HP (Hewlett-Packard) 8808A User Manual

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TM 11-6625-2872-14&P

TECHNICAL MANUAL

OPERATOR'S, ORGANIZATIONAL,

DIRECT SUPPORT AND GENERAL SUPPORT

MAINTENANCE MANUAL

(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)

FOR

PREAMPLIFIER, LOGARITHMIC

AM-6681(V)1/U

(HEWLETT-PACKARD MODEL 8808A)

(NSN 6625-00-134-3557)

HEADQUARTERS, DEPARTMENT OF THE ARMY

12 MARCH 1981

SAFETY STEPS TO FOLLOW IF SOMEONE IS THE VICTIM OF ELECTRICAL SHOCK

12345

DO NOT TRY TO PULL OR GRAB THE INDIVIDUAL

IF POSSIBLE, TURN OFF THE ELECTRICAL POWER

IF YOU CANNOT TURN OFF THE ELECTRICAL POWER, PULL, PUSH, OR LIFT THE PERSON TO SAFETY USING A DRY WOODEN POLE OR A DRY ROPE OR SOME OTHER INSULATING MATERIAL

SEND FOR HELP AS SOON AS POSSIBLE

AFTER THE INJURED PERSON IS FREE OF CONTACT WITH THE SOURCE OF ELECTRICAL SHOCK, MOVE THE PERSON A SHORT DISTANCE AWAY AND IMMEDIATELY START ARTIFICIAL RESUSCITATION

This manual contains copyright material reproduced by permission of the Hewlett-Packard Company.

TM 11-6625-2872-14&P

TEHNICAL MANUAL HEADQUARTERS No. 11-6625-2872-14&P WASHINGTON, DC, 12 March 1981

}

OPERATOR'S, ORGANIZATIONAL, DIRECT SUPPORT,

AND GENERAL SUPPORT MAINTENANCE MANUAL

(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)

FOR

PREAMPLIFIER, LOGARITHMIC AM-6681(V)l/U

(HEWLETT-PACKARD MODEL 8808A)

(NSN 6625-00-134-3557)

DEPARTMENT OF THE ARMY

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS You can help Improve this manual. If you find any mistakes or if you know of a way to improve the procedures, please let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms), or DA Form 2028-2 located in back of this manual direct to Commander, US Army Communications and Electronics Materiel Readiness Command, ATTN: DRSEL-ME-MQ, Fort Monmouth, NJ 07703. In either case, a reply will be furnished direct to you.

This manual is an authentication of the manufacturer's commercial literature which, through usage, has been found to cover the data required to operate and maintain this equipment. Since the manual was not prepared in accordance with military specifications, the format has not been structured to consider levels of maintenance.

SECTION 0. INTRODUCTION

Scope...................................................................................................... 0-1 0-1

Indexes of Publications . . . . .. ............................................................. 0-2 0-1

Maintenance Forms, Records, and

Reports ............................................................................................. 0-3 0-1

Reporting Equipment Improvement

Recommendations (EIR).......................................................................... 0-4 0-1

Administrative Storage ............................................................................ 0-5 0-1

Destruction of Army Electronics

Materiel............................................................................................. 0-6 0-1

I. GENERAL INFORMATION

Description .............................................................................................. 1-1 1

II. INSTALLATION

Portable Case or Rack Mounting ............................................................. 2-1 3

Installation in Sanborn Recording

Systems............................................................................................ 2-5 3

III. OPERATION

Operating Controls................................................................................... 3-1 3

Balancing ................................................................................................ 3-9 4

Calibration............................................................................................... 3-11 4

Alternate Calibration Procedure............................................................... 3-12 4

Operation ................................................................................................ 3-14 4

50 dB Span Operation ............................................................................. 3-17 5

100 dB Span Operation ........................................................................... 3-21 5

Operation with Monitoring Instruments ..................................................... 3-25 5

Simultaneous Recording and Monitoring

of 8808A Output................................................................................ 3-27 5

TM 11-6625-2872-14&P

TABLE OF CONTENTS

Paragraph Page

IV. PRINCIPLES OF OPERATION

Output ..................................................................................................... 4-1 6

Stage Description .................................................................................... 4-2 6

Signal Flow.............................................................................................. 4-3 6

Dynamic Range....................................................................................... 4-4 6

Block Diagram Information ...................................................................... 4-5 6

Detector Outputs ..................................................................................... 4-6 6

DB SPAN Switch Circuit.......................................................................... 4-7 6

LOG ZERO Level Setting........................................................................ 4-8 6

V. REPLACEABLE PARTS

Introduction.............................................................................................. 5-1 8

Ordering Information................................................................................ 5-3 8

TM 11-6625-2872-14&P

TABLE OF CONTENTS - Continued

Page

APPENDIX A. REFERENCES.................................................................................................... A-1

B. COMPONENTS OF END ITEM LIST (COEIL)

(Not applicable)

C. BASIC ISSUE ITEMS LIST (BIIL)

(Not applicable)

D. MAINTENANCE ALLOCATION

Section I. Introduction.......................................................................................................... D-1

II. Maintenance Allocation Chart for Plug-In

Amplifier AM-6681(V)1/U .............................................................................. D-3

III. Tool and Test Equipment Requirements for

Plug-In Amplifier AM-6681(V)1/U .................................................................. D-4

iii

TM 11-6625-2872-14&P

LIST OF ILLUSTRATIONS

Number Page

1-1 8808A Log Level Preamplifier.................................................................................................... 1

4-1 8808A Successive Detector ...................................................................................................... 7

4-2 8808A Block Diagram ................................................................................................................ 7

FO 5-1 Model 8808A Log Level Schematic............................................................................................ In back

of manual

LIST OF TABLES

Number Page

1-1 Specifications ............................................................................................................................ 2

3-1 Bottom and Full Scale Signal Levels.......................................................................................... 3

5-1 Reference Designation Index ..................................................................................................... 9

5-2 Part Number - National Stock Number

Cross Reference Index ........................................................................................................ 17

TM 11-6625-2872-14&P

SECTION 0

INTRODUCTION

0-1. SCOPE.

This manual describes Logarithmic Preamplifier AM-6681(V)1/U and provides instructions for operation and maintenance. Throughout this manual, the preamplifier is referred to as Hewlett-Packard Model 8808A Log-Audio Preamplifier.

0-2. INDEXES OF PUBLICATIONS.

a. DA Pam 310-4. Refer to the latest issue of DA Pam 310-4 to determine whether there are new editions, changes, or additional publications pertaining to the equipment.

b. DA Pam 310-7. Refer to DA Pam 310-7 to determine whether there are modification work orders (MWO's) pertaining to the equipment.

0-3. MAINTENANCE FORMS, RECORDS, AND REPORTS.

a. Reports of Maintenance and Unsatisfactory Equipment. Department of the Army forms and procedures used for equipment maintenance will be those prescribed by TM 38-750, The Army Maintenance Management System.

b. Report of Item and Packaging Discrepancies. Fill out and forward SF 364 (Report of Discrepancy (ROD)) as prescribed in AR 735-11-2/DLAR 4140.55/NAVMATINST 4355.73/AFR 400-54/MCO 4430.3E.

c. Discrepancy in Shipment Report (DISREP) (SF 361). Fill out and forward Discrepancy in Shipment Report (DISREP) (SF 361) as prescribed in AR 55-38/NAVSUPINST 4610.33B/AFR 75-18/MCO P4610.19C and DLAR 4500.15.

