A couple things in your symptoms (ie locking scrambled channels and the 11966 freq being out of range) suggest to me that you might not have the LO freq (lnbf type) set correctly, and/or it is not switching correctly.
Ie, I think your lnbf is a universal 9750/10600 LO , which on my receiver (different model) is listed as Universal 1. Make sure those two LO freqs show up in the LNBF settings for every satellite you try to tune.
Also, don't forget that when you have one of those
motorized systems, that there are 2 "dish elevation" angle settings, one on the motor, and one on the dish itself. Make sure you haven't reversed which is which. If you have these angles wrong, you won't be able to tune your due south sat, which is why, as others suggest, you should always start by getting that to work first before trying a sat further east or west.