Check and double check and then check again all connections and layout before you power it up. Power it up with a variac.
Safety from when I used service CRTs many years ago.
- When prodding around checking voltage, ensure your meter probe handles are designed for high voltage.ALWAYS keep one hand behind your back.
- After you’ve powered it down AND let it discharge, ALWAYS keep one hand behind your back. Never let yourself become part of the circuit.
- Discharge the power supply caps with a high wattage resistor. Measure B+ with meter to ensure it is discharged.
- Ground your equipment
- Tell your wife/friend what you are doing and to keep an eye out and do not work alone.
- Have a safety procedure e.g. check and double check power is off and supply is discharged before working on unit etc.