0-4. REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR).

If your equipment needs improvement, let us know. Send us an EIR. You, the user, are the only one who can tell us what you don't like about your equipment. Let us know why you don't like the design. Tell us why a procedure is hard to perform. Put it on an SF 368 (Quality Deficiency Report). Mail it to Commander, US Army Communications and Electronics Materiel Readiness Command, ATTN: DRSEL-ME-MQ, Fort Monmouth, New Jersey 07703. We'll send you a reply.

0-5. ADMINISTRATIVE STORAGE.

Administrative storage of equipment issued to and used by Army activities shall be in accordance with TM 740-90-1. 0-6. DESTRUCTION OF ARMY ELECTRONICS MATERIEL.

Destruction of Army electronics materiel to prevent enemy use shall be in accordance with TM 750-244-2.

0-1/(0-2 Blank)

SECTION I

GENERAL INFORMATION

1-1. DESCRIPTION. 1-2 The 8808A is a Log Level Preamplifier which

produces a dc output proportional to the logarithm of the ac input signal, over an extremely wide range of signal amplitudes. The input signal dynamic range can be up to 100 dB (100,000:1). In addition, a 50 dB (320:1) span is provided for greater signal resolution

1-3. The Preamplifier is designed for use with low output impedance accelerometers, as well as vibration and acoustic transducers, which have outputs in the frequency range of 5 Hz to 100 kHz. It is also useful for continuous monitoring or recording of signal output in dB during frequency analysis of amplifiers, filters, transmission networks, and similar devices.

1-4. The 8808A can be plugged into Sanborn direct writing recording systems. When used with recorders having 50 division chart paper, the calibrated output is 2 dB per division for the 100 dB span, or 1 dB per division for the 50 dB span. Also, the preamplifier can be benchtop or rack mounted, with the output connected to a monitoring instrument such as a voltmeter or oscilloscope. For recording, a strip chart recorder or magnetic tape recorder can be connected to the output.

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1-5. The range switch provides nine bottom scale sensitivities in 10 dB steps from 0 dBV to -80 dBV (dBV = decibels referred to 1 volt RMS). For the 50 dB span, the full scale signal is 50 dB above the bottom scale level. For the 100 dB span, the full scale signal is 100 dB above the bottom scale level.

1-6. All nine RANGE switch positions can be used with the 50 dB span. The four switch positions outlined in red on the panel (-50, -60, -70, -80) are used for the 100 dB span only.

1-7. Specifications for the 8808A Log Level Preamplifier are given in Table 1-1.

Figure 1-1. 8808A Log Level Preamplifier

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Table 1-1. Specifications

ELECTRICAL SPECIFICATIONS

INPUT RESISTANCE: Single-ended to ground 1 megohm minimum. SIGNAL DETECTION: Full-wave average. 50 dB or 100 dB span, switch selected from front panel. DETECTION ACCURACY: ± 1 dB maximum error, sine wave input. MAXIMUM SENSITIVITY: 100 µV rms of sine wave corresponds to bottom scale on most sensitive range. GAIN STABILITY: Temperature: Less than 2 dB/10°C, 0° to 40°C. Line Voltage: Less than 0.5 dB, 103 to 127 volts. ATTENUATION: 50 dB span ranges: 9 bottom scale ranges at -80 dBV to 0 dBV in 10 dB steps corresponding to

100 µV, 320 µV, 1 mV, 3.2 mV, 10 mV, 32 mV, 100 mV, 320 mV and 1 volt. Top scale is nominally 50 dB (320X) above bottom scale.

100 dB span ranges: 4 bottom scale ranges at -80 dBV to -50 dBV in 10 dB steps corresponding to 100 µV, 320 µV, 1 mV and 3.2 mV. Top scale is normally 100 dB (100,000X) above bottom scale.

ATTENUATION ACCURACY: ± 3% maximum error (0.25 dB) for -80 to -50 dBV attenuation ranges. For other ranges, detection error (± 1 dB) may add to attenuation error.

OUTPUT: Single-ended to ground, ± 2..5 V maximum or 0 to +5 volts across 1000 ohms minimum. OUTPUT RESISTANCE: Approximately 10 ohms. SIGNAL BANDWIDTH: 5 Hz to 100 kHz, less than 3 dB down from mid-band level on SLOW response range. 500 Hz to

100 kHz on FAST response range. SIGNAL CREST FACTOR: 3 to 1 at full scale on 100 dB span, ±500 volts peak maximum allowed. DETECTION RESPONSE TIME: For a step change in input amplitude with ratio of 40 dB (100:1) or greater, the time

required for the output to increase or decrease between values corresponding to 105 and 90% of the maximum applied signal (i.e. , 20 dB below max. applied signal and 1 dB below max applied signal) is approximately 20 msec in FAST position and 2 sec in SLOW position. i. e. , average rate of change of output under these conditions corresponds to approximately 900 dB/ sec in FAST: 9 dB/sec in SLOW.

OUTPUT NOISE: Maximum noise appears at bottom scale. 50 dB span: 80 mV pp: 100 dB span: 40 mV pp. INTERNAL CALIBRATION: -80 and +20 dBV, internally adjustable; -30 dBV accurate to + 0.5 dB. Stability: less than

0.25 dB, 10° to 40°C or 103 to 127 volts; approximately 500 Hz.

GENERAL SPECIFICATIONS

Terminals: DC output on front panel. Input and auxiliary DC output on rear of mating power supply. Front Panel Controls: RANGE switch; GAIN potentiometer locking; LOG ZERO, 10-turn potentiometer, locking; 50/100

dB SPAN switch; SPAN BALANCE, screwdriver adjust; RESPONSE TIME/CAL switch. Internal Controls: Signal Board: Balance adjust; CAL adjust (2); Zero Suppression adjust; Attenuator compensation trimmers (4). Detector Board: 100 dB span mid-scale adjust. Weight: Approximately 5 lb. (2, 3 kg). Front Panel Dimensions: 7" high, 2-1/16" wide (178 x 52 mm). Note: When Preamplifier is used in a recording system, these specifications are affected by performance of the recorder

and driver amplifiers. (Consult data sheet of appropriate system for details.) All Sanborn 8800 Series Amplifiers are tested for performance under normal production environmental conditions:

ambient temperature 20° to 30° C and relative humidity less than 80% unless otherwise noted.

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TM 11-625-2872-14&P

SECTION II INSTALLATION

2-1. PORTABLE CASE OR RACK MOUNTING. 2-2. The 8808A is operated as a self-contained instrument using an 860-500 Power Supply to furnish operating power for

the preamplifier. The preamplifier power supply combination operates on a 115/230 volt 50 or 60 Hz power line. See the power supply Operating and Service Manual, IM-860-500-3.

2-3. The preamplifier power supply combination can be mounted in the 860-1400 Case for single channel benchtop operation. For two channel operation, two preamplifiers and power supplies mount in an 860-200 Module, for benchtop or rack mounting.

2-4. When the 8808A is operated with the 860-500 Power Supply, preamplifier input and output signal connections are made on the rear panel of the power supply as follows:

Signal Input Jack J3: Plus (+) signal pin A

Signal ground pin B Mating connector is 10G3-34FW

Signal Output Jack J2: Plus (+) signal pin A

Signal ground pin E Mating connector is 10B9-5MW

For monitoring, connect the preamplifier output signal to a voltmeter, oscilloscope, or other voltage indicating instrument which has a signal range of 0 to +5 volts or 2.5 volts. The output signal can be recorded using a strip chart recorder, magnetic tape recorder, or other instrument which will operate with an input of 0 to +5 volts, or ± 2. 5 volts.

