HP TM 11-6625-2779-14&P Factory Selected Values, Resistance Checks, Range dBm Pin 1 to Pin 2 to

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Section V

Table 5-9. Range Attenuation and Amplifier Gain

	Attenuator Pads Used				Amplifier Gain
	(See Figure 7-3)				Switching
RANGES	1	2	3	4

+30	X	X	X
+20	X	X		X
+10	X	X
0		X	X
-10		X		X
-20		X
-30			X
-40				X
-50
-60					A2R13, A2R14
-70					A2R13
-80
Ranges Affected	+30	-20	+30	+20	-60 and -70
If Defective	+20	thru	0	-10
	+10	+30	-30	-40

Model 3555B

Table 5-11. Factory Selected Values

Designator	Purpose
C4	Adjust balance at 600kHz, 135 BAL
A1C5	Padding capacitor for A1 C4
A1C9	Adjust balance 20kHz, 600 BAL (VF/Nm)
A1C8	Padding capacitor for A1C7
A1C10 and	Frequency response correction for A1TI
A1R12
A1R14	600 BAL, VF/Nm calibration
A3C1	Padding capacitor for A2C12
A3C15	Frequency response, 20Hz, -80dBm, 600
	BAL (VF/Nm)
A3R46	Adjust the bias level for A3Q10 (-10V at +
	side of A3C24)
A3R72	Response, 20Hz, 600 BAL (VF/Nm)
	-70dBm and 20Hz, 900 BAL, 0dBm.
	Compromise between these two settings.
A3R74and	Meter tracking at 1/3 full scale. Resistors
A3R75	should be the same value.

Table 5-10. Resistance Checks

RANGE (dBm)	Pin 1 to 3		Pin 2 to 3	Pin 1 to 2
-50 thru +30	154 kilohms		0	Infinity
-60	13 kilohms		28.64 kilohms	41.6 kilohms
-70	2.33 kilohms		28.64 kilohms	31 kilohms
-80	0		28.64 kilohms	28.64 kilohms
	5-16

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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 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 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 MSG dBm 3kHz Flat dBm 15kHz Flat dBm Program dBm Filter Response ChecksFilter Response Checks TMS Brdg Input BalanceBridging Loss Input TMS BrdgUnbal Calibration Adjustment and Calibration ProcedurePower Supply Check Attenuator CalibrationBalance Check Frequency Response AdjustmentCommon Mode Adjustment Filter Calibration Assembly RemovalTroubleshooting Procedures 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 TermRange dBm Pin 1 to Pin 2 to 11. Factory Selected Values10. Resistance Checks 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 NumberTransmission and Noise Measuring SET Appendix CManual Backdating Changes 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