Ok I just got sucked down this rabbit hole even though I was in the camp “I don’t need a tube tester”. Won on an offer a Hickok 600A in very good working condition per seller and pics. It was calibrated in 2022. Cost me $250 + tax shipped to my door. Only issue reported is a stuck settings scroll which is no big deal. A printed list will work just fine instead. Pretty nice testing unit feature wise at a price that can’t do much damage if I decide to resell. Certainly not a nice Amplitrex AT1000.