMac (20-inch Early 2008)
© 2008 Apple Inc. All rights reserved.
Product View
General Information
Product Features
The iMac (20-inch Early 2008) computer has the same overall look as the previous iMac. The big
dierences are the upgraded processor (Intel Penryn chip) and the faster RAM speeds.
New features:
2.4 or 2.66 GHz Intel Core 2 Duo processors •
1066 MHz front side bus•
2 GB and 4 GB memory options, PC2-6400 (800 MHz) DDR2, 4 GB max•
Mac OS X version 10.5.2 Leopard•
iMac (20-inch Early 2008) Take Apart — General Information 10
Product Congurations
To conrm the conguration from the Apple menu, choose About This Mac. The Processor listing
will show the speed of the processor followed by the processor type.
The following table shows the iMac (20-inch Early 2008) model congurations at introduction:
Feature Good Model Better Model
Intel Core 2 Duo processor 2.4 GHz 2.66 GHz
Memory 1 GB (1 x 1 GB) 800 MHz
DDR2 (4 GB max)
Hard Drive, Serial ATA
7200 rpm
Optical Drive 8x PATA SuperDrive 8x PATA SuperDrive
Display 20-inch, 1650x1080, Tn, 98ppi, 300nits
Graphics M74 + 128 MB M76XT + 256 MB
Audio I/O Combo digital in, Mic, Stereo speakers
Wireless PCIe 802.11a/b/g/n, Bluetooth 2.1
Power Supply 180W Universal
250/320/500 GB 320/500/750 GB
2 GB (2 x 1 GB) 800 MHz DDR2
(4 GB max)
Opening the Computer
Important: • The glass panel on the iMac should only be removed by Apple authorized
technicians. Removing the glass panel requires special tools and they must be used to
replace any module other than the SO-DIMMs.
Read and follow all of the handling and cleaning recommendations to prevent damaging •
the glass and LCD panel.
Follow ESD precautions when the front bezel and the LCD display are removed.•
Note About Images in This Manual
Small dierences in appearance between the images pictured and the actual computer you are
servicing may exist, however the steps and sequence are the same unless otherwise noted.
iMac (20-inch Early 2008) Take Apart — General Information 11
Serial Number Location
On the bottom of your iMac stand, you’ll nd a label with the serial number printed on it.
General Tools
The following tools are required to service the computer:
ESD-safe workstation and mat•
Soft, clean towel or cloth (to protect the display and removed parts from scratches)•
Black stick (or other nonconductive nylon or plastic at-blade tool)•
Phillips #2 screwdriver•
Torx T6 screwdriver (magnetized)•
Torx T8 screwdriver (magnetized)•
Torx T10 screwdriver (magnetized)•
Flat-blade screwdriver•
Isopropyl alcohol•
ESD bags•
Required Special Tools
Special tools are required to remove, handle, and clean the glass panel such as the following.
View the tools in the Glass Panel take apart chapter.
1.
922-8252 Suction cups, Pkg. of 2
922-8261 Sticky silicone roller (6-inch) to clean the glass panel 2.
922-8262 Sticky sheet pads to clean the silicone roller 3.
922-8263 Polishing cloths, clean, anti-static, optical grade micro ber “terry” style cloth4.
iMac (20-inch Early 2008) Take Apart — General Information 12
922-8253 Gloves, lint-free, anti-static, Pkg. of 2 5.
922-8259 Microfoam bag to store the glass panel, Pkg. of 56.
922-8258 ESD bags, 24x20, Pkg. of 5, to store the LCD panel. 7. Note: To prevent the buildup
of static charges which may attract dust particles to the surface of the display, store the LCD
panel in an anti-static bag whenever it has been removed from the system.
8.
iKlear Apple Polish or Brillianize anti-static spray cleaning solution. A list of where iKlear/
Brillianize can be obtained is listed in the Glass Panel chapter of the service manuals. Note:
IPA (isopropyl alcohol) can be used to clean the glass if you are unable to source iKlear or
Brillianize.
Cleaning Tools Starter Kit
The following tools are oered in the starter kit (076-1277).
