Most of the audio component service vid's. are vague because if they showed or told everything, no one would use their services.
Those audio - radio etc YT videos pretty much just hobby people trying to appear like a trusted servicer.
"Backyard Mechanics" is what I call them.
Hey, I'm not against someone looking for income, or added benefits, but don't convince or deceive people that you're "the man" to come to, when you're really not
Hand them a screwdriver, a radio shack soldering iron, and a cheap Harbor Freight multimeter, and instantly they become someone to trust.
LOL!
They can even show their workbenches loaded with real test equipment, and use terminology for things just to sound "professional".
I can still see through the BS.
Again, it's just to gain their existance in the online world, perhaps with motives of making money from people who contact them for services.
The average viewer doesn't really know or understand about proper servicing.
Because these so-called Internet Techs are easy for Me to pick out.
I
know the difference between a Professional and a hobbyist.
Some, are clearly educated from DIY Internet "learning", which is not a reliable or qualifiied source giving them the knowledge
only learned though accredited classroom/institutional courses.
I've watched some of those videos, and just laughed, noting their mistakes and improper procedures - things I'd never waste my time on.
I didn't bust my azz going though the proper educational training for nothing.
AND, I've seen the results of these un-qualified internet junkies enough of times, when a customer brought something into my shop with horrendous and sloppy "repairing", due to those Online wanna-be techs.
Which cost the customer additional money and my labor time to correct.