Apple imac 20 inch late 2006 User Manual

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 171
Optical disc constantly ejects
Disconnect all peripheral devices, especially the mouse in cases where the disc is constantly 
1.  
ejecting. Retest. If the issue is resolved, reconnect peripherals one-at-a-time until faulty 
peripheral is identified.
Try cleaning the disc. If the disc is dirty or scratched, it may not mount.  
2.  
Is the issue resolved? 
Yes: Problem solved.  
No: Try a different disc. If the issue persists, go on to the next step.
Boot from Apple Hardware Test (hold down the “D” key at startup). If you can boot to this 
3. 
volume, run the Quick and Extended tests.  
Does the unit pass the tests?  
Yes: Restart to the internal hard drive and test again.  
No: Replace the component (s) indicated by the test results. If you cannot boot to Apple 
Hardware Test because it ejects, go on to step 4. 
Boot from the system install DVD (use Startup Manager, hold down the Option key at 
4.  
startup). If you can boot from this volume, perform an Archive and Install with the Install 
DVD that came with the computer and test.  
Is the issue resolved?
Yes: 
5.  Problem solved.  
No: If you cannot boot to Apple Hardware Test or to the Install DVD because they eject, 
reseat the optical drive flex cable and retest.
Replace the optical drive flex cable.
6.  
Replace the optical drive.
7.  
Replace the logic board
8.   
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 2
Fan Sound
Fans running at full speed after the computer turns on
The customer may have entered a diagnostic mode that causes the fans to run at full speed.* 
Restarting the system will not restore normal fan operation. To solve the problem, the user or 
technician should do the following:Shut down the system.
1.  
Disconnect the power cord and wait 15 seconds.
2.  
Reconnect the power cord and wait 5 seconds.
3. 
Power on the system.
4.  
*Note:  Customers reporting this symptom should be told to press the power button AFTER the 
power cord has been fully inserted.  Inserting the power cord while pressing the power button 
will cause the fans to run at full speed.
Loud fan noise coming from inside the computer
The iMac has a trio of fans that circulate air throughout the system. It also includes temperature 
sensors, and advanced thermal software that spins the fans fast or slow as needed. As the system 
usage increases, the fans will adjust their speed using advanced thermal software to meet the 
cooling needs of the system.
Under normal conditions, rotating fans will make a slight hum that varies in relationship with 
their rotational speed and the amount of air that they are moving. In addition, the normal 
functioning of the hard drive and optical drive will generate additional whirring and scratching 
sounds that may be audible. All of these sounds are normal and do not indicate a failure with 
your computer.
To begin troubleshooting a possible fan issue, we need to qualify the sound that you’re 
experiencing. Does the sound occur only under specific light/heavy usage conditions? 
1.  
 
Yes: CPU intensive applications such as iTunes, Garage Band, DVD Player, etc., or two or more 
applications open at once will cause the fans to run at an increased rate making them more 
noticeable. If the sound only occurs when one or more of these applications is running, this 
is normal.  
 
No: If the sound isn’t affected by CPU intensive application it may be due to other factors. Go 
on to the next step. 
Is the sound always present, or does the sound vary? 
2.  
  
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 3
The sound is always present: The normal functioning of the hard drive and optical drive will 
generate additional whirring and scratching noises that may be audible. Check whether this 
sound is related to one of the components. Go to step 4.
 
 
The sound varies: Under normal conditions rotating blowers will make a slight hum that 
varies in relationship with their rotational speed and the amount of air that they are moving. 
Let’s see if this is indeed the case. Go to Next Step. 
Are the fans making a normal humming sound that increases/decreases in relation to 
3. 
processor usage? As the fans increase their speed to cool the system the sound level will 
increase.  
 
Launch the Activity Monitor application included with Mac OS X in the Utilities folder to 
determine whether the noise corresponds with heavy usage of the CPU. Does fan activity 
increase / decrease with the CPU Usage graph in Activity Monitor? Check by running CPU 
intensive applications such as iTunes.  
 
Yes: This is normal operation and none of the fans require replacement.  
No: If the fan activity does not coincide with CPU usage, the sound you’re hearing may not 
be fan activity. Go to the Next Step.
The normal functioning of the hard drive and optical drive will generate additional whirring 
4.  
and scratching noises that may be audible. We can isolate these noises by booting the 
computer to the iMac Install Mac OS X Install Disc 1.  
 
- Place the disc in the drive, and restart your machine while holding down the “C” key as the 
machine starts up.  
 
- Once at the Installer window, choose Open Disk Utility from the Installer Menu.  
 