Suction cups, one pair•
Sticky silicone roller (6-inch) to clean the glass panel •
Sticky sheets to clean the silicone roller, 2 pads•
Polishing cloths, clean, anti-static, microber “terry” style cloth (5 cloths)•
Gloves, lint-free, anti-static, two pairs •
Microfoam bag to store the glass panel (5 bags) •
ESD bag for LCD display storage, (5 bags)•
Removing the Glass Panel
Rubber suction cups (922-8252) and anti-static gloves (922-8253) are required to remove the glass
panel. Lift the glass straight up and o the bezel. Review the movie in the Glass Panel chapter.
iMac (20-inch Early 2008) Take Apart — General Information 13
View Under the LCD Panel
Note: To prevent the buildup of static charges which may attract dust particles to the surface of
the LCD display, store the display in an anti-static bag whenever it has been removed from the
system.
View of the Main Modules
iMac (20-inch Early 2008) Take Apart — General Information 14
View of Inside the Rear Housing
Inside the rear housing you can see the chassis, AC inlet lter, the mechanism, the hard drive
fan, the DC/power supply/SATA/inverter cable, the microphone cable, the camera cable, and the
antennas.
Back View
The input/output ports are located on the bottom left side on the back of the computer. The
power on button is located on the bottom right side on the back of the computer.
iMac (20-inch Early 2008) Take Apart — General Information 15
I/O Ports
The input/output ports from left to right are:
Headphone out/optical digital audio out port•
Audio in/optical digital audio in port•
USB 2.1 ports (3)•
FireWire 400 port•
Firewire 800 port•
Ethernet (10/100/1000 Base-T) port•
Mini-DVI port•
iMac (20-inch Early 2008) Take Apart — General Information 16
Cleaning and Handling the Glass Panel
Follow the cleaning procedures in this manual to ensure the glass panel is free of dust and other
particles before returning the computer to the customer.
Note: To view the movie, make sure the manual is opened in Acrobat.
The iMac (20-inch Early 2008) model has a glass panel that attaches to the outside of the •
front bezel.
The glass panel is not tempered and will break into sharp pieces if mishandled. A scratched •
or broken glass panel is not covered under warranty.
Removing the glass panel requires special tools such as lint-free gloves, rubber suction cups, •
microfoam storage bags, and the iKlear cleaning solution.
The glass panel must be removed prior to replacing any module other than the SO-•
DIMM’s.
To prevent contamination, handle the glass panel only by the edges while wearing lint-free •
gloves.
The complete list of tools and resources can be found in the Glass Panel take apart chapter.
iMac (20-inch Early 2008) Take Apart — General Information 17
Do’s and Don’ts
DO
Handle glass panel using lint free gloves.•
Use only a sticky silicone roller to clean the inside surface of the glass and the LCD panel.•
Use iKlear • ONLY on the outside surface of the glass panel or use the LENSPEN.
Place the glass panel into a clean protective microfoam bag when it is not installed on an •
iMac.
Store the glass panel in a safe area where it will not be broken or damaged.•
Store the LCD panel in an anti-static bag to prevent the buildup of static charges which may •
attract dust particles to the display’s surface.
Store the silicone roller and sticky paper within a temperature range of 39-104 degrees F •
(5-40C).
Wash the silicone roller in warm soapy water or wipe with isopropyl alcohol if the roller is no •
longer tacky. Replace the silicone roller if the tackiness does not return.
DO NOT
Touch the inside of the glass with bare hands or dirty gloves. Fingerprints will be dicult to •
remove.
Clean the inside surface of the glass or the LCD with iKlear or other cleaning solutions.•
Place the glass panel onto a work surface where it may collect dust and other contaminants •
unless it has rst been placed into its protective microfoam bag.
Use iKlear to clean the glass.•
Handling a Broken Glass Panel
The glass panel is not tempered and will break into sharp pieces if mishandled.
If the glass is broken it must be carefully removed from the iMac to prevent irreparable damage
to the front surface of the LCD. If the front surface of the LCD is scratched by the broken glass the
LCD may need to be replaced.
Do not handle broken glass unless you are wearing protective cut-resistant gloves. The lint-free
gloves used to prevent contamination of the glass panel are not suitable for handling broken
glass.
Use a broom and dust pan to sweep up as much of the broken glass as possible. Glass fragments
may have travelled several feet from the location of the glass panel so be sure to thoroughly
clean the entire area. Use a vacuum to remove the smaller fragments not picked up by the
broom.
iMac (20-inch Early 2008) Take Apart — General Information 18
Safety
WARNING: HIGH VOLTAGE: The highlighted module below is an AC/DC power supply that
poses a shock hazard. When the computer is under power, be aware that the power supply
contains high voltages that pose a potential hazard to your personal safety. Never work on or
near the power supply with the unit powered on; and as a further precaution, always make sure
the unit is unplugged when working on it with the front bezel removed. A white, shock- hazard
warning symbol is silk-screened in the middle of the power supply module.
