Agilent 3586 Tech 060992 Datasheet

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Page 1

TM 11-6625-3087-12

TECHNICAL MANUAL

OPERATOR’S AND ORGANIZATIONAL

MAINTENANCE MANUAL

FOR

FREQUENCY SELECTIVE LEVEL METER

AN/USM-490

(NSN 6625-01-138-3351) (EIC: N/A)

DISTRIBUTION STATEMENT A – Approved for Public Release; Distribution is Unlimited.

HEADQUARTERS, DEPARTMENT OF THE ARMY

1 JANUARY 1987

Page 2

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TM 11-6625-3087-12

SAFETY STEPS TO FOLLOW IF SOMEONE IS THE

VICTIM OF ELECTRICAL SHOCK

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 WOODEN POLE OR A 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

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TM 11-6625-3087-12

WARNING

HIGH VOLTAGE

is used in the operation of this equipment

DEATH ON

may result if personnel fail to

Never work on electronic equipment unless there is another person nearby who is familiar with the operation and hazards of the equipment and who is competent in administering first aid. When the technician is aided by operators, he must warn them about dangerous areas.

Be careful not to contact high-voltage connections of 115-volt ac input when installing or operating this equipment.

Whenever the nature of the operation permits, keep one hand away from the equipment to reduce the hazard of current flowing through vital organs of the body.

Do not be misled by the term “LOW VOLTAGE” Potentials as low as 50 volts may

cause death under adverse conditions.

CONTACT

observe safety precautions

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TM 11-6625-3087-12

CHANGE ) Headquarters

) Department of the Army

No. 1 ) Washington, D.C., 25 August 2005

TECHNICAL MANUAL

OPERATOR’S AND ORGANIZATIONAL

MAINTENANCE MANUAL

FOR

FREQUENCY SELECTIVE LEVEL METER

AN/USM-490

(NSN 6625-01-138-3351) ( EIC: N/A)

DISTRIBUTION STATEMENT A – Approved for Public Release; Distribution is

Unlimited.

TM 11-6625-3087-12, dated 1 January 1987, is changed as follows:

1. Remove old pages and insert new pages as indicated below. New or changed material is indicated by a vertical bar in the outer margin of the page. Illustration changes are indicated by a pointing hand. New or changed part numbers are indicated by an asterisk (*). Completely revised sections or chapters are indicated by a vertical bar adjacent to the title only.

Remove Pages Insert Pages None C/(D blank) i, ii i, ii B-1 through B-10 B-1 through B-7/(B-8 blank) DA Forms 2028-2 DA Forms 2028 COVER COVER

2. File this change sheet in front of the publication for reference purposes.

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TM 11-6625-3087-12 C1

By Order of the Secretary of the Army:

Official:

SANDRA R. RILEY

Administrative Assistant to the

Secretar

y of the Army

0519207

PETER J. SCHOOMAKER

General, United States Army

Chief of Staff

DISTRIBUTION: To be distributed in accordance with initial distribution number (IDN) 511719, requirements for TM 11-6625-3087-12.

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TM 11-6625-3087-12

INSERT LATEST CHANGED PAGES. DESTROY SUPERSEDED PAGES.

LIST OF EFFECTIVE PAGES

NOTE ON A CHANGED PAGE, THE PORTION OF THE TEXT AFFECTED BY THE LATEST CHANGE IS INDICATED BY A VERTICAL LINE OR OTHER CHANGE SYMBOL IN THE OUTER MARGIN OF THE PAGE.

Date of issue for original and changed pages are: Original.. 0 .. 1 Jan 1987 Change 1 25 Aug 2005

Total number of pages in this publication is 106 consisting of the following: Page * Change

No. No.

Cover......................................... 1

C/(D blank)................................. 1

i.................................................. 1

ii, iii............................................. 0

1-0 through 3-14 ....................... 0

A-1/(A-2 blank) .......................... 0

B-1 through B-7/(B-8 blank)....... 1

C-1 through C-2......................... 0

D-1/(D-2 blank).......................... 0

E-1/(E-2 blank) .......................... 0

INDEX........................................0

* Zero in this column indicates an original page.

Change 1 C/(D blank)

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TM 11-6625-3087-12

TECHNICAL MANUAL } HEADQUARTERS

NO. 11-6625-3087-12 } DEPARTMENT OF THE ARMY WASHINGTON, D.C., 1 January 1987

OPERATOR’S AND ORGANIZATIONAL MAINTENANC E MANUAL

FOR

FREQUENCY SELECTIVE LEVEL METER AN/USM-490

(NSN 6625-01-138-3351) (EIC: N/A)

REPORTING ERRORS AND RECOMMENDING IMPROVEME NTS

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 or DA Form 2028 (Recommended Changes to Publications and Blank Forms) directly to: Commander, U. S. Army Aviation and Missile Command, AMSAM-MMC-MA-NP, Redstone Arsenal, AL 35898-5000. A reply will be furnished to you. You may also provide DA Form 2028 information to AMCOM via email, fax or the World Wide Web. Our fax number is: DSN 788-6546 or Commercial 256-842-6546. Our email address is:

[email protected]. Instructions for sending an electronic 2028 may be found at the back of this manual immediately

preceding the hardcopy 2028. For the World Wi de We b u s e: https://amcom2028.redstone.army.mil.

DISTRIBUTION STATEMENT A – Approved for Public Release; Distribution is Unlimited.

Page HOW TO USE THIS MANUAL……………………………………………… iii

CHAPTER 1

INTRODUCTION………………………………………………………………

1-1 Section I General information……………………………………………………………. 1-1 II Equipment Description…………………………………………………………. 1-2 III Technical Principles of Operation……………………………………………… 1-5

CHAPTER 2

OPERATING INSTRUCTIONS……………………………………………….

2-1 Section I Description and Use of Operators Controls, Indicators, and Connectors……… 2-1 II Operator Preventive Maintenance Checks and Services (PMCS)……………... 2-17 III Operation Under Usual Conditions…………………………………………….. 2-18 IV Operation Under Unusual Conditions………………………………………….. 2-41

CHAPTER 3

ORGANIZATIONAL MAINTENANCE………………………………………

3-1 Section I Repair Parts, Special Tools, TMDE, and Support Equipment…………………. 3-1 II Service Upon Receipt…………………………………………………………... 3-1 III Troubleshooting………………………………………………………………… 3-2 IV Maintenance Procedures………………………………………………………... 3-5 V Preparation for Storage of Shipment…………………………………………… 3-15

CONTENTS – Continued

Change 1 i

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TM 11-6625-3087-12

CONTENTS—Continued

APPENDIX A REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

B MAINTENANCE ALLOCATION . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .

C COMPONENTS OF END ITEM AND BASIC ISSUE ITEMS LIST . . . . C-1

D ADDITIONAL AUTHORIZATION LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B-1

D-1

E EXPENDABLE SUPPLIES AND MATERIALS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SUBJECT INDEX

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E-1

INDEX-1

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TM 11-6625-3087-12

HOW TO USE THIS MANUAL

This manual tells you about your Frequency Selective Level Meter AN/USM490 and contains instructions about how to use it during maintenance on other electronic equipment.

The technical manual for the electronic equipment you are maintaining will tell you where to make certain connections and when to use various accessories which are part of the AN/USM-490.

When you first receive your AN/USM-490, start at the front of the manual and go all the way through to the back. Become familiar with every part of the manual

and the AN/USM-490.

This manual has an edge index which will help you find specific information in a

hurry. Simply spread the pages on the right edge of the manual until the printed

blocks can be seen. Open the manual where the block on the edge of the page

lines up with your selected topic printed on the front cover block.

iii

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TM 11-6625-3087-12

1-0

Figure 1-1. Frequency Selective Level Meter AN/USM-490.

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TM 11-6625-3087-12

CHAPTER 1

INTRODUCTION

Section I. GENERAL INFORMATION

1-1. SCOPE.

a. Type of Manual: Operator’s and Organizational Maintenance Manual. b. Equipment Name and Model Number: Frequency Selective Level Meter AN/USM-490.

Purpose of Equipment: The Level Meter is designed for use in installation and maintenance of Frequency Domain

Multiplexing (FDM) Systems, wave analysis, frequency synthesis, carrier frequency, and voice channel measurements.

1-2. CONSOLIDATED INDEX OF ARMY PUBLICATIONS AND BLANK FORMS.

Refer to the latest issue of DA Pam 310-1 to determine whether there are new editions, changes, or additional publications pertaining to the equipment.

1-3. MAINTENANCE FORMS, RECORDS, AND REPORTS.

a Report of Maintenance and Unsatisfactory Equipment.

equipment maintenance will be those prescribed by DA PAM 738-750 as contained in Maintenance Management Update.

b. Report of Packaging and Handling Deficiencies. Fill out and forward SF 364 (Report of Discrepancy) as prescribed in

AR 735-1102/DLAR 4140.55/NAVMATINST 4355.73B/AFR 400-54/MCO 4430.3H.

c. Discrepancy in Shipment Report (DISREP) (SF 361). Fill out and forward Discrepancy in Shipment Report (SF

361) as prescribed in AR 55-38/ NAVSUPINST 4610.33C/ AFR 75-18/ MCO P4610.19D/DLAR 4500.15.

1-4. ADMINISTRATIVE STORAGE.

Refer to TM 740-90-1 for administrative storage procedures.

1-5. DESTRUCTION OF ARMY ELECTRONICS MATERIEL.

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

1-6. 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 the design. Put it on an SF 368 (Quality Deficiency Report). Mail it to Commander, US Army Communications-Electronics Command and Fort Monmouth, ATTN: Jersey 07703-5000. We’ll send you a reply.

1-7. WARRANTY INFORMATION.

The AN/USM-490 is warranted by Hewlett-Packard Company for one year. Warranty starts on the date of shipment to the original buyer. Report all defects in material or workmanship to your supervisor who will take appropriate action.

1-8. NOMENCLATURE CROSS-REFERENCE LIST.

Department of the Army forms and procedures used for

AMSEL-PA-MA-D, Fort Monmouth, New

Common names will be used when major components of the Frequency Selective Level Meter are mentioned in this manual.

NOTE

Official nomenclature must be used when filling out report forms or looking up Technical Manuals.

Common Name

Level Meter AIWUSM-490

Official Nomenclature

Frequency Selective Level Meter AN/USM-490 Frequency Selective Level Meter AN/USM-490

1-1

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TM 11-6625-3087-12

1-9. LIST OF ABBREVIATIONS.

This list identifies abbreviations and descriptions that are used in this manual.

AUTO AVE CAL CARR CNTR CONT DEMOD DIST Distortion FDM LSB MEAS MIN

MIP OVLD para pW Picawatt STBY SSB T THSHLD USB

1-10. EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES.

Automatic Average Calibration Carrier Counter Continue Demodulation

Frequency Domain Multiplexing Lower side band Measure Minutes Maximum input power Overload Paragraph

Standby Single side band Time Threshold Upper side band Weighted

Section Il.

EQUIPMENT DESCRIPTION

a CHARACTERISTICS.

Provides means for maintenance of Frequency Division Multiplex (FDM) systems. Allows for:

Testing message channels (voice and carrier). Troubleshooting voice channel malfunctions. Message channel voice traffic simulation.

RMS wideband power measurements. Harmonic level and distortion analysis.

Testing of high frequency radio systems. Meets North American (Bell) Standards. Designed for bench top use.

b. CAPABILITIES AND FEATURES.

Push button control allows for easy operation of equipment.

Annunciator lights on front panel for constant equipment status. Nine digit LED for frequency display. Four digit LED for amplitude display. Self-test function for operational verification.

Programmed interface for remote operation.

1-2

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TM 11-6625-3087-12

1-11. EQUIPMENT DATA.

