When using a PIM tester out in the field, make sure that you do not have your unit plugged into your vehicle as you turn the vehicle on.? Doing this can damage the 5V internal power supply within your unit.? To also help limit the risk of damage to the internal electronics of your PIM tester, always use the power adapter that came with the unit from the manufacturer.? The OEM power adapter is specifically made for your PIM unit and has safety measures built in to choke excess voltage and current that may damage your tester.
The best way to power your PIM unit on-site is to first turn the vehicle on, then plug in your OEM power adapter into your PIM unit, followed by plugging the power adapter into the vehicle.? This ensures that your unit will continue to work properly and help extend the life of the unit.