This may sound like a daft question but, where does the dish bracket go on the motors arm?
Right at the bottom, half way or top?
I have fixed it as per the picture in the manual (just above the first hole).
The problem I have is when I tune it to Thor, it works well but tune back to sky it looses half the sky channels.
I have the dish and motor bracket angles set bang on, so the positioning on the arm is the only thing I can think of that might cause this problem.
Sorry to be a pain.