no sound on ibook g3, too

[Norbert Lange-Schäfer <bopa-mema@t-online.de>]

Hi,
I'm running lenny with kernel 2.6.21-2 on my Dual-USB-ibook (500 MHz).
reading Bob Lounsbury 2007-08-03 I thought to give it a try to get sound
working.
so far:
alsaconf did find snd-powermac card, but 
lsmod |grep snd
showed no module loaded. Alsamixer "failed for default"
after a
[~]#> modprobe -v snd-powermac
[~]#> lsmod |grep snd
snd_powermac           48160  0
snd_aoa_i2sbus         24356  0
snd_pcm_oss            52096  0
snd_mixer_oss          20384  1 snd_pcm_oss
snd_pcm                92004  3 snd_powermac,snd_aoa_i2sbus,snd_pcm_oss
snd_timer              25828  1 snd_pcm
snd_page_alloc         11208  1 snd_pcm
snd                    67476  6 
snd_powermac,snd_aoa_i2sbus,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer
soundcore               8900  1 snd
snd_aoa_soundbus        7908  1 snd_aoa_i2sbus

alsamixer could be opend, card: PowerMac Tumbler. Master etc worked, but the
PC Speaker stayed on [00].
Added snd-powermac to /etc/modules.On reboot flashed 
Setting up ALSA...done
Still no change in alsamixer.
Funny: If I plug in headphones, the settings changed from [MM] into [00] and
PCSpeaker from [00] to [MM]. But both settings could not set.
Funny 2: USB-Headphone loads some more modules, but alsamixer is unchanged

Where to go from here?
Thanks for any suggestions!
Norbert