The training memo posted from Dish says that + - 5.0 LNB drift qualifies for a new LNB. When I called tech support about missing channels, even with good signals in Point Dish (and a GOOD Check Switch readout), I noted that my drift was about e -6.7 on 110 and 119.
I asked if I could get a free DPP Twin replacement - based on the + - 5 memo. The lady tech, who sounded pretty sharp during our rather long talk, said that the guidelines were not to talk about a replacement until the Drift became => +- 8.
They sent me a replacement 510 instead! Same problem. Good signal strengths, Check Switch Good, but still many missing channels.
I spent days testing, swapping coaxes, etc., and took over 30 pages of notes, before insisting to my dealer (a good friend) that he come by and replace the DPP Twin. I could have ordered one myself and installed it, but I wanted him to witness the difference that the new DPP Twin would probably make. For the record. I had no stomach for calling tech support and argue with them that it was 95% certain the DDP Twin was bad.
I paid my dealer to replace the DPP Twin (Dish 1000, DVR622/DVR510), and all my channels came back.
So much for guidelines and esoteric menu options - and Check Switch results that are wrong!
Oh, yes. During the 510 replacement, the replacement-receiver tech (8 on your touchpad) had me do a Check Switch (it was GOOD) and at the point where the screen showed "Authorizing Receiver," he bid me farewell. When I suggested he hang around until I had pictures to test, he said all would be okay, since my Check Switch showed ALL ALL ALL and GOOD. Wrong! Not okay.