WEIGHTS AND DIMENSIONS

Frequency selective level meter:

Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50LB (23Kg)

Length Width Height

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18.38 IN. (466.7

16.75 IN. (425.5 7 IN. (177

MM) MM)

MM) BNC to BNC adapter: Contact centers

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.750 IN. (44.5

MM)

POWER REQUIREMENTS

Voltage

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

100 to 240Vac (+5, -10%)

Frequency . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... 48 to 66Hz

Power

Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

2.0 Amp 115Vac operation

1.0 Amp 240Vac operation

150V/A

ENVIRONMENTAL

Operating temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to +55° C

Storage temperature range

Storage temperature range Relative humidity Operating altitude

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

-40 to +75° c 40 to +75° c

95% maximum

15,000 feet

Storage altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,000 feet

PERFORMANCE

Frequency range:

75 and unbalanced

124 balanced 135 balanced

600 bridged

Frequency resolution

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

50Hz to 32.5 MHz

4KHz to 10 MHz

4KHz to 1MHz

100Hz to 108 KHz

0.1HZ

Tuned frequency accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±2 times 10-

Counter accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

±1.0Hz

Input connector type:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

124

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

600

BNC female

WECO 372

WECO 241A

WECO 310

Return loss:

75 , 50Hz to 32.5 MHz

124 ,

10 KHz to 10MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 KHz to 1MHz

135 ,

600 ,

50Hz to 108 KHz

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30dB 30dB 30dB 25dB

Balance:

124

10KHz to 10MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135 ,

10 KHz to 1MHz

600 ,

50Hz to 108 KHz

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

30dB 30dB 25dB

1-3

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TM 11-6625-3087-12

Bandwidth selectivity Carrier rejection:

20Hz

400Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60dB,±1100Hz

3100HZ Adjacent charnel rejection, ±2850Hz, 3100Hz BW Passband flatness:

20Hz 400Hz

3100HZ

Amplitude measurement range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +25dBm to–120dBm

Amplitude resolution Amplitude accuracy (–100dBm to +20dBm):

75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... ±0.95dB

124

135 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... ±1dB

600

Spurious responses:

Image rejection (100 to 132MHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -80dBc

IF rejection (15625Hz)

Non–harmonic spurious signals (> 1600Hz offset)

Residual (>349Hz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -115dBc

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20Hz, 400Hz, and 3100HZ

30dB, ±45Hz, 60dB, ±90Hz

60dB, ±1850Hz 75dB minimum

±0.3dB at ±3Hz

±0.3dB at ±50Hz

±0.3dB at 11000Hz

±0.1dB

±1dB

±0.75dB

-80dBc

Distortion:

Harmonic (>4KHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70dB below full scale

Intermodulation (>10MHz) . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70dB below full scale

Wideband power accuracy Noise floor:

75 , 100KHz to 32.5MHz, 3100HZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -116dBm

75 , 100KHz to 32.5MHz, 20Hz and 400Hz

75 and 600 2 KHz to 100KHz . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -105dBm

124 , 100KHz to 10MHz, 3100HZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116dBm

124 , 100KHz to 10MHz,20Hzand 400Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -120dBm

135 , 100KHz to 1MHz, 3100HZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116dBm

135 , 100KHz to 1MHz,20Hz and 400Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -120dBm

All input impedance, 10KHz to 100 KHz

Demodulated audio output amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0dBm into 600

Tracking output:

Amplitude

Flatness (200Hz to 32.5MHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.5dB

Phase jitter:

Demodulated tone frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960Hz to 1060Hz

Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±(10% +0.5° p-p)

Input signal level

Residual phase jitter (50KHz to 32.5MHz)

Frequency response . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Hz to 300Hz

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0dBm into 75 at 10KHz, ±0.5dB

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

<30dB below full scale, –65dBm minimum

±2dB

-120dBm

-105dBm

<0.5° p-p

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TM 11-6625-3087-12

Weighted noise filter:

C-message

Accuracy

Impulse noise counting rate

Threshold accuracy Notch filter rejection (995 to 1025Hz)

1-12. GENERAL FUNCTIONAL DESCRIPTION.

(Fig. 1-2). Frequency Selective Level Meter AN/USM-490 accepts signals from 50Hz to 32.5MHz and, dependent on the measurement mode selected, displays the desired results on the front panel.

impedance ranges and can be balanced, unbalanced or bridged.

The desired value is displayed as amplitude in the MEASUREMENT/ENTRY display/analog meter and frequency in the

FREQUENCY/ENTRY display. Demodulated audio can be listened to using the front panel speaker or headphone jack.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section Ill. TECHNICAL PRINCIPLES OF OPERATION

Signals are applied using one of the five

The input signal connected to the front panel is measured, then amplified or attenuated to a usable level. This 50Hz to 32.5MHz signal is then mixed with the first local oscillator frequency of from 50MHz to 82.5MHz. This mixing produces the first intermediate frequency of 50MHz.

143 ins/count ±5%

±1dB at 1700Hz

50dB minimum

1004Hz ±.5dB

A low pass filter keeps input frequencies greater than 32.5 MHz from being processed. This 50MHz intermediate frequency is amplified and passed to the IF/audio section.

When CAL is on and a calibration cycle occurs, the input signal is disconnected and a precise calibration signal from the calibration tracking section is mixed with the first local oscillator. This is then used to automatically check and adjust the Level Meter for operation within specified limits. Once the calibration cycle is completed, the input signal is reconnected and normal operation is resumed.

The 50MHz intermediate frequency from the input section is passed to the IF/audio section where it goes through a 50MHz filter to bandpass to 10KHz. This 50MHz signal with 10 KHz wide bandpass is mixed with the second local oscillator frequency of 49.984375MHz to produce a second intermediate frequency of

15.625KHz. This 15.625 KHz signal with a 10KHz wide bandpass is amplified and split into two separate signals. One signal goes through a 400Hz filter. The result is one 15.625KHz, 400Hz wide bandpass signal and one 15.625KHz, 10KHz wide bandpass signal,

Depending on the front panel bandwidth selection, one of the 15.625KHz signals is passed or filtered, and then amplified. The desired selected bandwidth of 20Hz, 400Hz, or 3100Hz is then obtained.

The 15.625KHz signal with the desired 20Hz,400Hz or 3100Hz bandwidth is amplified and split three ways.

The first path is to the digital section where the frequency of the input signal is determined. The second path is computed to an RMS voltage and passed to the digital section where the amplitude of

the input signal is determined.

The third path is to the impairments section for demodulating single sideband audio. A voltage is developed for the front panel analog meter and to the rear panel METER output connector. Audio from the impairments section is amplified and passed to the speaker. Detected audio also goes to the rear

panel AUDIO connector. The digital section monitors most functions in the Level Meter. This includes processing data, front panel

display changes, monitors circuit card operation, handles all front panel operator entries, performs calibration, and diagnostic tests. operation.

It also contains all the front panel displays, annunciators and switches necessary for

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1-6

TM 11-6625-3087-12

Figure 1-2

Page 19

TM 11-6625-3087-12

One of the outputs from the IF/audio section is compared to the first local oscillator frequency and the input frequency is calculated. The other is a RMS voltage that is processed and the amplitude of the input signal is calculated. These values are then sent to the front panel and shown as frequency and amplitude in the appropriate display.

The front panel keyboard and frequency fine tune knob entries are processed in the digital section and passed to the appropriate assembly for processing. The status of the assemblies is returned to the digital section for corrective action or operator notification. This notification is in the form of error codes and annunciator lights on the front panel.

The digital section contains the stored software necessary to execute the diagnostic tests and calibration cycle. A memory is also available for store/recall of nine different front panel configurations.

The first local oscillator frequency of from 50 to 8.25 MHz is mixed with 50MHz from the frequency reference section to produce a 0 to 32.5 MHz signal. This signal matches the tuned frequency on the front panel display. The 0 to 32.5MHz signal is amplified and split two ways.

The first path is to the rear panel BNC connector marked Fo. The second path is used to generate the calibration output signal of from 20KHz to 32.5MHz. When

calibration is activated, this signal goes to the input section.

When wideband mode is selected, the average broadband power present on the input signal is measured, and goes

to the digital section for display on the front panel. The input signal is monitored for correct amplitude and if incorrect, sends an overload or underload message to

the digital section. The first local oscillator generates a frequency of from 50MHz to 82.5MHz. This frequency is exactly 50MHz

higher than the tuned frequency displayed on the front panel. The input to the first local oscillator is a precise

10MHz and 100KHz signal from the frequency reference section.

The first part of the frequency reference section uses DC voltage to generate a stable, accurate 10MHz signal. This signal is either:

Coupled to internal circuits using a rear panel adapter.

Not used. If not used, a stable external source of 5MHz, 3.333333MHz, 2.5MHz, 2MHz or 1MHz must be used.

The second part of the frequency reference section generates a 5MHz signal. This 50 MHz is divided and

amplified to generate the required operating frequencies of 50MHz, 10MHZ, 2MHz, 1MHz and 100KHz. These signals are then used in various internal operations of the Level Meter.

The impairments uses the single sideband demodulated output from the IF/audio section. A DC phase jitter output is generated and passed to the digital section for display on the front panel. An AC phase jitter output is provided on the rear panel.

When C-message 3100Hz is selected, the single sideband demodulated audio is applied to a weighted filter to measure noise.

When NOISE/TONE is selected, the single sideband demodulated audio is applied to a notch filter to remove the

1004Hz tone. When all other modes, except impulse, are selected, the single sideband demodulated audio bypasses the filters. When IMPULSE is selected, the single sideband demodulated audio is passed to the weighted filter, if selected

and then to the notch filter. The noise is then compared to the threshold level set by the operator. Any impulse

noise spike that exceeds the threshold level is counted and passed to the digital section for display on the front panel.

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TM 11-6625-3087-12

The interface section accepts data or instructions from the rear panel connector and sends it to the digital section for processing. It also accepts data from the digital section and sends it to the rear panel connector for use by other instruments.

The power supply uses the 100 to 240VAC input power, and supplies all operating voltages to the internal circuitry of the Level Meter. These include + 12VDC, –12VDC, +5VDC, +15VDC, +2.5VDC, and +23VDC.

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CHAPTER 2

OPERATING INSTRUCTIONS

TM 11-6625-3087-12

Section I.

2-1. INTRODUCTION.

This section describes all of the operator controls and indicators for the Level Meter. Due to the large number of controls and

indicators on the front panel, it is necessary to separate the panel into five different portions. Figure 2-1 (views A thru E) shows each portion of the front panel. The rear panel is shown in figure 2-2.

DESCRIPTION AND USE OF OPERATOR’S CONTROLS, INDICATORS,

AND CONNECTORS

Figure 2-1. Operator’s Controls, Indicators, and Connectors, front view.

2-1

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TM 11-6625-3087-12

KEY

CONTROL, INDICATOR,

OR CONNECTOR

POWER switch

Analog meter

STBY indicator

OVLD indicator

MEASUREMENT/ENTRY

FUNCTION

Changes Level Meter from standby to on. Push in for on and push in again for standby.

Indicates strength of signal scale setting. Meter scale is and bottom scale is –100dB.

Indicates Level Meter is in standby mode when on.

Flashes if input signal power level is too high. When flashing, Level Meter is overloaded and will not measure input signal. In entry full scale, full scale level

must be increased. In auto, full scale is automatically adjusted and indicator will

flash briefly during autoranging.

Displays power level of input signal being measured. Also displays entry levels

for offset, full scale, and threshold along with error messages; calibration

messages; and underload or overload conditions.

being measured.

determined by range selection. Top scale is 10dB

Sensitivity is controlled by full

2-2

Page 23

KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

UNIT push buttons

dBr indicator

p-p indicator

dBm indicator

dBpW indicator

Selects unit of measurement for input signal. Selections are limited to dBm, dBpw, and dB.775V. OdBm reference level is one miliwatt dissipated at the input impedance selected. OdBpw reference level is one picowatt dissipated at the input impedance selected. OdB.775V reference level is 0.775 volts. Lights

in push buttons indicate selection in use.

Unit of measurement for offset. When on, indicates MEASUREMENT/ENTRY is displaying offset.

Unit of measurement for phase jitter.

When on, indicates

MEASUREMENT/ENTRY is displaying phase jitter in degrees peak to peak.

For use with phase jitter measurements only.

Unit of measurement for all modes.

When on, indicates

MEASUREMENT/ENTRY is displaying in dBm. Works with dBm push

button.

Unit of measurement for all modes.

When on,

indicates MEASUREMENT/ENTRY is displaying in dBpW. Works with dBpW push button.

O indicator

dB indicator

OFFSET push button

OFFSET indicator

THSHLD indicator

Indicates value in MEASUREMENT/ENTRY display is offset. Works with OFFSET push button.

Unit of measurement for all modes.

When on,

indicates MEASUREMENT/ENTRY is displaying in dB. Works with dB.775V push button.

Subtracts stored offset from input signal power level. Zero is subtracted if no value is stored in offset. MEASUREMENT/ENTRY displays result. When in use, O indicator opposite unit of measure indicator lights and push button lights. Push for on and push again for off.

Indicates Level Meter is ready to store an offset

value.

MEASUREMENT/ENTRY displays value. Lights when offset is used.

Indicates Level Meter is ready to store a threshold

value.

MEASUREMENT/ENTRY displays value. Lights when threshold is used.

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TM 11-6625-3087-12

CONTROL, INDICATOR,

KEY

OR CONNECTOR

FUNCTION

AVE push button

SCALE indicator

ENTRY push button

AUTO push button

100dB push button

Five level measurements of the input signal power level are taken and then averaged. Analog meter or MEASUREMENT/ENTRY then displays new value. Used when readings in the measurement display and analog meter are erratic. When in use, push button lights. Push for on and push again for off.

Indicates Level Meter is ready to store a full scale value. MEASUREMENT/ENTRY displays value. Lights when full scale is used.

Used to manually enter full scale value. Value entered must be higher than the input signal level or an overload will exist. When in use, push button lights, Push for on.

Tells Level Meter to automatically select full scale value for best signal to noise ratio without overloading. When required, Level Meter will autorange to find new full scale value. When in use, push button lights. Push for on.

Selects entire Level Meter operating range (80dB) for use in input signal detection. Any signal level between full scale and 80dB below full scale can be

measured. MEASUREMENT/ENTRY resolution is 0.1dB. When in use, push button lights. Push for on.

Use 100dB scale on analog meter when selected.

10dB push button

AUTO CAL push button

Selects most linear 10dB region of Level Meter operating range (80dB) for use in detection of input signals. Any signal level between full scale and 10dB below full scale can be measured. Use 10dB scale on analog meter when selected. MEASUREMENT/ENTRY resolution is 0.01dB. This selection cannot be used

in wideband and impulse measurement modes. When in use, push button lights. Push for on.

Tells Level Meter to automatically calibrate all ranges and bandwidths of the internal circuitry. When off, the data stored during the last calibration is used to correct the signal being measured. measurement modes. When in use, push button lights. Push for on and push -

again for off.

