powerbook g4 connected to stereo but no sound

[jrwilkins]

audio into g4
connection from stereo phone to audio in on g4
prefs set to audio in and input level indicate sound in
volume is turned up
but no sound from g4 speakers
these work, and no phones connected

audio out to stereo
Connection from g4 phones to stereo aux in
prefs set for internal speakers built in audio
but no sound from stereo speakers