Sound doesn't work in Edgy

[Jonathan Byrne]

Hi,

I'm getting no joy at all with sound in Edgy.

Case 1 is a fresh install onto empty disks, mobo is an ECS KN1 LIte with 
nforce chipset, onboard sound:

cat /proc/asound/modules
 0 snd_intel8x0


 aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: CK804 [NVidia CK804], device 0: Intel ICH [NVidia CK804]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 0: CK804 [NVidia CK804], device 2: Intel ICH - IEC958 [NVidia CK804 - 
IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

 asoundconf list
Names of available sound cards:
CK804

Checked volume levels in alsamixer, all are fine.
Sound system in KDE is set to autodetect. This looks like it ought to work, 
but there is no sound.

Case 2: upgrade from Dapper to Edgy on a Dell Optiplex SX280:

Output is the same as above, including same driver, but the device is an Intel 
ICH6.

Results are the same, no sound there either. It worked fine under Dapper.

I've googled various incidences of sound trouble under Edgy and none exactly 
fit this bill, and none of things people have done to resolve them have 
helped here. Everything looks like it should work and I'm out of 
troubleshooting ideas.

TIA for any advice,

Thanks,

Jonathan