- Once Disk Utility is open, select the system’s hard drive and on the toolbar choose 
Unmount. Note: if the drive has multiple partitions, unmount each of these partitions.  
This will spin down the hard drive. The optical drive will also be busy at this time; wait a 
moment for the optical drive to spin down also and then listen to the machine.  
 
Is the sound still present? 
 
Yes: With the hard drive and optical drive inactive, all you should be hearing are the fans 
in the machine. While booted to the CD, these fans should be running at a lower level 
since CPU activity is low with both drives inactive. Fan sound that includes objectionable 
ticking, whistling, or squealing may require further investigation and/or replacement of the 
particular fan. Go on to the next step.  
 
No: The normal functioning of the hard drive and optical drive will generate additional 
whirring and scratching sounds that may be audible. All of these sounds are normal and do 
not indicate a failure with the machine. If you wish to check the health of the hard drive, see  
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 174
article 152349, “Replacing a disk before it fails.”
Shut down the computer, remove the power cord and any other connected cables, and 
5. 
remove the access door, front bezel, and EMI shield.  
Stand up the computer, plug it in, and start it up by pressing the external power button.  
 
As the machine starts up, listen carefully to each of the three fans, and see if you can locate 
the fan from which the objectionable ticking, whistling, or squealing sound is coming. The 
CPU fan is the left-most fan, the hard drive fan is in the center, and the optical drive fan is on 
the right.  
 
Can you pinpoint the fan making the sound? 
 
Yes: Replace the noisy fan.  
 
No: If you can hear an objectionable ticking, whistling, or squealing sound, but you cannot 
identify the source of the sound, contact Apple Technical Support.
Fans are running at a constant high speed
If the fans on the system are running at a constant high speed, or ramp very quickly to high 
speed and do not vary once this speed is reached, the fans are most likely receiving incorrect 
thermal input. Follow these steps:
Reset the SMC and then test to see if the fans still exhibit the issue.
1.  
Boot to Apple Service Diagnostic tests. This will test the fans and thermal input of the 
2.  
sensors. If the tests fail, replace the component (s) indicated by the test.
Verify that the hard drive temperature sensor cable, and the optical drive temperature 
3. 
sensor cable are plugged in correctly. If necessary, replace the hard drive and optical drive 
temperature sensor cables.
Replace the hard drive and optical drive temperature sensors.
4.  
Replace the hard drive.
5. 
Replace the logic board.
6.  
Audible buzzing, whining, or ticking noise
The iMac contains several mechanical devices such as motors and fans that may make audible 
buzzing, ticking, or whining noises when they are operating in a normal manner. The sounds will 
vary depending on how the system is used.  
 
When troubleshooting abnormal noises try the following:
Verify that the computer is running a supported version of the Mac OS X operating system. 
1.  
If an earlier version of the operating system has been installed then the fans may run at 
excessive speeds.  
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 5
Determine that this noise is related to the computer by removing and shutting down all 
2.  
other devices in the vicinity of the computer that could be causing a sound.
Eject any media inserted into the optical drive. The optical drive will make a variety of normal 
3. 
sounds when accessing the optical media.
Quit all applications and test the computer again. Processor intensive applications may cause 
4.  
the fans to run at a higher RPM and therefore be more audible.
Boot to Apple Service Diagnostic or later and select the EFI test suite by holding down the D 
5. 
key during startup.  The diagnostic tests fan speeds and thermal sensor functionality.  Should 
tests fail, replace any parts indicated by the diagnostic.
Reboot the computer and check the computer again. If the noise persists and is unusually 
6.  
loud, contact Apple Technical Support. 
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 6
AirPort
Not able to connect wirelessly with AirPort
1. From the Apple menu, choose About this Mac. 
2- Click on More Info. System Profiler should open. 
3- In System Profiler, in the column on the left, look under Network for a line called “AirPort Card”. 
Select that line. 
4- Does the section to the right say “No Information Found”? Yes: The computer doesn’t realize it has an AirPort card installed. Go to step. 5 
No: The iMac recognizes that it has an AirPort card installed. Go to step 6. 
5- Remove the front bezel, lower EMI shield, and two card mounting screws and reseat the 
AirPort card. Re-install the two card mounting screws and check System Profiler again to see if 
the computer sees the AirPort card. Does it recognize the card now?
 
