Tektronix 370B Service Manual

370B Programmable Curve Tracer

ZZZ

Service Manual

*P070A84250*

070-A842-50

370B Programmable Curve Tracer

ZZZ

Service Manual

Revision C

Warning

The servicing instructions are for use by qualiﬁed personnel only. To avoid personal injury, do not perform any servicing unless you are qualiﬁed to do so. R efer to all safety summaries prior to performing service.

www.tektronix.com

070-A842-50

tional copyright laws and international treaty provisions.

Tektronix pro previously published material. Speciﬁcations and price change privileges reserved.

TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

ducts are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes that in all

Contacting Tektronix

Tektronix, Inc. 14200 SW Karl Braun Drive P.O. Box 500 Beaverton, OR 97077 USA

For product information, sales, service, and technical support:

In North America, call 1-800-833-9200. Worldwide, visit www.tektronix.com to ﬁnd contacts in your area.

Warranty 2

Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If any such product proves defective during this warranty period, Tektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement i n exchange for the defective product. Parts, modules and replacement products used by Tektronix for warranty work may be new or reconditioned to like new performance. All replaced parts, m odules and products become the property of Tektronix.

In order to obtai n service under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for packaging and shipping the defective product to the service center designated by Tektronix, with shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the Tektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any other charges for products returned to any other locations.

This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate maintenance and care. Tektronix shall not be obligated to furni sh servi ce under this warranty a) to repai r damage resulting from attempts by personnel other than Tektronix representatives to install, repair or service the product; b) to repair damage resulting from improper use or c onne ction to incompatible equipment; c) to repair any dam age or malfunction caused by the use of non-Tektronix supplies; or d) to service a product that has been modified or integrated with other products when the effect of such modification or i ntegration increases the time or difficulty of servicing the product.

THIS W ARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER W ARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENT AL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Specifications

Operating Information

General Safety Summary vii...................................

Service Safety Summary ix....................................

Preface xi...................................................

Introduction xv..............................................

Product Overview 1--1.........................................

Specifications 1--3.............................................

Performance Conditions 1--3...........................................

Electrical Specifications 1--4...........................................

Mechanical Specifications 1--17.........................................

Functional Specifications 1--18.........................................

Environmental Specifications 1--19......................................

GPIB Interface 1--22..................................................

Operating Information 2--1.....................................

Installation 2--1.....................................................

Kelvin Sense 2--5....................................................

Rackmounting Information 2--7........................................

Repacking for shipment 2--13...........................................

Theory of Operation

Theory of Operation 3--1.......................................

Block Diagram Description 3--1........................................

Circuit Operation 3--6................................................

Maintenance

Maintenance 4--1..............................................

Preventive Maintenance 4--1...........................................

Corrective Maintenance 4 --4...........................................

Performance Verification

Performance Verification 5--1...................................

Using Procedure 5--3.................................................

Power Supply 5--12...................................................

CRT 5--17...........................................................

Display 5--26........................................................

Horizontal 5--44......................................................

Vertical 5--54........................................................

Step Generator 5--71..................................................

Collector Supply 5--104.................................................

AUX Supply 5--119....................................................

370B Service Manual i

Table of Contents

Instrument Options

Electrical Parts List

Diagrams

Mechanical Parts List

Configuration 5--122...................................................

Key Operation and Floppy Disk Drive 5--129................................

Options 6--1........................................................

Accessories 6--2.....................................................

Replaceable Electrical Parts 7--1.................................

Parts Ordering Information 7 --1.........................................

Using the Replaceable Electrical Parts List 7--2............................

Diagrams 8--1.................................................

Mechanical Parts List 9--1......................................

Parts Ordering Information 9 --1.........................................

Using the Replaceable Parts List 9--2....................................

ii 370B Service Manual

List of Figures

Table of Contents

Figure 2--1: Example of Kelvin sense connection 2--6................

Figure 2--2: Location of the Rackmount Latch Release 2--7...........

Figure 2--3: Rackmount hole spacing 2--8..........................

Figure 2--4: Rackmounting Length and Clearance 2--8..............

Figure 2--5: Rackmounting Hardware 2--9.........................

Figure 2--6: Mounting Stationary Rackmount Sections 2--10...........