Inoperable in phase jitter and impulse

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Page 25

TM 11-6625-3087-12

KEY

CONTROL, INDICATOR, OR CONNECTOR

CENTER indicator

FREQUENCY/ENTRY Displays frequency of input signal being measured. Also displays frequency,

SRQ indicator Used only when external device is connected to Level Meter. When on, one or

LISTEN indicator

TALK indicator

REMOTE indicator Used only when external device is connected to Level Meter. When on, Level

FUNCTION

—

Indicates Level Meter is in selective measurement

FREQUENCY/ENTRY display shows center frequency of Level Meter

bandwidth. Works with LO DIST or LO NOISE push buttons.

frequency steps, time and counts along with operator messages.

more external devices connected to Level Meter are requesting attention.

Used only when external device is connected to Level Meter. When on, the Level Meter can receive data.

Used only when external device is connected to Level Meter. When on, Level Meter can send data.

Meter can be controlled from a remote location.

mode.

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TM 11-6625-3087-12

CONTROL, INDICATOR,

KEY

OR CONNECTOR

FUNCTION

LOCAL push button

OVEN indicator

Hz indicator

kHz indicator

COUNTER push button

Used only when external device is connected to Level Meter. When used, Level Meter is switched to remote operation and REMOTE indicator will come on. All front panel controls except volume, power and local are disabled. Push for on and push again for off. If local is pressed and Level Meter not set up for remote operation, “addr=XX”.

Indicates frequency reference oven is cold and its output is disabled. Comes on when oven is cold and goes out when oven reaches operating temperature.

Unit of measurement for all modes. displaying in hertz.

Unit of measurement for all modes.

displaying in kilohertz.

Used to display strongest single frequency signal within Level Meter bandpass. Appropriate Hz or KHz indicator lights. Display fills with dashes if input signal level is too low to count. When in use, push button lights. Push for on and push again for off.

FREQUENCY/ENTRY will display digital address

When on, FREQUENCY/ENTRY is

push button

TONE push button

CARRIER push button

T/COUNT indicator

CNTR indicator

Used only when measuring telecommunication signals. Allows Level Meter to receive upper sideband signals. When in use, push button lights. Push for on.

Used only when measuring telecommunication signals. Allows Level Meter to receive lower sideband signals. When in use, push button lights. Push for on.

Used to fine tune Level Meter to telecommunication signals. RF frequency of a

1004Hz test tone is entered and shown. When in use, push button lights. Push

for on.

Used to fine tune Level Meter to telecommunication signals. RF frequency of carrier is entered and shown. When in use, push button lights, Push for on.

Indicates Level Meter will accept a time in minutes and seconds for impulse duration. Works with TIME push button.

Indicates FREQUENCY/ENTRY is displaying measured input signal frequency.

2-6

Page 27

KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

STEP indicator

CARR indicator

TONE indicator

I Indicates Level Meter is readyto store frequency step interval value. Works with

FREQ STEP push button.

Indicates Level Meter single sideband channel mode entry frequency is set to

carrier. Works with CARRIER push button.

Indicates Level Meter single sideband channel mode entry frequency is set to tone. Works with TONE push button.

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Page 28

TM 11-6625-3087-12

CONTROL, INDICATOR,

KEY OR CONNECTOR

45A

45B

WIDEBAND push button

SHIFT push button

LO DIST push button

LO NOISE push button

FUNCTION

Used to measure total input signal power level. When selected, all frequency

related controls are inoperative. See paragraph 2-12 for additional information.

Selects MEASUREMENT MODE group push button functions. When in use, push button lights and LO NOISE, START push buttons can be used. Push for on and push again for off.

Used for selective level measurement of non-telecommunication signals. When in use, push button lights.

information.

Used for selective level measurement of signals spread across bandwidth. When in use, SHIFT push button is on and LO NOISE push button lights. Push for cm. See paragraph 2-11 for additional information.

When in use, push button lights. Push for on.

JITTER, NOISE/TONE, IMPULSE, and

Push for on. See paragraph 2-10 for additional

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Page 29

KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

46A

46B

47A

47B

48A

48B

NOISE/DEMOD push button Used for monitoring telecommunication signals or measuring noise levels on

telecommunication signal message channels. When in use, push button lights.

Push for on. See paragraph 2-13 for additional information.

Ø JITTER push button

TONE 1004Hz push button

NOISE/TONE push button

CARRIER push button Used to measure telecommunication carrier leak signals. When in use, push

IMPULSE push button

Used to measure phase jitter of 1004HZ test tone on telecommunication signal

message channels. When in use, SHIFT push button is on and

button lights. Push for on. See paragraph 2-14 for additional information.

Used to measure test tone level of telecommunication signals. When in use,

push button lights. Push for on. See paragraph 2-15 for additional information.

Used to measure noise levels in presence of 1004Hz test tone on telecommunication signal message channels. When in use, SHIFT push button is on and NOISE/TONE push button lights. Push for on. See paragraph 2-16 for additional information.

button lights. Push for on. See paragraph 2-17 for additional information.

Used to count telecommunication signal message channel noise spikes. When

in use, SHIFT push button is on and IMPULSE push button lights. Push for

on. See paragraph 2-18 for additional information.

JITTER push

49A 2600Hz push button Used to measure telecommunication signaling tones. When in use, push button

lights. Push for on. See paragraph 2-15 for additional information.

49B

52 600 connectors

START push button

BRIDGED push button

600 push button Used to select balanced floating input for 600 connector. Termination

Used with impulse to start counting noise spikes. When in use, SHIFT and IMPULSE push buttons are on but START push button does not light when pushed. Push for on.

Used to select balanced 600 input for 600 connector. Termination impedance is 10K shunted by 50pF. When in use, push button lights. Push for on.

impedance is 600 . When in use, push button lights. Push for on.

Used to connect bridged or 600 source to Level Meter when 600 termination

impedance is required. Connector mates with WECO type 310 plug.

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TM 11-6625-3087-12

CONTROL, INDICATOR,

KEY OR CONNECTOR

FUNCTION

135 push button

135 connectors

124 push button

124 connectors

75 push button

Probe Power connector

75 connector Used to connect source to Level Meter when 75 termination impedance is

Used to select balanced input for both 135 connectors. Termination impedance

is 135 . When in use, push button lights. Push for on.

Used to connect source to Level Meter when 135 termination impedance is required. Connector mates with WECO type 241 A plug.

Used to select balanced input for both 124 connectors. Termination impedance is 124 When in use, push button lights. Push for on.

Used to connect source to Level Meter when 124 termination impedance is required. Connector mates with WECO type 372A plug.

Used to seIect unbalanced input for 75 connector. Termination impedance is 75 . When in use, push button lights. Push for on.

Used to supply power for active probes. Mates with probe plug.

required. Mates with BNC plug. Frequency from 50Hz to 32.5MHz.

10k 50pF push button

Used to select unbalanced input for 75 connector. Termination impedance is

10K shunted by 50pF. When in use, push button lights. Push for on.

2-10

Page 31

TM 11-6625-3087-12

KEY

CONTROL, INDICATOR, OR CONNECTOR

FREQ push button Used to store, raise, lower, or display Level Meter tuned frequency. Push to

FREQ STEP push button

Numeric keys

MHz -dB push button Used to terminate entries from numeric keys. Frequency and frequency step are

KHz +dB push button

FUNCTION

display present value, and if desired, enter new value from 50Hz to 32.5MHz using numeric keys and appropriate Hz, KHz or MHz key.

Used to store, raise, lower, or display Level Meter step value. Push to display present value, and if desired, enter new value from 50Hz to 32.5 MHz using numeric keys and appropriate Hz, KHz or MHz key.

Used to enter numeric value with decimal point for frequency, frequency step, full scale, offset, threshold and time. Push desired key.

assigned MHz. Full scale, offset, and threshold are assigned -dB. Push for on.

Used to terminate entries from numeric keys. Frequency and frequency step are

assigned KHz. Full scale, offset, and threshold are assigned +dB. Push for on.

2-11

Page 32

TM 11-6625-3087-12

CONTROL, INDICATOR,

KEY

OR CONNECTOR

FUNCTION

MEAS CONT push button

Hz MIN push button

RDNG-> OFFSET push

CNTR-> FREQ push button

push button

Used to control measurement sequence. displayed, push button flashes until pushed.

Used to terminate entries from numeric keys. Frequency and frequency step are assigned Hz. Time is assigned minutes. Push for on.

Used to store value shown in MEASUREMENT/ENTRY display as new offset in Level Meter. Push for on,

Used to fine tune Level Meter to value shown in FREQUENCY/ENTRY display. Used only when counter is on. Push for on.

Used to lower values each time push button is pushed. Frequency step, threshold, and time are lowered by one; full scale is lowered by five; frequency step is lowered by power of two; and frequency is lowered by frequency step value stored in Level Meter. Push for on.

Used to raise values each time push button is pushed. Frequency step, threshold, and time are raised by one; full scale is raised by five; frequency step is raised by power of two; and frequency is raised by frequency step value stored in Level Meter. Push for on.

After value has been entered and

TIME push button

RECALL push button

THSHLD push button

STORE push button

Used to enter, raise, lower, or display duration of an impulse noise measurement. Press to display present value, and if desired, enter a new value from O to 99

minutes 59 seconds using the numeric keys and MIN. Format is minutes,

decimal point seconds.

Used to recall Level Meter front panel measurement setup. Push for on.

Used to enter, raise, lower, or display the minimum level of noise spikes used for impulse noise measurement. counted, Press to display present value, and if desired, enter a new value from –116dBm to +28dBm using the numeric keys and -dB or +dB.

Used to store Level Meter front panel measurement setup. Push for on.

Spikes present below this level will not be

2-12

Page 33

KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

OFFSET push button

FULL SCALE push button

Used to enter, raise, lower, or display offset value stored in Level Meter. Press to display present value, and if desired, enter anew value from -199.99dB to

+ 199.99dB using the numeric keys and -dB or +dB. New value can be stored

with offset on or off.

Used to enter, raise, lower, or display full scale value stored in Level Meter. Press to display present value, and if desired, enter a new value using the numeric keys and -dB or +dB. New value can be from -45dB to +25dB in 5dB steps for 100dB range and from –120dB to +25dB in 5dB steps for 10dB range.

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CONTROL, INDICATOR, OR CONNECTORKEY

OFF push button

AUTO push button

FREQUENCY TUNE knob

FREQ STEP push button

20Hz push button

FUNCTION

Used to disable frequency tune knob. Push for off.

Used to vary frequency tune resolution based on bandwidth selection. Frequency steps are 100Hz for 3100Hz bandwidth, 20Hz for 400Hz bandwidth, and 1Hz for 20Hz bandwidth for 100dB range. bandwidth, 4Hz for 400Hz bandwidth, and .2Hz for 20Hz bandwidth for 10dB range. When in use, push button lights. Push for on.

Used to vary frequency shown in FREQUENCY/ENTRY display. Clockwise rotation raises frequent y and counterclockwise rotation lowers frequency. Step size determined by value stored in FREQ STEP or bandwidth selected in AUTO.

Used to vary frequency tune resolution based on frequency step value stored in Level Meter. When in use, push button lights. Push for on.

Used to measure 20Hz section of input signal. When in use, push button lights. Push for on.

Frequency steps are 20Hz for 3 100Hz

2-14

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KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

VOLUME knob

400Hz push button

3100Hz push button

Loudspeaker

Headphone connector

WTD 3100Hz push button

Used to vary audio level to speaker and headphone jack. Clockwise rotation raises volume and counterclockwise rotation lowers volume.

Used to measure 400Hz section of input signal. When in use, push button

lights. Push for on.

Used to measure 3100Hz section of input signal. When Ø Jitter on, measures 20Hz to 300Hz. When in use, push button lights. Push for on.

Used for audio monitoring of input signals or impairment measurements.

Used to audio monitoring of input signals or impairment measurements through

headphones. Output impedance is 600 and output power is 0dBm. Connector

mates with 1/4” phone plug.

Used to measure noise in 3100Hz section of input signal on telephone message channels. When making phase jitter measurements, bandwidth is 4Hz to 300Hz. When in use, push button lights. Push for on.

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TM 11-6625-3087-12

KEY

Figure 2-2. Operator’s Controls, Indicators, and Connectors, rear view.

CONTROL, INDICATOR, OR CONNECTOR

Line voltage switch

Interface connector

Interface control switch

Fo (0-32MHz) connector

FUNCTION

Used to select 100, 120, 220, or 240 volt operation. Two two-position

switches. Up-up for 100Vac operation, up-down for 120Vac operation, down-up for 220Vac operation, and down-down for 240Vac operation.

Input and output connector for all external devices. Connector has 24 pins with metric posts.

Used to select tracking generator operating mode and address of AN/USM-490. Seven-position DIP switch.

Position one is interface troubleshooting test. Position two sets tracking generator operating mode. Positions three thru seven are for address settings.

Used for network analysis. Output frequency is 0 to 32.5 MHz and tracks the

front panel displayed frequency. Output power is 0dBm and impedance is 75 .

Leave open for normal use. Connector mates with BNC plug.

2-16

10MHZ connector

Used for a signal reference to synchronize external devices to Level Meter

frequency reference. Output power is +8dBm at 50 Leave open for normal operation. Connector mates with BNC plug.

