Problem solved,
Followed instructions at
http://ubuntuforums.org/archive/index.php/t-969611.html, in particular adding:
options snd-hda-intel probe_mask=1
to /etc/modprobe.d/alsa-base
I also removed pulseaudio as explained at
http://fedorasolved.org/Members/fenr...nd-workarounds, but not entirely sure it was necessary as I removed it before I made the changes to etc/modprobe.d/alsa-base.
Vince