[Trevor]

while I was in the trade I was called to a faulty Rotel tuner on opening it up i could see that the input socket was corroded on checking the installation I noted that the coax feeder cable when opened up was full of water ! My conclusion an open connection box at the arial end had allowed rain water in .This along with the height difference created enough pressure for the rain water to enter the tuner and create the corrosion
Trev