2-5. INSTALLATION IN SANBORN RECORDING SYSTEMS. 2-6. The 8808A can be installed in Sanborn Recording Systems 7701A, 7702A, 7704A, 7706A, 7708A, for 1, 2, 4, 6, or 8

channels of recording using the heated stylus recording technique. Operating power for the preamplifier is supplied by the recording system. See the recording system instruction manual for installation information.

2-7. The 7701A Recorder is supplied in a portable case. The 7702A Recorder is supplied either in a mobile cart, or for rack mounting. The 7706A, 7708A Recorders are rack mounted.

SECTION III OPERATION

3-1. OPERATING CONTROLS. 3-2. RANGE switch selects the bottom scale

signal level. Scale is calibrated in dBV (decibels referred to a 1 volt rrns signal). Full scale signal for 50 Db span operation is 50 dB

50 DB SPAN Range Switch Bottom Scale Full Scale Setting dBV Volts rms dBV Volts rms

above bottom scale signal. For 100 dB span, full scale signal is 100 dB above bottom scale signal. Bottom scale and corresponding full scale signal levels for each setting of the RANGE switch are given in Table 3-1.

3-3. DB SPAN switch selects either 50 dB or 100 dB maximum span between the bottom scale and full scale input signal levels.

NOTE

On the 100 dB span, only the 50, -60, -70, -80 RANGE switch positions are used.

Switch also indicates recorder calibration: 1 dB/div for 50 dB span. 2 dB/div for 100 dB

0 0 1 V +50 316 V

-10 -10 .316V +40 100 V

-20 -20 .100V +30 31.6 V

-30 -30 31.6 mnV +20 10 V

-40 -40 10 mV +10 3.16 V

-50 -50 3.16 mV 0 1 V

-60 -60 1 mV -10 .316 V

-70 -70 316 µV -20 .1 V

-80 -80 100 µV -30 31.6 mV 100 DB SPAN

-50 -50 3.16 mV +50 316 V

-60 -60 1 mV +40 100 V

-70 -70 316 µV +30 31.6 V

-80 -80 100 µV +20 10 V

span.

Table 3-1. Bottom and Full Scale Signal Levels

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3-4. GAIN control sets the preamplifier output level for a full scale cal signal applied to the preamplifier input. For use in recording systems, full scale output corresponds to the top division on the recorder chart ( approx. -2.5 volts preamp output). For use with a voltmeter or oscilloscope, full scale output is +5 volts.

3-5. LOG ZERO control sets the preamplifier output level for a bottom scale cal signal applied to the preamplifier input. For use in recording systems, bottom scale output-corresponds to the bottom division on the recording chart (approx. -2.5 volts preamp output). For use with a voltmeter or oscilloscope, bottom scale output is 0 volts.

3-6. SPAN BALANCE control balances the preamplifier, to obtain the same output on the 100 and 50 dB spans for a -80 dBV calibration signal level.

3-7. RESP TIME,/CAL DB switch selects the operating mode. FAST and SLOW response times are the use positions. OFF position disconnects the input signal from the preamplifier, and grounds the preamplifier input. -80, -30, +20 dB CAL positions select calibration voltage levels supplied by a 500 Hz oscillator in the preamp.

3-8. OUTPUT jack provides the preamplifier output signal at the front panel, for monitoring purposes. Mates with 10G222MW plug.

3-9. BALANCING 3-10. Allow preamplifier to warm up several minutes before balancing.

a. Set the RESP TIME/CAL DB and RANGE switches to the -80 position.

b. Adjust the LOG ZERO control for approximately bottom scale output.

c. Alternately set the DB SPAN switch to the 50 and 100 positions while adjusting the SPAN BALANCE control for minimum change in the preamp output.

NOTE

Approximately ± 20 mnV noise normally present at the preamplifier output will cause a slight fluctuation in the reading observed on a voltmeter or oscilloscope connected to the output.

3-11. CALIBRATION

a. Set the DB SPAN switch to 100.

b. Set the RANGE switch to 80.

c. Set the RESP TIME/CAL DB switch to -80.

d. Adjust the LOG ZERO control for bottom scale output.

e. Set the RESP TIME/CAL DB switch to +20 and adjust the GAIN control for full scale output.

f. Repeat steps 3-11 (c) through 3-11 (e) to eliminate the effects of control interaction.

g. Set the RESP TIME/CAL DB switch to OFF. With the switch OFF, a negative voltage is normally present at the preamp output, which will position the recorder stylus offscale.

NOTE

Preamp RANGE switch must be in the -80 position during the calibration procedure. 3-12. ALTERNATE CALIBRATION PROCEDURE. 3-13. To calibrate the preamplifier with the DB SPAN switch in the 50 dB position, use the below procedure:

a. Set the DB SPAN switch to 50. b. Set the RANGE switch to -80. c. Set the RESP TIME/CAL DB switch to -80. d. Adjust the LOG ZERO control for bottom scale output. e. Set the RESP TIME/CAL DB switch to -30 and adjust the GAIN control for full scale output. f. Repeat steps 3-13 (c, d, e) to eliminate the effects of control interaction. g. Set the RESP TIME/CAL DB switch to OFF. With the switch OFF, a negative voltage is normally present at the

preamp output, which will position the recorder stylus offscale. 3-14. OPERATION 3-15. Set RESP TIME/CAL DB switch to OFF. Connect input signal to preamplifier. For applications where preamplifier

is installed in Sanborn recorder, the output signal is displayed on recorder chart paper. For applications where the preamplifier output is to be monitored with an oscilloscope or voltmeter, the output is available from the preamplifier front panel OUTPUT jack, or from a rear connector on the preamplifier power supply.

3-16. Set the DB SPAN switch to the 50 dB or 100 dB position, depending on the expected range of input signal amplitudes.

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3-17. 50 dB SPAN OPERATION. 3-18. Set the RANGE switch to the position which corresponds to the minimum expected signal level. See examples 1

and 2. EXAMPLE 1: Minimum expected signal level 10 mnV rms. This corresponds to a -40 dBV signal level (see Table 3-1).

Set the RANGE switch to the -40 dBV position. The full scale signal level is 50 dB higher:

-40 dBV

add +50 dB

+10 dBV = Full scale input signal = 3.16 volts rms

EXAMPLE 2: Minimum expected signal level .5 volt rms. This corresponds to a -6 dBV signal level. Since there is no 6 dBV switch position, set the switch to the next lower step, which is -10 dBV. The full scale signal level is 50 dB higher:

-10 dBV

add +50 dB

-40 dBV Full scale input signal = 100 volts rms

3-19. Set the RESP TIME/CAL DB switch to the FAST or SLOW position, depending on the signal bandwidth, and the detection response) time desired. (For FAST response, the preamp) bandwidth is 500 to 100,000 Hz. For SLOW response, bandwidth is 5 to 100,000 Hz.)

3-20. For 50 division chart paper, the calibration is 1 dB/div. The bottom division on the chart represents the bottom scale signal level in dB indicated on the RANGE switch.

