Neon C1997F - odd sound

[Turnip]

Hi folks,

Have one of these where DVB is perfect but all other inputs including DVD,  sound is very overloaded - audio can be adjusted but distortion is incredible.

Thought to try 'Reset All' - made no difference. Note options for 'Special reset' and 'Shipping mode' in service menu but thought to ask advice B4 giving them a try.

Any thoughts ? - Thanks - Chris.