HP TM 11-6625-2779-14&P manual Adjustment and Calibration Procedure, Power Supply Check

Page 42

Section V

CARRIER 600 and repeat the above procedure. Between 1kHz and 10kHz, the balance must be greater than 70dB. Between 10kHz and 100kHz, the balance must be better than 60dB. Between 100kHz and 600kHz, balance must be better than 40dB.

5-14. ADJUSTMENT AND CALIBRATION PROCEDURE.

5-15. The following is a complete adjustment and calibration procedure for the Model 3555B. These adjustments should be performed only after it has been determined by the performance checks that the set is not operating within its published specifications.

5-16. POWER SUPPLY CHECK.

5-17. Before attempting the following calibration procedures, first check the power supply voltage to be sure that it is correct and that the ripple voltage is not abnormal. To do this perform the following steps.

NOTE

Calibration of the 3555B should be performed with the set operating from the internal battery except for the power supply ripple check in the following steps. Operate the set from the ac power source long enough to make this check and then return the set to internal battery operation. This is accomplished by changing the position of the slide switch mounted on the side of the set. When operating from the battery, disconnect the ac power cord from the set.

a.Remove the set from the case and connect the 3440A/3445A dc voltmeter between the - 20V supply and ground. The negative side of A3C34 is a convenient place.

b.Turn the set on. The 3440A/3445A should indicate -20 volts ±1.0V.

c.Connect the 400FL AC Voltmeter to the negative side of A3C34 and measure the ripple voltage. The maximum allowable ripple is 200uV rms.

5-18. 75 UNBAL CALIBRATION.

a.Connect the 654A and 3440A/3445A as shown in Figure 5-2and set the 3555B controls as follows:

FUNCTION ................ 75 UNBAL INPUT..................... TMS, TERM RANGE ..........................+10dBm

b.Set the 654A frequency to 10 kHz, 75 UNBAL, and adjust the output level for 866 mV (+ 10 dBm) indication on the 3440A/3445A.

Model 3555B

c.Set the 654A meter for a reference indication and be sure to maintain this indication throughout the following procedures unless

otherwise instructed. Disconnect the 3440A/3445A voltmeter.

d.Change the 654A to -50dBm and change the 3555B RANGE switch to -50dBm.

e.Disconnect the 3440A/3445A, the 11094A termination and the cable. Connect the 654A output directly to the 3555B input.

f.Adjust A3R43 for 0dBm indication on the 3555B meter.

g.Change 654A frequency to 3MHz maintaining the reference established on the 654A meter.

h.Adjust A3C8 for 0dBm indication on the 3555B meter.

5-19. ATTENUATOR CALIBRATION.

a.Remove the FUNCTION board and replace it with the test board supplied with the set.

b.With the equipment and controls set as in the preceding check, change the 3555B RANGE to 40dBm and change the 654A attenuator to -40dBm. Change the 654A frequency to 100kHz.

c.Adjust A2C12 for 0dBm indication on the 3555B meter.

d.Change the 3555B RANGE switch to -30dBm and change the 654A attenuator to - 30dBm. Adjust A2C7 for 0dBm indication on the 3555B meter.

e.Change the 3555B RANGE switch to -20dBm and change the 654A attenuator to - 20dBm. Adjust A2C4 for 0dBm indication on the 3555B meter.

f.Change the 3555B RANGE switch to +10dBm and change the 654A attenuator to +10dBm. Adjust A2C1 for 0dBm indication on the 3555B meter.

g.Check the frequencies listed in Table 5-2for the tolerance indicated. If any of the checks in Table 5-2do not meet the indicated tolerances, repeat steps b through f.

5-20. FUNCTION CALIBRATION.

a.Remove the test board from the set and install the function board assembly. Connect the 654A balanced output to the 3555B balanced input terminals. See Figure 5-5.Set the 3555B controls as follows:

FUNCTION........ CARRIER, 600 BAL INPUT ........................... TMS, TERM RANGE ................................ -50dBm

b.Set the 654A frequency to 10kHz and adjust the output attenuators for -5OdBm output level, using the 600 BAL output function.

