The left channel on my crack just went out. I have been testing new input tubes, so I have a feeling that is where the problem is. What is odd is that when I plug my headphone in half way, I get sound from both channels. The LCD's still both light up. This weekend I am going to go over all my solder joints again, and I am sure that is where the problem lies. I thought I would ask in case someone had this issue before and it ended up being something else.