Strong signal on 3 transponders, no signal on others

II just ordered HD service and replaced standard dish with Slimline-3.  I'm getting a good signal (95-97%) on transponders 28,30, and 32 on the satellite at 101 deg. but 0% on the other 29.  For the satellite at 72.5 deg., I'm getting a signal on transponders 1, 3, 4, 5, and 6 at 67-69%.  All others are also 0.  I've spend hours adjusting tilt, pitch, azimuth, etc. but can't get a better signal.  Is it possible the LNB is defective?  Is there another way to diagnose the issue?