Most G-2 run off a divider. First the focus apx 6KV is dropped by high
ohm resistors off the HV. then the low side of the focus is divided out
to put the G-2 in range. Typ G-2 is 400 +- vdc.
Alex mentioned A.K.B. ( auto kine bias) & yes most Sony used it.
They also made it so the video would be cut off if the jug was weak.
I asked Sony FS tech about that & he said sony did NOT want a set with a bad pix so you get none !
Symptom usually no raster then blinking raster as it warms up.
On AKB sets if you shrink the V size a little you will see 3 color stripes
at the top. Thats the guns firing to collect current data.
A few more tricks if need be.
Anyhows I am going to cool off. Spent the morn at Hampton beach N.H.
and wow was it hot
Zeno