As was stated earlier, 771 error is caused by loss of satellite signal to your receiver. The confusion can arise when you are watching a two tuner system. The tuner you are watching is just fine, while the signal on the second tuner, which is probably looking at a different satellite or transponder, drops significantly. The receiver tells you it has lost the signal, and sometimes , it tells you which tuner it is affecting. There is not a good way to determine which tuner you are watching on your receiver, so the message may mean the other tuner is having a problem. I believe this was much more prevalent on the legacy systems, than on SWM systems. And the cable that go from the 6x8 multiswitch, do NOT go to any splitters, correct? The run directly from the 6x8 to the receivers. If any of those cables are split, (running to two different receivers) you can have intermittent problems since in the legacy system, the voltages from the receiver going up to the multiswitch, determine which satellite, transponder, and channel are selected.