Page 37

KEY

CONTROL, INDICATOR, OR CONNECTOR

TM 11-6625-3087-12

FUNCTION

10 MHz oven connector

EXT REF 10MHz+N connector

Meter connector

Audio connector

Phase jitter connector

Power input connector

Provides a long-term, high stability frequency reference for Level Meter. Connect to EXT REF 10MHz+N connector with BNC to BNC adapter

(supplied) for normal operation. Connector makes with BNC plug.

Used to connect 10MHz external reference to Level Meter. Input power can be no less than - 10dBm. Connect to 10MHz oven connector with BNC to BNC adapter (supplied) for normal operation. Connector mates with BNC plug.

Connection providing MEASUREMENT/ENTRY display reading in DC voltage. Sensitivity is 100mv/dB on the 10dB range and 10mv/dB on the 100dB range. Leave open for normal use. Connector mates with BNC plug.

Used for impairment measurements.

Output impedance is 1,000 . Leave open for normal operation. Connector mates with BNC plug.

Used for additional analysis of phase jitter signal. Sensitivity is 166mv per degree of phase jitter. Output impedance is 10,000 . Leave open for normal operation. Connector mates with BNC plug.

Connector for line voltage power cable (supplied). Connector mates with CEE

22 plug.

Output level is nominally 750mV p-p.

Section Il.

2-2. GENERAL.

To be sure that your equipment is always ready for your mission, you must do scheduled preventive maintenance checks and

services (PMCS). When you are doing any PMCS or routine checks, keep in mind the WARNINGS and CAUTIONS about

electrical shock and bodily harm.

2-3. PMCS PROCEDURES.

Tools, Materials, and Equipment Required for Preventive Maintenance.

operator preventive maintenance. Cleaning materials required are listed in Appendix E, items 1 and 2.

b. PMCS for Level Meter is limited to routine checks such as shown below.

cleaning, dusting, wiping, checking for frayed cables, storing items not in use, covering unused receptacles, checking for loose nuts, bolts, and screws.

Perform these routine checks anytime you see they must be done.

OPERATOR PREVENTIVE MAINTENANCE CHECKS AND SERVICES

No tools or equipment are required for

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TM 11-6625-3087-12

Section Ill. OPERATION UNDER USUAL CONDITIONS

2-4. GENERAL.

Operation is broken down into ten individual operating procedures. Before measurement of a specific signal can be made, the operator must determine which of the ten operation modes will perform the desired measurement. Table 2-3 is a crossreference of the Level Meter measurement mode to the type of signal to be measured. Error messages encountered during operation will be displayed in the measurement/entry area. Table 2-2 lists all operator errors and the probable cause.

2-5. PREPARATION FOR USE.

a. Connect the BNC adapter (1) to the 10MHz OVEN output and EXT REF 10MHZ input connectors on the rear panel. b. Locate line voltage switch (2) on rear panel of Level Meter. Verify line voltage switch and fuse size are correct for

your power source (table 2-1 ).

Table 2-1. Line Voltage Switch Settings and Fuse Size.

Input Voltage

90 to 105 108 to 126 198 to 231

216t0252

c. Check fuse (3) to see if it is missing, broken, or appears to be blown. If fuse is missing, broken, or appears to be

blown, contact organizational maintenance.

Switch Position

UP UP 2 amp UP DOWN UP DOWN DOWN

DOWN

Fuse

2 amp

1 amp 1 amp

2-6. TURN-ON PROCEDURES.

With the power cable connected to the rear panel power input connector, verify that the STBY light is illuminated.

a. b. Push the POWER BUTTON (1) in and release. Verify that the button remains in and that all front panel controls and

indicators illuminate for approximately two seconds and then go blank. Verify that the fan on the rear panel is operating.

Verify that the FREQUENCY/ENTRY (2) displays “3586 b OP”. The MEASUREMENT ENTRY (3) display will

c. cycle an AUTO CALIBRATION. It will display “CAL”. present in the MEASUREMENT/ENTRY display, If an error is displayed, “CE”, “E” or “Err” followed by a number, see table 2-2 for probable cause.

2-18

Verify that after the calibration cycle completes, no errors are

Page 39

Verify the following condition exists on the Level Meter front panel:

TM 11-6625-3087-12

MEASUREMENT/ENTRY display FREQUENCY/ENTRY display CENTER indicator KHz indicator AUTO CAL push button

10dB push button AUTO push button dBm push button CARRIER push button HIGHER push button LO DIST push button

10k shunted by 50pF push button 3100Hz push button All other controls and indicators

If the above condition is obtained and no errors are displayed, the Level Meter is ready for use in one of the ten

measurement modes (table 2-3).

If the power cable has been disconnected for a period of time, the OVEN indicator will be illuminated for approximately 20 minutes. OVEN indicator on. The measurements obtained will not be within specification.

2-7. STORE/RECALL PROCEDURES.

ON ON ON ON ON ON ON ON

ON ON ON ON ON OFF

NOTE

Do NOT operate the Level Meter with the

Up to nine front panel control settings and entry parameters can be stored for recall at a later date as follows:

1. To store a set-up: Press the STORE (4) push button and the desired number from 1 to 9 using the numeric key board (6). The number

selected will flash in the MEASUREMENT/ENTRY display. If a set-up was previously stored at the location selected (1-9), it will be erased and the new set-up will be stored.

2. To recall a set-up:

Press the RECALL (5) push button and the desired number from 1 to 9 using the numeric key board (6). The set-up

previously stored at that location will display.

3. To reset the Level Meter to the turn-on condition:

Press RECALL (5), and then O (6).

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TM 11-6625-3087-12

2-8. ERROR MESSAGES.

Some operator actions and Level Meter failures cause error messages to appear in the MEASUREMENT/ENTRY display. See table 2-2 for a list of error messages and probable cause.

NOTE

If an error appears that is not listed in table 2-2, notify next higher level of maintenance.

Table 2-2. Error Messages.

ERROR

Err 1

E 1.2

E 2.2

E 2.3

E 2.9

Err 3

E4.1

E 4.2

Err 5

PROBABLE CAUSE

The FULL SCALE level cannot be changed by the operator while the Level Meter is in AUTOMATIC FULL SCALE.

The 10dB range cannot be used when the Level Meter is set

up in the WIDEBAND or IMPULSE measurement modes. Ø Jitter cannot be measured because the signal level is 40dB or more

below full scale in entry.

Jitter cannot be measured because the 1 KHz test tone is not

present due to improper test setup. 0 Jitter is out of range.

Level Meter failure.

The Level Meter is in REMOTE operation and will not respond to front panel controls.

CORRECTIVE ACTION

Press MEAS CONT, then ENTRY push buttons.

Press MEAS CONT push button.

Select AUTO then 10dB RANGE.

Correct test setup.

Verify test setup. If correct, notify

next higher level of maintenance. Notify next higher level of

maintenance.

Notify next higher level of

maintenance. Notify next higher level of

maintenance. Verify test setup. If correct, notify

next higher level of maintenance.

E 6.1

E 6.2

Err 7

CE-1 to 9

2-20

Accurate impulse measurements are unlikely because the THSHLD

level is 56dB or more below full scale.

The THSHLD level is more than 3dB above full scale.

Level Meter failure.

Press MEAS CONT push button. Increase THSHLD level or decrease Full Scale.

Press MEAS CONT push button.

Decrease THSHLD level or increase Full Scale.

Notify next higher level of maintenance.

Notify next higher level of

maintenance.

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TM 11-6625-3087-12

2-9. OPERATING PROCEDURES.

The operating procedures for the Level Meter are broken down into ten individual measurement modes. See table 2-3 for the measurement mode required to perform the desired signal measurement.

NOTE

If a signal has been measured in any one operational mode listed, the Level Meter can be switched to another measurement mode without having to coarse or fine tune to the input signal.

Table 2-3. Level Meter Measurement Mode Index.

TYPE OF SIGNAL MEASUREMENT

Non-telecommunication signals. Provides the best overall performance for measuring signals other than telecommunication.

Non-telecommunication signals. Provides best performance for measuring low level components of high level signals.

Any input signal from 50Hz to 32.5MHz. Measures only total power of an input signal.

Telecommunication signals. Measures idle message channel noise or translates message channel signals to voice frequencies for monitoring or for audio output.

Telecommunication signals. Measures incidental phase modulation of

1lKHz tones on message channels.

Telecommunication signals. Measures the 1004Hz signal on a message channel. Can be used with NOISE/TONE for signal to noise ratio on a message channel.

Telecommunication signals. Measures noise on a message channel. Removes 1004Hz signal component from message channel. Can be

used with TONE 1004Hz for signal to noise ratio on a message channel.

Telecommunication signals. Measures carrier leak signals or pilot tones.

LEVEL METER MEASUREMENT MODE

LO DISTORTION (para 2-10).

LO NOISE (para 2-11).

WIDEBAND (para 2-12).

NOISE/DEMODULATION (para 2-13).

PHASE JITTER (para 2-14).

TONE 1004Hz (para 2-15).

NOISE/TONE (para 2-16).

CARRIER (para 2-17). Telecommunication signals. Measures noise spikes on message channels. Telecommunication signals. Measures the 2600Hz signal on a message

channel. The 2600Hz tone indicates an idle message channel. Measures the insertion loss of cables and other connection devices used

in any given testing hook-up.

IMPULSE (para 2-18).

2600Hz (para 2-15).

NETWORK ANALYSIS (para 2-19).

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TM 11-6625-3087-12

2-10. LOW DISTORTION MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL ( 17) then number 0 ( 16) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (21).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (5).

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4. If an OFFSET is required,

Press OFFSET (18). Enter offset value ( 16). Press MEAS CONT (7).

Do not change the units after offset has been entered.

5. On Level Meter, Press FREQ (20) and enter approximate frequency of input signal. Press AUTO (11 ) and adjust FREQ TUNE KNOB (12) for stable indication in MEASUREMENT/ENTRY display

(3). Press COUNTER (9). Press CNTR->FREQ (13).

Verify FREQUENCY/ENTRY and MEASUREMENT/ENTRY indications are stable.

TM 11-6625-3087-12

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

If indications are unstable, proceed with step 8.

6. If an offset was entered in step 4, press OFFSET (6).

7. MEASUREMENT/ENTRY display (3) indicates input signal power level. FREQUENCY/ENTRY display (8) indicates input signal frequency.

8. If MEASUREMENT/ENTRY display is unstable,

Press AVE (2). If display still unstable, turn AVE off.

Press ENTRY (1),

Press FULL SCALE (19), UP ARROW (15) or DOWN ARROW (14) then MEAS CONT (7) push buttons until display is stable. Verify OVLD indicator (3) remains off.

Select 100dB RANGE (22). Select 400Hz BW (10). Select 20Hz BW (10).

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TM 11-6625-3087-12

2-11. LOW NOISE MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (17), number 0 (16), then SHIFT (22) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (21).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (5).

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TM 11-6625-3087-12

4. If an OFFSET is required, Press OFFSET (18). Enter offset value (16). Press MEAS CONT (12).

NOTE

Do not change the units after offset has been entered.

5. On Level Meter, Press FREQ (20) and enter approximate frequency of input signal.

Press AUTO (10) and adjust FREQ TUNE KNOB (11) for stable indication in MEASUREMENT/ENTRY display

(4). Press COUNTER (8). Press CNTR->FREQ (13).

Verify FREQUENCYLENTRY and MEASUREMENT/ENTRY indications are stable.

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

If indications are unstable, proceed with step 9.

6. If an offset was entered in step 4, press OFFSET (6).

7. MEASUREMENT/ENTRY display (4) indicates input signal power level. FREQUENCY/ENTRY display (7) indicates input signal frequency.

8. On Level Meter, record MEASUREMENT/ENTRY indication. Press SHIFT (22) push button. Compare recorded value to present indication. The desired mode is the one with lowest MEASUREMENT/ENTRY indication.

9. If MEASUREMENT/ENTRY display is unstable,

Press AVE (2). If display still unstable, turn AVE off.

Press ENTRY (1). Press FULL SCALE (19), UP ARROW (15) or DOWN ARROW (14) then MEAS CONT (12) push buttons until

display is stable. Verify OVLD indicator (3) remains off. Select 100dB RANGE (23). Select 400Hz BW (9). Select 20Hz BW (9).

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TM 11-6625-3087-12

2-12. WIDEBAND MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the

same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (11), number 0 (10), then WIDEBAND (15) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMNATION (14).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (5).

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4. If an OFFSET is required, Press OFFSET (12). Enter offset value ( 10). Press MEAS CONT (7). Press OFFSET (6).

NOTE

Do not change the units after offset has been entered.

5. MEASUREMENT/ENTRY display (4) indicates input signal power level.

NOTE

Input signal modulation (AM or FM) may cause instability in MEASUREMENT/ENTRY display.

6. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (2). If display still unstable, turn AVE off.

TM 11-6625-3087-12

Press ENTRY (1). Press FULL SCALE (13), UP ARROW (9) or DOWN ARROW (8) then MEAS CONT (7) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

NOTE

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full scale level.

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TM 11-6625-3087-12

2-13. NOlSE/DEMODULAT10N MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (19), number O (18), NOISE DEMOD (24), then WTD 3100HZ (13) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (23),

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may darnage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (4).

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TM 11-6625-3087-12

4. If an OFFSET is required, Press OFFSET (20).

Enter offset value (18). Press MEAS CONT (15),

NOTE

Do not change the units after offset has been entered.