3-21. 100 dB SPAN OPERATION. 3-22. Only the four RANGE switch positions outlined in red (-80, -70, -60, -50) are used for the 100 dB span. Set the

RANGE switch to the position which corresponds to the expected minimum signal level. EXAMPLE 1: Minimum expected signal is 1 mV rms. This corresponds to a -60 dBV level (see Table 3-1). Set RANGE

switch to the - 6OdBV bottom scale position. The full scale signal level is l00dB higher:

- 60 dBV

add +100 dB

+ 40 dBV = Full scale input signal = 100 volts rms

EXAMPLE 2: Minimum expected signal is 500 µV rms. This corresponds to a -66 dBV level. Set the RANGE switch to the next lower step, which is the -70 dBV bottom scale position. The full scale signal level is 100 dB higher:

- 70 dBV

add +100 dB

+ 30 dBV = Full scale input signal = 31.6 volts rms

3-23. Set the RESP TIME/CAL DB switch to the FAST or SLOW position, depending on the signal blind bandwidth, and the detection response time desired. (For FAST response, the preamp bandwidth is 500 to 100,000 Hz. For SLOW response, bandwidth is 5 to 100,000 Hz.)

3-24. For 50 division chart paper, the calibration is 2 dB/div. The bottom division on the chart represents the bottom scale signal level in dBV indicated on the RANGE switch.

3-25. OPERATION WITH MONITORING INSTRUMENTS. 3-26. When the preamplifier output is connected only to a monitoring instrument such as a dc voltmeter or oscilloscope,

perform the balancing (Section 3-9) and calibration (Section 3-11) procedure as indicated. Bottom scale output refers to 0 volts preamplifier output. Full scale output is -5 volts preamplifier output. The 50 dB span calibration is .1 volts/dB. The 100 dB span calibration is .05 volts/dB.

3-27. SIMULTANEOUS RECORDING AND MONITORING OF 8808A OUTPUT. 3-28. To simultaneously record and monitor the 8808A output signal, perform the balancing and calibration procedure

using the recorder. The dc voltmeter, oscilloscope, or other monitoring instrument connected to the output of the preamp will read approximately -2.5 volts for a bottom scale input signal, and approximately +2.5 volts for a full scale input signal. The monitor instrument calibration is .1 V/dB on the 50 dB span, and .05 V/dB on the 100 dB span.

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TM 11-6625-2872-14&P

SECTION IV

PRINCIPLES OF OPERATION

4-1. The 8808A Log Level Preamplifier is designed to produce a logarithmic output (in decibel units) on a linear scale for a wide dynamic range (100 dB) of input signals. The wide dynamic range is achieved by the use of a combination of series and shunt successive detector stages. The block diagram (Figure 4-1) shows a simple series of successive detector stages with logarithmic compression networks, similar to those used in the 8808A.

4-2. Each stage consists of a linear amplifier having a gain of 16-2/3 dB. Limiting diodes at the input of each stage prevent amplifier saturation. The full-wave detector output drives a logarithmic response shaping network. The outputs of all stages are connected to a summing resistor. This series of stages handles the first 50 dB of amplifier signal input. For 100 dB span operation, a second series of successive detectors covers the remaining 50 dB of signal range.

4-3. Signal flow as shown in Figure 4-1 is as follows: A small ac signal appearing at the input is amplified by stage 3, but not sufficiently to provide detector output. The signal is further amplified by stage 2, but is still not sufficient amplitude to detect. The signal is amplified by stage 1 to a level sufficient to operate the first detector. The output of the fullwave detector is compressed by a three-line segment logarithmic compression network. All compression network outputs are connected to the summing resistor. As the input level increases, successive compression in stages 2 and 3 perform a similar function, feeding their output to the summing junction.

4-4. The very wide dynamic range of the 8808A is made possible by the progressive summing of the outputs of each of the detector stages, which by themselves operate linearly over a 16-2/3dB range.

4-5. The overall block diagram for the 8808A is shown in Figure 4-2. A signal at the input sees the input Attenuator which is followed by a differential, low noise operational amplifier using field effect transistors. The amplifier output is connected to a series of detector and compressor networks to provide the first 50 dB of operating range. A shunt signal path with a hybrid emitter follower drives the lower series of detector networks for the remaining, 50 dB of signal level.

4-6. The detector outputs are summed into a balanced dc amplifier. The SPAN BALANCE, control and zero suppression circuit outputs are also summed into the balanced amplifier. The action of the SPAN BALANCE control is to produce the same bottom scale output from the dc amplifier on the 50 dB and 100 dB spans. The zero suppression circuit works in conjunction with the input Attenuator.

4-7. The DB SPAN switch circuit is located in the feedback loop of the balanced dc amplifier to produce a 2:1 gain change in the amplifier output, depending on the setting of the SPAN switch.

4-8. The output of the balanced amplifier is fed to a shunt gain control, followed by the output differential to single-ended dc amp which has a dc signal summed in from the LOG ZERO control to set log zero level.

ELECTRICAL SAFETY

The electrical safety of this product has been considered in its design and production, and its construction has employed techniques and components in accordance with the National Electrical Code and Underwriters Laboratories, Inc. These safety features apply only if the product is connected to a primary power distribution system which provides adequate grounding and is installed and maintained in accordance with the National Electrical Code. When this product is interconnected with other electrical appliances in its normal operation, it is important that these other appliances also be provided with adequate grounding protection, where required, if they are, in turn, connected to a primary power source. Faults occurring in any interconnected appliance can degrade the safety of this product by means of the electrical interconnections necessary for its normal systems operation. Recommendations indicating some of the accessory appliances which may be used with this product are given elsewhere in this publication.

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Figure 4-1. 8808A Successive Detector Stages

Figure 4-2. 8808A Block Diagram

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SECTION V

REPLACEABLE PARTS

5-1. INTRODUCTION. 5-2. This section contains information for locating and ordering replacement parts. Table 5-1 provides the following information for each item.

a. Lists electrical parts in alpha-numeric order of their reference designators. b. The Sanborn stock number. c. The part description.

d. Lists miscellaneous parts in numerical order 5-3. ORDERING INFORMATION. 5-4. To order a replacement part, note the part number and then cross reference that part number to the National Stock Number in table 5-2; then order through normal ordering channels. If the part number does not have a National Stock Number, then order the part through normal ordering channels using the commercial part number. Specify the following information for each part:

a. Model and s/n of the instrument.

b. Sanborn stock number.

c. Circuit reference designator.

d. Description. 5-5. To order a part not listed in the tables, give a complete description of the part and include its function and location.

