Apple M9628LL Service Guide - Page 154

Display, When displaying a single color over the screen area, the LCD panel shows one

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At startup, a dialog box comes up stating "kernel panic" in Mac OS X 1. If a RAM card is installed in the expansion slot, remove it and restart. • If symptom repeats, replace logic board. • If symptom does not repeat, replace RAM card with known-good RAM card and restart. 2. If no RAM card is installed, replace logic board. Related article: 111772: iBook (Dual USB): Beeps Are Heard at Startup (one to four beeps) Display No display, or dim display, but computer appears to operate correctly 1. Remove any connected peripherals. 2. Try known-good power outlet, power adapter and power cord. 3. Press F2 (with the fn key pressed and not pressed) to increase the screen brightness setting. 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. Verify backlight cable and LVDS cable connections are seated properly and that the cables are not damaged (refer to display assembly replacement instructions). 6. Replace display assembly. 7. 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 significantly increase the retail price for products using LCD displays. These factors apply to all manufacturers using LCD 8 - iBook G4 (14.1 LCD) Troubleshooting Symptom Charts

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8 -
iBook G4 (14.1 LCD) Troubleshooting
Symptom Charts
At startup, a dialog box comes up stating “kernel panic” in Mac OS X
1.
If a RAM card is installed in the expansion slot, remove it and restart.
•
If symptom repeats, replace logic board.
•
If symptom does not repeat, replace RAM card with known-good RAM card and
restart.
2.
If no RAM card is installed, replace logic board.
Related article:
111772: iBook (Dual USB): Beeps Are Heard at Startup (one to four beeps)
Display
No display, or dim display, but computer appears to operate correctly
1.
Remove any connected peripherals.
2.
Try known-good power outlet, power adapter and power cord.
3.
Press F2 (with the fn key pressed and not pressed) to increase the screen brightness
setting.
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.
Verify backlight cable and LVDS cable connections are seated properly and that the
cables are not damaged (refer to display assembly replacement instructions).
6.
Replace display assembly.
7.
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 significantly increase the retail
price for products using LCD displays. These factors apply to all manufacturers using LCD