RF Cafe visitor Vincent
saw the "Barney
Turns Inventor" episode of "Mac's Radio Service Shop" series recently posted
here which told of Barney's idea for a vacuum tube tester that would set all
the switches and voltages based on a coded card for the particular tube type.
That story appeared in a 1950 issue of Radio & Television News
magazine. I don't know when Hickok came out with their first "Cardmatic" tube
tester, but as Vince noted in his message to me, the idea might have been borne
of John Frye's fictional scenario. This full-page advertisement for the Hickok
Model 121 High-Speed Portable Cardmatic Tube Tester comes from the March 1958
issue of Radio & TV News. A YouTube video of a Model 121 Cardmatic
is included below.
Said Vincent, "I headed up an electronics lab for the Canadian
National Research Council [in the 1980s] which designed and built custom
electronic equipment for the support of scientific research at the
Herzberg Institute of Astrophysics in Ottawa Canada. We had two of these
Cardmatic testers which I used extensively. If memory serves me correctly they
were the Model 123 version." Further, "In the Hickok version the cards were
a plastic sheet full of holes which you slid into a holder with your right hand
while holding down a large palm operated spring loaded plunger with your left
hand. Releasing the plunger engaged the mechanism that sensed the holes in the
card and programmed the tester (For some reason the palm operated plunger always
made me think of the emergency SCRAM control on a nuclear reactor)...<see
more at bottom>
Hickok High-Speed Portable Cardmatic Tube Tester Ad
Hickok Model 121 "Cardmatic" Vacuum Tube Tester
New, Low Price
$249.50 Net (Includes 300 cards)
320 heater voltages.
140 fixed bias potentials.
640 plate voltages.
640 screen voltages.
100 self-bias settings
1000 quality-value sensitivity ranges.
Instant shorts indication.
Active card magazine holds over 600 cards instantly available with time saving
automatic filing feature.
See the 121 Today!
Tests any tube in 8 to 12 seconds ... including handling of tube test data
card. Here is the new, low cost version of the famous Hickok Cardmatic so popular
with leading lab engineers. Especially designed for high speed service work,
this new 121 is high quality in a lightweight portable ... and the price is
The Hickok Cardmatic switch sets up all tests automatically and eliminates
fussing around with adjustments. You can accurately check a tube for dynamic
mutual conductance, controlled emission, cutoff point "Knee" point, shorts,
leakage, gas and voltage drop ... and rectifier tubes at their rated loads.
Any way you look at it, this new automatic tube testing machine will be helpful
to you in your work. It will pay for itself in a very short time ... and give
you many years of accurate dependable service.
The new 121 incorporates a fully automatic mechanism actually incorporating
187 individual switches providing an almost unlimited number of voltage combinations
to any tube element. This mechanism has been life tested in a cycling process
over 100,000 times - without fail, and has proven superior to all other switching
Now is the time to ...
Trade up to a Hickok
Ask for a demonstration of the new 121 or write for descriptive literature.
The Hickok Electrical Instrument Co.
10524 Dupont Avenue • Cleveland 8, Ohio
More from Vincent: "Thinking about tube testers has stirred
some old memories. My first gig after graduating from Ryerson U. in Toronto in
1975 was to keep all of the communications equipment (VHF & UHF transmitters,
receivers, communication control systems, radio positions, etc.) operating
properly at Toronto International Airport. All of the TX and RX used vacuum
tubes and were much older than I was! It never struck me as odd at the time, but
we did not have tube testers. If you suspected a tube was bad you tried a
substitution and having a very limited set of types of equipment this was a
There was an aspect of this that always struck me as ironic. In Canada at the
time civilian controllers frequently communicated with military aircraft. To
facilitate this we "paired" VHF (civil) and UHF (military) frequencies so that
when the controller keyed the TX he went out on 2 frequencies and the received
audio from 2 receivers was mixed and sent to the radio position. The UHF
equipment was R361 receivers and T282 transmitters which were owned by the US
military, loaned to the Canadian Military, who then loaned to us for use.
Towards the end of my time at this job (1980) I noticed that the tubes we
were receiving as spare parts were arriving in plain white boxes with Cyrillic
writing on them and a rubber stamp with the north American tube type
designation. Since North American manufacturers were shutting down tube
production due to dwindling sales the Canadian Government procurement agents
were purchasing vacuum tube from Russia! So here I was, during the cold war,
using Russian vacuum tubes to repair U.S. Military receivers and transmitters!
Posted January 27, 2021