Well, I went and did something that upset my amp. I was working on 2 amps at the same time. Went over to look at the rectifier tubes in my Mesa, took one out, got distracted then turned it on because I was going to put 2 Jan Phillips in for rectifiers but wanted to hear it once again with the Mesa tubes. Amp was on for a minute when I realized one of the rec tubes was not in it. Now it won't make music. Turns on, but no sounds. Any advice on what to troubleshoot? Thanks.