Figure 2--7: Cabinet-to-Rackmount Conversion 2--12.................

Figure 3--1: 370B Block Diagram 3--3.............................

Figure 5--1: Diagnostic test pattern display 5--32.....................

Figure 5--2: Looping compensation display 5--40....................

Figure 5--3: Checking Collector high current range 5--67..............

Figure 5--4: Examining and Adjusting for Step Generator Offset 5--73..

Figure 5--5: Adjusting for Current Amplifier Bias 5--75...............

Figure 5--6: Checking for Maximum OFFSET of 200 mA Range 5--83..

Figure 5--7: Checking for Maximum Current Output of 100 mA

and 200 mA range 5--96......................................

Figure 5--8: Adjusting for Collector Supply Amplifier Offset 5--105......

Figure 5--9: Examining for DC and LEAKAGE operation 5--113........

Figure 8--1: 370B circuit board locator 8--1........................

Figure 9--1: Cabinet, Rear 9--9...................................

Figure 9--2: Display, Front 9--10..................................

Figure 9--3: Chassis Circuit Boards 9--17...........................

Figure 9--4: Power Supply 9--18...................................

Figure 9--5: Front Panel: L-O-R 9--27..............................

Figure 9--6: LV, L-O-R, Looping Circuit Boards 9--28................

Figure 9--7: FDD, Config. Relay, Sense Circuit Boards 9--35...........

Figure 9--8: Accessories 9--36.....................................

370B Service Manual iii

Table of Contents

List of Tables

Table 1--1: Collector Supply 1 -- 4.................................

Table 1--2: Step Generator 1--7..................................

Table 1--3: AUX Supply 1--10....................................

Table 1--4: Non-store Vertical Deflection System 1--10................

Table 1--5: Digital Storage Vertical Acquisition 1--12.................

Table 1--6: Non-store Horizontal Deflection System 1--13.............

Table 1--7: Digital Storage Horizontal Acquisition 1--14..............

Table 1--8: CRT and Readout 1--15...............................

Table 1--9: Adapter Connectors 1--16..............................

Table 1--10: Power Supply 1--17..................................

Table 1--11: Surge Current 1 -- 17..................................

T able 1--12: Mechanical Specification 1--17.........................

Table 1--13: Digital Storage Acquisition Mode 1--18.................

Table 1--14: Text Display 1--18...................................

Table 1--15: Environmental Specification 1--19......................

Table 1--16: Certifications and Compliances 1--20...................

Table 1--17: Installation category and Pollution degree Descriptions 1--21

Table 1--18: GPIB Interface 1--22.................................

Table 2--1: Line voltage ranges 2--1...............................

Table 2--2: Power Cord Color Conductor Identification 2--2..........

Table 2--3: Power cord identification 2--3.........................

Table 4--1: Power-on System Error Messages 4--24..................

Table 4--2: Front Panel Control Identification 4--25..................

Table 5--1: Performance Check and Adjustment Procedure Options 5--2

T able 5--2: Performance Check Summary 5--4.....................

Table 5--3: Test Equipment 5--10.................................

Table 5--4: Voltage Regulation and Ripple 5--13.....................

Table 5--5: Base/Emitter Voltage Accuracy 5--48.....................

T able 5--6: Collector Voltage Accuracy 5--50........................

Table 5--7: Displayed Horizontal Noise 5--53........................

T able 5--8: Emitter Current Accuracy 5--61........................

T able 5--9: Collector Current Accuracy 5--63.......................

T able 5--10: Collector High Current Accuracy 5--67.................

iv 370B Service Manual

Table of Contents

Table 5--11: Displayed Vertical Collector Noise in CONFIGURATION

BASE to COLLECTOR SUPPLY mode 5--70...................

Table 5--12: OFFSET Voltage 5--79...............................

Table 5--13: OFFSET Voltage 5--80...............................

Table 5--14: OFFSET Current 5--82...............................

Table 5--15: Max Peak Volts 5--108.................................

Table 5--16: Max Peak Volts 5--109.................................

Table 5--17: Maximum Peak Currents 5--111........................

Table 5--18: Auxiliary Supply Accuracy 5--120.......................

T able 6--1: Standard accessories 6--2.............................

Table 6--2: Optional accessories 6--2..............................

