Try setting up the dish on a satellite with Ku LNB and arms as they were, then put in temporary new arms and work on them till you get the signal right on the satellite you were on--that way you know the LNB is at the same spot as the old. I did something like that to get the Ku band at max with C/Ku band LNB (but it might also be why I lost some of the signals I was getting on C band--the max signal on C band is not always the best for Ku from what I can tell though that might be due to where I have dish rather than intrinsic issue).