I have plug this device in and dose power on. Have not done a full test on this device “lack of knowledge”. However the power cord has seen better days and needs to be replaced it’s in very poor condition and brittle crumbling apart The Vintage Triplet 1503 Multipurpose Tube Tester is a unique tool designed to test radio and TV tubes for power. With its brand being Triplet, this product is likely to have a classic and reliable design that is perfect for vintage electronics enthusiasts. This multipurpose tube tester is an essential accessory for those looking to restore or maintain the functionality of old audio and video equipment.