No sound. Display doesn't change when vol knob turned. All controls work, except Volume

[ziz]

Hi guys!

Today my stereo decided to stop working. It's been fine, until today.

The problem:

• display works
• radio scan & auto-tunes
• tape runs
• all other buttons work fine
• but I have NO SOUND
• volume button does nothing when I turn the knob the volume numbers don't appear on the display (can still press to turn on/off)
• the volume buttons on the steering wheel do nothing either
• BUT when I press the AST button I can hear a beep from the Speakers - makes me think the amp is still working
• audio control knob (balance, fade, EQ) seems to work i.e. display changes and values change when I twist/press knob

As I've got display, audio controls work, tuner tunes, can hear a beep from Speakers when AST button pressed makes me think the amp is still working and rest of stereo is also working. But i'm confused as to why volume knobs/buttons appear to do nothing and display does not change to show volume numbers changing when I turn volume knob or press buttons on steering wheel.

Surely it can't be some kind of short from a lose connection on the Speakers, otherwise i'd not hear a beep from the AST?!

Makes me think there's some kind of issue with the stereo itself

Any help would be appreciated!

Cheers

[ziz]

Btw it's a 2005 Avensis Tourer I've got!