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Table 5-1. Reference Designation Index

Circuit Assembly Reference Part Number Description Location

END ITEM 8808A LOG LEVEL PREAMPLIFIER A1

08808-60020 PRINTED CIRCUIT BOARD ASSY. A2 08808-60030 PRINTEID CIRCUIT BOARD ASSY. A3 08808-60050 SWITCH ASSEMBLY A4

ACCESSORY Page 15 MISCELLANEOUS Page 16

C1 8PA-6 Capacitor, 100 pF A2 C2 8PA-6 Same, as C1 A2 C3 0121-0163 Capacitor, 7-45 pF A2 C4 0160-2388 Capacitor, 47 MFD 400V A2 C5 8PA-35 Capacitor, 1000 pF 5% A2 C6 0160-2386 Capacitor, 470 pF A2 C7 0121-0160 Capacitor, 210-1000 pF A2 C8 0160-2384 Capacitor, 120 pF A2 C9 0121-0160 Same as C7 A2 C10 0160-2383 Capacitor, 100 pF 1% A2 C11 8C-61 Capacitor, 20 MFD 20V A2 C12 8C-61 Same as C11 A2 C13 0160-2387 Capacitor, 1000 pF 1% A2 C14 8B-201 Capacitor, .0047 MFD 10% A2 C15 8B-213 Capacitor, .0033 MFD A2 C16 8B-145 Capacitor, .005 MFD 5% A2 C17 0180-0374 Capacitor, 10 MFD 20V A3 C18 8B-68 Capacitor, .01 MFD A3 C19 0180-0022 Capacitor, 3.9 MFD 35V A3 C20 8T-31 Capacitor, .22 MFD A3 C21 0180-0374 Same as C17 A3 C22 0180-0195 Capacitor, .33 MFD A3 C23 0180-0022 Same as C19 A3 C24 8T-31 Same as C20 A3 C25 0180-0374 Same as C17 A3 C26 0180-0195 Same as C22 A3 C27 0180-0022 Same as C19 A3 C28 8B-68 Same as C18 A3 C29 8B-68 Same as C18 A3 C30 0121-0163 Capacitor, 7-45 pF A2 C31 0160-2385 Capacitor, 150 pF A2 C32 8B-68 Same as C18 A3 C33 0180-0022 Same as C19 A3 C34 0180-0374 Same as C17 A3 C35 8B-68 Same as C18 A3 C36 0180-0022 Same as C19 A3 C37 8T-31 Same as C20 A3 C38 0180-0374 Same as C17 A3 C39 8B-68 Same as C18 A3 C40 0180-0022 Same as C19 A3 C41 8T-31 Same as C20 A3 C42 0180-0374 Same as C17 A3 C43 8B-68 Same as C18 A3 C44 0180-0022 Same as C19 A3

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index (Cont.)

Circuit Assembly Reference Part Number Description Location C45 5080-3722 Capacitor, 27 MFD 10V A2 C46 5080-3723 Capacitor, .22 MFD A2 C47 5080-3722 Same as C45 A2 C48 5080-3723 Same as C46 A2 C49 8B-68 Capacitor, .01 MFD A2 C50 8B-68 Same as C49 A2 C51 8B-68 Same as C49 A2 C52 8B-213 Same as C15 A2 C53 0180-1862 Capacitor, 120 MFD 15V A3 C54 0180-1862 Same as C53 A3 C55 0180-1862 Capacitor, 120 MFD 15V A2 C56 0180-1862 Same as C55 A2 C57 8B-181 Capacitor, .22 MFD A2 C58 8E-28 Capacitor 0033 MFD A2 C59 8E-28 Same as C58 A2 C61 8E-21 Capacitor, 68 pF A2 CR1 16A-79 Diode A2 CR2 16A-79 Same as CR1 A2 CR3 16A-79 Same as CR1 A2 CR4 16A-79 Same as CR1 A2 CR5 16A-79 Same as CR1 A2 CR6 16A-83 Diode (3 Pellet) A2 CR7 16A-83 Same as CR6 A2 CR8 16A-79 Diode A3 CR9 16A-79 Same as CR8 A3 CR10 16A-79 Same as CR8 A3 CR11 16A-79 Same as CR8 A3 CR12 1901-0378 Diode, Silicon Stabistor (2 Pellet) A3 CR13 1901-0378 Same as CR12 A3 CR14 1910-0016 Diode, Germanium A3 CR15 1910-0016 Same as CR14 A3 CR16 16A-45A Diode A3 CR17 1901-0378 Same as CR12 A3 CR18 1901-0377 Diode, Silicon Stabistor (3 Pellet) A3 CR19 16A-79 Same as CR8 A3 CR20 16A-79 Same as CRR A3 CR21 16A-79 Same as CR8 A3 CR22 16A-79 Same as CR8 A3 CR23 1901-0378 Same as CR12 A3 CR24 1901-0378 Same as CR12 A3 CR25 1910-0016 Same as CR14 A3 CR26 1910-0016 Same as CR14 A3 CR27 16A-45A Same as CR16 A3 CR28 1901-0378 Same as CR12 A3 CR29 1901-0377 Same as CR18 A3 CR30 16A-79 Same as CR8 A3 CR31 16A-79 Same as CR8 A3 CR32 16A-79 Same as CR8 A3 CR33 16A-79 Same as CR8 A3 CR34 1901-0378 Same as CR12 A3 CR35 1901-0378 Same as CR12 A3 CR36 16A-45A Same as CR16 A3 CR37 16A-45A Same as CR16 A3 CR38 16A-45A Same as CR16 A3 CR39 1901-0378 Same as CR12 A3

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index (Cont.)

Circuit Assembly Reference Part Number Description Location CR40 1901-0377 Same as CR18 A3 CR41 1910-0016 Same as CR14 A3 CR42 1910-0016 Same as CR14 A3 CR43 16A-45A Same as CR16 A3 CR44 1901-0378 Same as CR12 A3 CR45 16A-79 Same as CR8 A3 CR46 16A-79 Same as CR8 A3 CR47 16A-79 Same as CR8 A3 CR48 16A-79 Same as CR8 A3 CR49 1901-0378 Same as CR12 A3 CR50 1901-0378 Same as CR12 A3 CR51 1910-0016 Same as CR14 A3 CR52 1910-0016 Same as CRI4 A3 CR53 16A-45A Same as CR16 A3 CR54 1901-0378 Same as CR12 A3 CR55 1901-0377 Same as CR18 A3 CR56 16A-79 Same as CR8 A3 CR57 16A-79 Same as CR8 A3 CR58 16A-79 Same as CR8 A3 CR59 16A-79 Same as CR8 A3 CR60 1901-0378 Same as CR12 A3 CR61 1901-0378 Same as CR12 A3 CR62 1910-0016 Same as CR14 A3 CR63 1910-0016 Same as CR14 A3 CR64 16A-45A Same as CR16 A3 CR65 1901-0378 Same as CR12 A3 CR66 1901-0377 Same as CR18 A3 CR67 16A-79 Same as CR8 A3 CR68 16A-79 Same as CR8 A3 CR69 16A-79 Same as CR8 A3 CR70 16A-79 Same as CR8 A3 CR71 1901-0378 Same as CR12 A3 CR72 1901-0378 Same as CR12 A3 CR73 1910-0016 Same as CR14 A3 CR74 1910-0016 Same as CR14 A3 CR75 16A-45A Same as CR16 A3 CR76 1901-0378 Same as CR12 A3 CR77 1901-0377 Same as CR18 A3 CR78 16A-45A Diode A2 CR79 16A-45A Same as CR78 A2 CR80 16A-45A Same as CR78 A2 J1 10G16-IMX Connector, 16-pin A1 J2 10G2-22FX Mini-Jack A1 Q1A, 1B 1855-0031 Transistor, Field Effect A2 Q2 1854-0202 Transistor, 2N3390 A2 Q3 1854-0202 Same as Q2 A2 Q4 16T-81 Transistor, SM9143 A2 Q5 16T-81 Same as Q4 A2 Q6 16T-79 Transistor, 2N3391 A3 Q7 16T-50 Transistor, 2N1309 A3 Q8 16T-79 Same as Q6 A3 Q9 16T-50 Same as Q7 A3 Q10 16T-79 Same as Q6 A3 Q11 16T-50 Same as Q7 A3

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index (Cont.)

