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ARMY TM 11-6625-3234-12MARINE CORPS TM 09078 B-12/1

TECHNICAL MANUALOPERATORS AND UNIT MAINTENANCE

MANUAL

(NSN0 S - 2 8

OSCILLOSCOPE8/G

6625-01-272-8054)

Distribution IS authorized to Department of Defense and DOD contractorsonly for official use or for administration or operational purposes. Thisdetermination was made on 27 August, 1988. Other requests for this

document will be referred to Commander, US Army Communications-Electronics Command and Fort Monmouth, ATTN: AMSEL-LC-ME-P Fort

Monmouth, NJ 07703-5000

DESTRUCTION NOTICE Destroy by any method that will preventdisclosure of contents or reconstruction of the document.

HEADQUARTERS, DEPARTMENT OF THE ARMY

HEADQUARTERS, U.S. MARINE CORPS.

15 JUNE 1990

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SAFETY STEPS TO FOLLOW IF SOMEONE IS THE VICTIM OFELECTRICAL 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 ADRY WOODEN POLE OR A DRY ROPE OR SOME OTHERINSULATING MATERIAL

SEND FOR HELP AS SOON AS POSSIBLE

AFTER THE INJURED PERSON IS FREE OF CONTACT WITHTHE SOURCE OF ELECTRICAL SHOCK, MOVE THE PERSONA SHORT DISTANCE AWAY AND IMMEDIATELY STARTARTIFICIAL RESUSCITATION

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WARNING

HIGH VOLTAGE

is used in the operation of this equipment.

DEATH ON CONTACT

may result if personnel fail to observe safety precautions.

Never work on electronic equipment unless there is another person nearby who is familiar with theoperation and hazards of the equipment and who is competent in administering first aid. When thetechnicians are aided by operators, they must be warned about dangerous areas.

A periodic review of safety precautions in TB 385-4, Safety Precautions for Maintenance ofElectrical/Electronic Equipment, is recommended. When the equipment is operated with covers removed.DO NOT TOUCH exposed connections or components. MAKE CERTAIN you are not grounded whenmaking connections or adjusting components inside the test instrument.

Be careful not to contact high-voltage connections or 115 volt AC input connections when installing oroperating this equipment.

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

Do not be misled by the term low voltage.

Potentials as low as 50 volts may cause death under adverse conditions.

For Artificial Respiration, refer to FM 21-11.

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Technical Manual HEADQUARTERS, DEPARTMENT OF THE ARMYNo. 11-6625-3234-12 AND HEADQUARTERS, MARINE CORPSTechnical Manual Washington, DC, 15 June 1990No. 09078 B-12/1

OPERATORS AND UNIT MAINTENANCE MANUAL

FOROSCILLOSCOPE OS-288/G(NSN 6625-01-272-8054)

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistakes or if you know of a way toimprove the procedures, please let us know. Mail your letter, DA Form 2028(Recommended Changes to Publications and Blank Forms), or DA Form 2028-2located in the back of this manual direct to: Commander, U. S. ArmyCommunication-Electronics Command, ATTN: AMSEL-LC-ME-PS, Fort Monmouth,New Jersey 07703-5000, Marine Corps units, submit NAVMC 10772 (Recommended

Changes to Technical Publications) to: Commanding General, Marine CorpsLogistics Base (Code 850) Albany, Georgia 31704-5000. In either case, a reply willbe furnished to you.

CHAPTER 1

Section I

Section II

Section Ill

CHAPTER 2

Section I

Section II

Section Ill

CHAPTER 3

Section

Section

Section

HOW TO USE THIS MANUAL

INTRODUCTION

General Information

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Equipment Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Technical Principles of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... .2-1

Description and Use of Operators Controls, Indicators and Connectors . . . . . . . . . 2-2

Operator Preventive Maintenance Checks and Services (PMCS) . . . . . . . . . . . . . . 2-23

Operation Under Usual Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

UNIT MAINTENANCE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Repair Parts, Special Tools, Test, Measurement, and Diagnostic Equipment

(TMDE); and Support Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Service Upon Receipt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Unit Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

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Section IV

Section V

APPENDIX A

APPENDIX B

APPENDIX C

APPENDIX D

APPENDIX E

Unit Maintenance Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Preparation for Storage or Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MAINTENANCE ALLOCATION CHART (MAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMPONENTS OFENDITEMAND BASIC ISSUEI TEMS LIST . . . . . . . . . . . . . . . .

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

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

3-11

A-1

B-1

C-1

D-1

E-1

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glossary-1

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index-1

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HOW TO USE THIS MANUAL

This manual tells about the Oscilloscope OS-288/G and contains instructions onhow to use it while testing and maintaining other electronic equipment.

The technical manual for the other electronic equipment being maintained willgive guidance in the correct method to make certain connections when testing andtroubleshooting with this oscilloscope.

When first receiving this oscilloscope, start at the front of the manual and go all theway through to the back. Become familiar with every part of this manual and theOS-288/G.

This manual has an edge index which will help find specific information quickly.Simply spread the pages on the right edge of the manual until the printed blocks canbe seen. Open the manual where the block on the edge of the page lines up with theselected topic printed on the front cover block.

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Figure 1-1. Oscilloscope OS-288/G.

1-0

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1-1.

a.

b.

c.

C H A P T E R 1

I N T R O D U C T I O N

P a r a P a g e

Administrative Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 1-2

Consolidated lndex of Army Publications and Blank Forms . . . . . . . . . . . . . . . . 1-2 1-1Destruction of Army Materiel to Prevent Enemy Use . . . . . . . . . . . . . . . . . . . . . . . 1-5 1-2

Equipment Characteristics, Capabilities, and Features . . . . . . . . . . . . . . . . . . . . 1-9 1-3

Equipment Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10 1-3

Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12 1-10

Maintenance Forms, Records, and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 1-1

Nomenclature Cross-Reference List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 1-2

Reporting Equipment improvement Recommendations (EIR) . . . . . . . . . . . . . . . 1-6 1-2

Safety, Care, and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11 1-9

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

Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8 1-2

Section I. G E N E R A L I N F O R M A T I O N

SCOPE.

Type of Manual. Operators and Unit Maintenance Manual.

Equipment Name and Model Number. Oscilloscope OS-288/G.

Purpose of the Equipment. The oscilloscope is a portable 400 MHz bandwidth analog instrumentused for general waveform-measurements. It has four vertical channels and a dual time-base with bothautomatic and manual operation capabilities.

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

Refer to the latest issue of DAPAM25-30 to determine whether there are new editions, changes, or additionalpublications pertaining to the equipment. Marine Corps personnel refer to the latest issue of SL-1-2 todetermine whether there are any new editions.

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

a. Reports of Maintenance and Unsatisfactory Equipment. Department of the Army forms andprocedures used for equipment maintenance will be those prescribed by DA PAM 738-750, as contained inMaintenance Management Update. Marine Corps maintains forms and procedures as prescribed by TM4700-15/1.

b. Reporting of Item and Packaging Discrepancies. Fill out and forward SF 364, Report ofDiscrepancy (ROD), as prescribed in AR 735-11-2/DLAR 4140.55/NAVMATlNST 4355.18/AFR 400-54/MCO4430.3J.

c. Transportation Discrepancy Report (TDR) (SF 361). Fill out and forward Transportation DiscrepancyReport (TDR) (SF 361) as prescribed in AR 55-38/NAVSUPlNST 4610.33 C/AFR 75-18/MCO P4610.19D/DLAR4500.15.

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1-4. ADMINISTRATIVE STORAGE.

Administrative storage of equipment issued to and used by Army activities will have preventive maintenanceperformed in accordance with the PMCS procedures before storing. When removing the equipment fromadministrative storage the PMCS should be performed to assure operational readiness.

1-5. DESTRUCTION OF ARMY MATERIEL TO PREVENT ENEMY USE.

Destruction of Army materiel to prevent enemy use is described in TM 750-244-2.

1-6. REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR).

a. Army. If your Oscllioscope OS-288/G needs improvement, let us know. Send us an EIR. You, the user,are the only one who can tell us what you dont like about your equipment. Let us know why you dont like thedesign or performance. Put it on an SF 368 (Product Quality Deficiency Report). Mail it to us at: Commander,US Army Communications-Electronics Command and Fort Monmouth, ATTN: AMSEL-PA-MA-D, FortMonmouth, New Jersey 07703-5000. Well send you a reply.

b. Marine Corps Users. ODR shall be reported on SF 368 in accordance with MCO P4855.10, ProductQuality Deficiency Report Manual. Submit to Commanding General, Marine Corps Logistics Base (Code856), Albany, Georgia 31704-5000.

