67 Radio and electronic phono technical
Description
This article is from the Antique Radios And Phonographs FAQ, by Hank van Cleef vancleef@netcom with numerous contributions by others.
67 Radio and electronic phono technical
WARNING: HIGH VOLTAGE. SHOCK and FIRE hazard.
Vacuum tube electronics runs on much higher voltages than transistor or
solid state devices. These sets were generally not provided with
interlocks or power fuses. In certain designs, the power line may be
connected directly to the chassis. Many home-entertainment electronic
devices had 250 volts or higher as a standard operating voltages, and
voltages as high as 750 or 800 volts, may be present in some circuits.
Fault conditions may cause HIGH VOLTAGE to be present ANYWHERE, even
after the set it turned off and disconnected from the power line
(mains). Use a grounding lead to assure that no voltage is present
before working on a set.
There is sufficient power to overheat components to the point that they
will catch fire, and many components used in old electronics will
support combustion. While addition of a fuse can reduce fire hazards,
it is not a sure and complete protection against overloads which may be
adequate to overheat components, but inadequate to blow the fuse. In
addition, soldering irons operate at temperatures of 400-500C (approx
700-900F), and are hot enough to ignite many flammable materials such as
paper and cloth.
Several of the CHEMICALS and PROCESSES discussed in the newsgroup, and
in this FAQ, present safety hazards of one type or another. Fire
hazards are common, and many chemicals and processes require substantial
ventilation as well. Read manufacturers' labels and follow all
instructions for safe handling closely. Above all, do not store
or use chemicals with food or food preparation items.
Small children (and some not so small)---if you have some of these
around, take some precautions to make sure their inquisitiveness does
not get them into something that will hurt them, or damage anything.
Old electronic equipment is full of bright colors that will attract
small fingers. The best thing to do with children is introduce them to
radio. Don't just tell them "no, don't touch," etc. It's amazing how
quickly, diligently, and thoroughly a child will learn mathematics
and physics, with the help of an old radio and someone who will take the
time to explain it to them. Noxious chemicals and children don't
mix.
Do not attempt any process unless you know exactly what you are doing,
have evaluated the risks, and have taken safety precautions. Many of
the regular contributors to rec.antiques.radio+phono have been formally
trained in chemistry and physics laboratory procedures, and use
chemicals and processes professionally. They may discuss techniques that
require substantial safety precautions without noting the hazards
involved.
If there is the slightest doubt in your mind about the safety of any
process or material, don't charge off and "just do it" because others
say "it works." Ask questions. There is no substitute for learning
under supervision. Many community colleges and high schools offer
courses open to adults, including courses in laboratory sciences and
shop practices.
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