I had a thread about my CBS-Columbia set a while ago. I did get that problem taken care of . I was still left with a small issue, The left side of the screen was a little brighter than the right. I rechecked every tube, cap, resistor and adjustment in the horiz. Everything was good. I got bored yesterday and took out the 6SN7 and the 12CU6 and put in different ones. Of course both were in the Horiz. and now the problem is gone. The tubes I took out and the ones I put in tested pretty much the same. Can anyone explain this?