No sound on Dell Inspiron 630m (FC5)

I'm hoping someone can advise me how to get sound on my Dell Inspiron 630m laptop running FC5.

Using the Gnome sound config tool I get...
Vendor: Intel
Model: Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller
Module: snd-hda-intel
Default PCM device: STAC92xx Analog
The sound test outputs no sound.

I have searched the net and found some references to making sure the sound is not spuriously muted and other suggestions to install the latest alsa drivers. The volume levels all appear high and my system is fully 'yum updated' so I assume I am already running the latest drivers available.

$ lsmod | grep snd
snd_hda_intel          17233  1
snd_hda_codec         112065  1 snd_hda_intel
snd_seq_dummy           3781  0
snd_seq_oss            28993  0
snd_seq_midi_event      7105  1 snd_seq_oss
snd_seq                47153  5 snd_seq_dummy,snd_seq_oss,snd_seq_midi_event
snd_seq_device          8909  3 snd_seq_dummy,snd_seq_oss,snd_seq
snd_pcm_oss            45009  0
snd_mixer_oss          16449  1 snd_pcm_oss
snd_pcm                76869  3 snd_hda_intel,snd_hda_codec,snd_pcm_oss
snd_timer              22597  2 snd_seq,snd_pcm
snd                    50501  11 snd_hda_intel,snd_hda_codec,snd_seq_oss,snd_seq,snd_seq_device,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer
soundcore               9377  1 snd
snd_page_alloc         10441  2 snd_hda_intel,snd_pcm

To my untrained eye this looks OK.

Is there a known problem with sound on this laptop? I've found no web references that would indicate this.

Hope can I debug this further?
Your advice is much appreciated.

Richard.
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Richard Conway (richard@xxxxxxxxxxxxx)