User manual FURUNO 42A12D OPERATORS MANUAL

[. . . ] Auxiliary Connections and Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Audio Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Utilizing the internal microphone and loudspeaker, the Test Set can perform an operational test on a beacon without removing the beacon from its mount on the aircraft. SPECIFICATIONS 42A12D ULTRASONIC TEST SET Size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 0" (7. 62 cm) x 4. 5" (11. 43 cm) x 2. 25" (5. 72 cm) Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ounces (368 grams) Tuning Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 45 kHz Battery*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V (Qty 1) Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 dB min. at 37. 5 k Hz Noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Less than one mW across 10 ohm load Undistorted Output. . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ohm load Microphone Sensitivity. . . . . . . . . . . . . . . . . -150dB re 1uPa Battery Life. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 40 hours Audio Output Jack. . . . . . . . . . . . . . . . . . . . . . . . Switchcraft type 43A, permits operation into headphones, oscilloscope, etc. in place of internal loudspeaker (impedance 10 ohm nominal) * NEDA Type 1604A. Figure 1. 1. Ultrasonic Test Set Model 42A12D. 03-TM-0038 REV 00 PAGE 1 of 5 Figure 1. 2. The microphone detects a beacon signal which is amplified and fed into the mixer. When tuned above or below the incoming signal, the difference frequency is the resultant output from the mixer, and will be in the audio range when the difference is within 1000 to 3000 Hz. When both frequencies are the same, the difference frequency is zero, hence no output from the mixer. The signals coming out of the mixer are amplified by the audio amplifier, where most of the gain of the test set is provided. The test set AUDIO OUTPUT jack circuit is designed to work into a load impedance of approximately 10 ohms which is ideal for attachment of low impedance head phones. Operation into higher impedance such as oscilloscopes, meters, chart recorders or other types of readout equipment is permissible. CAUTION A SHORT ACROSS THE AUDIO OUTPUT JACK MAY CAUSE DAMAGE TO THE TEST SET CIRCUITRY. SOME FORM OF PROTECTION SHOULD BE PRO-VIDED WHERE SPLASH CONDITIONS EXIST. 03-TM-0038 REV 00 PAGE 2 OF 5 SECTION II OPERATION 2. 1. Should this occur, replace battery before resuming operational testing. Rubbing fingers in front of microphone should produce a rushing noise from speaker. Actuate a beacon under test by immersing the water switch in tap water, or by shorting the water switch terminal to the case by means of a shorting tab. The beacon need not be removed from its mount on the aircraft to perform operational testing. Point the microphone of the Test Set towards the water switch end of the Beacon for best results. If the Beacon is mounted, position the Test Set for maximum unobstructed signal. The tuning control permits reception of an acoustic signal operating anywhere within the 30 to 45 kHz frequency range. The audio response is peaked at about 3200 Hz; therefore, the test set should be tuned to produce an output signal of approximately this frequency to achieve greatest sensitivity. [. . . ] Monitoring the frequency, adjust R16 for the maximum L. O. , approximately 42 kHz or as high as possible. Repeat steps C through E as many times as necessary until both ends are tuned. 3. 4. Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . NEDA Type 1604A B T1 R 13 10K S1 W S P WR W OE L1 2. 02 C 13 68 R 20 10 R 31 R 32 10 10 LS 1 SEKR PAE D 3 1N 4454 D 4 1N 4454 R 24 2. [. . . ]