Since this sticky thread is the "be all guide to CRTs," I would like to ask a very common and related question regarding defective or potentially defective CRTs. People who come to this thread are most likely looking for more than just historical tidbits on vintage Mac CRTs. Indeed many coming here are most likely looking for detailed information on how to test a potentially defective CRT and then how to replace it with something suitable. I therefore would like to pose this question...

If a vintage Mac owner has been fiddling around inside their Mac, then bumped something which caused their CRT to flake out (e.g., displaying little more than a white glow at all times), is it safe to remove that CRT and test it in a known good Mac of the same type? And what about CRTs that experienced a heater to cathode short? Would placing potentially defective CRTs and a known good Mac put that known good Mac (analog board and/or digital board) at risk of being damaged by that that CRT?

If the known good Mac is at risk of potentially being damaged by bad CRT during testing, then how does one appropriately test a potentially bad vintage Mac CRT?

Thank you.