Apple imac usb 2 0 User Manual

16 - iMac (USB 2.0) Troubleshooting
No Video Symptom Charts
No Video 
Screen is dark, fan is running and the hard drive is spinning. You may hear the startup 
chime as well.
1. Reset parameter RAM. Press Command-Option-P-R during startup before “Welcome to Macintosh” 
appears.
2. The system software could be damaged. Start up from the system CD that came with the computer.
3. Remove the user access panel on the bottom of the computer. With the unit powered on, check if a red  LED is visible in the...

iMac (USB 2.0) Troubleshooting - 17
No LED Symptom Charts
No LED
LED on the 17-inch 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.
LED on the 15-inch display bezel does not...

18 - iMac (USB 2.0) Troubleshooting
Display Tilt Symptom Charts
Display Tilt
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 the flat panel.
2. For the 15-inch: Remove the three screws and lift the cable retainer off the panel shield.
3. For the 17-inch: Remove the four...

iMac (USB 2.0) Troubleshooting - 19
Display Tilt Symptom Charts 4. For either size display, loosen the screws under the metal cable retainer and tilt the screen the opposite 
direction of the tilt.  Note:  The picture below shows the four screws on the 15-inch model; the 17-inch 
model looks very similiar. 
5. While holding the display bezel in the level position, tighten the screws.
6. Replace the panel and check that the display is now horizontally level.  Important: If you are replacing 
the 17-inch...

20 - iMac (USB 2.0) Troubleshooting
Display Tilt 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...

iMac (USB 2.0) Troubleshooting - 21
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...

22 - iMac (USB 2.0) Troubleshooting
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...

iMac (USB 2.0) Troubleshooting - 23
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. 

24 - iMac (USB 2.0) Troubleshooting
Sound In Symptom Charts
Sound In 
No sound is recorded
1. Check System Preferences > Sound > Input and make sure that Internal microphone is selected, and 
that the input volume is at a reasonable level to pick up sound. Use the Input level indicator to judge if 
the microphone is picking up sound.
2.  Check the microphone cable connection.
3. Replace the internal microphone. The internal microphone cable assembly is part of the of 20 and 17  Display bezel, and cannot...

iMac (USB 2.0) Troubleshooting - 25
Error Beep(s) Symptom Charts
Error Beep(s)
Computer beeps at startup.
1. RAM expansion DIMMs for the iMac must be DDR 333 PC2700 compliant 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.