Tangible Media: Removable Storage of Image, Sound, Motion and Data
Tangible Media: Removable Storage of Image, Sound, Motion and Data
Tangible Media: Removable Storage of Image, Sound, Motion and Data
Hickok Cardmatic 123R






Rubberized vinyl


5⅝ in. × 3 in. (143 × 76 mm)


The Hickok Electrical Instrument Co.


Cleveland, Ohio, United States

If you grew up in the 1960s, your parents might have sent you to the local drugstore to test radio or TV vacuum tubes (“valves” in the UK). The tube tester, an imposing device with dozens of sockets and a large meter, sat on top of a cabinet with shelves of new tubes to choose from if the meter pointed to REPLACE when you plugged yours in.

The self-service tube tester was a simplified version of those used by professional technicians and the military, for which thoroughly testing a particular type of tube (of which there were hundreds) required setting multiple switches and dials—and a mistake could ruin the tube. The Hickok Cardmatic tube tester solved this with punch cards. When a card was inserted, an array of 187 switches was pressed against it. As described in the 1961 Hickok catalog: “the absence of a hole completes a particular circuit; the presence of a hole causes the circuit to remain open.”

These cards are from a set for the Cardmatic 123R, which came out in 1961; they also work in the earlier Cardmatic 123A. The 123 came with 500 cards, but more could be ordered from Hickok. Users could also create their own cards using a hole punch (see below), although since most of the 187 switches were open for a typical tube, manual hole punching would have been somewhat tedious.

The Cardmatic is a dynamic mutual conductance tester, which measures the tube's output current relative to AC and DC voltages applied to its inputs. (For more than a hand-waving explanation see The Valve Museum.)

Two cards for the Hickok Cardmatic Model 123 tube tester punched with holes to set up the tester for tube #6663
Testing a tube could require anywhere from one to six cards.
A three-card test with instructions
A typical vacuum tube (known as a “valve” in the UK).
32bitmaschine ( CC BY-SA 3.0 via Wikimedia Commons)
Ad for a self-service "drugstore" tube tester
The Hickok Cardmatic 123R. A tray built into the device could hold approx. 600 cards.
The card reader. The knob to the left was pushed down to insert the card and released to read it.
The array of 187 switches (several pins missing and some parts removed for visibility). All switches in the open position
Switches blocked by the card remain in the closed (conducting) position.
Manual for punching cards by hand