In the 1950s I lived for a while on a remote farm in Lincolnshire.
There was an ancient and unreliable diesel generator in an outhouse.
The thump thump thump from the engine could be felt through the floor, and it produced a pulsating line across the TV screen.
When the engine started to conk out, it ran down very slowly, having a heavy flywheel, so was only initially noticeable as a change in note. But the TV picture would get smaller and then cut out.
My aunt lit the oil lamps while my uncle went out to struggle with the engine. After a while the slow thumping would gradually resume, and the picture came back on.
My father recalled that in Leeds in the 1920s there were two electricity suppliers, depending on the exact area. They were at slightly different voltages (210 and 250, I think) and all appliances, lightbulbs etc were rated differently depending on where you lived.
I still have his 65w soldering iron, which overheats if left on too long because it was made for the low voltage region.