5-8

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Contents HEADQUARTERS, Department of the Army Technical Manual Headquarters Department of the Army Reporting Errors and Recommending ImprovementsTM 11-6625-2779-14&P NSNReplaceable Parts List of Illustrations List of TablesIii Maintenance Forms, Records, and Reports Section IntroductionScope Administrative Storage Destruction of Army Electronics MaterielReporting Equipment Improvement Recommendations EIR Items Comprising an Operable Equipment Specifications Voice Frequency Level Measurements 20Hz to 20kHzSection Section General Information IntroductionInstrument Identification Accessory Equipment SuppliedAccessory Equipment Supplied BAL ModificationPower Requirements Section Installation InspectionWarranty Exception BatteryInstallation and Removal of Battery Cover RemovalSection Controls Connectors IndicatorsBattery Operating InstructionsFront Panel Controls, Indicators, and Connectors Front, Side and Rear Pane Side Panel Controls and Connectors Level and Noise Measurements Level MeasurementsPage Noise Measurement Recorder Compatibility ApplicationsRecorder Compatibility Chart Crosstalk Measurements Identifying Noise CharacteristicsTransmission Loss Measurements Crosstalk Correction FactorMeasurements in DBC Input jacks are connected in parallel. If a 600 ohm Reinstall the set in its case0dBm 135 BALStep Procedure Level Measurement Noise Metallic MeasurementsExample Noise-to-Ground Measurements Balance MeasurementRecorder Calibration Transmission Loss MeasurementBlock Diagram Description Section Theory of Operation IntroductionDetailed Circuit Description Simplified Dial BAT FunctionInput Amplifier A3. Schematic No Range Attenuator A2Range Attenuator Setting AttenuationFILTERS. Schematic No Pads UsedKHz Flat and Program Weighting Curves C-MSG and 1SkHz Flat Weighting Curves Meter AMPLIFIER. Schematic No DETECTOR. Schematic NoPower Supply and Series Regulator Schematic No Factory Selected Values Section Maintenance IntroouctionInstrument Recommended Type Required Characteristics Model BAL ConversionFunction CARRIER, 75 Unbal Performance ChecksLevel Accuracy Checks TMS, TermFrequency Unbal Carrier Accuracy CheckRange 30Hz to 1MHz 100Hz to 600kHz 1MHz to 3MHzReturn Loss Check 20Hz to 20kHz 40Hz to 15kHz 100Hz to 20kHz 100Hz to 15kHzReturn Loss Test Set-Up Filter Response Checks Filter Response ChecksMSG dBm 3kHz Flat dBm 15kHz Flat dBm Program dBm TMS Brdg Input BalanceBridging Loss Input TMS BrdgUnbal Calibration Adjustment and Calibration ProcedurePower Supply Check Attenuator CalibrationFrequency Response Adjustment Common Mode AdjustmentBalance Check Assembly Removal Troubleshooting ProceduresFilter Calibration Troubleshooting Tree Front Panel Trouble Analysis Dial BATRange Troubleshooting Front Panel TroubleshootingFunction Troubleshooting Front Panel Trouble Analysis ContdTroubleshooting the Meter Amplifier and Detector Troubleshooting Input AmplifierFilter Troubleshooting Defective FunctionTip to Ring Tip to Ground Ring to Ground Function Switch Resistance ValuesFunction Input Jacks DIAL/AC MON Jacks Brdg Term11. Factory Selected Values 10. Resistance ChecksRange dBm Pin 1 to Pin 2 to Carrier 75 Unbal Level Accuracy Check Performance Check Test CardDescription Check Carrier 135 BAL Level Accuracy CheckPerformance Check Test Card Contd Carrier 600 BAL Level Accuracy CheckProgram Return Loss CheckFilter Response Checks MSG Bridging Loss CheckSection Replaceable Parts Introduction Ordering InformationReplaceable Parts 03555-66507 PC Board Assy functionReplaceable Parts Contd 03555-66508 Board Assy amplifierA3 Contd 03555-66506 PC Board Assy filter A4 Contd Chassis Mounted Components Chassis Mounted Components Contd MiscellaneousMiscellaneous Contd Fscm Replacement National Part Stock Number FscmPart Number National Stock Number Cross Reference Index National Stock NumberPage Model 3555B Appendix a Code List of Manufacturers Schematic Diagrams Circuit DiagramsFunctional Block Diagram Reference DesignationsSection Model 3555B Functional Block Diagram 7-4A1 Function Assembly Schematic and Component Location 7-67-8 A4 Filter Schematic and Component Location 7-1011/7-12 Appendix a ReferencesAppendix B Maintenance Allocation Section I. Introduction GeneralMaintenance Function Column EntriesTool and Test Equipment Requiremen ts Sec Remarks SecAudio Level Meter TA-885/U TM 11-7725-2779-14&P REF Code NumberAppendix C Manual Backdating ChangesTransmission and Noise Measuring SET Delete CR6 across M1 Government Printing Office 1980-603-128/66Major General, United States Army Adjutant General General, United States ArmyChief of Staff Active ArmyPage PIN
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