I just tried turning on the amp and nothing happened. The LED light on the power switch did not light up. I am sure the source of power is working because I have other items plugged into the power strip. The preamp uses a 12AU7 tube. Is this the likely source or could it be something as simple as a fuse? In the "old days" blown fuses were often the source of the problem, but I don't know about these new amps. I also noticed the amp is completely enclosed in the back and it looks like it would be a effort to get the panel off. I've been using a Tascam bass trainer, but knocked it off the table one too many times and it quit working, so I have been using the Ampeg amp for the last 3 months. Since I play often during the day, I may average turning it on 5-6 times per day. Is this good for the amp? Thanks in advance for your help.