Ibook G4 Internal Speakers not working

my ibook g4 internal speakers are not working nor my headphone jack. I have usb speakers and they work. i have checked the system preferences output, mute and any other obvious reasons. I have also troubleshooted myself with reseting nvram-reset all and tried to reset the pram but did not hear anything. Also i've tried using garage band and creating a new account on the computer. PLEASE help. thanks