Aviation Electronics Technician 1 - Historic Naval Ships Association

esults in three output signals, which are sent to theECA. These coils are located in the MAD boom.COMPENSATION COILS.— There are threecompensating coils located in the boom. These coilsgenerate the magnetic field that opposes theaircraft-generated noise fields for compensation.There is one coil each for the transverse, vertical, andlongitudinal fields.CP-1390 MAGNETIC FIELD COMPUTER.—The magnetic field computer, along with the magneticfield indicator, computerizes the compensationprocedure. The correlation portion of the system, the2A5 board in the ECA, becomes redundant to thecomputer. The magnetic field computer receives themaneuver signals, MAD signals, and thepotentiometer outputs. From these signals, itcomputes the adjustment values for the nine magneticterms simultaneously.ID-2254 MAGNETIC FIELD INDICATOR.—The magnetic field indicator (fig. 4-29) allows theoperator to select various weapon loads and initiatethe self-test, auto compensation, and weapon deploymentprograms. It also displays the most recentcomputer-calculated term difference value.The PWR/OFF switch accesses aircraft power.The DISPLAY indicator is a four-digit numericaldisplay and a polarity indicator. It shows the variousBITE codes, term values, or calibration values. TheEXEC push button initiates all commands. Thisbutton must be pressed after each selection of theMODE switch.The MODE switch is a 14-position rotary switchthat provides computer identification and control offixed compensation functions. The OFF positionmeans that there are no functions processed. TheBITE position conducts a built-in test and reports theresults via the digital readout. In the COMP position,pressing the EXEC button conducts the nine-termcompensation program. The WD position enables thefour-term weapon deployment compensationprogram. In the CAL position, a digital valuemeasurement of the magnetic coils for calibrationaccuracy is initiated. The other nine positions reportthe most recent computer-calculated term differencevalue via the DISPLAY. Remember, after selectingany of the positions on the MODE switch, the EXECbutton must be pressed.The FAULT indicator illuminates whenever afault condition exists. The WPN LOAD switch is anine-position switch labeled 0-8. The number ofweapons being carried is selected on this switch priorto compensation. This provides compensation for atleast 80 percent of the weapons interference field.AN/ASA-71 Selector Control GroupThe selector control group consists of two units.These units are the MAD selector control panel andthe selector control subassembly.C-7693/ASA-71 SELECTOR CONTROLPANEL.— This selector control (fig. 4-30) selects thesignal to be recorded on the MAD recorder andadjusts the threshold voltage for the SAD system.The two knobs labeled BLACK PEN and RED PENFigure 4-29.-ID-2254 magnetic field indicator.Figure 4-30.-C-7693/ASA-71 selector control panel.4-23