Motorola ts907 low hv

[Yamamaya42]

Phase-locked loop controlled oscillator.

Keyed off the sync pulses of the incoming video signal, shaped and processed by the SYNC SEP & SYNC AMP and passed on to the VERT MULT & HORZ AFC respectively.

However both of these have the ability to free run w/o need of control input in a randomized mode.
But in your case, horizontal section is having a problem doing this, there could be any number of things causing it, a resistor or capacitor that does not sit well with the circuit, even if they test OK, the wrong types can upset things, as been mentioned , it's a tuned circuit using feedback including the yoke, and the FBT, it's very easy to make it unhappy. Especially with dual horizontal output tubes...