High Voltage Safety

The plate voltage used by high power vacuum tube amplifiers is the most dangerous hazard in the RF subsystem. Lethal potentials in excess of 4100 volts, with momentary current capability greater than 100 amps, are present in the amplifiers and their power supplies during operation.

Interlock switches are provided on the covers of power supply and amplifier decks to minimize the danger of electrocution; however, they should never be taken for granted.

All circuit breakers on the rear of the RF cabinet must be off and tagged, and cabinet power cords must be unplugged before opening any modules containing high-voltage circuitry. Allow at least five minutes for filter capacitors to discharge before removing any module covers for service.

Always assume that a circuit is "hot" until proven otherwise. Discharge high-voltage circuitry by shorting to ground and across terminals of floating power supplies before touching components. Do not rely on bleeder resistors to discharge capacitors. While they will eventually reduce voltages to safe levels, bleeder circuits have time constants as long as several minutes to limit heat dissipation during normal operation.