Secret Life of Machines was a huge influence on me, it took me from accepting that things came in boxes and that magic happened inside, to taking the lids off to find out how they worked. Tim and Rex were definitely of the 'Don't turn it on - take it apart!' school of thinking.
I remember a Z80 with a whole bunch of LED's on and they had that running with the clock slowed down so you could see it in action. It was full of simple, practical illustrations like that, the best was to show how pressure switches worked on washing machines using bits of old washing machines bolted onto the side of another old washing machine.
I recorded a lot of them when they were first on, but sadly, most didn't survive the years. Ironically, I did find one episode on an old tape and it turned out to be the one about the VCR. I kept looking out for repeats or DVDs but there doesn't seem to have been any, so I was excited to find all the episodes on the net a couple of years ago, and lost a whole weekend watching them all through.
Great stuff, well worth a watch as a lot of it is fundamental principles and is still relevant 20 years later.