Based on the latest AJ list (but after I re-ordered some channels using MediaBox Studio Editor), I noticed the following channels had sound but no video:-

Heart, Planet pop, capital TV, clubland TV, baby TV, Nick Jr, Nicktoons and Nicklodeon +1

After a while of checking the channels I noticed these channels were down as MP4 (instead of MPG) and the transponder was down as S2 so I changed the transmission video to MPG but this never worked so I changed the transponder (all these channels are broadcast from one of two satellites) from dvb-S2 to dvb-S stanard.

This worked for me.

I don't know if this problem was present in AJ's original list (ie untouched) or because I re-ordered it and it may have got corrupt or something) when I used MediaBox Studio Editor.

I had this problem in both F5S and S10.