Looks more like the horizontal hold is off. I have nothing on this
set. The 3 holes are probably vert height, vert lin & vert hold.
Be VERY careful trying to adjust them. The tiny pots break easily !!!
Also use an insulated screwdriver, not for risk of shock but
risk of shorting something.
Maybe someone is familiar with this set, I have been in the bowels
of tens of thousands of sets but never this one.
Good luck
73 Zeno