1-7. NOMENCLATURE CROSS-REFERENCE LIST.

Common names will be used when Oscilloscope OS-288/G is mentioned in this manual.

NOTE

Official nomenclature must be used when filling out report forms or looking uptechnical manuals.

Common Name Official Nomenclature

OS-288/G Oscilloscope OS-288/G

OS-288 Oscilloscope OS-288/G

Oscilloscope Oscilloscope OS-288/G

Instrument Oscilloscope OS-288/G

1-8. WARRANTY INFORMATION.

The Oscilloscope OS-288/G is not covered under a warranty.

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Section Il. EQUIPMENT DESCRIPTION

1-9. EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES.

a. Characteristics.

Provides parametric or cursor measurement capabilities

Allows for:AC voltage and DC voltage measurements.Frequency measurements.Rise Time and Fall Time measurements.Time and Period measurements.Amplitude Modulation measurements.Frequency Modulation measurements.Propagation Delay measurements.Phase Difference measurements.

Designed for portable and bench top use.

Battery operation through use of DC Inverter, mounting brackets (2) and battery pack (seeAppendix D).

b. Capabilities and Features.

Auto setup presents a clear signal display easily.Parametric measurements at a push of a button.Indication lights on front panel for constant equipment status.Menus for user-friendly operation.

Save/Recall offers a way of saving up to 30 front panel settings.Error codes define instrument malfunctions.Direct digital on screen readings.

1-10. EQUIPMENT DATA.

WEIGHT

Weight with Accessories and Pouch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.4 lb (10.2 kg)

Weight without Accessories and Pouch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.5 lb (9.3 kg)

Domestic Shipping Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28.2 lb (12.8 kg)

DIMENSIONS

Height without Pouch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..6.29 in (160 mm)

Height with Feet and Pouch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.96 in (202mm)

Width with Handle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.31 in (338 mm)

Depth with Front Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.1in(434 mm)

Depth with Handle Extended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..20.0 in (508 mm)

OPERATING CHARACTERISTICS

Power Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 VAC to 250 VAC, 48 t0 440Hz

Maximum Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 watts (180 VA)

Line Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2A, 250 V, AGC/3AG fast blow or1.6 A, 250 V, 5 x 20 mm quick acting

Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5to131F (-15to 55C)

Operating Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Up to 15.000 ft. (4.500 m)

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VERTICAL DEFLECTION SYSTEM CHANNEL 1 AND CHANNEL 2

Deflection Factor

Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 mV/Division to 5V/DivisionAccuracy

59 to 95F (150 to 35C)

On Graticule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Within 2%

AV Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . (1.25% of reading + 0.03 div + signal aberrations)5 to 59Fand 95 to 131F

(-15to15C and 350 to 55C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Add +2% of reading.50 ohm Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Add 1% of reading

CH 2 Inverted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Add 1% of reading

AV Measurement Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 divisions times the VOLTS/DIV settingVOLTS/DIV VARRange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Extends deflection factor to

> 12.5 V/division, continuously var.

Frequency Response

-3 dB Bandwidth

59 to 95F (15 to 35C) . . . . . . . . . . . . . . . . > 5 mV/DIV: DC to 400 MHz; 2 mV/DlV: DC to 350 MHz

5 to 59Fand 95 to 131F

(-15 to15C and 35 to 55C) . . . . . . . . . . . > 5mV/DIV: DC to 350 MHz; 2mV/DlV: DC to 300 MHz-4.7 dB Bandwidth

5to 95F (-150 to 35C) . . . . . . . . . . . . . . . . > 5mV/DIV: DC to 400 MHz;2mV/DlV: DC to 300 MHz

95to 131F (35to 55C) . . . . . . . . . . . . . . . . . > 5mV/DlV: DC to 350 MHz:2mV/DIV: DC to 300 MHz

AC Coupled, Lower -3dB Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 HZ or less

With Standard Accessory Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...1 Hz or less

Step ResponseTime (Tr = 0.35/BW) . . . . . . . . . . . . . . . . . . . . . . . > 5mV/DlV: < 875 ps, 2mV/DIV: < 1 nsChannel Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 100:1 at 100 MHz; > 50:1 at 400 MHz

Displayed Channel 2 Signal Delay

With Respect to the Channel 1 Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . -500 ps to +500 ps, adjustable

lnput R and C (1 Megohm)

Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Megohm to.5%Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..15 pF 2 pF

Maximum Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 V (DC + peak AC) 800 V p-p AC: < 10kHz(DC, AC, or GND Coupled)

lnput R (50 ohms)

Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 ohms 1%

VSWR, DC to 300 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. < 1.45.1

VSWR, 300 to 400 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 1.6:1

Maximum Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V rms, averaged for 1 s; 50 V peakCascaded Operation

Deflection Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200V/DIV 10%

CMRR (ADD Mode with Channel 2 Inverted) . . . . . . . . . . . . . . . . . . . . . > 20:1 at 50 MHz for common-mode

signals of eight divisions or less

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VERTICAL DEFLECTION SYSTEM - CHANNEL 3 AND CHANNEL 4

Deflection Factor

Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mV/division and 500 mV/division

Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . within 10%

VERTICAL DEFLECTION SYSTEM - ALL CHANNELS

Low-frequency Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 division or less compression or expansionof a two-division, center-screen signal

Bandwidth Limiter . . . . . . . . . . . . . . . . . . . . . . Reduces upper 3 dB band pass to a limit of 13 MHz to 24 MHz

Vertical Signal Delay . . . . . . . . . . . . . . . . . . . . . . . . > 30 ns of the sweep is displayed before the triggeringevent if SEC/DIV set > 10 ns/DIV. At 5 ns/DIV, > 10 ns of

sweep is displayed before the triggering event

Chopped Mode Switching Rate . . . . . . . . . . . With SEC/DIV between 20 s and 2 s/DIV, the switching rate

is 2.5 MHz 0.2%. Otherwise, the rate is 1.MHz 0.2%

TRIGGERING

Minimum peak-to-peak Signal Amplitude forStable Triggering from CH 1 or CH 2 Source

De coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.35 division from DC to 50 MHz; 1.0 division at300 MHz; 1.5 divisions at 500 MHz

NOISE REJ Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 1.2 divisions from DC to 50 MHz;

3 divisions at 300 MHz; 4.5 divisions at 500 MHz

AC Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . 0.35 division from 60 Hz to 50 MHz; 1.0 division at 300 MHz;

1.5 divisions at 500 MHz; attenuates signals below 60 Hz

HF REJ Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0.5 division from DC to30 kHz

LF REJ Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 division from 80 kHz to 50 MHz; 1.0 division at

300 MHz; 1.5 divisions at 500 MHz

Minimum p-p Signal Amplitude forStable Triggering from ADD Source . . . . . . . . . . . . . . . . . . . . . Add 0.5 division to CH 1 or CH 2 requirement

at 300 MHz and 500 MHz

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Minimum p-p Signal Amplitude for

Stable Triggering from CH 3 or CH 4 Source . . . . . . . . . . . . . . . . . . . 0.5 times the CH 1 or CH 2 requirementMinimum p-p Signal Amplitude for

Stable Triggering from Composite,Multiple Channel Source, ALT Vertical Mode . . . . . . . . . . . . . . . . . . . . . . Add 1 division to the single-channel

source specification

Maximum p-p Signal Rejected by NOISE REJCOUPLING Signals Within the Vertical Bandwidth

CH 1 or CH 2 SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 0.4 division for VOLTS/DIV > 10 mV/DIV

CH 3 or CH 4 SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 0.2 division

Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 50 ps with 5 divisions of 400 MHz at 500 ps/division

LEVEL Control Range

CH 1 or CH 2 SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 divisions times the VOLTS/DIV setting

CH 3 0r CH 4 SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 divisions times the VOLTS/DIV settingLEVEL Readout Accuracy

CH 1 or CH 2 SOURCE

59to 95F(15to 35C) . . . . . . . . . . . . . . . . . . . . . . . . . . Within (3% of reading +3% of p-p signal

+0.2 division +0.5 mV + (0.5 mV x probe

attenuation factor)) (vertical Input at 1 Megohm DC,CH 2 Source not Inverted, and the TRIGGER DC Coupled)

5 to 59F and 95 to 131F(-15 to 15C and 35 to 55C) . . . . . Add 1.5 mV times the probe attenuation to (59 to 95 F) spec.

