A TV Tube: As It Is Made - In Germany - In U.S.A. March 1958
March 1958 Popular Electronics
of Contents]People old and young enjoy waxing nostalgic about and learning some of the history of early electronics.
Popular Electronics was published from October 1954 through April 1985. All copyrights (if any) are hereby acknowledged.
it or not, cathode ray tubes (CRTs) are still manufactured for specialty products and for replacement
parts. Even with a high level of automation, there are still steps in the manufacturing process
that require human handling. A comparison between CRT plants in the USA and Germany show the similarity
but distinctly different processes in a Sylvania and Telefunken operations, respectively. The
photos shown are from an article in a 1958 edition of Popular Electronics. At the bottom of this
page are videos of a modern CRT manufacturing process and a CRT recycling effort. As you will
see, properly recycling a CRT is about as manually intensive as manufacturing one (but with no
quality control and functionality concerns). I am not sure where the profit is in recycling unless
inflation over the 10-20 years since manufacturing makes the value of materials worth the effort.
A très cool documentary film on the designing and manufacturing process of
RCA Victor television
sets is at the very bottom.
U. S. photos taken at Sylvania Electric plant at Seneca Falls N.Y., USA -
German photos taken at the Telefunken Company plant at Ulm, Germany
Bulb washing with hydrofluoric acid, then water, is done on assembly line at Sylvania, and on
circular "washautomaton" at Telefunken. In this and following steps, the process in both plants
is generally automatic, but workers move bulbs from one line to next.
2 After "screen settling," bulbs
filled with a phosphor solution are "poured" off as they move along vibration-free conveyor belts.
When the fluorescent coating has dried, a thin lacquer coating is applied in the same manner,
to serve as a base for aluminizing - the next step.
To assure brighter screen and clearer raster, both plants apply an aluminum coating to the inside
of the bulb. A small piece of aluminum is heated to incandescence in the evacuated bulb, depositing
a micron-thin film of the metal over the interior lacquer coating which was applied earlier.
4 Baking in lehr (oven) removes
lacquer coat, leaving a smooth aluminum coat.
The sealing process is the marriage of bulb and gun, effected in both plants on a circular assembly
line. While the German photo does not show it, the bulbs must be placed on the line by workers,
as in the Sylvania shot. Sealing is automatic as is following inspection process.
6 Evacuating the tubes at high
temperature is accomplished on a screened-off line as a safeguard against implosions, which occur
infrequently. "Getter" is then flashed to absorb foreign gases, after which the tubes are aged
and tested. Inspection and packing are last.
Here is how CRTs are made today
(this is not high volume production):
How It's Made: Cathode Ray Tubes (CRTs)
Now, here is how they are properly disposed of after their
This is an RCA Victor Television Production Plant Documentary
- Dig the Test Equipment!
If you take the time to watch this video of the RCA Victor television development process,
you will be impressed with the amount of engineering that went into those units. By contrast,
a large percentage of the manual design and testing in today's electronics is done on a computer
with simulation programs (typically NOT in America). Huge
databases of component characteristics data are available for just about every electrical, mechanical,
and chemical parameter of every type of material. All of this significantly cuts down on design
and development time needed for getting products to market.
Every capacitor, resistor,
inductor, transformer, tube base, connector, cable, and every wire connecting all the parts together
had to be installed by hand back in the era. The same goes for mechanical assemblies. There were
no automated test protocols for checking accelerated lifetimes and FCC compliance (see the OATS*
setup in the video). Documentation was drawn on a drafting board with a pencil and typed on paper
with typewriters. Promotional material and user manuals were laid out on a cutting and lay-up
board where text and graphics needed to be brought together. It was a lot of work that kept a
huge army of highly skilled engineers, technicians, draftsmen, stylists, and craftsmen employed,
many of whom had cut their teeth during the WWII and Korean War defense contracting eras.
America and most other Western countries were powerhouses of intellectual and physical creativity
hands-on genius. Nowadays our factories are empty and the national know-how is focused on playing
video games and perfecting ways to have the government give you other people's hard-earned stuff.
* OATS = Open Air Test Site for RF testing
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