Hello Zen,
last night i got a little more time and i tried this tip that someone wrote below, to put a ferrite ring on the base of the transistor when testing.
I use a Chinese component tester, the same as in your video.
There were no consecutive results on the basis of which anything could be concluded.
But when I use the external crocodile clips that I mounted on that tester, and when I connect E-C with my fingers,
the phantom leakage diode disappears.
This has worked for me enough times that it could be said to be a general behavior.
I don't have enough data, but what I notice is that all the transistors I have, and they are specified for high frequencies, behave like this.
I opened another 475 on which I started work, this time I was particularly interested in these transistors.
I noticed that they have different colored dots on the back, in some places in the oscilloscope where they are next to each other.
I checked them and interestingly, in three places I noticed that the HFE is identical to the color code, that is, it matches exactly the same hfe number.
I don't believe it's a coincidence, this really had to be chosen that way during production.
Most often, the yellow/purple combination of markings prevails, there are some that also have three dots, whatever they mean.
greeting