WARNING:
Text or photographs marked by this symbol indicate that a potential hazard to your personal
safety exists from a high voltage source.
The AC/DC power supply board is a high-voltage source with the unit under power, and remains
powered up whenever the system is plugged in, whether or not the system is turned on. Use
extreme caution when troubleshooting the system with the front bezel removed.
Disconnect power to the system before performing maintenance.•
Disconnect ESD wrist straps when working on a plugged in system. •
Don’t work alone. In the event• of an electrical shock, it is important to have another
individual present who can provide assistance.
Keep one hand in your pocket when working on any • computer that is plugged in. This
will help ensure that your body does not provide a path to ground in the event that you
accidentally make contact with the line voltage.
Don’t wear jewelry, watches, necklaces, or other metallic articles that could present a risk •
if they accidentally make contact with the power supply circuitry.
iMac (20-inch Early 2008) Take Apart — General Information 19
EMI Shielding
The rear cover of the computer is wrapped in EMI shielding that is easily torn and damaged. To
maintain a properly shielded unit, you must repair all accidental tears and cracks to the shielding
by covering them with EMI tape that can be ordered from Apple service.
iMac (20-inch Early 2008) Take Apart — General Information 20
iMac (20-inch Early 2008) Take Apart 21
Access Door
Tools
Phillips #2 screwdriver•
ESD-safe workstation and mat•
Soft , clean towel or cloth•
Preliminary Steps
Before you begin, place the computer face down on a clean, soft, lint-free cloth so that the
bottom is facing you.
Part Location
iMac (20-inch Early 2008) Take Apart — Access Door 22
Removing the Access Door
Disconnect all cables and the power cord from your iMac.1.
Place a soft, clean towel or cloth on your work surface. Hold the side of the iMac and lay it 2.
down so that the screen is against the surface and the bottom is facing you.
3.
Raise the stand and use a Phillips #2 screwdriver to loosen the captive screw on the memory
access door by turning it counterclockwise.
Important: When removing and installing the RAM access door it is important that you use
the correct size Phillips screwdriver. Using one that is too small or too big may damage the
screw head, and/or screwdriver. Before trying to remove the RAM access door screw, make
sure that the screwdriver tip is in good shape without rounded edges and that it rmly seats
into the screw head. If the screwdriver doesn’t seat well then do not use it.
If the RAM access door screw head has been severely damaged and cannot be removed with
a Phillips #2 screwdriver you may be able to use a small jewelers at blade screwdriver to
engage the screw head and carefully remove it. In some cases it may be necessary to use a
screw extractor tool. When using a screw extractor make sure that no metal shavings from
the damaged screw drop inside the system. For more information on screw extractors and
how to use them type ‘screw extractor’ into your favorite internet search engine.
4.
Remove the access door.
Replacing the Access Door
Position the computer face down on a clean, soft, lint-free cloth so that the bottom is facing 1.
you.
2.
Position the access door on the rear housing over the memory compartment.
Use a Phillips #2 screwdriver to tighten the captive screw.3.
Important4. : To ensure proper cooling the iMac should not be operated without the memory
access door installed.
iMac (20-inch Early 2008) Take Apart — Access Door 23
Memory
Tools
ESD mat •
Soft , clean towel or cloth•
Preliminary Steps
Before you begin, remove the access door.
Warning: Always shut down the computer and remove the power cord before installing memory.
Do not attempt to install memory in the computer while it is plugged in.
Part Location
iMac (20-inch Early 2008) Take Apart — Memory 24
Removing the Memory
Shut down the computer, and disconnect all cables including the power cord.1.
Holding the sides of the computer, lay it face down on a soft, clean cloth so the stand is 2.
facing you.
3.
After removing the access door, touch the metal stand or bezel to discharge any static
electricity from your body.
Important: Always discharge static before you touch any parts such as the memory board.
To avoid generating static electricity, do not walk around the room until you have nished
replacing the memory.
iMac (20-inch Early 2008) Take Apart — Memory 25
4.
Untuck the tab in the memory compartment. Pull it to eject the installed memory module.
Set the memory modules in an anti-static bag and set them aside.5.
iMac (20-inch Early 2008) Take Apart — Memory 26
Replacing the Memory
With the computer face down, orient the notch on the DIMM with the notch in the memory 1.
slot. In this case, the notch is on the left.
