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Archive for July 16th, 2009

PowerBook G4 17 – Backlight Cuts Out

July 16th, 2009 No comments
PowerBook G4 Backlight Cable

PowerBook G4 17" Backlight Cable and Hinge

Machine: PowerBook G4 17″

Symptom: When the screen is moved, the backlight to the screen flickers or cuts out.

Likely Cause: Damaged backlight cable.

The backlight cable provides the power to the LCD’s backlight.

The cable runs from the logic board (1) through the left side of the hinge (2) and into the inverter board which in turns connects to the LCD.

The backlight cable runs through the hinge with the bluetooth and airport cable.

Over time, the hinge can get loose and the backlight cable can become worn causing the connection to cut in and out.

To solve the problem, the hinge is tightened (or replaced depending on damage) and a new cable is installed (with more protection.)

Since most customers initially believe the issue is with the screen or logic board, they’re happy to learn it’s only a cable. This repair itself is quite involved but the end results are perfect.

MyService Free Diagnostic ] Suspect your PowerBook has this issue? We can help.

Apple Hardware Test

July 16th, 2009 No comments
Hold down the "D" Key on boot.

Hold down the "D" Key on boot.

The Apple Hardware Test (AHT) is a diagnostic program that tests the basic functionality of your Mac’s hardware.

All MacBook Airs and MacBook Pros (2008 later) have the AHT loaded on the hard drive, other Macs will list the AHT version on one of their restore disks.

While the AHT is not always accurate in determining a hardware issue, it’s a great first troubleshooting step.

The AHT tests basic functionality like the GPU, processor, HD and RAM and may provides error code(s) that can be useful in determining an issue.

To run the AHT, disconnect any peripherals like printers or keyboards. Connect your Mac to power and either:

Insert the restore disk that contains the AHT and hold down the “d” key on boot.


If you have a late model MacBookPro or Air, you may just need to hold down the “d” key on boot.

Note: The AHT can take up to an hour to run.