Precautions While Testing Capacitors
It is essential for your safety and to prevent damage to the device under test as well as your test equipment that large or high voltage capacitors be fully discharged before measurements are made. During the early days when i was still fresh in this electronic repair line, i’ve blown up few meters by the high voltage discharged from the Monitor filter capacitor. If you really want to safely discharge the big filter capacitor in a switch mode power supply, please don’t use a screw driver as it may destroy the circuit board, melt the tips of the screw driver and even the debris may fly into your eyes. Just use a 100 watt light bulb to place across the leads of the capacitor and the charge will be gone in less than couples of seconds. As for me i prefer using a 10 watt 2.2 k ohm resistor to do the job.