Power Control — Know and control the state of both ac line voltage and dc power
supplies. Physically disconnect line cords and other power cables when you are not working on live equipment. Use a lockout on circuit breakers. Double-check visually and with a meter to be absolutely sure power has been removed.
Interlocks — Unless specifically instructed by the manufacturer’s procedures to do so, never bypass an interlock. This is rarely required except in troubleshooting and should only be done when absolutely necessary. Interlocks are there to protect you.
The One-Hand Rule — Keep one hand in your pocket while making any measurements on live equipment. The hand in your pocket removes a path for current to flow through you. It’s also a good idea to wear shoes with insulating soles and work on dry surfaces. Current can be lethal even at levels of a few mA don’t tempt the laws of physics.
Patience — Repairing an amplifier isn’t a race. Take your time. Don’t work on equipment when you’re tired or frustrated. Wait several minutes after turning the amplifier off to open the cabinet — capacitors can take several minutes to discharge through their bleeder resistors.
A Grounding Stick — Make the simple safety accessory and use it whenever you work on equipment in which hazardous voltages have been present. The ground wire should be heavy duty (#12 AWG or larger) due to the high peak currents (hundreds of amperes) present when discharging a capacitor or tripping a circuit breaker. When equipment is opened, touch the tip of the stick to every exposed component and connection that you might come in contact with. Assume nothing accidental shorts and component failures can put voltage in places it shouldn’t be.
The Buddy System and CPR — Use the buddy system when working around anyequipment that has the potential for causing serious injury. The buddy needn’t be aham, just anyone who will be nearby in case of trouble. Your buddy should know how to remove power and administer basic first aid or CPR.