5. On Level Meter, select desired sideband CHANNEL (10).

6. Tune the Level Meter to the input signal frequency as follows: If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (8), FREQ (22),

and enter the carrier frequency. If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (9), FREQ (22), and

enter the tone frequency.

7. If an offset was entered in step 4, press OFFSET (6).

8. Verify FREQUENCY/ENTRY and MEASUREMENT/ENTRY indications are stable.

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

If indications are unstable, proceed with step 11.

9. MEASUREMENT/ENTRY display (5) indicates input signal power level. FREQUENCY/ENTRY display (7) indicates tuned carrier or tone frequency.

10. Tune the Level Meter to voice signals as follows: Enter FREQ STEP of 1Hz. Press MEAS CONT (15). Increase AUDIO VOLUME (11). Press FREQ STEP (12). Using the FREQUENCY TUNE knob (14), slowly adjust for natural sound.

11. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (2). If display still unstable, turn AVE off. Press ENTRY (1).

Press FULL SCALE (21), UP ARROW (17) or DOWN ARROW (16) then MEAS CONT (15) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

NOTE

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase

full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full

scale level and/or select 100dB RANGE (25).

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TM 11-6625-3087-12

2-14. PHASE JITTER MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the

same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (12), number 0 (11), SHIFT (15), then Ø JITTER (16) push buttons.

2. On Level Meter, If 20-300Hz band is desired, press 3100Hz (8) push button. If 4-300Hz band is desired pressWTD3100Hz (9) push button.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

3. On Level Meter, select desired TERMINATION (14).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

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TM 11-6625-3087-12

NOTE

Only 124 or 135 input may be used at one time.

4. On Level Meter, select desired sideband CHANNEL (6).

5. Tune the Level Meter to the input signal frequency as follows: l If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (3), FREQ (13),

and enter the carrier frequency. If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (4), FREQ (13), and

enter the tone frequency.

6. Fine tune the Level Meter to the input signal frequency as follows: Press COUNTER (7).

Press CNTR->FREQ (10).

7. MEASUREMENT/ENTRY display (2) indicates input signal phase jitter. FREQUENCY/ENTRY display (5) indicates

input signal frequency.

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

8. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (1). If display still unstable, turn AVE off.

NOTE

Use AVE only when necessary because it will decrease the accuracy of this measurement.

Select 100dB RANGE (17).

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2-15. TONE 1004Hz AND 2600Hz MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (18) then number 0 (17) push buttons.

2. On Level Meter, If 1004Hz measurement is desired press 1004Hz (23). If 2600Hz measurement is desired press 2600Hz (22).

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

3. On Level Meter, select desired TERMINATION (24).

When using BNC input, use only 75 BNC plugs. Use of other

damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

4. On Level Meter, select desired UNIT of measurement (5).

2-32

impedance

plugs may

Page 53

5. If an OFFSET is required, Press OFFSET (19).

Enter offset value (17). Press MEAS CONT (13).

NOTE

Do not change the units after offset has been entered.

6. On Level Meter, select desired sideband CHANNEL (10).

7. Tune the Level Meter to the input signal frequency as follows:

If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (7), FREQ (21 ), and enter the carrier frequency.

If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (8), FREQ (21), and enter the tone frequency.

8. Fine tune the Level Meter to the input signal frequency as follows: Press 3100HZ (12).

TM 11-6625-3087-12

Press COUNTER (11).

Press CNTR->FREQ (14). Press 400Hz (12).

9. If an offset was entered in step 5, press OFFSET (6).

10. MEASUREMENT/ENTRY display (4) indicates input signal power level. input signal frequency.

FREQUENCY/ENTRY display (9) indicates

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

11. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (2), If display still unstable, turn AVE off.

NOTE

Use AVE only when necessary because it will decrease the accuracy of this measurement. Press ENTRY (1). Press FULL SCALE (20), UP ARROW (16) or DOWN ARROW (15) then MEAS CONT (13) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full scale level and./or select 100dB RANGE (25).

Repeat step 8.

NOTE

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2-16. NOlSE/TONE MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (17), number 0 (16), SHIFT (23), then NOISE/TONE (22) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (21).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (5).

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4. If an OFFSET is required Press OFFSET (18). Enter offset value (16). Press MEAS CONT (12).

NOTE

Do not change the units after offset has been entered.

5. On Level Meter, select desired sideband CHANNEL (10).

6.Tune the Level Meter to the input signal frequency as follows: If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (7), FREQ (20),

and enter the carrier frequency. If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (8), FREQ (20), and

enter the tone frequency.

7. Fine tune the Level Meter to the input signal frequency as follows: Press SHIFT (23). Press COUNTER (11). Press CNTR->FREQ (13).

Press SHIFT (23).

8. f an offset was entered in step 4, press OFFSET (6).

9. MEASUREMENT/ENTRY display (4) indicates input signal power level. FREQUENCY/ENTRY display (9) indicates input signal frequency.

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

10. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (2). If display still unstable, turn AVE off.

NOTE

Use AVE only when necessary because it will decrease the accuracy of this measurement. Press ENTRY (1). Press FULL SCALE (19), UP ARROW (15) or DOWN ARROW (14) then MEAS CONT (12) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase

full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full

scale level and/or select 100dB RANGE (24).

Repeat step 7.

NOTE

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2-17. CARRIER MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the

same power source for the Level Meter and the unit under test.

1. On Level Meter, press RECALL (18), number 0 (17), then CARRIER (22) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (23).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 i nput may be used at one time.

3. On Level Meter, select desired UNIT of measurement (4).

2-36

Page 57

TM 11-6625-3087-12

4. If an OFFSET is required, Press OFFSET (19). Enter offset value (17). Press MEAS CONT (13).

NOTE

Do not change the units after offset has been entered.

5. On Level Meter, select desired sideband CHANNEL (10).

6. Tune the Level Meter to the input signal frequency as follows:

If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (7), FREQ (21 ),

and enter the carrier frequency.

If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (8), FREQ (21), and

enter the tone frequency.

7. Fine tune the Level Meter to the input signal frequency as follows: Press 3100HZ (12). Press COUNTER (1 1). Press CNTR->FREQ (14). Press 20Hz (12).

8. If an offset was entered in step 4, press OFFSET (6).

9. MEASUREMENTLENTRY display (5) indicates input signal power level. FREQUENCY/ENTRY display (9) indicates

input signal frequency.

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

10. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press AVE (2). If display still unstable, turn AVE off.

NOTE

Use AVE only when necessary because it will decrease the accuracy of this measurement. Press ENTRY (1). Press FULL SCALE (20), UP ARROW (16) or DOWN ARROW (15) then MEAS CONT (13) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

NOTE

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full scale level and/or select 100dB RANGE (24).

Repeat step 7.

2-37

Page 58

TM 11-6625-3087-12

2-18. IMPULSE MEASUREMENT.

NOTE

To insure optimum performance, keep cable lengths as short as possible. Try to use the

same power source for the Level Meter and the unit under test

1. On Level Meter, press RECALL (18), number 0 (16), SHIFT (24), then IMPULSE (2) push buttons.

The maximum input power must not exceed +27dBm or damage to internal circuitry may result.

2. On Level Meter, select desired TERMINATION (23).

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

NOTE

Only 124 or 135 input may be used at one time.

3. On Level Meter, select desired UNIT of measurement (4).

2-38

Page 59

TM 11-6625-3087-12

4. On Level Meter, enter minimum number of noise spikes to be counted as follows: Press THSHLD (19). Enter threshold level ( 16).

Press MEAS CONT(11).

NOTE

Do not change the units after threshold has been entered.

5. On Level Meter, select desired sideband CHANNEL (9).

6. Tune the Level Meter to the input signal frequency as follows: If the carrier frequency is to be used to tune the Level Meter to a message channel, press CARRIER (6), FREQ (21),

and enter the carrier frequency. If the tone frequency is to be used to tune the Level Meter to a message channel, press TONE (7), FREQ (21), and

enter the tone frequency.

7. If 1004Hz test tone is on message channel, fine tune Level Meter as follows: Press NOISE/TONE (25). Press COUNTER (10).

Press CNTR->FREQ (12).

Press IMPULSE (2).

8. On Level Meter, enter duration as follows: If counting for a specific time limit, press TIME (17) and enter time in minutes, decimal point, and seconds. Press

MEAS CONT (11).

If counting is to be continuous, press TIME (17) and enter 1000000. Press MIN (14). Verify “CON” appears in

FREQUENCY/ENTRY display (8). Press MEAS CONT (11).

9. Press START (22).

10. MEASUREMENT/ENTRY display (5) indicates input signal power level. FREQUENCY/ENTRY display (8) indicates time duration (left side) and number of impulse spikes (right side).

NOTE

Input signal modulation (AM or FM) may cause instability in either display.

11. If MEASUREMENT/ENTRY display is unstable or constantly resets full scale level, Press ENTRY (1), Press FULL SCALE (20), UP ARROW (15) or DOWN ARROW (13) then MEAS CONT (11) push buttons until

display is stable. Verify OVLD indicator (3) remains off.

NOTE

If OVLD indicator is on or “OL” appears in MEASUREMENT/ENTRY display, increase full scale level. If “UL” appears in MEASUREMENT/ENTRY display, decrease full scale level.

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TM 11-6625-3087-12

2-19. NETWORK ANALYSIS MEASUREMENT.

1. On Level Meter, press RECALL (7) then number 0 (6) push buttons.

The maximum input must not exceed ±27dBm or damage to internal circuitry may result

2. On Level Meter,

Select 75 input (8).

Connect rear panel Fo (0-32 .5MHz) output connector to front panel 75 BNC input using 75 cable supplied.

When using BNC input, use only 75 BNC plugs. Use of other impedance plugs may damage Level Meter.

3. On Level Meter, select desired UNIT of measurement (1).

4. On Level Meter, Press 20Hz (4). Press RDNG—>OFFSET (5).

5. Disconnect cable from front panel 75 BNC input.

6. On Level Meter, press OFFSET (3).

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TM 11-6625-3087-12

8. MEASUREMENT/ENTRY display (2) indicates insertion loss of the device connected to BNC input plus output level shifts due to unequal source and termination impedance.

NOTE

If device impedance is not 75 impedance matching devices must be used between device to be measured and Level Meter.

Section IV. OPERATION UNDER UNUSUAL CONDITIONS

2-20. OPERATION IN EXTREME HEAT AND EXTREME COLD.

a. Operate the Level Meter only in a temperature range of 0 to +55° C (32 to 131° F). b. Make sure the filter is clean and at least one inch of open space exists from the rear and side panels.

2-21. OPERATION IN WET WEATHER.

a. The Level Meter will operate normally in 95% relative humidity at +40° C. b. If the Level Meter has gotten wet, allow it to dry completely before using.

2-22. OPERATION IN SANDY OR DUSTY AREAS.

a. Do not operate the Level Meter in sandy or dusty areas.

2-23. EMERGENCY PROCEDURES.

a. Reduction of power. The Level Meter will operate with power reduced from 90 to 105Vac, 108 to 126Vac, 198 to

231Vac or from 216 to 252Vac. The Level Meter will not operate with any further reduction of power.

2-41/(2-42 Blank)

Page 62

Page 63

CHAPTER 3

ORGANIZATION MAINTENANCE

TM 11-6625-3087-12

Section I.

3-1. COMMON TOOLS AND EQUIPMENT.

Common tools and equipment required for organizational maintenance of Frequency Selective Level Meter AN/USM-490 are

listed in the Maintenance Allocation Chart (MAC) (Appendix B).

3-2. SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT.

There are no special tools, TMDE, or support equipment required.

3-3. REPAIR PARTS.

Repair parts are listed and illustrated in the repair parts and special tools list, TM 11-6625-3087-24P.

3-4. SERVICE UPON RECEIPT OF MATERIAL.

a. Unpacking. Special design reusable packing material inside this shipping carton provides maximum protection for Level Meter. Avoid damaging carton and packing material during equipment unpacking. Use the following steps for unpacking Level Meter

Cut and remove paper sealing tape on carton top and open carton. Grasp Level Meter firmly while restraining shipping carton and lift equipment and packing material vertically.

Place Level Meter and end cap packing material on a suitable flat clean and dry surface.

REPAIR PARTS, SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT

Section Il. SERVICE UPON RECEIPT

Remove end cap packing material while firmly supporting Level Meter. Remove protective plastic bag from Level Meter. Place desiccant bags back inside protective plastic bag. Place protective plastic bag and end cap packing material inside shipping carton. Return shipping carton to supply system.

b. Checking Unpacked Equipment.

Inspect the equipment for damage incurred during shipment. If the equipment has been damaged report the damage on SF-364, Report of Discrepancy (ROD).

Check the equipment against the packing slip to see if the shipment is complete. Report all discrepancies in accordance with the instructions of DA Pam 738-750.

Check to see whether the equipment has been modified.

3-5. PRELIMINARY SERVICING AND ADJUSTMENT OF EQUIPMENT.

Perform all items under preparation for use (para 2-5).

b. Perform the turn-on procedures (para 2-6).

Perform operational test (para 3-7).

3-1

Page 64

TM 11-6625-3087-12

Section Ill.

TROUBLESHOOTING

SYMPTOM INDEX

Level Meter

Symptom

1. LEVEL METER WILL NOT TURN-ON

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. LEVEL METER QUITS DURING OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. FREQUENCY/ENTRY DISPLAY BLANK

4. ERROR MESSAGE PRESENT IN MEASUREMENT/ENTRY DISPLAY

5. FREQUENCY TUNE KNOB WILL NOT CHANGE FREQUENCY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . .. . . . . . . . . . . . .

