Sanyo CRT TV screen flashing on and off?

I have a 31" Sanyo DS31580. Several years ago the picture started flashing on and off rapidly accompanied by noise through the audio system. I replaced the flyback with a new one, but no improvement. Spring came, the farm required my attention and that was the end of it until the other day. I was doing spring cleaning and figured I either needed to make another effort to fix it or junk it.

I'm well experienced with electrical systems but I'm pretty weak with electronics. I know just enough to be a menace to society. I originally suspected a bad capacitor, but without a schematic searching for the culprit was hit and miss. I now doubt my earlier suspicions. I fired it up tonight and here's the symptoms. At first the pictures flashes on and off approximately 3 times per second. As it runs, the flashing gradually slows down. After approximately 90 minutes, the picture stays on for around 8-9 seconds, then the screen goes gray for approximately 4-5 seconds, but not without some squiggly lines and other antics. When the picture goes off, the audio makes a sound reminiscent of a kid making a motorcycle sound as they shift gears. The picture then suddenly comes back on, but with a few seconds of degraded audio.

I'd appreciate any help from people smarter in electronics than I. I'd like to get it going because I know my 27 year old RCA console TV isn't going to last forever.