I have an old Sky dish on the side of my house that i feed into the bedroom TV.  It's been going fine for the past 4 years but over the past month I notice that there is digital noise in the form of  breakup bars on the screen every second of so.  I've check the wiring at both ends and it's OK.  Turned  of the STB for a day   to see it it is a thermal problem bit it's still there when powered on.
Would I be correct and assume that the LNB is on it's way out??
PS.  The dish hasn't moved .