Apple imac 17 inch late 2006 cd User Manual

							
 Service Source
© 2006 Apple Computer, Inc. All rights reserved.
Troubleshooting
iMac (17-inch Mid 2006) and iMac (17-inch Late 2006 CD) 
						

							
iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 122
  
General Information
Serial Number
iMac serial number is located on the bottom of the computer stand.
Power On Self Test (POST)
Intel-based Mac computers rely on a combination of tones and blinking LEDs to display Power 
On Self Test (POST ) error codes.
If the computer detects out-of-specification or no SDRAM or the RAM installed does not 
meet the appropriate specifications, the screen will remain black but the power LED on the 
front of the computer will blink once per second to signal the error. 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 
blink the power LED on the front of the computer three times, pause, and repeat the blinking 
until the computer is turned off.
The solution to both of these situations is to first re-seat the memory and test the computer 
again. If the memory fails the POST test again, try memory that has been verified to work 
correctly on another system (i.e., “known-good”) or order new memory.
•
•
• 
						

							
iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 123
DDR Memory
The iMac computer has two SDRAM slots in the bottom of the computer. The iMac ships from the 
factory with at least 512 MB of DDR2 SDRAM, installed as a 256 MB DIMM in the top slot and a 
256 MB DIMM in the bottom slot. ( The computer may come with more RAM, depending on how 
the computer was ordered from Apple.)
Although you can install a single SO-DIMM, it is recommended that memory be installed in 
matched pairs for improved graphics performance.
The maximum amount of RAM you can install in the iMac is 2 GB total (a 1 GB SO-DIMM in each 
of the two slots). You can use small-outline dual inline memory modules (SO-DIMMS) of 512 MB or 
1 GB that meet all of these criteria:
PC2-5300
unbuffered
nonparity
200-pin
667 MHz DDR2 SDRAM
Note:  DIMMs with any of the following features are NOT supported in this iMac:
registers or buffers
PLLs
ECC
parity
EDO RAM
•
•
•
•
•
•
•
•
•
•
• 
						

							
iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 124
How to Reset the System Management Controller (SMC)
The System Management Controller (SMC) is a chip on the logic board that controls all power 
functions for your computer. If your computer is experiencing any power issue, resetting the SMC 
may resolve it. The SMC controls several functions, including:
Telling the computer when to turn on, turn off, sleep, wake, idle, and so forth.
Handling system resets from various commands.
Controlling the fans.
Note that resetting the SMC does not reset the PRAM. Resetting the SMC will not resolve issues 
in which your computer is unresponsive—in these situations, restarting your computer will 
generally suffice. If your computer isn’t responding, perform these steps one at a time, in this 
order, until the issue has been resolved:
Force Quit (Option-Command-Escape).
Restart (Control-Command-Power).
Force Shut Down (press the power button for 10 seconds).
Resetting the SMC can resolve some computer issues such as not starting up, not displaying 
video, sleep issues, fan noise issues, and so forth. If your computer still exhibits these types of 
issues after you’ve restarted the computer, try resetting the SMC.
To reset the SMC on an iMac
From the Apple menu, choose Shut Down (or if the computer is not responding, hold the 
power button until it turns off ).
Unplug all cables from the computer, including the power cord.
Wait at least 15 seconds.
Plug the power cord back in, making sure the power button is not being pressed at the time. 
Reconnect your keyboard and mouse to the computer.
Press the power button on the back to start up your computer.
•
•
•
1.
2.
3.
1.
2.
3.
4.
5.
6. 
						

							
iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 12
Diagnostic LEDs
The iMac has three built-in diagnostic LEDs and a front LED on the main logic board (shown 
below) that can help you to troubleshoot the computer. 
To Access the LEDs:
Follow the take apart instructions to remove the RAM access door, front bezel, and lower 
EMI shield.
Locate the SO-DIMM slot and LVDS video connector. The three troubleshooting LEDs 1, 2, 
and 3 are located to the right of the LVDS cable connector, under a square of black tape. Peel 
back the tape to view the LEDs. Note that the LEDs are marked 1, 2, 3 from left to right, as 
show below. An additional front LED is located in an opening at the center of the right 
speaker, as shown below.   
1.
2. 
						

							
iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 12
 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 (Mid 2006 17-inch) 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 off only if the AC power source is disconnected or the 
power supply is faulty.
LED #2
Indicates that the main logic board has detected proper power from the power supply when 
the computer is turned on. 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 LCD display are communicating. This LED will be ON 
when the computer is turned on and video signal is being generated.
Front LED
Indicates that the computer has power but no video signal (e.g., the computer is starting up 
or the display has entered Sleep mode, turning off the video signal). This LED will pulse when 
the entire system has entered Energy Saver mode.  
•
•
•
• 
						

							
iMac (17-inch (Mid 2006/Late 2006 CD) Troubleshooting — Symptom Charts 12
Symptom Charts
How to Use the Symptom Charts
The Symptom Charts included in this chapter will help you diagnose specific symptoms related 
to the product. Because cures are listed on the charts in the order of most likely solution, try 
the cures in the order presented. Verify whether or not the product continues to exhibit the 
symptom. If the symptom persists, try the next cure. 
Note:  If a cure instructs you to replace a module, reinstall the original module before you 
proceed to the next cure. 
						

