Remember that the 621-2 has a universal KU LNB so it has a 22Khz switch in the KU LNB in addition to the
DiSEqC switch that is in the
C band section.
If the 22Khz switch uses the same switching system as the switch in the c band side, then it will have the same weaknesses.
I have never had the opportunity to take apart a 621-2 so I am assuming that the universal LNB uses two distinct RF amp paths, with two distinct LO’s and two distinct mixers, with a 22Khz switch that selects between the two outputs.
It may use the 22khz two switch between the two local oscillators feeding the same mixer, and RF path. If that is the case, then I don’t really have any idea of the possible failure modes.