Circuit Assembly Reference Part Number Description Location Q12 16T-78 Transistor, 2N3393 A2 Q13 16T-76 Transistor, 53-10 A2 Q14 16T-79 Same as Q6 A3 Q15 16T-50 Same as Q7 A3 Q16 16T-79 Same as Q6 A3 Q17 16T-50 Same as Q7 A3 Q18 16T-79 Same as Q6 A3 Q19 16T-50 Same as Q7 A3 Q20 5080-3724 Transistor, 54-23 A2 Q21 5080-3724 Same as Q20 A2 Q22 16T-76 Same as Q13 A2 Q23 16T-76 Same as Q13 A2 Q24 16T-78 Same as Q12 A2 Q25 16T-78 Same as Q12 A2 Q26 16T-81 Same as Q4 A2 Q27 16T-61 Transistor, 2N3053 A2 Q28 16T-61 Same as Q27 A2 Q29 16T-61 Same as Q27 A2 R1 50AB-155J Resistor, 1.5 Meg ±5% A4 R2 50AB-335J Resistor, 3.3 Meg ±5% A4 R3 0698-4981 Resistor, 32.4K 1%o A2 R4 50E-124F Resistor, 120K 1% A2 R5 50E-825-3F Resistor, 825K 1'% A4 R6 50E-976-3F Resistor, 976K 1% A2 R7 50E-205F Resistor, 2 Meg 1% A2 R8 50AB-472J Resistor, 4.7K 5% A2 R9 50E-503F Resistor, 50K 1% A2 R10 56PA-17 Potentiometer, 250 Ohm A2 R11 50E-403F Resistor, 40K 1% A2 R12 50E-503F Same as R9 A2 R13 50AB-472J Same as R8 A2 R14 0757-0309 Resistor, 61.9K 1% A2 R15 50E-104F Resistor, I00K% A2 R16 50E-104F Same as R15 A2 R17 50E-204F Resistor, 200K 1% A2 R18 50AB-472J Same as R8 A2 R19 50AB-222J Resistor, 2.2K 5% A2 R20 50AB-471J Resistor, 470 Ohm 5% A2 R21 50E-316-2F Resistor, 31.6K 1% A2 R22 50AB-331J Resistor, 330 Ohm 5% A2 R23 50AB--221J Resistor, 220 Ohm 5% A2 R24 50E-101F Resistor, 100 Ohm 1% A2 R25 50AB-223J Resistor, 22K ±5% A3 R26 50AB-472.J Resistor. 4.7K ±5% A3 R27 50E-133-2F Resistor, 13.3K ±1% A3 R28 50E-202F Resistor, 2K ±1% A3 R29 50AB-472J Same as R26 A3 R30 50AB-332J Resistor, 3.3K ±5% A3 R31 50E-153F Resistor, 15K ±1% A3 R32 50E-153F Same as R31 A3 R33 50E-104F Resistor, 100K ±1% A3 R34 50E-104F Same as R33 A3 R35 50AB-152J Resistor, 1. 5K 5% A2 R36 50E-504F Resistor, 500K ±1% A3 R37 50E-353F Resistor, 35K ±1% A3

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index (Cont.)

Circuit Assembly Reference Part Number Description Location R38 50E-105F Resistor, 1 Meg ±1% A3 R39 50E-105F Same as R38 A3 R40 50AB-223J Sane as R25 A3 R41 50AB-472J Same as R26 A3 R42 50E-133-2F Same as R27 A3 R43 50E-202F Same as R28 A3 R44 50AB-472J Same as R26 A3 R45 50AB-332J Same as R30 A3 R46 50E-153F Same as R31 A3 R47 50E-153F Same as R31 A3 R48 50E-104F Same as R33 A3 R49 50E-104F Same as R33 A3 R50 50E-504F Same as R36 A3 R51 50E-353F Same as R37 A3 R52 50E-105F Same as R38 A3 R53 50E-105F Same as R38 A3 R54 50AB-223J Same as R25 A3 R55 50AB-472J Same as R26 A3 R56 50E-133-2F Same as R27 A3 R57 50E-202F Same as R28 A3 R58 50AB-472J Same as R26 A3 R59 50AB-332J Same as R30 A3 R60 50E-153F Same as R31 A3 R61 50E-153F Same as R31 A3 R62 50E-104F Same as R33 A3 R63 50E-104F Same as R33 A3 R64 50E-105F Same as R38 A3 R65 50E-104F Same as R33 A3 R66 50E-105F Same as R38 A3 R67 50E-105F Same as R38 A3 R68 50E-185F Resistor, 1.8 Meg 1% A2 R69 50E-204F Same as R17 A2 R70 50AB-224J Resistor, 220K 5% A2 R71 50E-153F Same as R31 A3 R72 50E-153F Same as R31 A3 R73 50E-104F Same as R33 A3 R74 50E-104F Same as R33 A3 R75 50E-504F Same as R36 A3 R76 50E-204F Resistor, 200K ±1% A3 R77 50E-105F Same as R38 A3 R78 50E-105F Same as R38 A3 R79 50AB-223J Same as R25 A3 R80 50AB-472J Same as R26 A3 R81 50E-133-2F Same as R27 A3 R82 50E-202F Same as R28 A3 R83 50AB-472J Same as R26 A3 R84 50AB-332J Same as R30 A3 R85 50E-153F Same as R31 A3 R86 50E-153F Same as R31 A3 R87 50E-104F Same as R33 A3 R88 50E-104F Same as R33 A3 R89 50E-504F Same as R36 A3 R90 50E-353F Same as R37 A3 R91 50E-105F Same as R38 A3 R92 50E-105F Same as R38 A3 R93 50AB-223J Same as R25 A3 R94 50AB-472J Same as R26 A3

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Table 5-1. Reference Designation Index (Cont.)

Circuit Assembly Reference Part Number Description Location R95 50E-133-2F Same as R27 A3 R96 50E-202F Same as R28 A3 R97 50AB-472J Same as R26 A3 R98 50AB-332J Same as R30 A3 R99 50E-153F Same as R31 A3 R100 50E-153F Same as R31 A3 R101 50E-104F Same as R33 A3 R102 50E-104F Same as R33 A3 R103 50E-504F Same as R36 A3 R104 50E-353F Same as R37 A3 R105 50E-105F Same as R38 A3 R106 50E-105F Same as R38 A3 R107 50AB-223J Same as R25 A3 R108 50AB-472J Same as R26 A3 R109 50E-103F Resistor, 10K 1% A3 R110 50E-202F Same as R28 A3 R111 50AB-472J Same as R26 A3 R112 56PA-47 Potentiometer, 10K A3 R113 50AB-332J Same as R30 A3 R114 50E-153F Same as R31 A3 R115 50E-153F Same as R31 A3 R116 50E-104F Same as R33 A3 R117 50E-104F Same as R33 A3 R118 50E-504F Same as R36 A3 R119 50E-353F Same as R37 A3 R120 50E-105F Same as R38 A3 R121 50E-105F Same as R38 A3 R122 50AB-221J Same as R23 A2 R123 50AB-123J Resistor, 12K 5% A2 R124 5OAB-474J Resistor, 470K 5% A2 R125 50AB-474J Same as R124 A2 R126 50AB-123J Same as R123 A2 R127 50E-103F Resistor, 10K l% A2 R128 50AB-682J Resistor, 6.8K 5% A2 R129 56PA-47 Potentiometer, 10K A2 R130 50E-503F Same as R9 A2 R131 50E-503F Same as R9 A2 R132 50E-1O1F Same as R24 A2 R133 50E-158-OF Resistor, 158 Ohm 1% A2 R134 56PA-17 Same as R10 A2 R135 56PA-37 Potentiometer, 2. 5K A2 R136 50E-202F Resistor, 2K 1% A2 R137 0757-1011 Resistor, 18K 1% A2 R138 50E-50OF Resistor, 50 Ohm 1% A4 R139 50E-252F Resistor, 2. 5K 1% A2 R140 50E-50OF Same as R138 A4 R141 50E-50OF Same as R138 A4 R142 50E-50OF Same as R138 A4 R143 50E-500F Same as R138 A4 R144 0811-1797 Resistor, 50K 3% A2 R145 56S-8 Potentiometer, 1000 Ohm (SPAN BAL) A1 R146 50E-254F Resistor, 250K 1% A2 R147 50AB-153J Resistor, 15K 5% A2 R148 50AB-153J Same as R147 A2 R149 50E-254F Same as R146 A2 R150 50E-253F Resistor, 25K 1% A2 R151 50AB-124J Resistor, 120K 5% A2