Ye s : Problem solved. Replace the lower EMI shield and front bezel and re-test the system to 
verify that the original symptom is resolved. 
No : Replace the AirPort card. Refer to the Take Apart section for AirPort Card.  If the issue 
persists after replacing the AirPort card, replace the logic board. 
6- Now that we know the iMac recognizes the AirPort card, check the antennas. If the antennas  
are not plugged in all the way, you may have very short AirPort range. 
7- Remove the access door, front bezel, lower EMI shield,  and the two AirPort card mounting 
screws . Disconnect the card, turn it over and reconnect the antenna cable connectors to the 
card. Make sure the antenna leads are firmly seated. Replace the card and other components and 
retest. 
8- If the antenna leads are plugged in properly and the AirPort card is recognized but the 
problem persists, there are a number of other things that could cause issues with wireless 
networking. Refer to Knowledge Base document 10685 8 for more networking information. 
9- Replace the AirPort card. Refer to Take Apart/Airport Card. 
10- Replace the AirPort antennas. Refer to Take Apart/AirPort Antennas. 
11- Replace the logic board. Refer to Take Apart/Logic Board.  
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 7
Bluetooth
Bluetooth devices won’t sync with my computer
1. Make sure the computer has a Bluetooth board installed.  Open System Preferences (from the 
Apple menu, choose System Preferences) and verify that “Bluetooth” appears in the Hardware 
section of the window.
2. Locate the Bluetooth board inside the computer. Reseat the Bluetooth board and the 
Bluetooth antenna.
3 Turn on Bluetooth.  In System Preferences, click Bluetooth and then click the Settings tab. If 
you don’t see “Bluetooth Power: On,” click the “Turn Bluetooth On” button. Make sure that you 
also enable Bluetooth on your device too (please refer to your device’s documentation for 
instructions).
4 Set up a new device.  To set up a Bluetooth phone or PDA, click the Devices tab in Bluetooth 
preferences and then click “Set Up New Device” to open the Bluetooth Setup Assistant. Follow the 
onscreen instructions to set up your device. To set up an Apple Wireless Keyboard and Mouse, 
open System Preferences, click Keyboard & Mouse, click the Bluetooth tab, and then click “Set Up 
New Device” to open the Bluetooth Setup Assistant. Follow the onscreen instructions to set up 
your keyboard and mouse. 
5 Recharge or replace your Bluetooth device’s battery. If your Bluetooth device’s battery is low, 
you may experience connection issues. 
6 Download and install the latest software for the device. 
7 Check for a Bluetooth update. Choose Software Update from the Apple menu (make sure that 
your computer is connected to the Internet). If newer Apple Bluetooth software exists, Software 
Update will find it.
8 Check for signal spoilers. Avoid situations in which metal objects come between your device 
and computer. Don’t put the computer under a metal desk or locked away behind a metal 
cabinet. Keep cordless phone base stations, microwave ovens, and other electrical devices that 
operate on a 2.4 GHz bandwidth away. And make sure that the device and computer aren’t more 
than 30 feet apart from each other.
9 Restart your computer. You may also want to try resetting your computer’s PRAM and NVRAM.
10 Reset your Bluetooth device. First try turning your device off and then on again. If that doesn’t 
work, see if you can reset your device.
11. Replace the Bluetooth board and test the computer again.
12. Refer to the Bluetooth Support site at http://www.apple.com/support/bluetooth.
13 Replace the logic board. 
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 8
IR Remote
Remote won’t communicate with system applications such as iTunes or iPhoto, or with the 
optical drive.
Make sure of the following when using the Apple Remote:  You are within 30 feet of the front of the computer.
• 
You have an unobstructed line-of-sight to the front of the computer.
• 
You are pointing the lens end of the Apple Remote directly at the front of the computer.
• 
The computer is powered on and awake.
• 
The “Disable remote control infrared receiver” checkbox in the Security pane of System 
• 
Preferences is NOT checked.
Make sure the active application works with Apple Remote. Apple Remote uses Front Row, 
• 
and from Front Row it can access DVD Player, iPhoto, iTunes, and QuickTime Player.
Make sure the remote is paired with the computer. Access the System Preferences/Security 
• 
pane and check “Unpair” if available. Close the Security pane, and re-pair the Apple Remote 
with the computer. See Knowledge Base article 302545.
Use a digital camera to test your Apple Remote.  
1.  
If you have a digital camera or DV camera with an LCD display, you can use it to see if your 
Apple Remote is emitting a signal. Infrared beams are invisible to the human eye, but most 
digital cameras and video cameras use Charged-Coupled Device (CCD) chips or image 
sensors that are sensitive to infrared light.  
 
