[old_tv_nut]

As Timmy says, describe the symptoms more completely please. Can you measure some voltages in the horizontal oscillator section? Do you have any raster at all? Even better, do you have a scope to look at some of the waveforms? Partial operation may be harder to diagnose than full failure.

As far as the way it's supposed to work, development of high voltage is not related to vertical. It is generated by the horizontal retrace pulse acting through the flyback transformer. (In some sets, there is a "boost voltage" of a few hundred volts generated by the horizontal sweep that may supply the vertical sweep circuit, but that doesn't appear to be the case in this set.)