Well before you start replacing cables, why not start by replacing the connectors.? Then try swapping over the 91 & 82 LNBF's.
You do not say what kind of switch you have, this could be the problem, if you have an SW44, check all the connections at the Power Inserter.
You do not say what kind of switch you have, this could be the problem, if you have an SW44, check all the connections at the Power Inserter.