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
are hereby acknowledged. See all articles from Popular Electronics.
Believe 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
television sets is at the very bottom.
A TV Tube: As It Is Made - In Germany - In U.S.A.
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
1 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.
3 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.
5 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 useful
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
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.
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.
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB.
Its primary purpose was to provide me with ready access to commonly needed formulas and reference
material while performing my work as an RF system and circuit design engineer. The Internet
was still largely an unknown entity at the time and not much was available in the form of
All trademarks, copyrights, patents, and other rights of ownership to images and text used
on the RF Cafe website are hereby acknowledged.