T able 6--3: Recommended accessories 6--3.........................

370B Service Manual v

Table of Contents

vi 370B Service Manual

General Safety Summary

Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazards, use this product only as specified.

Only qualified personnel should perform service procedures.

ToAvoidFireor

Personal Injury

Use Proper Power Cord. Use only the power cord specified for this product and certified for the country of use.

Use Proper Voltage Setting. Before applying power, ensure that the line selector is in the proper position for the power source being used.

Connect and Disconnect Pr operly. Do not connect or disconnect probes or test leads while they are connected to a voltage source.

Ground the Product. This product is grounded through the grounding conductor of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, ensure that the product is properly grounded.

Observe All Terminal Rat ings. To avoid fire or shock hazard, observe all ratings and markings on the product. Consult the product manual for further ratings information before making connections to the product.

The common terminal is at ground potential. Do not connect the common terminal to elevated voltages.

Do not apply a potential to any terminal, including the common terminal, that exceeds the maximum rating of that terminal.

Do Not Operate Without Covers. Do not operate this product with covers or panels removed.

Use Proper Fuse. Use only the fuse type and rating specified for this product.

Avoid Exposed Circuitry. Do not touch exposed connections and components

when power is present.

Do Not Operate With Suspected Failures. If you suspect there is damage to this product, have it inspected by qualified service personnel.

Do Not Operate in Wet/Damp Conditions.

Do Not Operate in an Explosive Atmosphere.

Keep Product Surfaces Clean and Dry.

Provide Proper Ventilation. Refer to the manual’s installation instructions for

details on installing the product so it has proper ventilation.

370B Service Manual vii

General Safety Summary

Symbols and Terms

Terms in this Manual. These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result in injury or loss of life.

CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property.

Terms on the Product. These terms may appear on the product:

DANGER indicates an injury hazard immediately accessible as you read the marking.

WARNING indicates an injury hazard not immediately accessible as you read the marking.

CAUTION indicates a hazard to property including the product.

Symbols on the Product. The following symbols may appear on the product:

WARNING

High Voltage

Protective Ground

(Earth) Terminal

CAUTION

Refer to Manual

Double

Insulated

viii 370B Service Manual

Service Safety Summary

Only qualified personnel should perform service procedures. Read this Service Safety Summary and the General Safety Summary before performing any service

procedures.

Do Not Service Alone. Do not perform internal service or adjustments of this product unless another person capable of rendering first aid and resuscitation is present.

Disconnect Power. To avoid electric shock, disconnect the mains power by means of the power cord or, if provided, the power switch.

Use Care When Servicing With Power On. Dangerous voltages or currents may exist in this product. Disconnect power, remove battery (if applicable), and disconnect test leads before removing protective panels, soldering, or replacing components.

To avoid electric shock, do not touch exposed connections.

370B Service Manual

Service Safety Summary

370B Service Manual

Preface

Manual Structure

This is the service manual for the 370B Programmable Curve Tracer. The manual contains information needed to service the 370B to the module level.

This manual is divided into sections, such as Specifications and Theory of

Operation. Further, some sections are divided into subsections, such as Product Description and Removal and Installation Procedures.

Sections containing procedures also contain introductions to those procedures. Be sure to read these introductions because they provide information needed to do the service correctly and efficiently. The following contains a brief description of each manual section.

H Specifications contains a description of the 370B Programmable Curve

Tracer and the characteristics that apply to it.

H Operating Information includes general information and operating

instructions.

H Theory of Operation contains circuit descriptions that support service to the

module level.

H Performance Verification contains procedures for confirming that the 370B

Programmable Curve Tracer functions properly and meets warranted limits.

H Adjustment Procedures contains a collection of procedures for adjusting the

370B Programmable Curve Tracer to meet warranted limits.

H Maintenance contains information and procedures for performing preventive

and corrective maintenance of the 370B Programmable Curve Tracer. These instructions include cleaning, module removal and installation, and fault isolation to the module.

H Options contains information on servicing factory-installed options.

H Electrical Parts List contains a statement referring you to Mechanical Parts

List, where both electrical and mechanical modules are listed.

H Diagrams contains an block diagram and an interconnection diagram.

H Mechanical Parts List includes a table of all replaceable modules, their

descriptions, and their Tektronix part numbers.

