Apple imac 17 inch flat panel User Manual

							iMac (17-inch Flat Panel) Troubleshooting - 19
No Video Symptom Charts 8. Replace the inverter board.
9. Replace the LCD display. Important: If you are replacing the display, be sure to install the new display 
shield and EMI gaskets that come with the new LCD panel. Installation instructions are included with the 
new display panel. Additional display shields/gasket kits are also available separately as a kit, part #076-
0958.
10. Replace the neck assembly
11. Replace the logic board. 
12. Replace the power supply board. 
						

							20 - iMac (17-inch Flat Panel) Troubleshooting
No LED Symptom Charts
No LED
LED on the display bezel does not light up
Note: The LED does not light up when the power is on; however, the LED should pulse when the computer 
is in Sleep mode. 
1. Put the computer into Sleep mode. Does the LED pulse now? If yes, there is nothing wrong with the 
LED. If no, replace the display bezel (922-5297) shown below. The LED is attached to the display bezel 
and cannot be ordered separately. 
						

							iMac (17-inch Flat Panel) Troubleshooting - 21
Display Symptom Charts
Display
LED on the display bezel does not light up
Note: The LED does not light up when the power is on; however, the LED should pulse when the computer is 
in Sleep mode. 
1. Put the computer into Sleep mode. Does the LED pulse now? If yes, there is nothing wrong with the LED. 
If no, replace the display bezel (922-5297). The LED is attached to the display bezel and cannot be 
ordered separately.
Screen tilts to the left or the right even after a manual adjustment.
Note:  It is normal for the screen on an iMac (Flat Panel) to have a small amount of horizontal play. However, 
the screen should be able to be adjusted so that it will stay in a level horizontal position.
1. Remove ten screws connecting the back cover to the flat panel LCD display (refer to the Take Apart 
chapter, display topic).
2. Disconnect the panel cables to gain access the three screws on the metal cable retainer shown below. 
Remove the screws and lift the cable retainer off the panel shield.  
						

							22 - iMac (17-inch Flat Panel) Troubleshooting
Display Symptom Charts 3. Loosen the four screws (shown below) that hold the panel shield to the neck assembly, and tilt the 
screen the opposite direction of the tilt.
4. While holding the display bezel in this position, tighten the same four screws that hold the panel shield 
to the neck assembly.
5. Replace the panel and check that the display is now horizontally level. Important: If you are replacing 
the display, be sure to install the new display shield and EMI gaskets that come with the new LCD 
panel. Installation instructions are included with the new display panel. Additional display shields/
gasket kits are also available separately as a kit, part #076-0958. 
						

							iMac (17-inch Flat Panel) Troubleshooting - 23
Display Symptom Charts
When displaying a single color over the screen area, the LCD panel shows one or more pixels  
that are not properly lit
Active-matrix LCD technology uses rows and columns of addressable locations (pixels) that render text and  
images on screen. Each pixel location has three separate subpixels (red, green, and blue) that allow the 
image to be rendered in full color. Each subpixel has a corresponding transistor responsible for turning the 
subpixel on or off. 
There are typically millions of these subpixels on an LCD display. For example, the LCD panel used in the  
Apple Cinema HD display is made up of 2.3 million pixels and 6.9 million red, green, and blue subpixels. 
Occasionally, a transistor does not work perfectly, which may result in the affected subpixel being turned on 
(bright) or turned off (dark). With the millions of subpixels on a display, it is quite possible to have a low 
number of faulty transistors on an LCD. Therefore, a certain number of subpixel anomalies is considered 
acceptable. Rejecting all but perfect LCD panels would significantly increase the retail price for products 
using LCD displays. These factors apply to all manufacturers using LCD technology—not just Apple  
products. 
To determine whether or not the display has an acceptable number of pixel anomalies, follow the steps  
below: 
1. Set the display image to one of the following colors: all-white display, all-red display, all-green display, or 
all-blue display.
2. Using a jeweler’s loupe, pocket microscope, or other magnifying device, identify and count each subpixel  anomaly: 
• Bright subpixel anomaly = subpixel that is always on
• Dark subpixel anomaly = subpixel that is always off
3. Important:  Check the number of subpixel anomalies with the following chart:
4. If the number of subpixel anomalies exceeds the acceptable number listed in the chart, replace the LCD  panel.
5. If the number of subpixel anomalies is acceptable, explain to the customer that the pixel anomalies are  within specifications, and no repair is necessary.  
Important:   Do not release the specifications to customers. Instead, inform them t\
hat a certain number 
of subpixel anomalies is considered acceptable, and these factors apply to all manufacturers using LCD  
technology—not just Apple products.
LCD Size  
(inches)
Acceptable Number of Subpixel 
Anomalies Replace the Display
Bright
Dark Combination BrightDark  Combination
1 7           up to  4   up to  6   up to  8   5 or  more  7 or  more  9 or  more 
						

