A well-known, and common problem on these great amplifiers is the failing input selector switch. With age these switches are by now becoming problematic, dropping channels and switching inputs randomly. An often quick solution is to clean the original, but this does not remove the oxidation and the problem will re-occur.
Our solution is to completely remove the original switch and replace it with a very high quality, sealed unit. The contacts are gold/silver plated and very long lasting: no more channels cutting out!