HP TM 11-6625-2779-14&P manual Circuit Diagrams, Functional Block Diagram, Schematic Diagrams

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Model 3555B	Section VII
	SECTION VII
	CIRCUIT DIAGRAMS
7-1. INTRODUCTION.	should be used in conjunction with the troubleshooting
	procedure described in Section V.

7-2. This section of the Manual contains circuit diagrams for the Model 3555B Transmission and Noise Measuring Set. The functional block diagram (Figure 7-

1)contains signal levels to assist in troubleshooting. The schematic diagrams (Figures 7-2through 7-5)show dc voltage levels which should also aid in locating faulty components.

7-3. FUNCTIONAL BLOCK DIAGRAM.

7-4. The functional block diagram (Figure 7-1) of the 3555B serves the dual purpose of showing how various circuits are arranged to form the set and at the same time gives voltages and adjustments for use in troubleshooting the set. This functional block diagram

7-5. SCHEMATIC DIAGRAMS.

7-6. The schematic diagrams (Figures 7-2through 7-

5)contained in this section show the detailed circuits in the Model 3555B. Components marked with an asterisk are those that are critical in value. The value of these components may vary slightly from one set to another due to variations in transistor Beta etc, and the values shown on the schematic are average.

7-7. Voltage levels have been included on the schematics which should greatly assist in

troubleshooting the set. When measuring these voltages a high input impedance voltmeter (1 megohm or greater) should be used to prevent circuit loading.

REFERENCE DESIGNATIONS

7-1

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Contents HEADQUARTERS, Department of the Army NSN Reporting Errors and Recommending ImprovementsTM 11-6625-2779-14&P Technical Manual Headquarters Department of the ArmyReplaceable Parts List of Tables List of IllustrationsIii Section Introduction Maintenance Forms, Records, and ReportsScope Destruction of Army Electronics Materiel Administrative StorageReporting Equipment Improvement Recommendations EIR Items Comprising an Operable Equipment Voice Frequency Level Measurements 20Hz to 20kHz SpecificationsSection General Information Introduction SectionBAL Modification Accessory Equipment SuppliedAccessory Equipment Supplied Instrument IdentificationBattery Section Installation InspectionWarranty Exception Power RequirementsCover Removal Installation and Removal of BatteryOperating Instructions Controls Connectors IndicatorsBattery SectionFront Panel Controls, Indicators, and Connectors Front, Side and Rear Pane Side Panel Controls and Connectors Level Measurements Level and Noise MeasurementsPage Noise Measurement Applications Recorder CompatibilityRecorder Compatibility Chart Crosstalk Correction Factor Identifying Noise CharacteristicsTransmission Loss Measurements Crosstalk MeasurementsMeasurements in DBC 135 BAL Reinstall the set in its case0dBm Input jacks are connected in parallel. If a 600 ohmLevel Measurement Noise Metallic Measurements Step ProcedureTransmission Loss Measurement Noise-to-Ground Measurements Balance MeasurementRecorder Calibration ExampleSection Theory of Operation Introduction Block Diagram DescriptionSimplified Dial BAT Function Detailed Circuit DescriptionRange Attenuator A2 Input Amplifier A3. Schematic NoPads Used Setting AttenuationFILTERS. Schematic No Range AttenuatorKHz Flat and Program Weighting Curves C-MSG and 1SkHz Flat Weighting Curves DETECTOR. Schematic No Meter AMPLIFIER. Schematic NoPower Supply and Series Regulator Schematic No BAL Conversion Section Maintenance IntroouctionInstrument Recommended Type Required Characteristics Model Factory Selected ValuesTMS, Term Performance ChecksLevel Accuracy Checks Function CARRIER, 75 Unbal30Hz to 1MHz 100Hz to 600kHz 1MHz to 3MHz Unbal Carrier Accuracy CheckRange Frequency20Hz to 20kHz 40Hz to 15kHz 100Hz to 20kHz 100Hz to 15kHz Return Loss CheckReturn Loss Test Set-Up Filter Response Checks Filter Response ChecksMSG dBm 3kHz Flat dBm 15kHz Flat dBm Program dBm Input TMS Brdg Input BalanceBridging Loss TMS BrdgAttenuator Calibration Adjustment and Calibration ProcedurePower Supply Check Unbal CalibrationCommon Mode Adjustment Frequency Response AdjustmentBalance Check Troubleshooting Procedures Assembly RemovalFilter Calibration Troubleshooting Tree Dial BAT Front Panel Trouble AnalysisFront Panel Trouble Analysis Contd Front Panel TroubleshootingFunction Troubleshooting Range TroubleshootingDefective Function Troubleshooting Input AmplifierFilter Troubleshooting Troubleshooting the Meter Amplifier and DetectorBrdg Term Function Switch Resistance ValuesFunction Input Jacks DIAL/AC MON Jacks Tip to Ring Tip to Ground Ring to Ground10. Resistance Checks 11. Factory Selected ValuesRange dBm Pin 1 to Pin 2 to Carrier 135 BAL Level Accuracy Check Performance Check Test CardDescription Check Carrier 75 Unbal Level Accuracy CheckCarrier 600 BAL Level Accuracy Check Performance Check Test Card ContdBridging Loss Check Return Loss CheckFilter Response Checks MSG ProgramOrdering Information Section Replaceable Parts Introduction03555-66507 PC Board Assy function Replaceable Parts03555-66508 Board Assy amplifier Replaceable Parts ContdA3 Contd 03555-66506 PC Board Assy filter A4 Contd Chassis Mounted Components Miscellaneous Chassis Mounted Components ContdMiscellaneous Contd National Stock Number Replacement National Part Stock Number FscmPart Number National Stock Number Cross Reference Index FscmPage Model 3555B Appendix a Code List of Manufacturers Reference Designations Circuit DiagramsFunctional Block Diagram Schematic DiagramsSection Model 3555B 7-4 Functional Block Diagram7-6 A1 Function Assembly Schematic and Component Location7-8 7-10 A4 Filter Schematic and Component Location11/7-12 References Appendix aColumn Entries Maintenance Allocation Section I. Introduction GeneralMaintenance Function Appendix BRemarks Sec Tool and Test Equipment Requiremen ts SecAudio Level Meter TA-885/U REF Code Number TM 11-7725-2779-14&PManual Backdating Changes Appendix CTransmission and Noise Measuring SET Government Printing Office 1980-603-128/66 Delete CR6 across M1Active Army General, United States ArmyChief of Staff Major General, United States Army Adjutant GeneralPage PIN