Apple powerbook g4 12 inch User Manual

							
 

PowerBook G4 (12-inch) Troubleshooting - 
 
9
 
 Symptom Charts
 
Display
 
No display, or dim display, but computer appears to operate correctly
 
1. Press F2 to increase the screen brightness setting.
2. Remove any connected devices. Allow the battery to charge to at least 10 percent before plugging in external devices.
3. Try known-good power outlet, power adapter and power cord.
4. Reboot the computer—hold down the Control and Command keys and press the  Power button, or press and hold the Power button for 5 to 10 seconds to shut down the 
computer, then press the Power button to restart.
5. Connect an external display, and check for video on external display. • If video is fine on external display, replace LCD panel.
• If video symptom is same on external display, replace logic board.
6. Verify backlight cable and LVDS cable connections are seated properly and that the  cables are not damaged (refer to display assembly replacement instructions).
7. Replace display assembly.
8. Replace logic board.
 
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 signi ficantly 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  
						

							
 

10 - 
 
PowerBook G4 (12-inch) Troubleshooting Symptom Charts
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 speci fications, 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.
 
Video (S-Video and Composite adapter)
 
No video on an external device
 
1. Make sure you are using the S-Video and Composite adapter cable.
2. Verify TV or VCR is set up properly with correct source.
3. Try different TV or VCR. Check owner’s manual for TV or VCR.
4. Replace adapter cable.
5. Replace logic board. 
 
The display is rolling (PAL instead of NTSC)
 
1. Make sure you are not using Apples A/V Video Cable.
2. Make sure you are using the S-Video and Composite adapter cable.
3. Go to Displays preference pane; change resolution from PAL setting to NTSC setting. 
4. Try a different TV or VCR.
5. Try a different adapter cable
6. Replace logic board.
 
LCD Size 
(inches) Acceptable Number of Subpixel 
Anomalies Replace the LCD Panel
 
Bright
Dark Combination BrightDark  Combination
12.1 to 15.2 up to 3 up to 5 up to 7 4 or  more 6 or more 8 or more 
						

							
 

PowerBook G4 (12-inch) Troubleshooting - 
 
11
 
 Symptom Charts
 
Display shows ghosting (signal reflection) 
 
1. Verify that cables are correctly installed and  firmly seated.
2. Replace video adapter.
 
Video (RGB adapter)
 
No video on an external device
 
1. Make sure RGB adapter cable is fully seated.
2. Click Detect Displays button to verify that monitor is being recognized in the Displays  preference pane, and is known-good and supported by this computer.
3. Try known-good RGB adapter.
4. Replace logic board.
5. Replace RGB adapter cable.
6. Replace logic board. 
 
Display shows ghosting (signal re flection) 
 
1. Verify that cables are correctly installed and  firmly seated.
2. Replace video adapter.
 
Bluetooth
 
Bluetooth not recognized when ADC monitor connected
 
1. Disconnect all devices except the monitor.
2. Restart the computer.
3. If Bluetooth is still not recognized, refer to Bluetooth topic articles in the Knowledge  Base for the latest information on optimizing Bluetooth performance. 
						

							
 

12 - 
 
PowerBook G4 (12-inch) Troubleshooting Symptom Charts
 
Misc. Symptoms
 
The computer runs with battery, but not with the power adapter plugged into 
wall outlet
 
1. Try known-good power outlet. 
2. Try known-good power adapter and power cord. 
 
Note:
 
 Verify that power adapter connector glows amber or green. If the power \
adapter light is green, turn over the computer and press the battery but\
ton. One to 
five lights glow to show the battery’s level of charge. One blinking \
light indicates that 
the battery does not have sufficient charge to turn on.
Reset the power manager by pressing the key combination Control-Option-S\
hift-
power. 
 
Warning: Make sure you do not hold down the fn key when resetting the 
power manager.
 
3. Replace DC-in board 
4. Replace DC-to-DC board.
5. Replace logic board. 
 
The computer runs when plugged into a wall outlet but not on battery power
 
1. Reseat battery to verify battery is seated correctly with battery lock engaged.
2. Try known-good charged battery.
3. Reset the power manager by pressing the key combination Control-Option-Shift- power. 
 
Warning: Make sure you do not hold down the fn key when resetting the 
power manager.
 
4. Replace DC-to-DC board.
5. Replace logic board. 
						

							
 

PowerBook G4 (12-inch) Troubleshooting - 
 
13
 
 Symptom Charts
 
The cursor does not move when you are using trackpad
 
1. Verify that no USB device is connected.
2. Boot from a Mac OS system CD to verify that it is not a software problem.
3. Reset the power manager by pressing the key combination Control-Option-Shift-power. 
 
