CRT Question - Old Calculator

Hello, all, I am in the midst of restoration of a very old (1964-ish) electronic calculator called the Wyle Laboratories Scientific Model WS-02. This is a transistorized electronic calculator that uses a magnetostrictive delay line for register storage, and a CRT display for showing the working registers and memory registers. The CRT is driven by sine/cosine signals to generate fully-formed stroke-style digits. I don't know if it's magnetically or electrostatically deflected...is there any easy way to tell? There are some coils around the neck of the CRT, but they are not as large as I'm used to seeing on CRT's of this size (8").

The question that I have is that I want to test out the power supply circuitry to make sure that all is healthy there. I have removed the logic module from the machine (the logic module contains all of the calculating and display generation logic, and comes out as a unit). I have also disconnected the video driver board. The connector at the back end of the CRT is unplugged. There are a couple of wires that go to the coils around the neck of the CRT, but they are connected to the video driver board, which is disconnected. The high voltage connector from the flyback is still connected to the CRT. At this point, I've traced out the main logic voltages (+12, -12) and a -30V supply that are used throughout the machine. I want to slowly bring up the power supply with a Variac and monitor the voltages and ripple to see if the power supply is still healthy. However, I'm concerned about having the high voltage supply connected to the CRT without any other connections on it? Could the high voltage supply be hurt because it may be missing signals it needs to oscillate properly? Could this hurt the CRT? I don't know enough about the way this kind of stuff works to know if I could cause any problems, either with the CRT, or the high voltage supply.