50 ohm lnput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Add 1% to 1 Megohm Input spec.

CH 2 Inverted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Add 1% of reading to the non-inverted spec.

NOISE REJ Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Add 0.6 division to the DC Coupled spec.

CH 3 or CH 4 SOURCE . . . . . . . . . . . . . . . . . . . Within (3% of reading + 4% of p-p signal + 0.1 division

+ (0.5 mV x probe attenuation factor))NOISE REJ Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Add 0.3 division to the DC Coupled spec.

AUTO LVL Mode Maximum Triggering Signal Period

A SEC/DIV Setting

< 10ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 20 ms

10 ms to 50 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At least four times the A SEC/DIV setting>50 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 200ms

AUTO Mode Maximum Triggering Signal Period

A SEC/DIV Setting

< 10 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 80ms

10 ms to 50 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At least 16 times the A/SEC/DIV setting>50ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 800ms

AUTO LVL Mode Trigger Acquisition Time . . . . . . . . . . . . . . . . . . . . . . . . . 8 to100 times the AUTO LVLM Mode

maximum triggering signal periodTRIGGER HOLDOFF

Minimum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 s at 5 ns/div; A SEC/DIV setting or 2 s(+33% to -10%),whichever is greater, at other A SEC/DIV setting values

Variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 25 times the minimum holdoff

SLOPE Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conforms to trigger source waveform

or AC power-source waveform

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HORIZONTAL DEFLECTION SYSTEM

A Sweep Time Base Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ms/DlV to 5 ns/DIV; X10 MAGextends maximum sweep rate to 500 ps/DIV

B Sweep Time Base Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 ms/DlV to 5ns/DIV; X10 MAGextends maximum sweep speed to 500 ps/DIV

X-Y Operation

X-Axis Deflection Factor Range, Variable,

and lnput Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Same as CH 1

Deflection Factor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Same as CH1

X-Axis Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC to 3 MHz

Phase Difference Between X and Y withBW LIMIT Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 1 from DC to 1 MHz; < 3 from 1 MHz to 2 MHz

X-Axis, Low-frequency Linearity . . . . . . . . . . . . . . . . . . . . . . < 0.1 division compression or expansion of atwo-division, center-screen signal

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DISPLAY

Cursor Position Range

DeltaVolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At least the center 7.6 vertical divisions

Delta Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At least the center 9.6 horizontal positions

Graticule

Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.15 in x 3.94 in (80mm x 100 mm)

Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 major divisions vertically and 10 majordivisions horizontally, with auxiliary markings

Trace Rotation Range . . . . . . . . . . . . . . . . . . . Adequate to align trace with center horizontal graticule line

Visual Writing Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 20 divisions/s

Z-AXIS INPUT

Sensitivity

DC to 2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Positive voltage decreases intensity;

+ 2 V blanks a maximum intensity trace

2 MHz to 20 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + 2 V modulates a normal intensity trace

Input Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (10 kilohms 10%)10 kilohms

Maximum Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 V peak; 25 V p-p AC at 10 kHz or less

SIGNAL OUTPUTSCALIBRATOR

Output Voltage and Current . . . . . . . . . . . . . . . . . . . 0.4 V 1% in to a 1 Megohm load, 0.2 V 1.5% intoa 50 ohm load; or 8 mA 1.5% into a short circuit

Repetition Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . Two times the A SEC/DIV setting for 100 ns to 100 ms

Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0.1% during sweep time

CH 2 SIGNALOUT

Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mV/DIV 10% into 1 Megohm;

10 mV/DIV 10% into 500hms

Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mV into 1Megohm when DC Balance has been

performed within 5C of operating temperature

A GATE OUT and B GATE OUT

Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 V to 5 V positive-going pulse, starting at 0 V to 400 mVOutput Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 A during Hl state; Sinks 2 mA during LO state

PARAMETRIC MEASUREMENTS

Period

Accuracy

59to 95F (15to 35C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0.9% +0.5 ns + Jitter Error

5 to 59F and 95 to 131F(-15to 15C and 35to 55C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Add 0.3%

Minimum Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 2ns

Maximum Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .> 100 ms (minimum frequency = 10Hz)

Minimum Signal Amplitude . . . . . . . . . . . . . . . . . < (60mV x probe attenuation factor) p-p; if DC coupled at

a VOLTS/DIV setting that gives a p-p signal > 4 divisions,the peak signal + DC offset must be < 12 divisions

Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calculated as 1/period

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1-11. SAFETY, CARE, AND HANDLING.

Observe all WARNINGS, CAUTIONS, and NOTES in this manual. This equipment can be extremelydangerous if these instructions are not followed.

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Sect ion I l l . TECHNICAL PRINCIPLES OF OPERATION

1-12. FUNCTIONAL DESCRIPTION.

The following is a basic functional description of the oscilloscope. Refer to Figure 1-2 for a block diagram.

NOTE

CH 1 and CH 2 attenuators are identical in operation, with corresponding circuitryin each channel performing the same function. Therefore, only CH 1 is described.

Input signals from the CH 1 input connector are routed through the Attenuator network by four pairs ofMagnetic-Latch Relay contacts. The attenuator circuits provide control of input coupling modes andvertical deflection factors.

There are three Preamplifier circuits, one each for CH 1 and CH 2 and one for both CH 3 and CH 4.

The Preamplifier circuits for CH 1 and CH 2 are nearly identical. The circuits produce eitheramplification or attenuation of the output signal. The Preamp also has provisions for VAR gain, verticalpositioning and trigger signal pick-off. CH 1 and CH 2 inputs are also used to provide horizontaldeflection. An invert circuit in the CH 2 Preamp permits inversion of the CH 2 signal.

The CH 3 and CH 4 Preamp provides similar functions as those provided by the CH 1 Preamplifier.CH 3 and CH 4 gains may be either 0.1 volt per division or 0.5 volts per division.

The Display Sequencer circuitry controls the sequences of the analog-type oscilloscope in realtime, dependent on control data it receives from the microprocessor. The A/B Trigger circuitry, undercontrol of the Display Sequencer detects when triggering requirements are met and initiates theappropriate sweep. The A Sweep and B Sweep circuits generate sweep ramps under control of theDisplay Sequencer when triggered by the A/B Trigger circuitry.

The Vertical Channel Switch selects one of the vertical signals for application to the Vertical OutputAmplifier and to the Channel Switch. The Vertical Output Amplifier provides the final amplification ofthe selected vertical signal, raising it to a level required to drive the CRT. The 78 ns Delay Line allowsthe Sweep and Z-Axis circuits to turn on before the triggering event begins vertical deflection of theCRT beam.

The Horizontal Output Amplifier provides the final amplification of the selected horizontal-deflectionsignal required to drive the CRT.

The Readout circuitry is responsible for displaying the alphanumeric readout characters on the CRT.

The power supply converts AC power-line voltage into voltages needed for oscilloscope operation.There is a high voltage and low voltage supply. The high voltage supply provides the voltage levels

and control circuitry for operation of the CRT. The low voltage supply provides voltage levels for theoverall operation of the oscilloscope circuits. The Z-Axis amplifier utilizes several input signals tocontrol the intensity level of the CRT.

The CRT provides a visual display of the electrical properties of the circuit or signal under test,

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Figure 1-2. Oscilloscope OS-288/G Simplified Block Diagram.

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CHAPTER 2

OPERATING INSTRUCTIONS

Absolute Voltage Measurement Using Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . .

Amplitude Modulation (Modulation Index) Measurement . . . . . . . . . . . . . . . . . . .

Astigmatism Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auto DC Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DC Voltage Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Modulation (Peak-to-Peak Measurement) . . . . . . . . . . . . . . . . . . . . . .

General, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

initial Adjustments and Daily Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Matching Channel 2 Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Measuring Off-Ground Signals and Canceling Interference . . . . . . . . . . . . . . . . .

Measuring Phase Difference Between Two Signals . . . . . . . . . . . . . . . . . . . . . . . .

Millivolt Signal Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Noise immunity Measurement.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Observing Coincidence of Digital Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Procedures . . . . . . . . . . . .

Peak-to-Peak Voltage Measurement

Period and Frequency Measurement

PMCS Procedures, . . . . . . . . . . . . . .

