I just pulled out my SVT-II Pro to play with. It hasn't been biased in I don't know how long. I figured going through the bias procedure in the manual was a good idea since it wasn't correct when I turned it on. I'm starting to wonder if one of the tubes is bad. It sounds totally fine, and it seems to bias correctly, but one of the middle 6550's isn't lit up or warm at all. Every other tube in this thing is glowing a nice healthy orange. It is my understanding (albeit, small) that the bias lights would not be happy green if one of the tubes was bad. The tube in question looks a little toasted compared to the others. The "mirror paint" in the top of the tube is pretty much gone, and there are some grey spots on the glass on the sides of the tube. Any thoughts? I'm not against taking it to a tech, but if I could do a little troubleshooting first that would be great.