Hitachi with blue out of focus or ghost imaging and have tried magic focus many times!
When you turn down the BLUE the TV will give a yellowish picture. That is why the TV has three CRT's, it needs all three colors. The problem most likely lies in the TV's Convergence Circuit. To repair yourself get KIT 10 @ 1-800-458-6053 or www. bdent.com. If not call a Factory Authorized Service Center and have them give a written estimate, avg cost $550.00.
good Luck, big IRISH.