My 1100S has on a couple of occasions a week or so apart displayed this message - the TV screen goes blank, sound is lost and the message appears at the top of the screen in a white box for a few seconds, the TV then returns to normal for a few seconds, then the blank screen & message again. This cycle continues, and only power cycling the box returns it to normal. More than one channel is affected, but not all. There has been no change to the signal connections, nor is any required to return the box to normal operation. Is this likely to be a hardware fault?