Scrambled Picture (Vertical Sync) Mit...

I have a Mitsubishi VS683R Rear Projection which appears to have a scrambled picture or sync problem. I have heard in the past that these sets had problems with PIP modules, However this set does not have a seperate PIP PCB. There is a very large board with a tuner, some audio circuits and IF circuits.Also on the tuner board is what appears to be a PIP circuit (not a module).There is no sync controls inside on the deflection board. Is this a bad tuner is that a PIP circuit on that large PCB with the tuner?