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index Cont.

Circuit Assembly Reference Part Number Description Location R152 50E-253F Same as R150 A2 R153 50AB-103J Resistor, 10K 5% A2 R154 50AB-392J Resistor, 3.9K 5% A2 R155 0811-1797 Same as R144 A2 R156 50E-303F Resistor, 30K 1% A2 R157 50AB-123J Same as R123 A2 R158 50E-303F Same as R156 A2 R159 0811-1797 Same as R144 A2 R160 0811-1797 Same as R144 A2 R161 50E-104-2F Resistor, 10.4K 1% A2 R162 50E-752F Resistor, 7.5K 1% A2 R163 50E-503F Same as R9 A2 R164 50E-103F Same as R127 A2 R165 50E-103F Same as R127 A2 R166 56S-35 Potentiometer, 250K (GAIN) A1 R167 50E-253F Same as R150 A2 R168 50E-103F Same as R127 A2 R169 50E-103F Same as R127 A2 R170 50E-316-2F Same as R21 A2 R171 50AB-472J Same as R8 A2 R172 50AB-123J Same as R123 A2 R173 50AB-272J Resistor, 2.7K 5% A2 R174 50AB-121J Resistor, 120 Ohm 5% A2 R175 50E-403F Same as R11 A2 R176 56E-7 Potentiometer, 50K (LOG ZERO) A1 R177 50E-403F Same as R11 A2 R178 50AB-1OOJ Resistor, 10 Ohm s5% A3 R179 50AB-1OOJ Same as R178 A3 R180 50E-154F Resistor, 150K 1% A2 R181 50AB-562J Resistor, 5.6K 5% A2

S1 62B-219 Switch, Rotary A1 S2 62B-220 Switch, Wafer 3-Section, 9-Position A4 S3 62D-48 Switch, Toggle DPDT A1

T1 56T-11 Thermister, 20K A2

ACCESSORY

10G2-22MW Phone Plug A1

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TM 11-6625-2872-14&P

Table 5-1. Reference Designation Index (Cont.)

Assembly

Quantity Part Number Description Location

MISCELLANEOUS

2 0370-0077 Knob A1 1 652-65 Nameplate (08808-00020) A1 1 816-64 Plate, Connector A1 1 833-5 P1 Stand-Off A1 1 833-6 P1 Nut A1 1 860-3002 Chassis, Upper A1 1 860-3003 Chassis, Lower A1 2 860-4005 Plate, Side A1 1 08800-20010 Handle A1 1 08808-00010 Panel, Front A1 1 08808-00050 Bracket, Printed Circuit Board A1 1 752-427 Printed Board A2 1 01260-20501 Heat Sink, Bottom A2 1 01260-20601 Heat Sink, Top A2 1 752-428 Printed Board A3

SHAFT LOCK (1/8 SHAFT)_817-C1

1 817-5 Bushing, Shaft Lock 1 817-2 Knob, Shaft Lock 1 7-7 Washer, Shaft Lock (Lower) 1 817-6 Washer, Shaft-Lock (Upper) 1 817-1 Nut, Shaft-Lock 1 81D-4-3/2Z 3/32 x 4-40 Allen Head Set Screw 1 81D-4-2Z 1/8" x 4-40 Allen Head Set Screw

SHAFT LOCK (1/4" SHAFT) 817-C2

1 817-4 Bushing, Shaft-Lock 1 817-3 Knob, Shaft-Lock 1 817-7 Washer, Shaft-Lock (Lower) 1 817-6 Washer, Shaft-Lock (Upper) 1 817-1 Nut, Shaft-Lock 1 81D-4-3/2Z 3/32 x 4-40 Allen Head Set Screw 1 81D-4-2Z 1/8" x 4-40 Allen Head Set Screw

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TM 11-6625-2872-14&P

Table 5-2.

PART NUMBER - NATIONAL STOCK NUMBER

CROSS REFERENCE INDEX

PART NATIONAL PART NATIONAL

NUMBER FSCM STOCK NO. NUMBER FSCM STOCK NO.

0180-0022 28480 5910-00-538-3597 0180-0195 28480 5910-00-444-6642 0180-0374 28480 5910-00-931-7050 0370-0077 28480 5355-00-767-9444 0370-1107 28480 5355-01-011-4975 0698-3420 28480 5905-00-931-4067 0757-0309 28480 5905-00-632-5238 0757-0837 28480 5905-00-850-2180 0757-0843 28480 5905-00-830-6751 1910-0016 28480 5961-00-954-9182 5080-3724 28480 5961-00-105-4694 8808A 28480 6625-00-134-3557

Foldout figure 5-1 is located in back of the manual.

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TM 11-6625-2872-14&P

APPENDIX A

REFERENCES

DA Pam 310-4 Index of Technical Publications: Technical Manuals, Technical Bulletins, Supply

Manuals (Types 7, 8, and 9), Supply Bulletins, and Lubrication Orders. DA Pam 310-7 US Army Equipment Index of Modification Work Orders. TB 11-6625-2751-35 Calibration Procedures for Dual Channel Recorder RO-460(V1)/U (HP Model 7702B)

and Oscillographic Recorder (HP Model 7418A); Preamplifier Power Supply (HP

8848A); Preamplifier Plug-In Unit PL-1306A/U (HP Model 8803A); and Preamplifier

Plug-In Units (HP Models 8801A, 8802A, 8805A, and 8808A). TB 43-180 Calibration Requirements for the Maintenance of Army Materiel. TB 385-4 Safety Precautions for Maintenance of Electrical/Electronic Equipment. TM 11-6625-537-14-1 Operator's, Organizational, Direct Support and General Support Maintenance Manual:

Electronic Voltmeters.ME-202A/U (NSN 6625-00-709-0288) and ME-202B/U (NSN

6625-00-972-4046). TM 11-6625-654-14 Operator's, Organizational, Direct Support, and General Support Maintenance Repair

Parts and Special Tools List (Including Depot Maintenance Repair Parts and Special

Tools List) for Multimeter AN/USM-223. TM 11-6625-683-15 Operator's, Organizational, Direct Support, General Support and Depot Maintenance

Manual: Signal Generator AN/URM-127 (NSN 6625-00-783-5965). TM 11-6625-2658-14 Operator's, Organizational, Direct Support, and General Support Maintenance Manual

for Oscilloscope AN/USM-281C (NSN 6625-00-106-9622). TM 38-750 The Army Maintenance Management System (TAMMS)

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TM 11-6625-2872-14&P

TM 740-90-1 Administrative Storage of Equipment. TM 750-244-2 Procedures for Destruction of Electronics Materiel to Prevent Enemy Use (Electronics

Command).

