HP TM 11-6625-2779-14&P Section Maintenance Introouction, Factory Selected Values, BAL Conversion

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Model 3555B

Section V

SECTION V

MAINTENANCE

5-1. INTROOUCTION.

5-2. This section of the manual contains information necessary in the maintenance of the -hp- Model 3555B Transmission and Noise Measuring Set. Included are performance checks, adjustment and calibration procedures and troubleshooting.

5-3. The test equipment needed to properly maintain and service the Model 3555B is listed in Table 5-1.Included in Table 5-1is the equipment to be used, required specifications 'and recommended model. If the recommended model is not available other equipments

can be substituted provided they meet the required specifications.

5-4. FACTORY SELECTED VALUES.

5-5. Factory selected values are denoted on the schematic diagrams by an asterisk. The nominal value is shown. The value in your instrument may be different or the part may be omitted.

5-6. 150 BAL CONVERSION.

a.To convert the 135 BAL function to a 150

BAL

Table 5-1. Required Test Equipment

INSTRUMENT		RECOMMENDED
TYPE	REQUIRED CHARACTERISTICS	MODEL
Oscillator	Frequency Range: 20Hz to 3MHz	-hp- 654A
	Levels: -80dBm to +30dBm
	Accuracy: ±0.1 5dB
Oscillator	Frequency Range: 100Hz to 20kHz	-hp- 201 C
	Amplitude: 30V
Transformer	Line matching	-hp- 11004A
Voltmeter,	Function: AC and DC	-hp- 3440A/3445A
digital	Accuracy: ±.1%
Amplifier	Voltage gain: 20 dB	-hp- 467A
Output:	+/-20V peak at 0.5A peak
Voltmeter, AC	Frequency Range: 20Hz-4MHz	-hp- 400FL
	Accuracy: ±2%
Termination	50 ohms ±.25%	-hp- 11048B
Termination	75 ohms ±.25%	-hp- 11094A
Cables	Balanced BNC to 310 plug	See Figure 5-1.
Adapter	BNC to 358 plug	Trompeter Electronics
		No. AD-1W
Resistors	576 ohms ±1% (1)	-hp- Part No. 06984598
	875 ohms ±1% (1)	(Use 825 ohm, 0757-0731 and
		49.9 ohm, 0698A4110 in series)
	300 ohms 0.1 % (4)	-hp- Part No. 0698-6295
	600 ohms ±0.1% (4)	-hp- Part No. 0698-7408
	135 ohms ±0.1%(4)	-hp- Part No. 0698-7364
	75 ohms ±0.1% (4)	-hp- Part No. 0698-7363
	900 ohms ±0.1%	Use 600 and 300 in series (0.1%)
	150 ohms ±.1% (2)	-hp- Part No. 0698-6774
	100 kilohms 1% (1)	-hp- Part No. 0757-0465


	5-1

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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 Iii List of IllustrationsList of Tables Scope Maintenance Forms, Records, and ReportsSection Introduction Reporting Equipment Improvement Recommendations EIR Administrative StorageDestruction of Army Electronics Materiel 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 MSG dBm 3kHz Flat dBm 15kHz Flat dBm Program dBm Filter Response ChecksFilter Response Checks Input TMS Brdg Input BalanceBridging Loss TMS BrdgAttenuator Calibration Adjustment and Calibration ProcedurePower Supply Check Unbal CalibrationBalance Check Frequency Response AdjustmentCommon Mode Adjustment Filter Calibration Assembly RemovalTroubleshooting Procedures 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 GroundRange dBm Pin 1 to Pin 2 to 11. Factory Selected Values10. Resistance Checks 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&PTransmission and Noise Measuring SET Appendix CManual Backdating Changes 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