Preparation for Use . . . . . . . . . . . . . .

Probe Compensation . . . . . . . . . . . . .

Propagation Delay Measurement . .

Recall a Setup . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

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

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

Rise Time and Fall Time Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Save a Measurement Setup.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Save a Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Setup and Hold Time Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Slew Rate Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Time Ratio (Duty Factor) Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Trace Rotation Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Turn-on Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Video Signal Measurement (lRE Units) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Para

2-14

2-24

2-9

2-7

2-15

2-25

2-2

2-6

2-1

2-11

2-27

2-23

2-16

2-28

2-26

2-12

2-13

2-17

2-3

2-4

2-10

2-19

2-32

2-18

2-31

2-30

2-20

2-21

2-22

2-8

2-5

2-29

Page

2-34

2-58

2-28

2-27

2-35

2-60

2-23

2-27

2-2

2-30

2-65

2-56

2-37

2-67

2-63

2-31

2-31

2-39

2-23

2-24

2-29

2-43

2-74

2-41

2-72

2-70

2-47

2-51

2-53

2-28

2-25

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Section I. DESCRIPTION AND USE OFOPERATORS CONTROLS, INDICATORS AND CONNECTORS

2-1. INTRODUCTION.

This section describes all of the operator controls, indicators, and connectors for the OS-288/G. Due to the

large number of controls, indicators, and connectors on the front panel, it is necessary to separate the panelinto seven different portions. Figure 2-1 shows each portion of the front panel The rear panel is shown inFigure 2-2.

Figure 2-1. Operators Controls, Indicators, and Connectors, Front View.

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N O T E

lines are available on the CRT. View A shows the readout Iocations forFour readoutmany of the oscilloscope functions.

KEY CONTROL, INDICATOR, OR FUNCTIONCONNECTOR

1 Trigger Control Indicator Indicates which trigger (A or B) is affected by the MODE,SOURCE, COUPLING, SLOPE, LEVEL, and INIT @ 50%TRIGGER controls.

2 Setup Number and Name Indicator Displays the number and name of a previously saved setupwhen RECALL and a setup-number button are pressed.

3 Trigger Source Indicator Indicates which channel (1, 2, 3, or 4) is supplying thetrigger signal. The channel is selected by the TRIGGER

SOURCE buttons.4 Trigger Level Indicator Displays the voltage at which triggering takes place. The

value IS set by the TRIGGER LEVEL control.

5 50 ohm Overload Indicator Indicates when an excessive signal is applied to the CH 1or CH 2 input connectors while 50 ohm Input Coupling isselected.

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6 Sweep Delay Time, Displays the following:Delta Voltage,Delta Time, and

- B Sweep Delay Time when set by the A SEC/DIV or JREF orDLY POS controls, and, if .lt or I/At are active, the .Jcontrol

1/Delta Time Indicator

- Delta Voltage if V is selected.- Delta Time if At IS selected.- 1/Delta Time if 1/ t is selected.

7 B Sweep Scale Factor Indicator Displays the B Sweep horizontal scale factor if the B Sweep isactive. If the SEC/DIV VAR control is not in its detent position,the scale factor contains a decimal point.

8 Holdoff Indicator Indicates that the HOLDOFF control is not in the MIN position.

9 A Sweep Scale Factor Indicator Displays the A Sweep horizontal scale factor. If the SEC/DIVVAR control is not in its detent position, the scale factorcontains a decimal point.

10 Channel 4 Scale Factor Indicator Displays the CH 4 vertical scale factor if CH 4 is selected fordisplay.

11 Channel 3 Scale Factor Indicator Displays the CH 3 vertical scale factor if CH 3 is selected fordisplay.

12 Bandwidth Limit Indicator Indicates that the 20 MHz BW LIMIT has been selected.

13 Channel 2 Scale Factor Indicator Displays the CH 2 vertical scale factor if CH 2 is selected fordisplay. A tilde ( w ) over the unit indicator (mV or V) indicatesAC input coupling and a ground symbol in front of the numberindicates GND input coupling. Also, a greater-than symbol(>) indicates that the VOLTS/DIV VAR control is not in itsdetent position.

14 Invert Indicator A down arrow indicates that the CH 2 input signal has beeninverted by pressing the INVERT button.

15 ADD Indicator A plus sign indicates that the algebraic sum of CH 1 and CH 2is displayed.

16 Channel 1 Scale Factor Indicator Displays the CH 1 vertical scale factor if CH 1 is selected fordisplay. The tilde, ground, and greater-than symbolsdescribed for the CH 2 Scale Factor (13) also pertain to CH 1.

17 Parametric Measurements Readout Parametric Measurements are displayed on the second andthird readout lines.

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18 CH1 MODE indicator When lit, indicates that CH 1 has been activated.

19 VERTICAL POSITION Control Adjusts the vertical position of the CH 1 signal trace. Whenusing the X-Y display mode, moves the display horizontally.

20 CH 2 MODE Indicator When lit, indicates that Channel 2 has been activated.

21 CH 3 MODE Indicator When lit, indicates that Channel 3 has been activated.22 VERTICAL POSITION Control Adjusts the vertical position of the CH 2 signal trace. When

using the X-Y display mode, moves the associated displayvertically.

23 CH 4 MODE Indicator When lit, indicates that Channel 4 has been activated.

24 CH 4 MODE Button Selects Channel 4 for display. If pressed while in theparametric measurements menu, produces configure menu.

25 20 MHz BW LIMIT Indicator When lit, indicates that the vertical deflection system is limitedto 20 MHz.

26 20 MHz BW LIMIT Button Press to activate. Limits the bandwidth of the verticaldeflection system to 20 MHz.

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27 CHOP/ALT Indicator When lit, indicates that the oscilloscope is in the CHOP mode.When more than one channel is selected, the vertical displayswitches sequentially through the selected channels at thechop-switching rate. When more than one channel is selected,

if the SEC/DIV setting for the displayed sweep is in the rangeof 20 s/div to 2 s/div, each channel is displayed for 400 ns.Otherwise each channel is displayed for 1 s.

When not lit, indicates scope is in ALT mode. When more thanone channel is selected, the vertical display switchessequentially through the selected channels. Alternateswitching occurs during sweep-retrace times. If both A and BSweeps are displayed in ALT horizontal mode, verticalswitching occurs at the completion of the B Sweep.

28 CHOP/ALT Button Press to activate. Selects the vertical display mode formultiple-channel displays. If pressed while in the parametricmeasurements menu, automatically measures the fall-time ofthe input waveform and displays the result.

29 CH 3 MODE Button Selects Channel 3 for display. If pressed while in theparametric measurements menu, automatically measuresinput waveform rise time and displays the results. If pressedwhile in the configure menu, selects the minimum frequencyfunction. This function enables the operator to select theminimum frequency (50 Hz or 10 Hz) for AUTO LVL,INIT @ 50%, and Parametric Measurement functions.

30 INVERT MODE Indicator Indicates INVERT MODE has been activated.

31 INVERT MODE Button Press to activate. Inverts the Ch 2 trace and the polarity of thesignal output at the CH 2 SIG OUT connector on the rearpanel. Pressing the INVERT button together with the ADDbutton displays the difference between CH 1 and CH 2. Ifpressed while in the parametric measurements mode, the

oscilloscope automatically measures the time of the inputwaveform and displays the result.

32 CH 2 MODE Button Selects Channel 2 for display. If pressed while in theparametric measurements menu, automatically measuresinput waveform voltage and displays the results. If pressedwhile in the configure menu, it selects the TIME function. TheTIME function enables the operator to manually select startand stop positions by using the AREF OR DLY control andAcontrol and then read the time interval on the display. Ifpressed while in the MINFREQ menu, AUTO SETUP willrespond to 10 Hz.

33 ADD MODE Indicator Indicates ADD MODE has been activated.

34 ADD MODE Button Press to activate. Displays the algebraic sum of thewaveforms applied to CH 1 and CH 2. Pressing the ADDbutton together with the INVERT button displays the differencebetween CH 1 and CH 2. If pressed while in the parametricmeasurements menu, automatically measures the width of theinput waveform and displays the result.