6. AUDIO NONOPERATIVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .

7. LEVEL METER WILL NOT MEASURE INPUT SIGNAL

8. OVLD INDICATOR FLASHING

9. OL/UL IN MEASUREMENT/ENTRY DISPLAY

. . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . .. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

3-6. TROUBLESHOOTING TABLE.

Page

3-2 3-3

3-3 3-3 3-3 3-4

3-4

Table 3-1 lists common malfunctions which you may find during operation or maintenance of the Level Meter or its components. You should perform the tests/inspections and corrective actions in the order listed.

This manual cannot list all malfunctions that may occur, nor all tests or inspections and corrective actions. If a malfunction is not listed or is not corrected by listed corrective actions, notify your supervisor.

Table 3-1. Troubleshooting.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. LEVEL METER WILL NOT TURN-ON. Step 1. Check the fuse and fuseholder cap.

Replace faulty component.

Step 2. Check to see if the power is available at the power receptacle.

Move to a working receptacle.

Step 3. Check power cable.

—

3-2

Replace faulty component. Notify next higher level of maintenance.

Page 65

Table 3-1. Troubleshooting--Continued.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

2. LEVEL METER QUITS DURING OPERATION Step 1. Perform malfunction No. 1. Step 2. Allow the Level Meter to cool and then try operating.

If Level Meter operates normally, check air filter. Clean as required. If Level Meter does not operate, notify next higher level of maintenance.

3. FREQUENCY/ENTRY DISPLAY BLANK. Step 1. Check to see if the Level Meter is in WIDEBAND mode.

Select another mode.

TM 11-6625-3087-12

Step 2. Check to see if an ERROR message is present in the MEASUREMENT/ENTRY display.

If error is present, go to malfunction No. 4. If error is not present, proceed with step 3.

Step 3. Press AUTO CAL push button.

If no calibration error is displayed, recheck operating instructions (para 2-9). If calibration error is displayed, notify next higher level of maintenance.

4. ERROR MESSAGE PRESENT IN MEASUREMENT/ENTRY DISPLAY.

Step 1. Check to see if error is listed in table 2-2.

Perform required action as listed.

Step 2. Press MEAS CONT push button.

If error disappears, resume normal operation. If error remains, notify next higher level of maintenance.

5. FREQUENCY TUNE KNOB WILL NOT CHANGE FREQUENCY. Step 1. Check to see if AUTO or FREQ STEP push buttons are on.

Select proper push button.

Notify next higher level of maintenance.

3-3

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TM 11-6625-3087-12

Table 3-1. Troubleshooting-Continued.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

6. AUDIO NOT OPERATIVE. Step 1. Verify in LO DIST, LO NOISE, or NOISE/DEMOD measurement modes.

Make proper selection.

Step 2. Check to see if the audio volume knob is fully CCW.

Increase volume (CW).

Step

7. LEVEL METER WILL NOT MEASURE INPUT SIGNAL.

Perform operational test (para 3-7).

If audio present at end of test, recheck operating instructions.

If audio is missing or weak, notify next higher level of maintenance.

Step 1.

Step

Step 3.

8. OVLD INDICATOR FLASHING. Step 1. Check full scale setting on Level Meter.

Step 2. Check amplitude of input signal.

9. OL/UL IN MEASUREMENT/ENTRY DISPLAY.

Check to see if the unit under test is on.

Apply power.

Press AUTO CAL push button.

If calibration error is displayed, notify next higher level of maintenance. If no calibration error is displayed, proceed with step 3.

Perform operational test (para 3-7).

If test passes, recheck operating instructions (para 2-9).

If test fails, notify next higher level of maintenance.

Select AUTO or increase full scale setting.

Decrease amplitude until indicator goes out. Notify next higher level of maintenance.

3-4

Step 1. Check amplitude of input signal.

Adjust amplitude until indicator goes out.

Step 2. Press AUTO CAL push button.

If no calibration error is displayed, recheck operating instructions. If calibration error is displayed, notify next higher level of maintenance.

Page 67

TM 11-6625-3087-12

Section IV.

3-7. OPERATIONAL TEST.

DESCRIPTION

This procedure covers: Test.

INITIAL SETUP

MAINTENANCE PROCEDURES

NOTE

PRELIMINARY PROCEDURES:

Perform turn on procedures (para 2-6).

TEST

1. Press ENTRY (1),100dB (2). Turn AUTO CAL (3) to off. Set full scale to –35dBm.

2. Press RECALL (4), . (decimal point) (5), CNTR—> FREQ (6), and number 9 (7) push buttons.

3. Verify that PASS is shown on the MEASUREMENT/ENTRY display (8)

4. Press MEAS CONT (9),

5. Press RECALL (4), . (decima

6. Verify that PASS is shown on speaker (12).

7. Press POWER SWITCH (13).

point) (5), CNTR->FREQ (6), and number 8 (10) push buttons.

the FREQUENCY/ENTRY display (11 ) for four tests, and musical tones are heard at the

END OF TASK

3-5

Page 68

TM 11-6625-3087-12

3-8. REPLACE FUSE.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

Working at the front panel, set

POWER switch (1) to STBY.

Working from rear, unplug power cable

2. (2).

Rotate the fuseholder cap (3)

3. counterclockwise until it stops.

Pull fuse (4) out of fuseholder cap (3).

INSTALL

Working from rear, insert the fuse (4)

1. into the fuseholder cap (3) and place it into the fuseholder body.

Push in and rotate the fuseholder cap

(3) clockwise until it locks.

Replace power cable (2).

3. Working from front, set POWER

switch (1) to ON.

3-6

END OF TASK

Page 69

3-9. REPLACE FRONT PANEL CONTROL KNOBS.

DESCRIPTION

This rocedure covers:Remove. Install,

REMOVE

1. Set POWER switch (1) to STBY.

2. Loosen two setscrews (2).

3. Pull knob (3) off shaft (4).

INSTALL

1. Push knob (3) onto shaft (4).

2. Tighten two setscrews (2).

3. Set POWER switch (1) to ON.

TM 11-6625-3087-12

END OF TASK

3-7

Page 70

TM 11-6625-3087-12

3-10. REPLACE FRONT PANEL PUSH BUTTONS.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

1. CAREFULLY pull push button (1) off

actuator (2) using a small pliers.

INSTALL

1. Align the push button (1) on the switch actuator (2).

2. Press the new push button (1) until it seats fully on the switch actuator (2).

3. Check the push button for free movement and proper operation.

3-8

END OF TASK

Page 71

3-11. REPLACE BOTTOM BUMPERS AND TILT STANDS.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

1. Place equipment on side.

2. Lift tab (1) and slide bumper (2) inward.

3. Pull bumper (2) out of bottom cover (3).

4. Remove stand (4) from bumper (2).

INSTALL

1. Replace stand (4) with bend facing away

from bottom cover into bumper (2).

TM 11-6625-3087-12

2. Align three studs on bumper (2) with three holes on bottom cover (3).

3. Slide bumper (2) outward until it locks.

END OF TASK

3-9

Page 72

TM 11-6625-3087-12

3-12. REPLACE AIR FILTER.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

1. Set POWER switch

2. Working from rear, nuts (2).

3. Pull off air filter (3).

INSTALL

1. Position air filter (3) on four screws (4).

2. Install four thumb nuts (2).

3. Set POWER switch (1) to ON.

(1) to STBY. remove four thumb

3-10

END OF TASK

Page 73

3-13. REPLACE REAR BUMPERS.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

1. Working from rear, remove screw (1)

and lock washer (2).

2. Pull bumper (3) from rear frame (4).

INSTALL

1. Working from rear, position bumper (3)

on rear frame (4).

2. Install screw (1) and lock washer (2).

TM 11-6625-3087-12

END OF TASK

3-11

Page 74

TM 11-6625-3087-12

3-14. REPLACE SIDE HANDLES.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

Working from side, remove screws (1).

1. Remove front (2) and rear (3) retainers.

2. Remove

INSTALL

Working from side, position side

handle (4), front (2) and rear (3) retainers.

Install screws (1).

side handle (4).

END OF TASK

3-12

Page 75

3-15. REPLACE FRONT HANDLES.

DESCRIPTION

This procedure covers: Remove. Install.

REMOVE

TM 11-6625-3087-12

1. Working

2. Remove screws (2).

3. Remove front handle

INSTALL

1. Working from side, position side handle (3) on front frame (4).

Install screws (2).

3. Install trim (1).

from side, remove trim (1).

(3).

END OF TASK

3-13

Page 76

TM 11-6625-3087-12

Sect

on V.

3-16. PACKAGING.

Package level meter in original shipping container. Refer to SB 38-100 for preservation, packaging, packing and marking materials

3-17. ADMINISTRATWE STORAGE.

Refer to TM 740-90-1 for administrative storage procedures.

3-18. ENVIRONMENT.

The level meter should be stored in aclean, dry environment. In high humidity environments, protect the level meter from temperature variations that could cause internal condensation. shipping and storage:

Temperature . . . . . . . . . . . . . . . . . .

Relative Humidity

Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PREPARATION FOR STORAGE OR SHIPMENT

The following environmental conditions apply to both

-40° C to +75° C (-40” F to +158° F) less than 95%

less than 15,300 meters (50,000 feet)

3-14

Page 77

TM 11-6625-3087-12

APPENDIX A

REFERENCES

A-1. SCOPE.

This appendix lists all forms, field manuals, technical manuals, and miscellaneous publications referenced in this manual.

A-2. FORMS.

Recommended Changes to Publications and Blank Forms Recommended Changes to Equipment Technical Manuals Discrepancy in Shipment Report (DISREP) Report of Discrepancy (ROD) Quality deficiency report

A-3. TECHNICAL MANUALS.

The Army Maintenance Management System (TAMMS)

Procedures for Destruction of Electronics Materiel to prevent Enemy Use (Electronics Command) . . . . TM 750-244-2

Organizational, Direct Support, and General Support Repair Parts and Special Tools List,

for Frequency Selective Level Meter AN/USM-490

Administrative storage procedures

A-4. MISCELLANEOUS.

Consolidated Index of Army Publications and Blank Forms

First Aid for Soldiers Safety Precautions for Maintenance of Electrical/Electronic Equipment

Abbreviations for Use on Drawings, Specifications, Standards and in Technical Documents . . . . . . . . . . . . . . . . . . . . MIL-STD- 12

Preservation, Packaging, Packing, and Marking Materials, Supplies and Equipment Used by the Army . . . . . . . . . . . . . SB 38-100

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TM740-90-1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-6625-3087-24P

DA Form 2028

DA Form 2028-2

Form SF 361 Form SF 364 Form SF 368

DA Pam 738-750

DA Pam 310-1

FM 21-11

TB 385-4

A-1/(A-2 Blank)

Page 78

Page 79

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

INTRODUCTION

The Army Maintenance System MAC

This introduction provides a general explanation of all maintenance and repair function authorized at the two maintenance levels under the Two-Level Maintenance System concept.

This MAC (immediately following the introduction) designates overall authority and responsibility for the performance of maintenance functions on the identified end item or component. The application of the maintenance functions to the end item or component levels, which are shown on the MAC in column (4) as:

Field – includes two columns, Unit maintenance and Direct Support maintenance. The Unit maintenance column is divided again into two more subcolumns, C for Operator or Crew and O for Unit maintenance. Sustainment – includes two subcolumns, general support (H) and depot (D).

The tools and test equipment requirements (immediately following the MAC) list the tools and test equipment (both special tools and common tool sets) required for each maintenance function as referenced from the MAC.

The remarks (immediately following the tools and test equipment requirements) contain supplemental instructions and explanatory notes for a particular maintenance function.

Maintenance Functions

Maintenance functions are limited to and defined as follows:

1. Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or

electrical characteristics with established standards through examination (e.g. by sight, sound, or feel). This includes scheduled inspection and gagings and evaluation of cannon tubes.

2. Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical

characteristics of an item and comparing those characteristics with prescribed standards on a scheduled basis, i.e., load testing of lift devices and hydrostatic testing of pressure hoses.

3. Service. Operations required periodically to keep an item in proper operating condition; e.g., to clean

(includes decontaminate, when required), to preserve, to drain, to paint, or to replenish fuel, lubricants, chemical fluids, or gases. This includes scheduled exercising and purging of recoil mechanisms. The following are examples of service functions:

a. Unpack. To remove from packing box for service or when required for the performance

of maintenance operations.

b. Repack. To return item to packing box after service and other maintenance operations. c. Clean. To rid the item of contamination. d. Touch up. To spot paint scratched or blistered surfaces. e. Mark. To restore obliterated identification.

4. Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or

by setting the operating characteristics to specified parameters.

5. Align. To adjust specified variable elements of an item to bring about optimum or desired

performance.

Change 1 B-1

Page 80

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

6. Calibrate. To determine and cause corrections to be made or to be adjusted on instruments of

test, measuring, and diagnostic equipment 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.

7. Remove/install. To remove and install the same item when required to perform service or

other maintenance functions. Install may be the act of emplacing, seating, or fixing into position a spare, repair part, or module (component or assembly) in a manner to allow the proper functioning of an equipment or system.

