Does anyone have any info on this set? About 12 years old. Turn it on and it works fine except if you are watching a channel above 20. Set it for 68 when cold and it is fine. In about 30 minutes raster turns to heavy noise. Drop down to 67 and it will be fine for a minute or so, drop down another, etc, etc, until you get to 20 or lower as they remain fine.
Bruce