I am having trouble receiving fta video or audio. I have a c, ku, colarotor with a 4dtv gi-900. I can receive c-span on c3-7. The pbs nebraska channels on t4 601 quit. I did the 2 splitter set up and the 4x1 diseqc to a Sonic view 360. When scanning the sonicview, failure appears on all the satellites. The splitters are voltage pass through on both sides. The setting for the diseqc switch is a ?. The dish is a 7.5ft. orbitron. Help