							
iMac (17-inch (Mid 2006/Late 2006 CD) Troubleshooting — Symptom Charts 12
Power Issues
No Power 
The iMac will not turn on. The display remains black and there are no sounds from the fans or 
drives.
1. Verify the power outlet is good. Plug a different device into the socket to ensure there is power, 
or plug the iMac into another outlet. Does the iMac power on now?
Yes: Resolved. Bad outlet.
No: Go on to the next step.
2. Check the power cord. Use a known good power cord. Does the iMac power on  now?
Yes: Your power cord has failed. Replace the AC power cord.
No: Go on to the next step.
3. Check the connection of the power cord on both ends. Verify that the power cord is securely 
plugged into both the AC outlet and back of the computer. Does the iMac power on now?
Yes: You may have a loose fit to your power cord. Replace the AC power cord and test.
No: Go on to the next step.
4. Follow instructions in the General Information chapter to reset the SMC. Does the iMac power 
on now? 
Yes: Issue resolved.
No: Go on to the next step.
5. Remove and reinstall the SO-DIMM memory modules. Does the iMac power on now?
Yes: Issue resolved.
No: Go on to the next step.
6. Remove the RAM access door, front bezel, and lower EMI shield to gain access to the three 
diagnostic LEDs.  See “Diagnostic LEDs” in the General Information chapter for complete 
instructions on this procedure.
7. Plug the power cord into the iMac and the power cord into the AC outlet. Check to see if LED 
#1 is On or Off.
LED #1 is On: This indicates that the power supply is getting good power from the AC outlet. 
Go on to the next step.
LED #1 is Off: This indicates that either the power inlet assembly or the power supply should 
be replaced. 
						

							
iMac (17-inch (Mid 2006/Late 2006 CD) Troubleshooting — Symptom Charts 12
8.  Press the power button. Check to see if LED # 2 comes On, comes on momentarily, or stays Off.
LED # 2 is On: The Power Supply is functioning. Go on to the next step.
LED # 2 comes on momentarily or stays Off: Replace the Power Supply.
9. At this point in the Power On process, you should hear a boot chime and see the front LED on 
the computer light up. When the main logic board and LCD panel communicate to deliver video, 
the front LED should go off, and LED # 3 should be on. Does the Front LED go off?
Yes: The LCD and main logic board have communicated. If there is no picture on the display, 
follow “No Video” troubleshooting.
No: Your logic board is not communicating with LCD panel.  Go on to the next step.
10. Check to see if LED # 3 is On or Off.
LED # 3 is On: The logic board is communicating with LCD panel. Follow “No Video” 
troubleshooting.
LED # 3 is Off: The logic board is not communicating with LCD panel. Reseat the LVDS cable 
and test again. If the issue persists, replace the main logic board.
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. 
If an earlier version of the operating system has been installed then the fans may run at 
excessive speeds. 
Determine that this noise is related to the computer by removing and shutting down all 
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 
sounds when accessing the optical media.
Quit all applications and test the computer again. Processor intensive applications may cause 
the fans to run at a higher RPM and therefore be more audible.
 Boot to the latest version of Apple Service Diagnostic for iMac (Mid-2006) and select the EFI 
test suite by holding down the D 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 
loud, contact Apple Technical Support.
1.
2.
3.
4.
5.
6. 
						

							
iMac (17-inch (Mid 2006/Late 2006 CD) Troubleshooting — Symptom Charts 130
No Video
No Video, No Boot Chime, White LED ON (Symptom 1)
The iMac will turn on (indicated by the front LED ON), but there is NO boot chime and No Video 
on the display. The faint sound of the fans, hard drive, and optical drive may  also be heard.
1. Follow instructions in the “General Information” chapter to reset the SMC. Does the computer 
display video after successfully resetting the SMC?
Yes: Problem solved.
No: Continue to next step.
2.  Verify that only supported SDRAM memory has been installed and that it has been installed 
correctly. Unsupported and/or defective memory can prevent the iMac from booting. It may be 
necessary to install known good memory for testing purposes and replace any unsupported 
or defective SO-DIMM’s identified during this process. Does the computer display video after 
verifying and/or replacing the memory with known good memory?
Yes: Problem solved. Verify full system functionality before return the system to the customer.
No: Replace the logic board.
No Video, Boot Chime heard, White LED ON  (Symptom 2)
The iMac will turn on, the boot chime can be heard, a white LED appears on the front bezel and 
sounds from the fan or drive activity can be heard, but the display has no picture or color.  
1. Check if the computer is sleeping. Press the space bar to wake the computer from sleep mode. 
Did the computer wake from sleep?
Yes: Put the computer to sleep from the Apple menu and wake the computer again to test. 
Check Energy Saver setting to see when the computer has been designated to sleep.
No: Continue to next step.
2. Reset your computer’s PRAM (Parameter RAM):
If your iMac is on, turn it off by holding the power button until the unit powers off. You 
should hear the fans go quiet.
 While the computer is off, with your left hand, hold down the Apple key, the Option key 
next to it, and the letter “R” key on the keyboard. When you have these keys all pressed 
down, push the power button with your right hand and then quickly move that hand 
to hold down the letter “P” on the keyboard. Keep these four keys pressed while the 
computer starts up.
 Make sure you hold down the four keys (P - R - Apple - Option) while the computer is 
starting up. When you hear the computer’s start up chime for the second time, you can 
let go of the keys on the keyboard.
If you didn’t hear at least two startup chimes, go to the top of this section and begin 
again. It’s important that you hear two startup chimes when performing this procedure. 
This indicates that you have successfully reset the computer’s PRAM (Parameter RAM).
-
-
-
-