Problem with imac G4

[matw79]

Hi my brother has a imac G4 and is having problems with his sound. no sound comes out of the speakers but sounds comes through the headphones. He has tried to reset the pram but nothing, and in system pref under sound in output is not showing external speakers just the headphones.
My Speakers are: harman kardon M6531 apple pro speakers
Thanks for your help

[matw79]

Hi
This post can be closed now my brother has sorted out the problem he reset the PMU button on his computer he has the sound coming through the speakers now.