8. Paint. To prepare and spray color coats of paint so that the ammunition can be identified

and protected. The color indicating primary use is applied, preferably, to the entire exterior surface as the background color of the item. Other markings are to be repainted as original so as to retain proper ammunition identification.

9. Replace. To remove an unserviceable item and install a serviceable counterpart in its place

“Repair” is authorized by the MAC and assigned maintenance level is shown as the third position code of the Source, Maintenance and Recoverability (SMR) code.

10. Repair. The application of maintenance services, including fault location/troubleshooting,

removal/installation, disassembly/assembly procedures and maintenance actions to identify troubles and 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.

NOTE

The following definitions are applicable to the “repair” maintenance function:

Services. Inspect, test, service, adjust, align, calibrate, and/or replace. Fault location/troubleshooting. The process of investigating and detecting the case of equipment malfunctioning; the act of isolating a fault within a system or Unit Under Test (UUT). Disassembly/assembly. The step-by-step breakdown (taking apart) of a spare/functional group coded item to the level of its least component, that is assigned an SMR code for the level of maintenance under consideration (i.e., identified as maintenance significant). Actions. Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.

11. Overhaul. That maintenance effort (service/action) prescribed to restore an item to a

completely serviceable/operational condition as required by maintenance standards 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.

12. 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 material maintenance applied to Army equipment. The rebuild operation includes the act of returning to zero those age measurements (e.g., hours/miles) considered in classifying Army equipment/components.

B-2 Change 1

Page 81

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

Explanation of Columns in the MAC

Column (1) Group Number, Column (1) lists FGC numbers, the purpose of which is to identify maintenance significant components, assemblies, subassemblies, and modules with the Next Higher Assembly (NHA).

Column (2) Component/Assembly. Column (2) contains the item names of components, assemblies, subassemblies, and modules for which maintenance is authorized.

Column (3) Maintenance Function. Column (3) lists the functions to be performed on the item listed in column (2). (For a detailed explanation of these functions, refer to “Maintenance Functions” outlined above).

Column (4) Maintenance Level. Column (4) specifies each level of maintenance authorized to perform each function listed in column (3), by indicating work time required (expressed as manhours in whole hours or decimals) in the appropriate subcolumn. The work time figure represents the active time required to perform that maintenance function at the indicated level of maintenance. If the number or complexity of the tasks within the listed maintenance function varies at different maintenance levels, appropriate work time figures are to be shown for each level. The work time 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 (including any necessary disassembly/assembly time), troubleshooting/fault location time, and quality assurance time in addition to the time required to perform the specific tasks identified for the maintenance functions authorized in the MAC. The symbol designations for the various maintenance levels are as follows:

C Operator or Crew maintenance O Unit maintenance F Direct Support maintenance

L Specialized Repair Activity H General Support maintenance D Depot maintenance

The “L” maintenance level is not included in column (4) of the MAC. Functions to this level of maintenance are identified by work time figure in the “H” column of column (4), and an associated reference code is used in the REMARKS column (6). This code is keyed to the remarks and the SRA complete repair application is explained there.

Column (5) Tools and Equipment Reference Code. Column (5) specifies, by code, those common tool sets (not individual tools), common Test, Measurement and Diagnostic Equipment (TMDE), and special tools, special TMDE and special support equipment required to perform the designated function. Codes are keyed to the entries in the tools and test equipment table.

Column (6) Remarks Code. When applicable, this column contains a letter code, in alphabetical order, which is keyed to the remarks table entries.

Field:

Sustainment:

NOTE

Change 1 B-3

Page 82

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

(1)

GROUP

NUMBER

00 Frequency Selective Level

01 Circuit Card Assembly A1

02 Circuit Card Assembly A2

03 Circuit Card Assembly A4

04 Circuit Card Assembly A5

05 Circuit Card Assembly A10

06 Circuit Card Assembly A11

07 Circuit Card Assembly A15

08 Circuit Card Assembly A16

09 Circuit Card Assembly A20

10 Circuit Card Assembly A21

11 Circuit Card Assembly A22

12 Circuit Card Assembly A40

13 Circuit Card Assembly A50

14 Circuit Card Assembly A60

COMPONENT/ASSEMBLY

Meter, AN/USM-490

(Input Multiplexer)

(Input Amp)

(Broadband Pwr/Cal/Overld)

(Input Mixer)

(Second Mixer)

(Second LO)

(Tracking Output)

(10MHz Freq Ref)

(IF Gain/Det)

(Analog-Digital Conv)

(Frequency Reference)

(Step Loop)

(Controller)

Table 1. MAC for Frequency Selective Level Meter, AN/USM-490

(2)

(IF Filter)

(3)

MAINTENANCE

FUNCTION

INSPECT

TEST

SERVICE

INSPECT

TEST

ADJUST

CALIBRATE

REPAIR REPAIR REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

INSPECT

TEST

REPAIR

UNIT DS GS DEPOT

C O F H D

0.5

1.0

0.2

0.1

0.2

0.1

0.2

(4)

MAINTENANCE LEVEL

FIELD SUSTAINMENT

1.0

8.2

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

0.5

1.0

10.0

TOOLS AND

EQUIPMENT

2, 5, 6, 7-43

2-14,1618,25,40-42 2,5-7,14,16-

18,25-42

2,4,6,8,12,17,

21,25

2,3,18,21

2,4-8,13,17-

18,21,25 2,3,57,12,18,21,25

2,4-6,8-12,17

2,3,5,6,12

2,4-6,810,12,17,18,25 2,3,5,6,10,12,1

2,4,5,8,11,12,1

4,18,18,25

2,3,5,6,11,12,1

4,17,25,33

2,4,5,6,8,10,

12,16,17

2,3,5,12

2,4,5,8,12,16,

2,3,5,12

6,8,10,12,16,

2,3,5,12

2,4,5,8,11,12,

14,16,17

2,3,5,6,11,12,1

4.16,33

2,4,5,6,8,12,17

2,3,5,6,12

2,4-6,8,

12-16,17

2,3,5,12-17

2,4-6,8-10,

12-16,17

2,3,5,12-16

2,4,5,8,10,12,1

4,16,17

2,3,5,12,14,16

2,4,5,8,12,16,

2,3,5,12

(5)

1 1 1 2

2-43

8,25

2,4-

(6)

REMARKS

1 2 3 4 5 6

7 8 9

B-4 Change 1

Page 83

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

(1)

GROUP

NUMBER

15 Circuit Card Assembly A70

16 Circuit Card Assembly A98

17 Circuit Card Assembly A99

COMPONENT/ASSEMBLY

(2)

(Impairments B)

(Switch/Didplay)

(Motherboard)

(3)

MAINTENANCE

FUNCTION

INSPECT

TEST REPAIR REPAIR

INSPECT

TEST REPAIR

INSPECT

TEST REPAIR

UNIT DS GS DEPOT

C O F H D

0.2

Table 2. Tools and Test Equipment for Frequency Selective Level Meter, AN/USM-490

(1)

TOOLS OR

TEST

EQUIPMENT

(2)

MAINTENANCE

LEVEL

NOMENCLATURE

(3)

REF CODE

1 O Tool Kit 5180-00-064-5178 TK-101/G 2 F,D Tool Kit 5180-01-195-0855 JTK-17 3 F,D Printed Circuit Repair

kit or equiv for use on

non-multi-layer CCA 4 F,D Transistor Test Set 6625-00-159-2263 TS-1836C/U 5 F,D Circuit Card Extender

Kit 6 F,D Synthesizer/Level

Generator 7 F,D Frequency Synthesizer 6625-01-107-8152 3325A (TMDE

8 F,D Oscilloscope 6625-01-034-3269 5440 (AN/GSM-286) 9 F,D Plug-In Unit 4931-01-008-1478 5S14N

10 F,D Spectrum Analyzer 6625-01-079-9495 AN/USM-489(V)/1 11 F,D Signal Generaror 6625-01-233-8615 SG-1207/U 12 F,D Digital Multimeter 6625-01-042-7415 3455A (TMDE

13 F,D Power Meter 6625-01-191-7679 AN/USM-491

14 F,D Thermistor Mount 5985-01-257-9470 478A (AN/GSM-

15 F,D Tester, Digital Circuit 6625-01-068-8641 TS-3791/U 16 F,D Counter, Frequency 6625-00-531-4752 5345A

17 F,D Voltage, DC Source 332 (AN/GSM-286) 18 F,D Attenuator 5985-00-957-1860 355D

(4)

MAINTENANCE LEVEL

FIELD SUSTAINMENT

0.5

1.0

0.5

1.0 2

0.5

1.0

TOOLS AND

EQUIPMENT

2,4-

6,8,9,12,15,16

2,3,5,6,12

2,8,12 2,3,12

(4)

NATIONAL

STOCK

TOOL NUMBER

NUMBER

5999-00-757-7042 MK-772/U

6625-01-132-1715 03586-84401(28480)

6625-01-151-8424 3335A-001

(AN/GSM-286)

A041022) (May use

(AN/GSM-286)

(With CAL sheet)

(5)

REMARKS

(5)

D040015)

HP 3478A)

286)

(6)

Change 1 B-5

Page 84

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

19 F,D 100 KHz Low Pass

Filter

20 F,D 10 MHz Low Pass

Filter

21 F,D 75 Ohm Directional

Bridge

22 F,D 124 Ohm Return Loss

Coupler

23 F,D 75 Ohm 0.5V Thermal

Converter 24 F,D Frequency Doubler G-3 (15542) 25 F,D 50/75 Ohm Minimum

Loss Pad (2 each) 26 F,D BNC “T”, 2 each 5935-00-103-7571 31-2208-1020

27 F,D Adapter, 2 each 5935-01-183-3404 29PP110-1 (24931) 28 F,D Adapter, 2 each 29JJ124-1 (24931) 29 F,D WECO 310 Plug to (f)

BNC Adapter (5each) 30 F,D (m) BNC to single

banana jack adapter (2

each) 31 F,D 600 OHM Feed Thru 6695-01-209-3205 7916916 32 F,D Large WECO to (f)

BNC adapter (3each) 33 F,D 600 Ohm Balance

Testing Apparatus 34 F,D 75 ohm to balanced

124 ohm matching pad 35 F,D 75 ohm to balanced

135 ohm matching pad 36 F,D 75 ohm to balanced

600 ohm matching pad 37 F,D 135 ohm balance

testing apparatus 38 F,D Power combiner 6695-01-209-1655 7916899 39 F,D 124 ohm balance

testing apparatus 40 F,D Attenuator 5985-00-763-7326 7910807 41 F,D High Impedance Probe 7420-00-623-3211 1120A 42 F,D Low Frequency

Spectrum Analyzer 43 F,D RF Amplifier 5996-01-208-8517 QB-188-2 (55027)

5915-01-212-4457 F2172 (19615)

5915-01-212-4456 F2171 (19615)

6625-01-132-7197 8721A/008

(28480)

5061-1137

(28480)

6625-01-213-0421 11051A/003 (28840)

(With CAL sheet)

6625-01-127-0094 11852A (28480)

(02660)

6625-00-107-8287 2798 (05276)

5935-00-665-6544 UG1090U

WECO 372 (14949)

6695-01-209-1651 7916897

6695-01-209-1652 7916895

6695-01-209-1653 7916896

6695-01-209-1654 7916898

6695-01-209-3206 7916894

6695-01-209-3207 7916893

6625-01-118-9963 3585A (or

equivalent)

(or equivalent)

B-6 Change 1

Page 85

TM 11-6625-3087-12 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC)

Table 3. Remarks for Frequency Selective Level Meter, AN/USM-490

REMARKS

CODE

1 Visual inspection of all external surfaces only. 2 Normal operational test. 3 Replacement of fuses, knobs, and any other maintenance on the external surface of the

AN/USM-490. 4 Visual inspection of all internal and external areas. 5 Fault isolate to piece parts. Circuit cards tested as part of end item. 6 All mechanical and/or electrical adjustments need to return the AN/USM-490 to

operational status. 7 Governed by TM-43-180 and the associated TB. 8 The following are repaired by replacement circuit card assemblies: A31, A32, A51,

A52, A53, A61, A62, A80, and cable assemblies W1, W3-W15, W17 and W18.

REMARKS

9 To be returned to the depot only in the event that TSG is unable to repair the AN/USM-

490 either due to a lack of parts or time factor.

10 Some procedures require the use of 75 ohm coaxial cables. 11 Tool number 5, circuit card extender kit, consists of the following:

A. 44 pin extender board (2 each) PN 03586-66590 B. 30 pin extender board (2 each) PN 03586-66591

Change 1 B-7(B-8 Blank)

Page 86

TM 11-6625-3087-12

APPENDIX C

COMPONENTS OF END ITEM AND BASIC ISSUE ITEMS LIST

Section I.

C-1. SCOPE.

This appendix lists components of the end item and basic issue items for the AN/USM-490 to help you inventory items required for safe and efficient operation.

C-2. GENERAL.

The components of End Item and Basic Issue Items List (BII) are divided into the following sections:

a Section II-Components of End Item.

requisition replacements. These are part of the end item, but are removed and/or separately packaged for transportation or shipment. As part of the end item, these items must be with the end item whenever it is issued or transferred between property accounts. Illustrations are furnished to assist you in identifying the items.

b. Section III—Basic Issue I/ems. These are the minimum essential items required to place the AN/USM-490 in

operation, to operate it, and to perform emergency repairs. Although shipped separately packaged, BII must be with the

AN/USM-490 during operation and whenever it is transferred between property accounts. This manual is your authority to request,requisition replacement BII, based on TOE/MTOE authorization of the end item.

