This is a mystery(?????) {:-? . I have a feeling there's interference, or something else causing loss of signal. If it is TI or earth noise, setting the feeds F/D setting to a higher value MAY help in that department. Is there anything inline that may be problematic? Have you tried it with the receiver "at the dish"? How about the same freq on another satellite? 99°W has one that should scan in. (Horizontal, 7328 SR) I really doubt that there's a "lock" in the hardware that "won't allow tinkering".