My friend, there is no any rust , I am an engineer...I have written that during daytime signal is fine , only at dedicated time this happens, I also mentioned that I have multiswitch , that supply 18v and 14v for H and V . Adaptors do not supply power to LNB , activ multiswitch supplies power to LNB , more over I mentioned that it happens only at evening time till morning, how is possible to have faulty power adapter working normal day and badly nigh time ?) Come on .)Check rusting in ur connectors including those fixed with jointer.... If this does not resolve issue then check LNB and Adaptor as fault in either will result in intermittent signal issues on channels
Adaptor issue causes problem as required power is not supplied constantly to the LNB while incase of other 2 cases Rusting in Connector or issue in Switches/ Circuit of LNB causes disruption in processing/supply of signal