370B Service Manual xi

Preface

Manual Conventions

This manual uses certain conventions that you should become familiar with.

Some sections of the manual contain procedures for you to perform. To keep those instructions clear and consistent, this manual uses the following conventions:

H Names of front panel controls appear in the same case (initial capitals, all

uppercase, etc.) in the manual as is used on the 370B Programmable Curve Tracer front panel. Front panel names are all upper-case letters; for example, REF, SAVE, VIEW etc.

H Instruction steps are numbered unless there is only one step.

Modules

Safety

Throughout this manual, any replaceable component, assembly, or part of the 370B Programmable Curve Tracer is referred to generically as a module. In general, a module is an assembly (like a circuit board), rather than a component (like a resistor or an integrated circuit). Sometimes a single component is a module; for example, the chassis of the 370B Programmable Curve Tracer is a module.

Symbols and terms related to safety appear in the Safety Summary near the beginning of this manual.

Finding Other Information

Other documentation for the 370B includes:

H The 370B Programmable Curve Tracer User Manual contains a tutorial to

quickly describe how to operate the370B Programmable Curve Tracer. It also includes an in-depth discussion on how to more completely use the 370B Programmable Curve Tracer features.

xii 370B Service Manual

Preface

370B Service Manual xiii

Preface

xiv 370B Service Manual

Introduction

This manual contains information needed to properly service the 370B Programmable Curve Tracer as well as general information critical to safe and effective servicing.

To prevent personal injury or damage to the analyzer, consider the following before attempting service:

H The procedures in this manual should be performed only by a qualified

service person

H Read the General Safety Summary and the Service Safety Summary,

beginning on page vii

H Read Preparation for Use in section 2, Operating Information

When using this manual for servicing, be sure to follow all warnings, cautions, and notes.

Performance Check Interval

Strategy for Servicing

Generally, the performance check described in section 4, Performance Verification, should be done every 12 months. In addition, performance check is recommended after module replacement.

If the analyzer does not meet performance criteria, repair is necessary.

Throughout this manual, the term, module, refers to any field-replaceable component, assembly, or part of the analyzer.

This manual contains all the information needed for periodic maintenance of the 370B Programmable Curve Tracer (Examples of such information are procedures for checking performance.)

Further, it contains all information for corrective maintenance down to the module level. To isolate a failure to a module, use the fault isolation procedures found in Troubleshooting, part of section 6, Maintenance. To remove and replace any failed module, follow the instructions in Removal and Installation Procedures, also part of section 6. After isolating a faulty module, replace it with a fully-tested module obtained from the factory. Section 9, Mechanical Parts List, contains part number and ordering information for all replaceable modules.

370B Service Manual xv

Introduction

Tektronix Service Offerings

Tektronix provides service to cover repair under warranty as well as other services that may provide a cost-effective answer to your service needs.

Whether providing warranty repair service or any of the other services listed below, Tektronix service technicians are well trained to service the waveform generator. They have access to the latest information on improvements to the 370B as well as new options.

Warranty Repair Service

Self Service

Tektronix warrants this product for one year from date of purchase. The warranty appears on the back of the title page in this manual. Tektronix technicians provide warranty service at most Tektronix service locations. The Tektronix product catalog lists all worldwide service locations or you can visit our Web site for service information: www.tektronix.com.

Tektronix supports repair to the module level by providing Module Exchange.

Module Exchange. This service reduces down-time for repair by allowing you to exchange most modules for re-manufactured ones. Each module comes with a 90-day service warranty.

For More Information. Contact your local Tektronix service center or sales engineer for more information on any of the repair or adjustment services just described.

xvi 370B Service Manual

Specifications

Product Overview

The 370B Programmable Curve Tracer is a high-performance, GPIB-programmable digital storage curve tracer that provides static and dynamic semiconductor device testing. This versatile instrument stimulates, measures, and displays the semiconductor characteristics of a variety of two-, three-, and four-terminal devices; including bipolar transistors, field effect transistors, silicon-controlled rectifiers, diodes, thyristors, opto-isolators, wafers, integrated circuits, etc. A variety of measurements can be performed using either grounded-emitter or grounded-base configurations.

