Okay... more nostalgia and a bit on safety
back in those days... so that we don't stray
too far from the subject matter of this
forum.
My first TV was a Motorola 7-inch round in
a Bakelite cabinet. The speaker was the
same size as the CRT.
My second was the famous RCA 10-inch round
chassis with 32 tubes. I could pull out
15 tubes and still have a usable picture.
Kyle mentions Packard Bell, which I considered
a straight-forward, good product. It used the
Standard Coil turret tuner.
The one that won my respect was Muntz TV.
It was CHEAP! When you looked inside the
chassis, there was nothing there compared to
the other TVs. They really knew how to take
the cost out of the TV! Amazingly enough,
its picture was among the best, and its
reliability was indeed the best -- no parts
to go bad! The company was owned by "Mad
Man Muntz," the classic Los Angeles used
car dealer.
In the mid-fifties, GE came out with a
transformerless 17-inch TV. One side of
the power line was tied to the chassis
(2-wire plug back in those days). The
only protection was the plastic knob on
the shafts of the various controls. When
servicing this TV, you quickly learned
never to touch the chassis!
The power supply was a simple full-wave
rectified power line. The tube heaters
were connected in a series-parallel
arrangement.
These sets were the initiation of UL's
investigation into antenna coupling
capacitors. These capacitors provided
the isolation between the TV antenna
terminals and the mains voltage.
TV sets of those days consumed between
400 and 600 watts. When they were turned
on, the cold filaments were a very low
impedance, so the turn-on current was
very high. The off-on switch was often
mounted on the back of the volume control.
Eventually, the contact resistance of the
switch would grow to the point where the
I**2*R power would melt the solder and
the power wires would come loose. It was
common to have a customer report that his
TV was dead, and it was due to the lack
of a good connection to the switch.
At one company, we had metal bat-handle
toggles blow out of the switch due to the
cold filament load.
Out of this experience, UL developed the
requirements for the TV-rated switch,
which had specially-designed contacts
that would not overheat when used in a
TV or similar application.
Best regards,
Rich
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