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MacBook (13-inch) Troubleshooting — Symptom Charts 332
it is quite possible to have a low number of faulty transistors on an LCD. Therefore, a certain
number of subpixel anomalies are considered acceptable. Rejecting all but perfect LCD panels
would signicantly increase the retail price for products using LCD displays. These factors apply
to all manufacturers using LCD technology—not just Apple products.
No display, or dim display, but computer appears to operate
correctly (if dim, display shows startup icon and/or desktop)
Remove any connected peripherals.
Try known-good power outlet, power adapter and power cord.
Press F2 (with the fn key pressed and not pressed) to increase the screen brightness setting.
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.
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.
Warning: Resetting the power manager means you will also need to reset the date and time
(using the Date & Time control panel).
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).
Connect an external display, and check for video on external display.
If video is ne on external display, troubleshoot LCD panel and verify cable connections to
inverter and LCD.
If video symptom is same on external display, replace logic board.
Verify LCD panel cable and LVDS cable connections are seated properly and that the cables
are not damaged.
Replace LCD panel.
Verify cable connections and check cables around the hinges for damage.
Replace logic board.
Distorted sound from speaker(s)
Verify sound is correct with external speakers/headphones. If sound is correct, replace top
case.
Verify speaker cables are inserted correctly, and check cables for damage.
Check balance in System Preferences: Sound: Output.
Compare same sound with two dierent units to make sure that sound is actually distorted.
In System Preferences, open Sound, select Output, and set the slider bar to either the
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