I went out to my music room to play through my old Marshall. I grabbed a guitar and a cable and plugged in and was swimming in glorious overdriven tube amp tones. I played for about an hour before I had to run some errands. I put away my toys and took care of my errands. An hour later I went back out to my music room to play through my old Marshall again. I grabbed a guitar and a cord and plugged in. I gave the amp a minute to warm up and took it off standby. I was met with a horrible noise! No, not my playing. It sounded like a red plating power tube. I quickly looked around the back of the amp to see which power tube was red plating but none were red so I shut off the amp quickly. What the heck? It must be a bad tube so I let the tubes cool and pulled all of the tubes and tested them on my Orange tube tester. All of the tubes tested good. I figured it must then be a bad ground inside the amp but before I pulled the chassis, I looked everything over very carefully. That's when I read two words and immediately knew I had made a mistake. I changed one thing and sixty seconds later I was again enjoying the sound of a sweet overdriven Marshall. What were the two words I read and what did I change? There is no prize except the honor of figuring out the answer to the puzzler. I'll give the answer in a week if no one figures it out before then. Btw, this actually happened to me.