PowerBook G4 (17-inch) Troubleshooting - 25
Hardware Symptom Charts
Display Display latch not working
Note: When the display is being closed, hooks in the top of the display housing should be
magnetically pulled down to the latch. When the latch button is pushed, the hook should
release and retract into the display housing.
1. Verify hook operation by using a small low-power magnet to exercise the latch
mechanism. Make sure hooks are not bent.
2. If the hook does not operate properly, replace the display panel assembly.
3. If the latch or latch button does not operate properly, replace the top case assembly.
When displaying a single color over the screen area, the LCD panel shows one
or more pixels that are not properly lit
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. Knowledge Base article 112125: Service
Diagnostics Matrix, has the LCD Tester Diagnostic Utility that will generate these
patterns on the screen.
2. Using a jeweler’s loupe, pocket microscope, or other magnifying device, identify and
count each pixel anomaly:
• Bright subpixel anomaly = subpixel that is always on
• Dark subpixel anomaly = subpixel that is always off
3. The number of acceptable pixel anomalies for this system is:
Acceptable Number of Subpixel Anomalies
4. If the number of subpixel anomalies exceeds the acceptable number listed in the
above chart, replace the display panel assembly.
Replace
Bright Up to 4
Dark Up to 6
Combination Up to 8
Bright 5 or more
Dark 7 or more
Combination 9 or more