With your ngers, press the DIMM fully into the slot until you hear a click. Repeat for the 2.
other DIMM slot.
3.
Fold the black tab over each DIMM.
Replace the 4. memory access door.
5.
Use a Phillips #1 screwdriver to tighten the captive screw on the memory access door.
Make sure the computer recognizes the new memory by opening System Proler, clicking 6.
More Info, and clicking Memory.
iMac (20-inch Early 2008) Take Apart — Memory 27
Glass Panel
Tools
This procedure requires the following tools, which are oered individually or as part of the
cleaning kit, 076-1277.
Suction cups (922-8252)•
Sticky silicone roller (6-inch) to clean the glass panel (922-8261)•
Sticky sheets to clean the silicone roller (922-8262)•
Polishing cloths, clean, anti-static, optical grade micro ber “terry” style cloth (922-8263)•
iKlear Apple Polish or Brillianize anti-static spray cleaning solution for the outside of the glass •
Isopropyl alcohol (IPA) or• LENSPEN to clean the inside of the glass
Gloves, lint-free, anti-static (922-8253)•
Microfoam bag to store the glass panel (922-8259) •
ESD bag for LCD display storage (922-8258)•
Note: Tools without part numbers can be sourced directly from the vendor. Refer to “Cleaning
Tool Resources” at the end of this chapter.
Part Location
iMac (20-inch Early 2008) Take Apart — Glass Panel 28
This iMac model has a glass panel that attaches to the outside of the front bezel. The glass panel
is not tempered and will break into sharp pieces if mishandled. A scratched or broken glass panel
is not covered under warranty. Removing the glass panel requires special tools such as lint-free
gloves, rubber suction cups, microfoam storage bags, and the iKlear cleaning solution. The glass
panel must be removed prior to replacing any module other than the SO-DIMM’s. To prevent
contamination, the glass panel must only be handled by the edges while wearing lint-free gloves.
Cleaning and Handling of the Glass Panel
Follow the cleaning procedures in this manual to ensure the glass panel is free of dust and other
particles before returning the computer to the customer. Refer to the movie in the sidebar for a
cleaning and handling demonstration.
Note: To view the movie, make sure the manual is opened in Acrobat.
iMac (20-inch Early 2008) Take Apart — Glass Panel 29
Isopropyl Alcohol (IPA)
Cleaning the Glass
In the unfortunate event that gloves are not worn, and ngerprints and oil smudges are visible
on the inside of the glass, cleaning should be done using a lint free cloth and IPA. Spray a small
amount of IPA onto a CLEAN lint free cloth to avoid introducing any other contaminants. Gently
wipe the area and allow the glass to dry. Note: The silicone rollers are only eective in removing
dust and other particles. If ngerprints or oil smudges are not removed prior to using the roller,
the silicone roller will transfer the ngerprints and oil smudges onto the glass.
Cleaning the Silicone Roller
Clean the silicone roller by wiping it down with IPA (Isopropyl Alcohol) or washing it with warm
soapy water.
DO
Handle glass panel using lint free gloves.•
Use only a sticky silicone roller to clean the inside surface of the glass and the LCD panel.•
Use iKlear • ONLY on the outside surface of the glass panel or use the LENSPEN.
Use Isopropyl alcohol or the LENSPEN to clean • ONLY the inside surface of the glass.
Place the glass panel into a clean protective microfoam bag when it is not installed on an •
iMac.
Store the glass panel in a safe area where it will not be broken or damaged.•
Store the LCD panel in an anti-static bag to prevent the buildup of static charges which may •
attract dust particles to the display’s surface.
Store the silicone roller and sticky paper within a temperature range of 39-104 degrees F •
(5-40C).
Wash the silicone roller in warm soapy water or clean it by wiping it down with isopropyl •
alcohol if the roller is no longer tacky. Replace the silicone roller if the tackiness does not
return.
DO NOT
Touch the inside of the glass with bare hands or dirty gloves. Fingerprints will be very •
dicult to remove.
Clean the inside surface of the glass or the LCD with iKlear or other cleaning solutions.•
Place the glass panel onto a work surface where it may collect dust and other contaminants •
unless it has rst been placed into its protective microfoam bag.
Use single wipe iKlear packets or other cleaning solutions to clean the glass.•
iMac (20-inch Early 2008) Take Apart — Glass Panel 30
Loading...