[Yamamaya42]

Again, I'm not saying this is the same problem that your set has, but it's the one that MINE had, I too had a weird problem with the 135v rail being very low, it did not cause me any sync problems, but did cause tuning and contrast problems, the fault was eventually tracked to the WHITE HI-Q 1500pf caps on the IF power rail, the ones with the red ends, NOT the brown tube like ones, on mine, many of those red ends seemed to have degraded and gotten gummy, some of the caps looked like they leaked something even, after replacing only those white HI-Q 1500pf caps, my 135v rail then came up to nominal range, and things worked much better, not perfectly as my tuner is a bit weak, but much better then when I started.

Again, not saying that this is the problem you are having, but worth looking at.