The side, top, and bottom cabinet panels provide protection to personnel from operating potentials present within the instrument. In addition, they reduce radiation of electromagnetic interference from the instrument. The cabinet panels are held in place by screws and four plastic panel retainers. To remove the panels, remove the four plastic retainers and three additional securing screws at the rear of the instrument. Pull each panel back to release the front edge. then lift the panels away from the instrument. Operate the instrument with the panels in place to protect the interior from dust, and to maintain cooling airflow.

The collector supply produces AC, rectified AC, or DC voltages ranging from 0 to 2000 volts. This high voltage, combined with a current sensitivity of 100 pA/div, permits extended breakdown measurements of a device under test. A step generator produces voltage or current steps of either polarity for application to the base or emitter terminal. The step generator may also be operated in a pulsed mode to control the power dissipated by the DUT.

370B Service Manual

In addition to conventional curve tracer performance, the 370B Programmable Curve T racer includes the following features:

H Digital storage capability that allows bright and stable display and useful

cursor measurements. The 370B has a mass storage system consists of non-volatile IC memory and 3.5-inch floppy disk drive. Up to 64 families of characteristic curves and front-panel setups can be stored in a floppy disk. Up to 16 families of characteristic curves and front-panel setups can also be stored in non-volatile IC memory. The stored characteristic curves can be recalled for additional analysis and comparison.

H Two extended acquisition modes, called Averaging and Envelope. Averaging

reduces display noise in high sensitivity ranges. Envelope mode displays only the maximum and minimum vertical or horizontal excursion of each curve, which is useful for detecting long-term variations such as thermal drift.

1- 1

Product Overview

H Almost all of the 370B front-panel settings can be controlled by GPIB

commands. (Exceptions are those controls intended only for manual operation, such as INTENSITY, FOCUS, GRAT ILLUM, etc.) Also, curve data can be sent to or received from an external controller through the GPIB.

H The printer interface permits sending displayed curve data and digital

on-screen readouts to a printer without an external controller.

H Other features include an auxiliary voltage supply, cursor measurement

readout, and diagnostic routines.

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370B Service Manual

Specifications

This section contains the 370B Programmable Curve Tracer specifications. All specifications are guaranteed unless labeled “typical”. Typical specifications are provided for your convenience but are not guaranteed.

Performance Conditions

The performance limits in this specification are valid with these conditions:

H The 370B Programmable Curve Tracer must have been calibrated/adjusted at

H The 370B Programmable Curve Tracer must be in an environment with

H The 370B Programmable Curve Tracer must have had a warm-up period of

H The 370B Programmable Curve Tracer must be operating at an ambient

an ambient temperature between +20

temperature, altitude, humidity, and vibration within the operating limits described in these specifications.

at least 20 minutes.

temperature between +10

_C and +40 _C.

_C and +30 _C.

Warranted characteristics are described in terms of quantifiable performance limits which are warranted.

370B Service Manual

1- 3

Specifications

Electrical Specifications

Table 1- 1: Collector Supply

Characteristic Performance Requirement Operating Information

Polarity

+ LEAKAGE Applies positive DC voltage to the collector or

base terminal. Measures emitter current. Sensitivity is increased 1000 times.

+DC Applies positive DC voltage to the collector or

base terminal. Measures collector or base current.

+ Applies positive swept voltage to the collector

or base terminal. Measures collector or base current.

AC Applies line-frequency sine wave to the

collector or base terminal. Measures collector or base current.

-- Applies negative swept voltage to the collector or base terminal. Measures collector or base current.

-- D C Applies negative DC voltage to the collector or base terminal. Measures collector or base current.

-- LEAKAGE Applies negative DC voltage to the collector or base term inal. Measures emitter current. Sensitivity is increased 1000 times.

DC mode ripple (no load)

Less than 2% of output voltage. VARIABLE COLLECTOR SUPPLY at 30% or

higher

Less than 0.5% of output voltage. VARIABLE COLLECTOR SUPPLY at 30% or

less

1- 4

370B Service Manual

Specifications

availa

V*V/(4R)

P=VV/(4R)for<220W

Table 1- 1: Collector Supply (Cont.)

Characteristic Operating InformationPerformance Requirement

Max peak volts

Max peak voltage 16 V, 80 V, 400 V, 2000 V Selected by the MAX PEAK VOLTS buttons.

