mitsubishi big screen

That panel is for convergence - it controls the alignment of the image from the three picture tubes. If the TV does not have an external vertical hold control then it is likely that some componentent(s) are faulty and it needs service. If you start turning internal controls without knowing the correct procedures you may make the TV much worse and make any repair much more expensive, because once the defective components are identified and replaced all the controls will have to be correctly readjusted. That process can cost you one to two hours of extra labor.

Don't mess with those knobs, you'll never get the convergence back right without a service manual and even then it can be a really fiddly and frustrating process.

Modern TVs don't have a vertical hold adjustment, if there's no vertical lock, something is faulty in the circuit and you can't adjust it out.

There are probably quite a few leaky electrolytic capacitors in the video, sync, pip, and vertical circuits. The electolyte leaks on the circuit board and the board itself begins to conduct between traces. I'd have a technician well versed in Mitsubishi television repair look at the set. The repair won't be inexpensive. Chuck