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KEY CONTROL, INDICATOR, OR FUNCTIONC O N N E C T O R

35 CH 1 MODE Button Selects Channel 1 for display. If pressed while in theparametric measurements menu, automatically measuresinput waveform frequency and displays the results. If pressedwhile in the configure menu, selects AUTO function. AUTO

function enables the operator, by pressing the appropriateMODE button, to select a function that will be performance withevery AUTO SETUP, If pressed while in the MINFREQ menu,AUTO SETUP will respond to 50 Hz.

36 MEASURE/HELP Button Press to display the Parametric Measurements menu.Repeated activation of the MEASURE button will cycle througha series of help messages on the display.

37 RECALL/HELP Button Press to activate. Repeated pressing cycles through severalhelp messages. Pressing any of the VERTICAL MODE buttons,recalls the associated saved setup. Press any button otherthan the VERTICAL MODE buttons to cancel.

38 SAVE/HELP Button Press to activate. Enables operator to name and save current

oscilloscope settings. Repeated pressing of SAVE/HELPbutton cycles through several help messages. Press anybutton other than the VERTICAL MODE buttons to cancel.

39 STEP/AUTO Button Press to activate. When the STEP indicator is not lit (AUTO),the oscilloscope automatically establishes triggering and alsoscales the waveform display vertically and horizontally. Withthe STEP indicator lit, the next step in a stored sequence ofsetups is recalled.

40 STEP/AUTO Indicator If not lit, indicates that the oscilloscope will perform the AUTOSETUP function when the STEP/AUTO button is pressed. If lit,the oscilloscope will perform the STEP function.

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VIEW C

KEY CONTROL, INDICATOR, ORCONNECTOR

41 AV Button

FUNCTION

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42 POSITION Control Horizontally positions the sweep displays.

43 At Button Activates the Delta Time Measurement function and cancels

with INTEN or ALT horizontal display modes, two delay timesare defined. When At is selected with either A Sweep orB Sweep horizontal display, two vertical cursors areestablished. One delay time or cursor position is controlled by

the A control. The display shows either the difference betweenthe two delay times or the equivalent time between the verticalcursors.

If SEC/DIV VAR is not in the detent position, and either theA Sweep or the B Sweep horizontal display mode is selected,the display shows the delta time as a ratio, where fivedivisions correspond to 100% ratio.

When the Delta Time function is active, pressing the At buttondeactivates the function.

l/At Function

measurement function. The waveform display and the Deltacontrols operate the same for t, but the readout shows thereciprocal of the time in Hz (frequency).

If the SEC/DIV VAR control is not in the detent position (fullclockwise rotation), and the A Sweep or B Sweep horizontaldisplay mode is selected, the readout displays the timebetween cursors as degrees of phase, where five divisionsare equal to 360.

When the 1/At function is active, pressing the t and AVbuttons together deactivates the function.

Each of these readouts includes a function name, a signed,floating-point numeral, and the appropriate unit symbol.Numerals are displayed with larger sized characters. Anumeral immediately following AV indicates which channelprovides the delta voltage scaling, the lowest numbered of thedisplayed channels. Sweep Delay Time (DLY) is displayed forthe INTEN, ALT and B horizontal display modes when none ofthe delta functions are selected. Except for DLY thesereadouts are enabled with Readout Intensity set for scaleFactors ON or Scale Factors OFF.

A question mark appears after the AV function label when thefunction applies to CH 3 or CH 4, indicating poorer accuracythan is available with CH 1 or CH 2.

A question mark appears in a DLY readout or in a At or 1/ treadout with a pair of sweep delays, when one or both of thesweep delay settings is less than 1% or maximum delay (fullscale) setting or when the B Trigger mode is TRIG AFT DLY.

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44 X10 MAG Indicator When lit, indicates the X10 MAG function has been activated.

45 X10 MAG Button Press to activate. Horizontally magnifies the portion of thesweep display positioned at the center vertical graticule lineby a factor of 10. When in Alt or B horizontal display mode,only the B Sweep is affected.

46 TRACK/lNDEP Indicator When lit, indicates the oscilloscope is in the TRACK mode.When not lit, the oscilloscope is in the INDEP mode.

47 TRACK/lNDEP Button Press to activate. Selects either the tracking or independentmode for the AREF OR DLY POS control. In the trackingmode, rotating the AREF OR DLY POS control changes bothdelays or both cursors equally until the limit of either isreached.

48 A Control

When Save mode is active, the Control selects items in the

menu and defines characters in event-count definitiondisplays.

49 B SWP Indicator When lit, indicates that the B Sweep has been selected.

50 SEC/DIV Control Selects A Sweep speeds, B Sweep speeds, Delay Timeranges, horizontal display mode, and CH 2 Delay Matchingmode. The SEC/DIV control can be rotated continuously ineither direction, but further rotation has no effect when eitherextreme setting has been reached.

A SEC/DIV Control When the A Sweep is displayed without the B Sweep,SEC/DIV selects 25 calibrated A Sweep speeds from500 ms/div to 5 ns/div. Full CCW rotation selects the X-Ydisplay feature. In X-Y, the CH 1 OR X input drives the

horizontal deflection system.B SEC/DIV Control SEC/DIV selects B Sweep speeds in 22 calibrated steps from

50 ms/div to 5 ns/div.

Horizontal Display ModeSelection (PULL-INTEN,TURN-ALT, PUSH-B)

A When the SEC/DIV control is in, the A Sweep is displayed,unless the B Sweep has been displayed and the B SEC/DIVsetting remains faster than the A SEC/DIV setting. Theexception is that CH 1 is displayed in the horizontal at theextreme CCW setting of SEC/DIV.

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KEY CONTROL, INDICATOR, OR FUNCTIONC O N N E C T O R

50 PULL-INTEN Pulling the SEC/DIV control out while the A Sweep iscont) displayed selects the Intensified horizontal display mode and

cancels the AV function if it is active. The A Sweep displayintensifies during the B Sweep. The B Sweep is not displayed,

but it runs either 100 times faster than the A Sweep or at 5 nsper division, whichever is slower. In Alt horizontal displaymode, setting B SEC/DIV equal to A SEC/DIV also selects theIntensified horizontal display mode.

With t or 1/ t, a pair of intensified zones appears, Withmultiple vertical displays, Alt vertical mode, and a single ATrigger source (CH 1, CH 2, ADD, CH 3, or CH 4), the pair ofintensified zones appear as follows:

1. The reference zone appears on the first selected trace inthe display sequence: CH 1, CH 2, ADD, CH 3, CH 4.

2. The delta zone appears on the second selected trace.

3. Both zones appear on additional traces when more than

two traces are selected.Both zones appear on all traces with Chop vertical mode ormultiple A Trigger sources.

Pulling the SEC/DIV control out at the fastest A SEC/DIV rateselects the CH 2 delay offset adjustment. The readoutdisplays one of two messages: CH 2 DLY-TURN A or "CH 2DLY DISABLED. If the adjustment is enabled, the A control orthe AREF control can adjust the apparent delay between theCH 1 signal and the CH 2 signal. The adjustment range issufficient to compensate for propagation delay variations upto + 500 ps.

TURN-ALT When the SEC/DIV control is out, clockwise rotation activates

the Alternate Horizontal Display mode. The Alt mode presents

the Intensified A Sweep alternating with the delayed B Sweep.The position of the intensified zone on the A Sweep indicatesthe time position of the B Sweep, and the length of theintensified zone indicates the B Sweep duration. A separate BSweep runs for each intensified zone.

PUSH-B In the Alt horizontal display mode, pushing in the SEC/DIVcontrol displays only B Sweeps. When the B Sweep speed isset equal to the A Sweep speed in Alt or B display mode, themode changes from A to B or from Inten to Alt.

51 TRACE SEP Control

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52 SEC/DIV VAR Control Continuously varies the sweep speed between SECDIVsettings for either the A Sweep or B Sweep. The detentposition, fully CW, produces the Basic sweep speed selectedby the SEC/DIV control. The fully CCW position slows thesweep by a nominal factor of three. The display shows theactual time-per-division scale factor for all settings of the VARcontrol. When the Intensified A Sweep or the B Sweep isdisplayed, VAR affects only the B-Sweep scale factor.

53 A SWP Indicator When lit, indicates that the A Sweep has been selected.

54 AREF OR DLY POS Control Sets the B Sweep Delay Position. It sets the referenceB Sweep delay when At or 1/At is active with two delays.When any cursor mode is active, the AREF OR DLY POScontrol positions the reference cursor (dotted line) and has noeffect on B Sweep delay.