Warning: Make sure you do not hold down the fn key when resetting the 
power manager.
 
4. Check trackpad cable and connection to the logic board (see separate Keyboard and Top Case replacement instructions for location under top case).
5. Replace top case.
6. Replace logic board.
 
The cursor intermittently does not move or moves erratically
 
Note:
 
 User must touch with the surface of only one  finger at a time and point directly down 
on the trackpad surface.
1. Clean trackpad surface (with computer off, using a non-static-inducing material).
2. Completely shut down, then press the power button to start the computer.
3. Reset the power manager by pressing the key combination Control-Option-Shift-
power. 
 
Warning: Make sure you do not hold down the fn key when resetting the 
power manager.
 
4. Try unit on battery power. If problem goes away, replace power adapter.
5. Place a Mac OS system CD in the optical disc drive, press the start button and hold down the C key. Check the cursor movement, to see if the problem is software.
6. Check trackpad cable and connection to the logic board (see separate Keyboard and  Top Case replacement instructions for location under top case).
7. Replace top case.
8. Replace logic board.
 
The microphone is not working
 
1. In the Sound preference pane select the Input tab. Make sure that the internal  microphone device is selected in the list.
2. In the Sound preference pane select the Input tab. Make sure that the input volume is  midrange or above.
3. In the Sound preference pane select the Output tab. Make sure the built-in audio  controller is selected. 
						

							
 

14 - 
 
PowerBook G4 (12-inch) Troubleshooting Symptom Charts
4. Create new Mac OS X user and log in as that user. (So that the customer does not 
question the new user, remove the user once disc is veri fied.)
5. Reset PRAM (Press the power button, then hold down the Option-Command-P-R  keys until you hear the startup chime at least one additional time after the initial 
startup chime).
6. Verify microphone cable connection to logic board.
7. Replace top case (which includes the microphone).
8. Replace logic board.
 
The latching mechanism that holds the display closed is not working
 
Note: 
 
As the display closes against the top case, a hook in the top of the display housing 
should be magnetically pulled down into a slot in the top case, and secured. When the 
latch button is pushed, the hook should release and retract into the display housing, 
allowing the display to open.
1. Verify hook operation by exercising the latch mechanism. 
2. If the hook does not operate properly, replace the display bezel.
3. If the latch or latch button does not operate properly, replace the bottom case  assembly. 
						

							
 

PowerBook G4 (12-inch) Troubleshooting - 
 
15
 
 Symptom Charts
 
Block Diagram: PowerBook G4 (12-inch DVI) 
						

							
 

© 2002 Apple Computer, Inc. All rights reserved.
 

 
 
 
Service SourceViews
 
PowerBook G4 (12-inch)
PowerBook G4 (12-inch DVI) 
						

							
 PowerBook G4 (12-inch) Views - 
 
1
 
  
Main Exploded View: PowerBook G4 (12-inch) 
Keyboard Kit
076-0982
Top Case
922-5652
Hard Drive Cable
922-5740
Modem
661-2632
Heatsink with Fan
922-5654
RJ11 Modem Board
922-5731
I/O Ports Shield
922-5820
Reed Switch Board
922-5656
Inner Frame
922-5657
DC-to-DC Board 922-5890
Top Bracket
922-5734
Shoulder Bracket
922-5745
Optical Drive Bezel
922-5819
Bottom Bracket
922-5733
Rear Panel with Speakers
922-5724
Bluetooth
922-5764
Subwoofer
922-5818
Not Shown, Memory:
128 MB SDRAM 661-2817
256 MB SDRAM 661-2818
512 MB SDRAM 661-2819
Hard Drive
40 GB 661-2793
60 GB 661-2794
Battery Connector Shield 922-5741
Logic Board 661-2788
Sleep Board 922-5659
Optical Drive Flex Cable 922-5732
DC-In Board Guide922-5655
Optical Drive
CD-RW/DVD-ROM 661-2800 SuperDrive 661-2814
AirPort Guide922-5744
Bottom Case 922-5651
Memory Door 922-5658
Battery
661-2787 
						

							
 2 -   
PowerBook G4 (12-inch) Views 
Display Exploded View: PowerBook G4 (12-inch) 
Antenna Cable
Assembly
922-5721
Right Hinge
with Bezel Brace 922-5711 Display Housing
922-5718
LVDS Cables
922-5720
Inverter Board
922-5719
Right Clutch Cap
922-5717
Clutch Cover
922-5715
LCD Panel
661-2791
Left Hinge
with Bezel Brace 922-5712
Display Bezel 922-5710
Left Clutch Cap 922-5716