							24 - iMac (17-inch Flat Panel) Troubleshooting
Hard Drive Symptom Charts
Hard Drive 
Hard Drive won’t mount to the desktop
1. Disconnect any connected peripherals.
2. Boot from the system CD that came with the computer and see if the hard drive mounts on the 
desktop.
3. Launch Drive Setup and update the hard drive driver.
4. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
5. Replace the hard drive cable.
6. Replace the hard drive.
7. Replace the logic board.
Flashing question mark appears on the screen
1. Boot from the system CD that came with the computer and see if the hard drive mounts on the 
desktop.
2. Launch Drive Setup and update the hard drive driver.
3. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
4. Replace the hard drive cable.
5. Reinstall the software drivers for the hard drive.
6. Reinstall system software. Backup the data first.
7. Reinitiation the hard drive.
8. Replace the hard drive.
9. Replace the logic board.
System hangs during normal startup process
1. Boot from the system CD that came with the computer and see if the hard drive mounts on the 
desktop.
2. Using Drive Setup, reinstall the system software drivers for the hard drive.
3. Using Drive Setup, reinitiation the hard drive.
4. Check all cable connections to and from the hard drive.
5. Replace the hard drive cable.
6. Replace the hard drive.
7. Replace the logic board. 
						

							iMac (17-inch Flat Panel) Troubleshooting - 25
Optical Drive Symptom Charts
Optical Drive 
Optical drive won’t mount to the desktop
1. Try cleaning the disc. If it is dirty or scratched, it may not mount.
2. Try a different disc.
3. Boot from Apple Hardware Test (hold down the “C” key at startup) or boot from the system install CD 
(use Startup Manager, hold down the Option key at startup).
4. Perform a clean install with the CD that came with the computer.
5. Replace the optical drive cable.
6. Replace the optical drive.
7. Replace the logic board.
Can’t boot from the optical drive
1. Try cleaning the disc. If it is dirty or scratched, it may not mount.
2. Try a different disc.
3. Boot from Apple Hardware Test (hold down the “C” key at startup) or boot from the system install CD 
(use Startup Manager, hold down the Option key at startup).
4. Perform a clean install with the CD that came with the computer.
5. Replace the optical drive cable.
6. Replace the optical drive.
7. Replace the logic board.
Optical disc constantly ejects
1. Disconnect all peripheral devices, especially the mouse in cases where the disc is constantly ejecting.
2. Try cleaning the disc. If it is dirty or scratched, it may not mount.
3. Try a different disc.
4. Boot from Apple Hardware Test (hold down the “C” key at startup) or boot from the system install CD 
(use Startup Manager, hold down the Option key at startup).
5. Perform a clean install with the CD that came with the computer.
6. Replace the optical drive cable.
7. Replace the optical drive.
8. Replace the logic board. 
						

							26 - iMac (17-inch Flat Panel) Troubleshooting
Sound Out Symptom Charts
Sound Out 
No sound from either internal or external speakers
1. Verify volume setting is correct in system preferences.
2. Replace the external speakers or headphone in question with a known-good device.
3. Reset parameter RAM. Press Command-Option-P-R during startup before “Welcome to Macintosh” 
appears.
4. Verify internal speaker cable is connected.
5. Replace the internal speaker.
6. Replace the logic board. 
						

							iMac (17-inch Flat Panel) Troubleshooting - 27
Sound In Symptom Charts
Sound In 
No sound is recorded
1. Check setup of the system preferences for the microphone.
2. Check the microphone cable connection.
3. Replace the internal microphone.
4. Replace the neck assembly. 
						

							28 - iMac (17-inch Flat Panel) Troubleshooting
Error Beep(s) Symptom Charts
Error Beep(s)
Computer beeps at startup.
1. RAM expansion DIMMs for the iMac must be PC133 compliant and use SDRAM devices. If the user 
installs a DIMM that uses EDO or SGRAM devices, the computer will beep several times when the 
user attempts to restart the computer.
2. Refer to “Power-On Self Test” mentioned earlier in this chapter.