"Michael Black" wrote in message ...
So a tv set forty years ago was handwired (I have no clue whether that
was a good or bad thing, but it was costly) on a heavy metal chassis, and
was a significant purchase for most households. But when something
broke, the cost of repair was low compare to the cost of replacement, to
that tv set would be taken to the local repair shop. But, pretty much
all the parts in that tv set were generic, so that repair shop did not
have to be in some relationship with the manufacturer, and the parts could
be had at the local electronics store (and since those stores were selling
to all kinds of people, the same general parts to repair that tv set were
also used by they hobbyist and even the professional, the stores could
survive with a relatively small stock that was bought by many), so the
repair shop often didn't need to keep a lot of stock, especially not
a lot of specialized stock.


Also because the failure rate was so high, most failures would be
simply a burnt-out vacuum tube. These repairs were relatively easy
to fix and a TV repairman could make a living charging for simple
quick house calls. Most corner drugstores had a tube-tester for the
DIY repairman and a stock of common tubes 12AU7, etc.

Eventually and after replacing a lot of tubes the TV would need
realignment.

Modern TV's hardly ever need to be realigned. This is not the
result of planned obselescence. It is the result of phasing-in
new improvements in technology as it develops. For instance,
it is just-as-easy to manufacture a chip with 100,000 transistors
as with one or two. This means circuitry can be made extra-stable,
and to some extent, self-healing, and self-aligning.

Don