The "knobs" are on the flyback. Look for the suction cup on the side of the tube, follow that back to the circuit board and you will see a big black component. The pots may be on that. The pots should be labeled Screen and Focus. Just adjust the Screen pot. DO NOT touch the bottom of the circuit board and you should also use a plastic tool to turn the knob if the set is on. I would NOT use a metal blade if it is on. The flyback is the component that steps up the voltage to the screen, on color sets it is KV, so it will kill you if you touch something you should not. always use one hand in the circuit at a time, if you want to play it safe. turn it off, unplug it, just turn the pot a hair to the right and THEN turn it back on. i just turned mine a hair and tested it before putting it back together. So far, so good.

I have an 8 year old 19" Sony Trinitron. A few weeks ago it started blinking when I would turn it onthen stop when warmed up. Now it is blinking continually. I figure the tube is going. I googled "my tv picture is blinking" and came upon this. Thanks. I was figuring out how I could manage to take off the back,but then I read a post mentioning the brightness knob.. I adjusted the brightness to darker, on my menu. The blinking stopped for a few minutes! It started again, but only once every couple of minutes. I know it probably will break soon, but at least it isn't constantly blinking, and it's just a little dark. Thank you all. Happy Easter 2008! Ree!