When TRACK mode is selected, AREF moves the referenceand delta cursors or delays, equally.

When Save mode is active, AREF selects character positionsin a setup name or attribute fields in a sequence stepdefinition.

When MEASURE is active, AREF selects items or item groupsin the Time Interval Configure menu and selects characterpositions in event-count definition displays.

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55 56 57 58 59 60 61

8180

79

78

77

76

75

74

73

72 71 70

VIEW D

62

63

64

65

66

67

68

69


55 TRIGGER HOLDOFF Control Varies the time from the end of an A Sweep to enabling the

next sweep to be initiated by the triggering signal. In the BENDS A position (fully CW), trigger holdoff time is minimum,and A Sweep terminates immediately at the end of the BSweep. This enables the fastest possible sweep-repetitionrate at slow A Sweep speeds.

56 + SLOPE TRIGGER Indicator Illuminates to indicate that the A Trigger or B Trigger willrespond to the positive-going slope of a signal.

57 TRIGGER READY Indicator Illuminates when Sgl Seq mode is selected and the A Sweepis armed and waiting for a triggering event to occur. Itextinguishes following the completion of ail the tracesselected for the Sgl Seq display.

58 A SWP TRIGD Indicator Illuminates when the A Sweep is triggered. It extinguishes a

short time after completion of a sweep unless a triggeringsignal is received.

59 - SLOPE TRIGGER Indicator Illuminates to indicate that the A Trigger or B Trigger willrespond to the negative-going slope of a signal.

60 TRIGGER SLOPE Button Press to select. Determines whether the A Trigger or B Triggerwill respond to the positive-going or the negative-going slopeof a signal.

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61 TRIGGER LEVEL Control Adjusts the amplitude point on the triggering signal at whichA Sweep or B Sweep triggering occurs. When the A Triggermode is set to AUTO LVL, the effect of the LEVEL control is

spread over the peak-to-peak amplitude of the triggeringsignal. When the control is rotated to either extreme, the peakvalues are measured, and the control range is redefined tocorrespond to the peak values. If LEVEL is fully CW, the initiallevel is near the positive peak. If LEVEL is fully CCW, the initiallevel is near the negative peak.

62 INIT @ 50% Button Press to activate. Initializes the trigger level at the midpointbetween peaks, for either the A Trigger or B Trigger, in anymode. If Vert trigger source is selected and more than onechannel is displayed, INIT @ 50% automatically sets thetrigger source to the lowest numbered of the displayedchannels.

63 VERT TRIGGER SOURCE Indicator When lit, the sweep triggers on the displayed channel when

only one channel is selected. If multiple vertical displays areselected, both the trigger Mode and the Chop/Alt selectionaffect the triggering source. With Alt vertical mode and withA Trigger modes other than Auto Lvl, each displayed channelin turn provides the triggering signal and the respective LEDindicator for each displayed channel is illuminated. With AutoLvl trigger mode or with Chop vertical mode, the lowestnumbered channel, or ADD if it is displayed, is thetriggering-signal source. The Source indicators show thesource of the triggering signal in any case, When Add isselected, both the CH 1 and the CH 2 indicators areilluminated.

64 DC TRIGGER COUPLING Indicator When lit, all frequency components of the input signal arecoupled to the trigger. This coupling is preferred for most

signals.

65 NOISE REJ TRIGGER COUPLING When lit, all frequency components of the input signal areIndicator coupled to the trigger. This coupling improves trigger stability

with signals accompanied by low-level noise.

66 HF REJ TRIGGER COUPLING When lit, high-frequency triggering-signal components aboveIndicator 50 kHz are attenuated.

67 LF REJ TRIGGER COUPLING When lit, signals are capacitively coupled, blocking the DCIndicator component of the triggering signal and attenuating the

low-frequency components below 50 kHz.

68 AC TRIGGER COUPLING Indicator When lit, signals are capacitively coupled. Frequencycomponents below 60 Hz are attenuated, and the DCcomponent of the input signal is blocked.

69 LINE TRIGGER SOURCE Indicator When lit, the triggering signal is obtained from a sample of the(A Trigger only) AC power source waveform. This triggersource is useful when vertical input signals are related to thefrequency of the AC power source voltage.

70 TRIGGER COUPLING Buttons Press either top or bottom button to activate. Selects themethod for coupling the triggering signal to the triggergenerator.

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71 TRIGGER SOURCE Buttons Press either the top or bottom button to activate. Selects thetrigger-signal source for either the A Sweep or B Sweep.

72 TRIGGER MODE Buttons Press either top or bottom button to select the mode of the ATrigger or the B Trigger. Pressing a button steps the MODE

selection once. Holding the button in causes the MODEselection to step repeatedly. Indicators show the selectedmode of either the A Trigger or the B Trigger according to theselected horizontal display mode and as directed by the A/BTRIG button.

73 TRIG ADLY MODE Indicator N/A without CTT option.74 TRIG AFT DLY MODE Indicator When lit, the B Sweep runs when triggered after the set delay,

determined by the same controls as for RUN AFT DLY,provided the A Sweep has not terminated.

75 RUN AFT DLY TRIGGER MODE When lit, the B sweep runs immediately after the delay timeIndicator set by A SEC/ DIV, AREF OR DLY POS, and if At or I/At is

active.

76 CH 1, CH 2, CH 3, CH 4 TRIGGER When lit, indicates which channel supplies the triggeringSOURCE Indicators signal.

77 SGL SEQ TRIGGER MODEIndicator

78 NORM TRIGGER MODE Indicator When lit, the sweep is triggered and runs when an adequateMode triggering signal is applied. In the absence of anadequate triggering signal, the A Sweep does not run, except

when the input coupling of the trigger source channel is set toGND. If the selected source is Vert, and the Add verticaldisplay is selected, the A Sweep free runs if CH 1 and CH 2input coupling are both set to GND.

79 AUTO TRIGGER MODE Indicator When lit, the sweep free runs in the absence of a triggeringsignal. The trigger level changes only when the LEVEL controlis adjusted to a new position or when INIT @ 50% is pressed.

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80 AUTO LVL TRIGGER MODE When lit, automatically establishes the trigger level on aIndicator triggering signal and free runs the sweep in the absence of a

triggering signal. With AUTO LVL mode and Vert triggersource, the lowest numbered channel is displayed, or Add, if

it is displayed, provides the trigger signal.

81 A/B TRIG Button Press to activate. The MODE, SOURCE, COUPLING, SLOPE,LEVEL, and INIT @ 50% controls are normally directed to theA Trigger. They are directed to the B Trigger with Inten, Alt, orB Sweep horizontal displays, or if B mode is TRIG AFT DLY,The trigger controls are directed to the opposite trigger whilethe A/B TRIG button is pressed. With Inten, Alt, or B-Sweephorizontal displays, and with B Trigger mode set to RUN AFTDLY or with A Trigger mode set to Sgl Seq, the trigger controlsare alternately directed to the A Trigger or to the B Triggereach time the button is pushed.

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82 VERTICAL POSITION Control Adjusts the vertical position of the Channel 3 signal trace.

83 VOLTS/DIV Button Press to activate. Select either 0.1 V or 0.5 V per divisiondeflection factor for Channel 3. Display readout will reflectselection.

84 VOLTS/DIV Button Press to activate. Select either 0.1 V or 0.5 V per divisiondeflection factor for Channel 4. Display readout will reflectselection.

85 VERTICAL POSITION Control Adjusts the vertical position of the Channel 4 signal trace.

86 CH 4 Connector BNC female connector which conducts external signals to theCH 4 vertical input. Contains a coding-ring contact for probes.This channel cannot be used for parametric measurementsand input coupling is 1 Megohm DC only. Can be used as theY input for XY operation.

87 CALIBRATOR Connector Provides a 0.4 V p-p square wave into a 1 Megohm load,0.2 V p-p into a 50 ohm DC-coupled load. The repetition rateof the output changes with A Sweep SEC/DIV changes.Ranges from 100 ms per division to 100 ns per division.Displays 5 cycles per 10 divisions. At 100 ms per division and

slower, the CALIBRATOR frequency is 5 Hz; at 100 ns perdivision or faster, the frequency is 5 MHz. Useful for checkingsweeps, delay-times and vertical deflection accuracies aswell as compensating voltage probes and checking theaccuracy of current probes.

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88 AUXILIARY GROUND Jack Accepts standard banana plugs and provides an auxiliarysignal ground.

