Usually there is no risk from the transformer if connected to the tube, there is the HV rectifier in between the tube charge and XFMR so this is reverse biased when connected.
The HV on a large colour CRT is between 20kv & 30Kv.
I am sorry I did not pick up all the TTL low scan monitors I could before they all went to the Dump.
I've used a few of these in the past on Fanuc and Mutsubishi.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.