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TM 11-6625-2872-14&P

APPENDIX D

MAINTENANCE ALLOCATION

Section I. INTRODUCTION

D-1. General This appendix provides a summary of the maintenance operations for the AM-6681 (V)/U. It authorizes categories of

maintenance for specific maintenance functions on repairable items and components and the tools and equipment required to perform each function. This appendix may be used as an aid in planning maintenance operations.

D-2. Maintenance Function Maintenance functions will be limited to and defined as follows: a. Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or electrical

characteristics with established standards through examination. b. Test. To verify serviceability and to detect incipient failure by measuring the mechanical or electrical characteristics

of an item and comparing those characteristics with prescribed standards. c. Service. Operations required periodically to keep an item in proper operating conditions, i.e., to clean

(decontaminate), to preserve, to drain, to paint, or to replenish fuel, lubricants, hydraulic fluids, or compressed air supplies.

d. Adjust To maintain, within prescribed limits, by bringing into proper or exact position, or by setting the operating characteristics to the specified parameters.

e. Align. To adjust specified variable elements of an item to bring about optimum or desired performance. f. Calibrate. To determine and cause corrections to be made or to be adjusted on instruments or test measuring and

diagnostic equipments used in precision measurement. Consists of comparisons of two instruments, one of which is a certified standard of known accuracy, to detect and adjust any discrepancy in the accuracy of the instrument being compared.

g. Install. The act of emplacing, seating, or fixing into position an item, part, module (component or assembly) in a manner to allow the proper functioning of the equipment or system.

h. Replace. The act of substituting a serviceable like type part, subassembly, or module (component or assembly) for an unserviceable counterpart.

i. Repair. The application of maintenance services (inspect, test, service, adjust, align, calibrate, replace) or other maintenance actions (welding, grinding, riveting, straightening, facing, remachining, or resurfacing) to restore serviceability to an item by correcting specific damage, fault, malfunction, or failure in a part, subassembly, module (component or assembly), end item, or system.

j. Overhaul. That maintenance effort (service/action) necessary to restore an item to a completely serviceable/operational condition as prescribed by maintenance standards (i.e., DMWR) in appropriate technical publications. Overhaul is normally the highest degree of maintenance performed by the Army. Overhaul does not normally return an item to like new condition.

k. Rebuild. Consists of those services actions necessary for the restoration of unserviceable equipment to a like new condition in accordance with original manufacturing standards. Rebuild is the highest degree of materiel maintenance applied to Army equipment. The rebuild operation includes the act of returning to zero those age measurements (hours, miles, etc.) considered in classifying Army equipments/components.

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TM 11-6625-2872-14&P

D-3. Column Entries a. Column 1, Group Number. Column 1 lists group numbers, the purpose of which is to identify components,

assemblies, subassemblies, and modules with the next higher assembly. b. Column 2, Component/Assembly. Column 2 contains the noun names of components, assemblies, subassemblies,

and modules for which maintenance is authorized. c. Column 3, Maintenance Functions. Column 3 lists the functions to be performed on the item listed in column 2.

When items are listed without maintenance functions, it is solely for purpose of having the group numbers in the MAC and RPSTL coincide.

d. Column 4, Maintenance Category. Column 4 specifies, by the listing of a "worktime" figure in the appropriate subcolumn(s), the lowest level of maintenance authorized to perform the function listed in column 3. This figure represents the active time required to perform that maintenance function at the indicated category of maintenance. If the number or complexity of the tasks within the listed maintenance function vary at different maintenance categories, appropriate "worktime" figures will be shown for each category. The number of task-hours specified by the "worktime" figure represents the average time required to restore an item (assembly, subassembly, component, module, end item or system) to a serviceable condition under typical field operating conditions. This time includes preparation time, troubleshooting time, and quality assurance/quality control time in addition to the time required to perform the specific tasks identified for the maintenance functions authorized in the maintenance allocation chart. Subcolumns of column 4 are as follows:

C - Operator/Crew O - Organizational F - Direct Support H - General Support D - Depot

e. Column 5, Tools and Equipment. Column 5 specifies by code, those common tool sets (not individual tools) and special tools, test, ,and support equipment required to perform the designated function.

f. Column 6, Remarks. Column 6 contains an alphabetic code which leads to the remark in section IV, Remarks, which is pertinent to the item opposite the particular code.

D-4. Tool and Test Equipment Requirement (sect III) a. Tool or Test Equipment Reference Code. The numbers in this column coincide with the numbers used in the tools

and equipment column of the MAC. The numbers indicate the applicable tool or test equipment for the maintenance functions.

b. Maintenance Category. The codes in this column indicate the maintenance category allocated the tool or test equipment.

c. Nomenclature. This column lists the noun name and nomenclature of the tools and test equipment required to perform the maintenance functions.

d. National/NATO Stock Number. This column lists the National/NATO stock number of the specified tool or test equipment.

e. Tool Number. This column lists the manufacturer's part number of the tool followed by the Federal Supply Code for manufacturers (5-digit) in parentheses.

D-5. Remarks (sect IV) Not applicable.

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SECTION II. MAINTENANCE ALLOCATION CHART

PLUG-IN AMPLIFIER AM-6681(V)1/U

(1) (2) (3) (4) (5) (6)

GROUP COMPONENT/ASSEMBLY MAINTENANCE MAINTENANCE CATEGORY AND

NUMBER FUNCTION C O F H D EQPT REMARKS

00 PLUG-IN AMPLIFIER AM-6681(V)1/U Inspect 0.5 Visual

FOR

TOOLS

only Service 0.5 6 Adjust 0.5 1,2,3 Test 1.0 1 thru 4 Repair 1.0 5 Overhaul 2.0 5

D-3

TM 11-6625-2872-14&P

SECTION III TOOL AND TEST EQUIPMENT REQUIREMENTS

PLUG-IN AMPLIFIER AM-6681(V) 1/U

TOOL OR TEST MAINTENANCE NATIONAL/NATO

EQUIPMENT CATEGORY NOMENCLATURE STOCK NUMBER TOOL NUMBER

REF CODE

1 H,D VOLTMETER, ELECTRONIC ME-202 6625-00-972-4046 2 H,D OSCILLOSCOPE AN/USM-281C 6625-00-106-9622 3 H,D GENERATOR. SIGNAL AN/URM-127 6625-00-783-5965 4 H,D MULTIMETER AN/USM-223 6625-00-999-7465 5 H,D TOOL KIT, ELECTRONIC EQUIPMENT TK-100/G 5180-00-605-0079 6 0 TOOL AND TEST EQUIPMENT AVAILABLE TO THE

ORGANIZATIONAL REPAIRPERSON BECAUSE OF ASSIGNED MISSION.

FOR

D-4

*U.S GOVERNMENT PRINTING OFFICE: 1981-703-029/1060