To use a camera to test your Apple Remote, follow these steps:  
• Turn on your digital camera or DV camera and remove any lens cover.  
• Point your Apple Remote toward the camera lens.  
• Press and hold the Menu button on the remote while looking at your camera’s LCD display.  
• If you see a faint blinking light coming from the Apple Remote in the camera’s LCD, then 
the remote is working properly.  
• If you don’t see any blinking light in the camera’s LCD, replace the battery in your Apple 
Remote and then test it again with your computer (see How to replace the Apple Remote 
battery” for instructions). (KBase article 302543)
Does the IR remote now communicate with an 
2.   active application that works with Apple 
Remote? 
Yes: IR remote is functioning correctly.  
No: Replace Apple Remote. 
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 17 9
IR Sensor/Receiver
Supported applications do not respond to input from the remote control.
Perform the checks above under “IR Remote” to verify that the Apple Remote is functioning 
1.  
correctly, and retest. Do supported applications now respond to input from the IR remote? 
Yes: Problem resolved.  
No: Go to the next step.
Verify that the IR Sensor can be seen in the Apple System Profiler. Open the Apple System 
2.  
Profiler and click on the “USB” section. You should see the following listed:  
 
Do you see the IR Receiver listed under the USB section of the Apple System Profiler? 
Yes: Go on to the next step. 
No: Replace the IR cable and retest. Refer to the “IR Board” take apart procedure 
Do supported applications now respond to input from the IR remote? 
  Yes: Problem resolved.  
  No: Replace the IR sensor board and retest. Refer to the “IR Board” take apart procedure. 
If the issue persists after replacing these parts, replace the logic board.
Access System Preferences and click Security. In the Security pane check the following:  
3. 
• Make sure “Disable remote control infrared receiver” checkbox is not checked.  
• If “Unpair” is available in the Security pane of System Preferences, another Apple Remote 
may be paired to the computer (pairing allows only one Apple Remote to control the 
computer). To delete a pairing between the remote and the iMac G5 (iSight),  click Unpair. 
(You may have to enter your Administrator password to make changes in the Security pane.) 
After making sure these features are disabled, does the Apple Remote control the machine 
now? 
Yes: Problem resolved.  
No: Replace the IR sensor board and retest. Refer to the “IR Board” take apart procedure. 
						

							iMac (20-inch Late 2006) Troubleshooting — Symptom Charts 180
Built-in iSight Camera
The built-in camera is not recognized.
Boot the iMac to the desktop and launch iChat AV. 
1.   Note: You do not need to be connected 
to a network to use iChat AV to troubleshoot. Verify that the correct versions of Mac OS X 
and iChat AV are installed. Reinstall or update software as needed. 
Open the iChat AV preferences and click on the ‘Video’ icon. Verify whether the camera is 
2.  
recognized by the iChat AV software. Is the camera recognized? 
 
Yes: the camera is recognized and video preview is normal: This indicates the camera is 
functioning. Pull down the ‘Video’ options from the menu bar and verify that the camera is 
enabled. The camera must be enabled to function.  
 
No : the camera is not recognized and no video preview is visible. This indicates the camera 
may not be functioning properly.  Open the iMac and inspect the camera board (inside the 
front bezel) and the attached cable. Reseat the cable on the camera board and check the 
other end of the camera cable connections to the logic board. The camera cable connectors 
are on the right side of the logic board, below the optical drive and to the right of the fan. 
Go on to the next step if this didn’t solve your problem.
Replace the camera board located inside the front bezel.
3. 
Replace the camera cable.
4.  
If the iSight camera still doesn’t appear in System Profiler on the USB bus after replacing the 
5. 
camera board or camera cable, replace the logic board.
Camera recognized but no video.
Verify that the lens assembly for the iSight camera located in the top middle of the front 
1.  
bezel is not obstructed by anything including Post-It notes or other objects. 
Replace the camera board in the front bezel and retest.
2.  
Camera image quality poor.
The built-in camera is recognized by iChat AV and other supported video applications however 
the image quality is poor.
Verify that the lens assembly for the iSight camera is clean. Fingerprints and other 
1.  
contaminants can affect image quality. Clean the lens using a lint free lens cleaning cloth 
being while being careful not to scratch the lens.
Verify that there is sufficient lighting to produce a good quality image. Lighting which is 
2.  
comparable to that found in a well lit office will product a good quality image. If possible, 
avoid having a brightly lit background. Diffused lighting is preferred over direct lighting.
Launch iChat AV and open the iChat AV preferences. Click on the ‘Video’ tab. Is the video 
3. 
quality acceptable? 
  Ye s: The camera is functioning normally. The image quality problems may be caused by 
bandwidth limitations when using iChat over the internet. Instruct the customer to use the