In the dim and distant past, 50 years ago, my first part time holiday job was working in the local radio/TV/electrical/bicycle shop.
This was in the day when valves were the dominant active device for all aspects of the TV circuit.
It was quite common for the owner or renter, (rented TVs were quite a big business at the time) to advise us of his expert diagnosis of the fault....
"It is the picture valve"
"It is the sound valve"
"It is the brightness valve"
or in the case of frame collapse, "It is the height valve"
Happy days back in the Doncaster - Rotherham area of South Yorkshire.
JimB
I can echo that Jim.
It used to be a funny thing- as soon as someone learned that you were in electronics, they would say, Oh I have an old TV/Radio Gram/ Record player that you would like to have a look at. I even had one guy say that he had a load of TVs in his shed that I could fix- it would be good practice for you! If you met a brain surgeon, you would hardly ask him to do a bit of surgery to fix your headache, of a butcher to do a bit of butchering for you. But I got this all the time.
A large poor family lived across the road and the husband knocked on the door most distraught. The kids had knocked their TV off the table and it was wrecked- could I possibly have a look at it. I felt sorry for him so went over to his house to see the damage.
The TV had fallen on to a hard floor from about 3 feet. The cabinet was cracked, but as far as I could see the tube and electronics hadn't been damaged. So I carried the set home and, in the garage, opened it up. It was a dual standard model and the PCB had cracked under the slide switch running the whole length of PCB. I spent about three nights in the freezing cold fixing that damn set- what a job. I even glued the cabinet back together and you could hardly see the join. Anyway, that weekend I took the set back to the owner. He was overjoyed and said thanks a lot that will tide us over nicely for a couple of days until the new set we have ordered arrives!
In complete contrast, one of the chaps I knew had an upmarket flat, in the best part of town. Everything in the flat was upmarket and of course he had a Bang and Olufsen hi fi system that cost the absolute earth. We were chatting one day and he mentioned in passing that when he plugged his cassette recorder into his hifi the sound was very low and hissey. He didn't ask me to sort it and just thought that his amplifier inherently didn't have enough power and that was that. I said that I would have a look at it, but he said it would not be possible to do anything because it was just the way the amp was.
Anyway, the next day after a nice Gin and Tonic, I took the amp and cassette deck home. Sure enough when the cassette deck was plugged into the amp tape input the output was way down. I whipped the lid of the amp and you wouldn't believe it but there was a circuit diagram on the inside. Also the tape input had a 20:1 attenuator wired directly across the pins of the tape input DIN socket. I unsoldered one resistor and lo and behold the cassette recorder blasted at full volume.
When I went to see the owner a week later with the amp and deck, he refused to believe that I had solved the problem. He was astounded when the cassette player came through loud and clear. He just could not figure where I had got the extra power from, and for years he told his mates that I was an electronics genius.