Hi, had the box for a week, came all set up by someone local ( as i'm useless with this stuff) did a scan for channels as requested- all ok so far, but after wathching a channel for say 20 mins it tends to go off and the sound stutters. sometimes just reverts to black screen. if I reboot all comes back on for a while but same again after a while. Is this normal. running commando6. Ta, Dunx.