"Frank" wrote in message
...
1. If you hear a 'boom' at the power up state, it's probably a VDR
(Voltage Dependent Resistor) normalize the magnetic field in the CRT. (The
cable that goes around the tube).

It's the degaussing coils causing a vibration at line frequency. The
thermistor in the degaussing circuit (not VDR) makes no noise.

Dave