I have a AVR300 with a DVD player connected via digital optical and a Freeview box (old without digital output) connected via analogue connection with direct selected. When I switch from watching a DVD to watching the Freeview box (Sat) I get no sound. I have to switch to another source then back to Freeview (Sat) to get any sound. Is this a known fault ? Can it be fixed with a software update ? The software version of my AVR300 is 2.90, DSP 1.12.