Your post has been moved to the Hitachi forum to maintain forum organization and to make information easier to find.
You will need to go into the service level convergence mode to attempt to adjust it. If it is not adjustable, you may need repair to the set. You should get service manual which will have the procedures for entering the service mode and will detail the adjustments. There is also a general document from Hitachi on DCAM (convergence mode) adjustments that will be useful if you can find it. There is a sticky in the DIY repairs forum with links to sites with service manuals. There are also sources for manuals in the vendors database available at the top of all forum pages. You should, however, be able to find a free copy for this set.