It is likely a capacitor that went bad. Often the electrolyte in old capacitors dries out. C811 doesn't tell you what the value of the capacitor is. It is only a reference to a part on a schematic drawing. The value can also usually be read of the side of the part. I would suggest you take the TV to an old fashioned TV repair shop or "friend of a friend who fixes TVs in his basement." I would stay away from large chain stores who in my experience charge a $75 diagnostic fee to tell you the item "can no longer be repaired."