1943, U.S. ARMY, SIGNAL CORPS, KEYER TG-34-A, SN.15107
民國32年，美國陸軍，通信部隊，TG-34-A 電碼機，序號:15107《Black Water Museum Collections | 黑水博物館館藏》
1. GENERAL.-Keyer TG-34-A, (fig. 1) is an automatic unit for reproducing audible code practice signals previously recorded in ink on paper tape. The unit is a component of Code Practice Equipment EE-94-C, EE-95-C, and EE-96-C. The unit can be used to provide code practice signals in permanent classrooms, for small groups in the field, or to provide a keying oscillator for use with a hand key. The unit is compact and portable, and reasonably weatherproof. It is self-contained, but requires an external a-c power source. Ventilation for tl\e cabinet is provided by a fan which is attached to the lower motor shaft.
2. COMPONENTS, WEIGHTS, AND DIMENSIONS.-
a. The dimensions of Keyer TG-34-A are 10-9/ 16 inches high, 10-1/ 2 inches wide, and 15-13/ 16 inches long. The unit weighs 38.5 pounds .
b. To operate the keyer the following additional equipment is necessary:
(1) Inked-paper tape recordings.
(2) Telegraph key.
3. SOURCE OF POWER.-a. Normal supply is 115 or 230-volt, 50 to 60-cycle alternating current.
(1) . The unit will operate satisfactorily on any voltage between 95 and 120 volts or between 190 and 240 volts.
4. POWER OUTPUT.-Under normal operating conditions the power output is approximately 3.5 watts, when the AC OFF VOLUME control is adjusted for maximum volume. Output impedances are 4, 8, and 15 ohms.
-a. Step-by-step proceclure.-(fig. 3)
(1) Turn ACOFF VOLUME control (127) to the right to point about halfway around dial. Panel light (137) will illuminate tape speed indicator dial (162) (fig. 6).
(2) Turn SPEAKER ON-OFF switch (133) to ON.
(3) Mount and .thread practice tape (par. 8b.).
(4) Turn MOTOR ON-OFF switch (134) to ON. Move the pressure roller downward until it contacts the tape on the drive roll. Tape will start to inove over anvil.
(5) Turn PE CELL control (125) to the right until keyed signal is heard. Exciter lamp (1 38) (fig. 6) wi ll light. Adjust PE CELL control to position which gives clear-cut signa ls. Additional cell voltage can be obtained by adjusting potentiometer (126) located on the chassis near the socket of tube VT-87-A (fi g. 6) (par. 12h).
CAUTION: Limit your use of the control to cases of unusually low or high supply voltage or to cases w h ere the VT-252 or VT-87-A tubes are b elow normal.
( 6) Adjust tape-speed control knob ( 160) to desired operating position, and AC OFF VOLUME control (1 27) to desired signal level.
(7) If headsets or remote speakers are being used, turn SPEAKER ON-OFF switch to OFF.
b. Rewinding the tape.-(fig. 3) When tape has run through keyer, rewind as follows:
(1) Turn MOTOR switch to OFF.
(2) Lift pressure roller off drive roll.
(3) Pass tape under second guide roll er over first guid e roller and into slot in rewind tape reel hub.
(4) Rotate rewind crank clockwise, with a slow even motion until suffi cient tape is rewound.