lost sound

Apologies if this is off-topic but I just need a bit of help.

I have lost the sound on the onboard soundcard in my Asus vivobook.

It was working fine and then suddenly not.

I have checked everything I can think of:

"aplay -l" shows the card and all of it's devices.

"aplay audio.wav" plays the wav file but it is barely audible the amp 
and speakers up full.

ffplay, mplayer and qsynth all give similar results.

The MATE sound app, alsamixer etc all show volume at max.

There are audible clicks from the speaker when aplay etc connect and 
disconnect from the card.

pipewire and pipewire-pulse (sockets and services) are both running 
(fedora has ditched pulseaudio).

rebooting and reinstalling packages did not resolve.

any ideas about waht to look at?

TIA,

Chuck.