None of the major improvements scheduled to take place at Churchill Downs will happen until December, but one of the most noticeable differences will be in place in time for the track's fall meet. Churchill plans to replace its current paddock video screen this week. In the past, reading the screen's information, which included current odds, closed-circuit coverage, and the races themselves, was difficult.The track's vice president of operations, David Sweazy, said many fans had requested an upgrade, but until now, a better option didn't seem to exist. Now Churchill feels it has found the right replacement--a 15 foot by 11 1/2 foot by 12 foot six inch Translux board. It is larger than the previous Sony screen, and should provide sharper pictures with a feature that will self-adjust brightness according to outdoor conditions. The fall meet at Churchill Downs opens Oct. 28 and runs through Nov. 24.