89 CH 3 Connector BNC female connector which conducts external signals to the

CH 3 vertical input. Contains a coding-ring contact for codedprobes. This channel cannot be used for parametricmeasurements and input coupling is 1 Megohm DC only. Canbe used as the Y input for XY operation.

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90 VOLTS/DIV Control Rotate in either direction. Used to selectt he CH 1 vertical de-

flection factor.

91 VOLTS/DIV VAR Control In the detent position, (fully CW), the vertical deflection factoris equal to the calibrated VOLTS/DIV control settings. Whenrotated CCW, provides variable, uncalibrated deflectionfactors between calibrated settings of the CH 1 VOLTS/DIVcontrol. When not in the detent position, (fully CW), a > signis displayed before the VOLTS/DIV readout on the display.

92 VOLTS/DIV Control Rotate in either direction. Used to select the CH 2 verticaldeflection factor.

93 VOLTS/DIV VAR Control In the detent position, (fully CW), the vertical deflection factoris equal to the calibrated VOLTS/DIV control settings. Whenrotated CCW, provides variable, uncalibrated deflectionfactors between calibrated settings of the CH 2 VOLWDIVcontrol. When not in the detent position, (fully CW), a > signis displayed before the VOLTS/DIV readout on the display.

94 INPUT COUPLING Buttons Press either the top or the bottom button to select the methodfor coupling input signals to Channel 1 and Channel 2. If theupper Channel 1 and upper Channel 2 input coupling buttonsare pressed together, the scope automatically performs a DCbalance of CH 1 and CH 2 vertical circuitry.

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KEY CONTROL, INDICATOR, OR FUNCTIONCONNECTOR I

95 CH 2 Connector BNC female connector which conducts external signals to theCH 2 vertical input. Contains a coding-ring contact for codedprobes. Can be used as the Y input for XY operation.

96 CH 1 or X Connector BNC female connector which conducts external signals to theCH 1 vertical input. Contains a coding-ring contact for codedprobes.

97 50 OHM DC Indicator When lit, all frequency components of the input signal arecoupled to the vertical, with the input terminated by 50 ohmsto ground.

98 1 MEGOHM GND Indicator When lit, the input of the vertical amplifier is grounded. Inputresistance is 1 Megohm to ground.

99 1 MEGOHM DC Indicator When lit, all frequency components of the input signal arecoupled to the vertical. Input resistance is 1 Megohm toground.

100 1 MEGOHM AC Indicator When lit, the input signal is capacitively coupled to the vertical

attenuator. The DC component of the input signal is blocked.

I

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101 POWER ON/OFF Indicator and When power is on, the indicator becomes green. When off, the

Illustration indicator is black. The illustration shows the power status foreach indicator color.

102 POWER Button Turns the OS-288 power on and off. Press to activate.

103 SCALE ILLUM Control Adjusts the level of graticule illumination. CW rotationincreases brightness.

104 ASTIG Control Adjusts the CRT beam shape in conjunction with the FOCUScontrol to obtain a well-defined display over the entiregraticule area.

READOUT INTENSITY Control Adjusts the intensity of the CRT readout display. CW rotationturns the SCALE FACTORS on. Center position turns theSCALE FACTORS off. CCW rotation from center disables thescale-factor and control-status displays. It also increases the

intensity of the measurements generated by the cursormethod.

106 TRACE ROTATION Control Aligns the no-signal trace with the horizontal graticule lines.

107 FOCUS Control Adjusts the CRT writing beam for optimum display definition.

108 BEAM FIND Button Press and hold in. Aids in locating off-screen displays bylimiting the CRT deflection both vertically and horizontally towithin the graticule.

109 INTENSITY Control Adjusts the brightness of the waveform. CW rotation increasesthe brightness.

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Figure 2-2. Operators Controls, Indicators, and Connectors, Rear View.

KEY CONTROL, INDICATOR, OR

CONNECTOR

FUNCTION

110 FUSE HOLDER Contains the AC power source fuse. Press cap and releasewith a CCW rotation to remove the fuse.

Connects the AC power source to the OS-288/G.111 DETACHABLE POWER CordReceptacle

112 EXT Z-AXIS IN Connector Provides an input for external signals to modulate the displayintensity.

Provides TTL-compatible, positive-going gate signals that areHIGH during its respective sweeps and LOW while the sweepis not running. When the A SEC/DIV switch is set to 5 ns perdivision, a gate is present at the B GATE OUT connector.

Accepts a standard, 2.5 mm, micro-phono plug. A contactclosure or TTL-low at this input produces the same effect asoperating the STEP/AUTO button.

113 B GATE OUT Connector

114 STEP/AUTO EXT SWITCH

115 A GATE OUT Connector Provides TTL-compatible, positive-going gate signals that areHIGH during its respective sweeps and LOW while the sweepis not running. When the A SEC/DIV switch is set to 5 ns perdivision, a gate is present at the A GATE OUT connector.

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KEY

116

117

CONTROL, INDICATOR, OR FUNCTIONCONNECTOR

CH 2 SIGNAL OUT Connector Supplies a normalized signal that represents the CH 2 inputsignal.

LINE VOLTAGE SELECTOR Switch Selects either 115 V or 230 V nominal AC power source volt-

age.

Section Il. OPERATOR PREVENTIVE MAINTENANCECHECKS AND SERVICES (PMCS)

2-2. GENERAL.

To be sure that your equipment is always ready for your mission, you must do scheduled preventivemaintenance checks and services (PMCS). When you are doing any PMCS or routine checks, keep in mindthe WARNINGS and CAUTIONS about electrical shock and bodily harm.

2-3. PMCS PROCEDURES.

a. Tools, Materials, and Equipment Required for Preventive Maintenance. No tools or equipment arerequired for operator preventive maintenance. Cleaning materials required are listed in Appendix E,Section II, items 1, 2, and 3.

b. PMCS for the oscilloscope are limited to routine checks such as shown below.q cleaningq dust ingq w i p i n gq checking for frayed cablesq storing items not in useq checking for loose nuts, bolts, and screws.

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

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Section Ill. OPERATION UNDER USUAL CONDITIONS

2-4. PREPARATION FOR USE.

Follow these instructions before connecting the oscilloscope to a power source.

The oscilloscope is equipped with a 3-wire power cable. When connected to agrounded AC power receptacle, this cable grounds the oscilloscope chassis. Donot use extension cords or AC adapters without a ground connection.

The oscilloscope may be damaged if operated with the LINE VOLTAGE

SELECTOR switch set for the wrong applied AC input-source voltage or if thewrong fuse is installed.

1. Verify the LINE VOLTAGE SELECTION switch (1) is set according to the available AC power source.

2. Verify the Line Fuse (3) is the correct type and value as shown below.

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LINE VOLTAGE RANGE FUSE TYPESELECTION

115V 190-132 V UL 198.6 (3AG), 2A FAST

230 V 180-250 V IEC 127, 1.6A (T)

3.

4.

5

2-5.

Verify the detachable power cord matches the available power source.

Ensure the air-intake holes on the bottom of the cabinet and the fan exhaust in the rear of the cabinet arefree of any obstruction to air flow.

Connect the power cord to the oscilloscope receptacle (2).

TURN-ON PROCEDURE.

1. Verify that the POWER button (6) is set to OFF. Connect the power cord to the AC power source.

2. Press the POWER button (6) to the ON position. A set of self diagnostic tests will automatically beperformed immediately after turn-on and run for several seconds. During the tests many of theoscilloscope indicators will light in an ordered sequence. If no faults are encountered, the instrumentoperates normally.

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3. If a failure is detected, it will be indicated by either a flashing TRIGD indicator or a bottom line readouton the display in the form of TEST XX FAIL YY as shown (17). If a failure occurs, notify the next higherlevel of maintenance.

4. Allow for a 20 minute warm-up period.

5. Set the controls as follows:

CH 4 Vertical POSITION (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. MidrangeCH 3 Vertical POSITION (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Midrange

SEC/DIV VAR (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Detent Position

CH 2 VOLTS/DlV VAR (4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Detent PositionCH 1 VOLTS/DIV VAR (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Detent Position

SCALE ILLUM (7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MidrangeREADOUT INTENSITY (8) . . . . . . . . . . . . . . . . . . . . . . . Midrange between OFF and fully clockwiseFOCUS (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MidrangeINTENSITY (10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..-. Midrange

CH 1 VERTICAL POSITION(11). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. MidrangeCH 2 VERTICAL POSITION (12).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. MidrangeHorizontal POSITION (13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Midrange

SEC/DlV knob (14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Pushed inHOLDOFF (15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MIN positionTRIGGER LEVEL (16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Midrange

N O T E

The AUTO SETUP feature automatically scales and displays a signal connected toany input. A baseline trace is therefore not a requirecl start for operation.

