On a TV that 150 V runs the video output/s. It comes from a FBT winding,
through a fuseable ( typ 1-2 ohm ), A rectifier, then a filter cap ( typ 5 or 10 mfd). On TV's the cap is super high fail rate BUT lowering the voltage
gives a brighter pix. If they tapped the FBT primary you are just reading the unboosted B+
A scope would narrow it down in seconds.
73 Zeno
LFOD !