I just got this receiver a couple days ago. No output from left channel. I swapped the preout/main in connections and the problem followed, so maybe the main is working. I have removed the controls? board from the faceplate and am preparing to remove and clean the volume pot. Even the working channel is scratchy so needs doing. I have read posts on cleaning the alps pots so have some idea how to proceed there. Any suggestions on likely culprits in the preamp would be welcome. I am really looking forward to getting this puppy going, it is really nice, the meters even seem to work.