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2-6. INITIAL ADJUSTMENTS AND DAILY CHECKS.

INITIAL ADJUSTMENT AND DAILY CHECKS are described in paragraphs 2-7 through 2-11. They must beperformed prior to oscilloscope operation to assure measurement accuracy.

N O T E

The following figure is referenced in paragraphs 2-7 through 2-11.

2-7. AUTO DC BALANCE.

N O T E

The following figure callouts refer to the figure in paragraph 2-6.

Press and hold the CH 1 upper Input Coupling button (23) and the CH 2 upper Input Coupling button (20) untilthe following message is displayed:

DC BALANCE IN PROGRESS 0

N O T E

The number shown will increment to 10. When the routine is complete, theoscilloscope will return to normal operation.

If power is interrupted during the routine, restart the DC Balance cycle after a 20-minute warm-up period. Also, if a defect were to prevent accurate DC balance,LIMIT will be shown on the display. The OS-288 should then be referred to thenext higher level of maintenance.

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2-8. TRACE ROTATION ADJUSTMENT.

1.

2.

3.

4.

N O T E

Perform Trace Rotation adjustment as required.

Except for item 30, the following figure callouts refer to the figure in paragraph2-6.

Connect the CH 1 Input (25) to the CALIBRATOR output (16) and ground (17) using the supplied probe.

Set the CH 1 Input Coupling (24) to GND. Select the 20 MHz BW LIMIT (9).

Adjust the CH 1 VERTICAL POSITION control (6) to position the trace (30) on the center graticule line.

If the trace is not parallel to the graticule line, adjust the TRACE ROTATION control (28) to align thetrace.

2-9. ASTIGMATISM ADJUSTMENT.

N O T E

Perform Astigmatism adjustment as required.

Except for item 31, the following figure callouts refer to the figure in paragraph

2-6.

1. Connect the CH 1 input (25) to the CALIBRATOR output (16) and ground (17) using the supplied probe.

2. Select the 20 MHz BW LIMIT (9).

3. Adjust the CH 1 VERTICAL POSITION control (6) to center the CALIBRATOR trace (31).

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5.

6.

7.

8.

9.

10.

2-10.

Position the A cursor near the top of the screen using the A control (14). Adjust both cursors for a AV1value of 1.2000 V.

Adjust the SEC/DIV control (18) to 1 s.

Adjust the FOCUS control (29) to obtain the best defined display of cursor dots.

If necessary, adjust the ASTIG control (27) for improved cursor definition.

Since the ASTIG and FOCUS adjustments interact, repeat steps 8 and 9 to obtain the best-defineddisplay over the entire graticule area.

PROBE COMPENSATION.

N O T E

Misadjustment of probe compensation is a common source of measurementerror. CH 1 and CH 2 probes should be compensated on their respectivechannels. CH 3 and CH 4 probes should be compensated on either CH 1 orCH 2.

Except for item 32, the following figure callouts refer to the figure in paragraph2-6.

Use the following steps to compensate the CH 1 probe.

1.

2.

3.

4.

Select the CH 1 VERTICAL MODE (5). Set the CH 1 Input Coupling (24) to 1 Megohm DC.

Connect the CH 1 input (25) to the CALIBRATOR output (16) and ground (17) using the supplied probe.

Press the AUTO SETUP button (4). If the STEP indicator (3) is lit, press RECALL (1), press SAVE (2), andthen AUTO SETUP (4).

Select the 20 MHz BW LIMIT (9).

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5.

6.

7.

8.

2-11.

Adjust the SEC/DIV control (18) to 1 ms.

Adjust the CH 1 VOLTS/DIV control (26) to 100 mV.

Observe the resulting display. If the front corners of the CALIBRATOR signal are not square, adjustmentis required.

If adjustment is required, insert an alignment tool through the hole in the probe box (32) and adjust thelow frequency compensation control.

MATCHING CHANNEL 2 DELAY.

N O T E

Except for item 33, the following figure callouts refer to the figure in paragraph 2-6.

Use the following steps to adjust the apparent signal delay in CH 2 up to 500 ps with respect to the apparentdelay in CH 1. CH 2 may also be matched with CH 3 or CH 4 following the same procedure.

1. Connect both the CH 1 input (25) and the CH 2 input (22), via probes, to the same fast-rise pulsegenerator output.

2. Set the VERTICAL controls as follows:

CH 1 VERTICAL MODE (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ON

CH 2 VERTICAL MODE (7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ON

CH 1 lnput Coupling (24) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Megohm DC

CH 2 Input Coupling (21) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Megohm DC

3. Press the AUTO SETUP button (4). If the STEP indicator is lit (3), press RECALL (1), press SAVE (2), andthen AUTO SETUP (4).

4. Select CH 2 as the TRIGGER SOURCE (15).

5. Equally adjust the CH 1 VOLTS/DIV control (26) and the CH 2 VOLTS/DIV control (19) to obtain a tracethat is 3 to 6 divisions in amplitude for each channel.

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7.

8.

9.

10.

11.

2-12.

Adjust the SEC/DIV control (18) to 5 ns (33).

Pull the SEC/DIV knob (18) out. The message CH 2 DELAY-TURN will be displayed.

N O T E

If the message CH 2 DLY DISABLED appears, refer the OS-288 to the next higherlevel of maintenance.

Select the X10 MAG function (13). Use the HORIZONTAL POSITION control (12) to center the risingedge of the two pulses.

Adjust the control (14) to superimpose the two edges horizontally.

Push in the SEC/DIV knob (18). The adjustment is now permanently stored for future operation even ifpower is interrupted.

OPERATING PROCEDURES.

Operating procedures for the OS-288 are provided in paragraphs 2-13 through 2-32. Parametric and cursormeasurement methods are presented for many of the procedures.

2-13. PEAK-TO-PEAK VOLTAGE MEASUREMENT.

Peak-to-Peak Voltage may be measured using the Parametric Measurement Method or the Cursor Method.

a. Parametric Measurement Method.


CH1 VERTICAL MODE (8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . .ON

CH1 Input Coupling (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . As required

2. Connect the CH 1 input (2) to the signal under test.

3. Press the MEASURE button (4).

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4. Select VOLTS from the menu by pressing the MODE 2 button (10).

NOTE

The display will blank momentarily and then show the message:

VOLTS MEASUREMENTS IN PROGRESS

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5. When the measurement is complete, the voltage values are displayed on the second and thirdreadout lines,

Negative peak value (14)

Positive peak value (15)Peak-to-Peak value (16)Average value (17)

b. Cursor Measurement Method

1.

2.

3.

4.

5.

6.

7.

8.

Set the VERTICAL controls as follows:

CH1 VERTICAL MODE (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON

CH1 lnput Coupling (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. As required

Connect the CH 1 input (2) to the signal under test.

Press the AUTO SETUP button (8). If the STEP indicator is lit (7), press RECALL (5), press SAVE (6),and then AUTO SETUP (8).

Adjust the CH 1 VOLTS/DIV control (3) to display the largest useable amplitude.

Select V (11).

Position the REF cursor at the negative peak of the trace using the REF control (12).

The displayed V1 value (18) indicates the equivalent voltage between the cursors. In this case, V1 is the peak-to-peak voltage.

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2-14. ABSOLUTE VOLTAGE MEASUREMENT USING CURSORS.


CH1 VERTICAL MODE (8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON

CH 1 lnput Coupling (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. As required2. Connect the CH 1 input (2) to the signal under test.

3. Press the AUTO SETUP button (6). If the STEP indicator is lit (7), press RECALL (4), press SAVE (5), andthen AUTO SETUP (6).

4. Adjust the CH 1 VOLTS/DIV control (3) to display the largest usable amplitude.

5. Select V (9).

6. Set the CH 1 Input Coupling (1) to GND.

8. Return the CH 1 Input Coupling (1) to 1 Megohm DC.

9. Position the A cursor at the point of interest on

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