Here are some of the waveforms I got with the picture locked.
Sync phase inverter (12SN7, pin 4)
IMG_0378.JPG
Horiz, AFC (6SN7, pin )
IMG_0379.JPG
Horiz, multivibrator (6SN7, pin 6)
IMG_0380.JPG
After I got these I tried to check the waveform on pin 1 of the oscillator tube.
When I connected the scope probe to that point the lock just disappeared completely.
Is that a clue?
Ignore the 2 dots in the pictures, its a reflection from the ceiling light.