C-3. EXPLANATION OF COLUMNS.

a Column (1)-lllusfration Number (1/lus Number). This column indicates the number of the illustration in which the

item is shown.

b. Column (2)--National Stock Number. This column indicates the national stock number assigned to the item and

will be used for requisitioning purposes.

c. Column (3)-Description. This column indicates the federal item name and, if required, a minimum description to

‘ identify and locate the item. The last line for each item indicates the FSCM (in parentheses) followed by the part number.

This listing is for information purposes only and is not authority to

INTRODUCTION

d Column (4)-Unit of Measure (UIM).

operation/maintenance function. This measure is expressed by a two-character alphabetical abbreviation (e.g., ea, in, pr).

e. Column (5)-Quantity Required (Qty Rqr). This column indicates the quantity of the item authorized to be used

with/on the equipment.

This column indicates the measure used in performing the actual

C-1

Page 87

TM 11-6625-3087-12

Section Il. COMPONENTS OF END ITEM

C-2

(1)

Illus

Number

(2) National Stock Number

6150-00-041-5038 CABLE ASSEMBLY, POWER

5935-01-149-2471

Description FSCM and Part Number

SELECTIVE LEVEL METER (28480) 3586B/001/001/003/004/907

(70903) KH7147 CABLE ASSEMBLY, BNC

(28480) 8120-0688

ADAPTER, ELECTRICAL CONN

(94375) RF03152M

(3)

(4) U/M

(5) Qty Rqr

Page 88

APPENDIX D

ADDITIONAL AUTHORIZATION LIST

TM 11-6625-3087-12

Section I.

D-1. SCOPE.

This appendix lists additional items you are

D-2. GENERAL.

This list identifies items that do not have to

items are all authorized to you by CTA, MTOE, TDA, or JTA.

D-3. EXPLANATION OF LISTING.

National stock numbers, descriptions, and quantities are provided to help you identify and request the additional items you require to support this equipment. The items are listed in alphabetical sequence by item name under the type document (i.e., CTA,

MTOE,

TD, or JTA) which authorized

Section Il.

(1)

NATIONAL

STOCK

NUMBER

FSCM and PART NUMBER

authorized for the support of the AN/USM-490.

accompany the AN/USM-490 and that do not have to be turned in with it. These

the item(s) to you.

ADDITIONAL

INTRODUCTION

AUTHORIZATION LIST

(2)

DESCRIPTION

USABLE ON CODE

(3)

U/M

(4)

QTY

AUTH

5920-00-280-4960

FUSE, CARTRIDGE

(81349) F02A250B1A

FUSE, CARTRIDGE (81 349) F02A250V2A

D-1/(D-2 Blank)

Page 89

Page 90

APPENDIX E

EXPENDABLE SUPPLIES AND MATERIALS LIST

TM 11-6625-3087-12

Section I.

E-1. SCOPE.

This appendix lists expendable supplies you will need for general support maintenance on frequency selective level meter

AN/USM-490. These items are authorized to you by CTA 50-970, Expendable items (Except Medical, Class V, Repair Parts, and Heraldic Items).

E-2. EXPLANATION OF COLUMNS.

a Column (1)---Item Number. This number is assigned to the entry in the listing and is referenced in the narrative

instructions to identify the material (e.g.,

b. Column (2)----Level. This column identifies the lowest level of maintenance that requires the listed item.

0- Organizational Maintenance.

c. Column (3)--National Stock Number. This column indicates the national stock number assigned to the item and

will be used for requisitioning purposes.

d Column (4)--Description.

identify the item. The last line for each item indicates the FSCM (in parentheses) followed by the part number.

Column (5)-Unit of Measure (U/M). This column indicates the measure used in performing the actual maintenance

function. This measure is expressed by a two-character alphabetical abbreviation (e.g., EA, IN, PR). If the unit of measure differs from the unit of issue, requisition the lowest unit of issue that will satisfy your requirements.

Section Il. EXPENDABLE SUPPLIES AND MATERIALS LIST

“Use cleaning compound, item 5, App. D“).

This column indicates the federal item name and if required, a minimum description to

INTRODUCTION

(1)

ITEM

NUMBER

(2)

LEVEL

(3)

NATIONAL

STOCK

NUMBER

8305-00-267-3015

6810-00-753-4993

(4)

DESCRIPTION

Cloth, Cheesecloth, Cotton, Lintless, CCC-C-440, Type II, Class 2 (81349)

Alcohol, Isopropyl, 8oz Can, MlL-A-10428, Grade A (81349)

(5)

U/M

E-1/(E-2 Blank)

Page 91

Page 92

INDEX

TM 11-6625-3087-12

Paragraph

Figure, Table,

Number

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Administrative Storage

Air Filter Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bumper Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .

Calibration/Tracking Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Capabilities and Features . . . . . . . . . . . . . . . . . . . . . . .

Characteristics, Performance . . . . . . . . . . . . . . . . . . . . . . . .

Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Checking Unpacked Equipment . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Common Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Common Tools and Equipment . . . . . . . . . . . . . . . . . . . . . . .

Components of End Item . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conditions, Operating

Unusual . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Usual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Controls, Indicators, and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Consolidated Index of Army Publications and Blank Forms . . . . . . . . . . . . .

Cross-Reference List . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .

1-9 1-4

3-12

3-11,3-13

1-12, F1-2

1-10 1-11 1-10

3-4

2-3

1-8 Appendix B Appendix C

2-20

2-9 2-1 1-2 1-8

Data, Equipment

Destruction of Army Materiel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Digital Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Environmental . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment, Common Tools . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .

Equipment Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Improvement Recommendation . . . . . . . . . . . .

Equipment Purpose

Equipment, Special Tools, TMDE, and Support . . . . . . . . . . . .

Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-11

1-5

1-12,F1-2

1-11

1-11,3-19

3-1

1-11

1-6 1-1

3-2

2-8,T2-2

INDEX-1

Page 93

TM 11-6625-3087-12

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

First Local Oscillator Section . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Reference Section

Front Handle Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . .

Functional Description . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

Fuse Replacement

lF/Audio Section

Impairments Section . . . . . . . .. . . . . . . . . . . . .

Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input Power Requirements . . . . . . . . . . . . . .

Input Sect ion

Inspections . . . . . . . . . . . . . . . . . . . . . . . .

Interface Section

Knob Replacement . . . . . . . . . . . . . . . . . . . .

Level Meter, AN/USM-490 . . . . . . .

List of Abbreviations . . . . . . . . . . . . . . . . . . . .

List of Capabilities

List of Characteristics . . . . . . . . . . . . . . . . .

List of Common Names . . . . . . . . . . . . . .

List of Control initial Setup positions . . . . . . . . . .

List of Equipment Data

List of Expendable Supplies and Materials . .. . . . . . . . . . . . . .

List of Operator Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .

List of PMCS Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of References

List of Voltage Selection Switch Positions and Fuses . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix E

Appendix A

1-10 1-12, F1-2 1-12, F1-2

3-15

1-12

1-12, F1-2 1-12, F1-2

1-12,F1-2 1-12, F1-2

1-8,F1-1

3-6,T3-1

2-5,T2-1

3-8

2-1

1-11

2-3

3-9

1-9 1-10 1-10

1-8

2-6 1-11

2-3

Maintenance Allocation Chart (MAC)

Maintenance Forms and Records, and Reports . . . . . . . . . . . . . . . . . .

Maintenance, Operator Preventive

Maintenance Procedures . . . . . . . . . . . . .

Nomenclature Cross-Reference List . . . . . . . . . .

INDEX-2

. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

Appendix B

1-3 2-3 3-7

1-8

Page 94

Operational Modes

2600Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Impulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LO Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Network Analysis . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .

Noise/Demodulation . . . . . . . . . . . . . . . . . .

Noise/Tone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Phase Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tone 1004Hz . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .

Wideband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Principles

Operating Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operation Requirements . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operational Test

Operator’s Controls, Indicators, and Connectors . . . . . . . . . . . . . . .

. . . . . . . . .. . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-6625-3087-12

2-15,T2-3 2-17,T2-3 2-18,T2-3 2-11,T2-3 2-19,T2-3 2-13,T2-3 2-16,T2-3 2-14,T2-3 2-15,T2-3 2-12,T2-3

1-12

2-1

1-11

3-7 2-1

Packing

Parts, Repair Performance Characteristics Power Requirement

Power Supply Section . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preparation for Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . .

Preparation for Use . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Principles of Operation . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .

Procedures, Operating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Procedures, Store/Recall . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .

Procedures, Turn-On . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .

Push Button Replacement . . . . . . . . . . . . . . . . . . . . . .

Records, Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .

Replacement, Air Filter

Replacement, Bumper . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

Replacement, Fuse . . . . . . . . . . . . . . . . . . . . . . . .

Replacement, Knob . . . . . . . . . . . . . . . . . . . . . .

Replacement, Push Button

Replacement, Front Handle . . . . . . . . . .

Replacement, Side Handle . . . . . . .. . . . . . . . . . . .

Reports, Maintenance . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-16

3-3

1-11

1-12,F1-2

3-16

2-5 2-3

1-12

2-9 2-7 2-6

3-10

1-3

Appendix A

3-3

3-12

3-11,3-13

3-8

3-9 3-10 3-15 3-14

1-3

Service Upon Receipt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Setup, Control Initial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Side Handle Replacement

Special Tools and Test Equipment . . . . .. . . . . . . . . . .

Storage . . . . . . . . . . . . . . . . . . . . . . . . . . .

. .. . .

3-4

2-6

3-16

3-14

3-2

3-17

INDEX-3

Page 95

TM 11-6625-3087-12

Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tools, Common Tools, Special Troubleshooting

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unusual Conditions

Warranty . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Weight . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix B

3-1 3-2

3-6,T3-1

3-4

2-20

1-7

1-11

INDEX-4

Page 96

By Order of the Secretary of the Army:

Official:

R.L. DILWORTH

Brigadier General, United States Army

The Adjutant General

DISTRIBUTION:

To be districted in accordance with DA Form 12-51 literature

requirements for AN/USM490.

JOHN A, WICKHAM, JR.

General, United States Army

Chief of Staff

Page 97

Page 98

These are the instructions for sending an electronic 2028

The following formatmust be used if submittingan electronic 2028. The subjectline must be exactly the same and all fields must be included; however only the following fields are mandatory: 1, 3, 4, 5, 6, 7, 8, 9, 10, 13, 15, 16, 17, and 27.

From: “Whomever” <[email protected]> To: [email protected]

Subject: DA Form 2028

1. From: Joe Smith

2. Unit: home

3. Address: 4300 Park

4. City: Hometown

5. St: MO

6. Zip: 77777

7. Date Sent: 19--OCT--93

8. Pub no: 55--2840--229--23

9. Pub Title: TM

10. Publication Date: 04--JUL--85

11. Change Number: 7

12. Submitter Rank: MSG

13. Submitter FName: Joe

14. Submitter MName: T

15. Submitter LName: Smith

16. Submitter Phone: 123--123--1234

17. Problem: 1

18. Page: 2

19. Paragraph: 3

20. Line: 4

21. NSN: 5

22. Reference: 6

23. Figure: 7

24. Table: 8

25. Item: 9

26. Total: 123

27. Text: This is the text for the problem below line 27.

Page 99

Page 100

RECOMMENDED CHANGES TO PUBLICATIONS AND

BLANK FORMS

For use of this form, see AR 25--30; the proponent agency is O DISC4.

UsePartII(reverse) for Repair Parts and Spe- cial Tool Lists (RPSTL) and Supply Catalogs/ Supply Manuals (SC/SM)

DATE

8/30/02

TO: (Forward to proponent of publication or form)(Include ZIP Code)

Commander, U.S. Army Aviation and Missile Command ATTN: AMSAM--MMC--MA--NP R eds t one A r s enal, AL 35898

PART1 -- ALL PUBLICATIONS (EXCEPT RPSTL AND SC/SM) AND BLANK FORMS

PUBLICATION/FORM NUMBER

TM 9--1005--433--24

ITEM

NO.

PAGE

NO.

1 WP0005

PG 3

PARA--

GRAPH

LINE

NO. *

2 Test or Corrective Action column should identify a different WP number.

FIGURE

NO.

TABLE

NO.

FROM: (Activity and location)(Include ZIP Code)

MSG, Jane Q. Doe 1234 Any Street Nowhere Town, AL 34565

DATE

16 Sep 2002

TITLE Organizational, Direct Support, And General Support Maintenance Manual for Machine Gun, .50 Caliber M3P and M3P Machine Gun Electrical Test Set Used On Avenger Air Defense Weapon System

RECOMMENDED CHANGES AND REASON

* Reference to line numbers within the paragraph or subparagraph.

TYPED NAME, GRADE OR TITLE

MSG, Jane Q. Doe, SFC

DA FORM 2028, FEB 74 REPLACES DA FORM 2028, 1 DEC 68, WHICH WILL BE USED. USAPA V3.01

TELEPHONE EXCHANGE/ AUTOVON, PLUS EXTENSION

788--1234

SIGNATURE

Agilent 3586 Tech 060992 Datasheet

TABLE OF CONTENTS

CHAPTER 1

Figure 1-2

CHAPTER 2

CHAPTER 3

APPENDIX A

APPENDIX C

APPENDIX D

APPENDIX E

INDEX