Apple Powerbank G4 manual Distorted sound from speakers

7.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).

Warning: Resetting the PRAM will permanently remove a RAM disk, if present, and all of its contents. You will also need to reset the date and time (using the Date & Time system preference pane).

8.Verify that the speaker cable is connected properly to sound board.

9.Check speaker cable. Verify left and right cable connections.

10.Check with headphones or external speaker, if audio is heard, replace speaker assembly.

11.Replace sound board flex cable.

12.Replace sound board.

13.Replace the logic board.

Distorted sound from speakers

1.Verify sound is correct with external speakers/headphones. If sound is correct, check speaker wire and connections.

2.In Sound system preference pane, check balance.

3.Compare same sound with two different units to make sure that sound is actually distorted.

4.Check speaker wire. If damaged, replace speaker assembly.

5.Replace sound board.

6.Replace sound board flex cable.

7.Replace logic board.

34 - PowerBook G4 (17-inch) Troubleshooting Hardware Symptom Charts