[time-nuts] Learning technology by taking the clock apart...

Chuck Harris cfharris at erols.com
Fri Jul 29 17:56:36 EDT 2005

Hi Poul,

Finally, my network access is back!

Poul-Henning Kamp wrote:
> In message <42E813E4.4090001 at erols.com>, Chuck Harris writes:
> [I split off this topic, it's interesting in its own right I think]
>>I must be very unusual, I fix modern TV's, radios, and other consumer
>>electronics doo-dads.    It isn't generally economical to do what I do, but
>>it does keep me in touch with the bleeding edge of consumer manufacturing
> Right, but if you were a 7 year old kid, would you *learn* from it ?

There a few things that can be learned, one is what the various surface
mount components look like.  Another is that there is actually something inside
that makes the set function .  At 7, ideas that there may be gnomes inside
that do the work wouldn't seem too far fetched.

Shielding is another issue, and even the most micro electronic'd tv set
will still have an RF section that is inside a can.  One can pop the top off of
the can, and see filters, etc.

And, of course, there are wires, connectors, speakers, and other gadgets
that are interesting.
> The problem is that microelectronics obscure the basic circuit and
> prevents you from poking around with anything but a few peripheral
> capacitors which are mostly there for decoupling anyway...

I agree to a point, we are certainly heading to a time where the integration
will be so high that a TV set will be nothing but connectors, and this tiny
block of electronics that cannot be viewed at all.  We aren't quite there yet
in the larger less expensive sets.
> When I took a television apart, there were a schematic pasted on the
> back panel, and I could trace the circuit and with a book about
> radio reception in hand, I could follow the signals progress.  I
> could look at the schematic and figure out what happened when I
> pushed this button and turned that knob.

I entered the playing field at about that time, and I can tell you the circuitry,
although it was visible, (and even point to point handwired) was so
economized that it wasn't at all obvious how it worked.  Radios were a better
source of inspiration than TV sets.
> If my kid takes a television apart, he can trace any wire with a
> signal until it hits an integrated circuit and then what ?

It isn't the set that has squelched the interest.  Around my house, there
are radios and test equipment of all vintages from vacuum tube, through
microelectronics.... And yet my kid doesn't even want to think about what is
inside.  He was curious before he went to school, but after starting school,
with its mandatory computer, and internet use, he now couldn't care less.

For grins, I offered to give the 5th graders a lesson in magnetics and electricity,
and I brought in a home made motor, a home made loud speaker, an oscilloscope,
and sweep function generator, and a simple security board that I made for some
client.  They kids and teachers were fascinated.  My lecture was supposed to go
from 9am to 10 am, and because of all of the questions, they almost missed their
1pm lunch.

I still hear from my son's classmates about the time his dad came in to school.
The teachers  were the ones that were really fascinated, as they had no idea
how motors and speakers really worked, and yet they were teaching a unit
on electricity and magnetism.

How can you teach what you don't know?  I'd love to teach an elementary school
science course, I 'd gladly take time out of my day to do it.  But with my MSEE,
I am not "qualified".  You have to have a master's degree in education to teach.


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