My JCM 800 has performed flawlessly for a long time. Yesterday I went to play it, and I am getting no sound st sll. All cables (including guitar), power tubes, and preamp tubes are good, and brightly lit. I am not getting any noise through the speakers (no hiss). I checked the cab with a different head, and it's not the cab. I also tried plugging into the low input. I checked the fuse and it is fine as well. Any advice on where to start looking? It is a 50W JCM 800 Canadian version from 1984. Let me know if there are any questions that need to be answered that I have not described. Thanks for the help!!!