Voltage accuracy Peak open circuit voltage on all ranges within

+15%, --0%.

Current available In PULSE mode of STEP GENERATOR,

Peak volts 16 V 80 V 400 V 2000 V In PULSE mode of STEP GENERATOR,

Range 10 A 2A 0.4 A 0.05 A

Max peak current 20 A 4A 0.8 A 0.1 A

Series Resistance Available Selection of 0.26 Ω,1.3Ω,6.4Ω,32Ω,

Min/Max resistance peak volts range

Minimum series resistance (Ω)

Maximum series resistance (Ω)

Resistance accuracy Within 5% or 0.2 Ω.

Peak power watts available Derived from nominal peak open-circuit

16, 80 and 400 V range

2000 V range 50 W, 10 W, 2 W, 0.4 W, 0.08 W

16 V 80 V 400 V 2000 V

0.26 6.4 160 20 k

800 20 k 500 k 12.5 M,

220 W, 50 W, 10 W, 2 W, 0.4 W, 0.08 W

At MAX PEAK POWER of 50 W.

available current is two times of DC mode.

blecurrent is two times ofDC mode.

160 Ω, 800 Ω,4kΩ,20kΩ, 100 kΩ, 500 kΩ,2.5MΩ, 12.5 MΩ

ollectorvoltageand nominalseries resistance values. P= P = (V--I*R)*I for 220 W

for < 220

Variable collector supply

0 -- 100.0% % of maximum peak voltage value is

displayed in the CRT readout area. Provides uncalibrated variable collector supply amplitude control from 0 to 100% in 0.1% increments.

Safety interlocks The protective cover must be in place over

test terminals and lid shut before voltage can be applied to the terminals. When protective cover is open, collector supply is not operated.

Warning indicator Red light indicates dangerous voltage is

applied to collector or base terminal.

Limiting indicator Indicates that internal sensing circuit

automatic protection is operating.

Looping compensation

Range At least 100 pF. Cancels stray capacitance between DUT

terminal and ground.

370B Service Manual

1- 5

Specifications

Table 1- 1: Collector Supply (Cont.)

Characteristic Operating InformationPerformance Requirement

Sweep start voltage accuracy

Applicable to FULL WAVE mode. Due to stray capacitance between collector and ground terminals, zero-volt-error may occur because of charged offset voltage.

16, 80, 400 V range

2000 V range

Thermal cutoff (typical)

Operating temperature

Current limit

Operating point At least 2.0 A, 1.2 A and 0.2 A of primary

Voltage limit

Operating point 50%, 25%, 5% of Max Peak Volts. Depends on Horizontal and Max Peak Volts

Arc killer Collector supply is disabled at least one cycle

Output control Circuit Breaker mounted on the front panel

2% of MAX Peak Voltage.

15% of MAX Peak Voltage.

70 _C 2.8 _C

current of collector transformer.

For Collector Supply Amplifier and Series Resistors.

Depends on Vertical and Max Peak Volts settings.

settings.

while the relays or switches are operated.

enables and disables Collector supply,Step Generator and AUX source.

No trip for 1.5 A of Collector Transformer primary current. (100% rating of circuit breaker)

Trip occurs between 3 second and 80 second for 2.025 A of Collector Transformer primary current. (135% rating of circuit breaker)

NOTE: The collector supply is limited to a maximum continuous peak current operating time under the following duty cycle and ambient temperature conditions:

50 W. Maximum continuous operating time at rated current (100% duty cycle) into a short circuit is 20 minutes at 25_C ambient, or 10 minutes at 40_C ambient.

220W. Maximum continuous operating time at rated current(, 100% duty cycle) into a short circuit is 3 m inutes at 25_C ambient, or 90 seconds at 40_C ambient.

Alternatively, the duty cycle may be limited to 50% at 25_C ambient or 25% at 40_C ambient. (A normal family of transistor curves will produce a duty cycle effect to 50% or less, even if operated continuously.)

Collector Supply over-dissipation temporarily shuts off the power, and prints a message on the screen. Collector Supply over-current trips the OUTPUTS breaker, prints a message on the screen, and reset the Collector Supply output to 0%. No damage results when over-dissipation occurs.

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370B Service Manual

+ 286 hidden pages