While the OP may no longer have this issue, I'll comment on anyone else that may come across this.
In addition to the suggestion of replacing the ICs above by Leadtech, the resistors also should be changed at the same time. Quite often, even if a single IC or both are replaced and the resistors are not, the issue will re-appear. There are a few locations selling a kit in the $50 range, so the difference for the additional resistors is minimal.
As for the sound issues, several owners of this and other Hitachi RPTVs in this line have had issues with their sound boards, which seem to be largely a defective product. Even replacement of these have resulted in the problem re-occurring at a later time. I would suggest using an external receiver and speakers as it may not be worth the time and money to repair this problem. -TD
Replace the convergence ICs. In this set the power resistors in the convergence circuit tend to change value, if not burn up. An alignment afterwards would be next. The audio may be as simple as the speakers turned off. The first thing to check would be the voltages to the output IC. If audio comes out of the audio out on the back of the set, you may use an amplifier for sound. Good Luck
Usually answered in minutes!