EasyManua.ls Logo

Tektronix 2230 Service Manual

Tektronix 2230
483 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #119 background imageLoading...
Page #119 background image
Theory of Operation2230 Service
When reading data out of the RAM, the Display Con
troller has direct access to the memory address bus (RA).
RAM row and column addresses to be read from are
sequenced through in order. When a display data read is
taking place, the dynamic memory is refreshed by the
Display Controller.
When the Display Controller has completed a display
frame, it signals the Microprocessor (using the INTR sig
nal) that the last field is finished and awaiting the next
frame request. After the interrupt is received, the
Microprocessor can request the next frame (FRAME), then
the Display Controller resumes control of the RAM for the
next frame of data. When PROC RQ (U9208 pin 3) is HI,
the Display Controller is in the middle of a display cycle
and the Microprocessor is denied access to the display
RAM. The Microprocessor can request access to the
Display RAM using the PROC RQ (RAM SEG) signal line
to either write in new waveform data or read out data for
the Communication Option. The Display Controller allows
the Microprocessor to access the display RAM by setting
the PROCEN (U9208 pin 5) signal line LO. A LO
PROC EN signal enables the circuitry that allows the WR,
PA14, and PA15 signals, from the Microprocessor, to con
trol the display RAM. Even though the memory addresses
are under control of the Microprocessor, the RAS and
CAS signals are generated by the Display Controller.
YDAC and XDAC
Data from display controller U9208 is applied to X- and
Y-axis DACs U9210 and U9220. These DACs are biased
to provide output currents (approximately 0 to 2 mA) pro
portional to the digital data. R9214 and R9224 are adjust
ments to align the storage signals on the crt. The DAC
currents are applied to the Vector Generator along with
various control signals from U9208 via W6100.
VECTOR GENERATOR
Vector Generators
Vector Generator circuitry is shown on Diagram 20.
U6303 and U6304 convert the DAC currents into bipolar
voltages (approximately 2.5 V to +2.5 V) which are
applied to sample and hold circuits U6305 and U6306.
Outputs of the sample and hold circuits are applied to
integrator stages U6307 and U6308 through electronic
switches in U6301A and C. The integrator output signals
are continuously fed back to the sample and hold inputs,
causing these input voltages to be equal to the difference
between the drive inputs and the integrator outputs. When
the vector sample (VECT-SMPL) control line (via U6301B)
is actuated, the outputs of the sample and hold circuits
store these difference signals. Since the integrator output
slopes are proportional to these signals, the net result is
to effectively connect the dots" which are equivalent to
the digital data values.
These circuits also have a dot mode available so that
the integrator outputs are stepped (dots) rather than con
tinuous (vectors). When the VECT/DOT signal is LO,
U6301A and C switch the integrator inputs directly to the
difference signals while also disconnecting the integration
capacitors C6315 and C6314. The feedback loops are thus
closed continuously, resulting in normal amplifier action.
Although the Vertical and Horizontal vector generators
operate the same, there are some differences between the
circuits and between their signal characteristics. To end up
with the proper signal polarities at the crt, X DAC U9210
(Horizontal) current is from 2 mA to 0 mA, while Y ,DAC
U9220 (Vertical) current is from 0 mA to 2 mA. Also, the
vertical integrator output is -2 V to +2 V while the hor
izontal integrator output is 2.5 V to +2.5 V. The
reduced vertical dynamic range allows proper interface to
the main deflection system. Since the vertical signal even
tually passes through the vertical delay line before reach
ing the crt, it is necessary to delay the horizontal signal as
well. This is done in the vector mode by delaying slightly
the vector sample signal applied to 1)6305 via R6320 and
C6312. In the dot mode the crt beam is blanked during the
transitions so the dots are only displayed after the signals
have arrived and settled.
VECTOR INTEGRATOR. The Y-axis (vertical) current
from the D/A Converter goes to the inverting input of
operational amplifier U6303. The amplifier is biased to pro
duce a bipolar output voltage, from -2.5 V to +2.5 V,
that is proportional to the input current. Negative feedback
from the parallel combination of R6303 and C6311 stabil
izes the amplifier.
Biasing of the non-inverting input of both the X-axis
and the Y-axis amplifiers is identical and supplied by a
resistive divider formed by R6304 and R6305 between
ground and the +5 V reference. Both resistors are equal
valued to produce a bias voltage of + 2.5 V. Resistor
R6308 provides a summing node for the input vector
current and the feedback current and develops the voltage
on the inverting input of U6303. Full current range of the
vector signal is from 0 to 2 mA. With no vector current in,
the feedback current supplies the full current through
R6308, and the output voltage of U6303 goes to -2 .5 V.
At maximum vector current input, the sum of the current
through R3608 must remain the same as with no vector
current; therefore the feedback current is reduced by the
amount of the vector current, and the output voltage goes
to +2.5 V.
SAMPLE-AND-HOLD. The voltage output of U6303 is
applied via R6309 to sample-and-hold circuit U6305.
Sample-and-Hold (S/H) switching is controlled by the
VECT SMPL signal from the Display Controller applied to
3-45

Table of Contents

Other manuals for Tektronix 2230

Question and Answer IconNeed help?

Do you have a question about the Tektronix 2230 and is the answer not in the manual?

Tektronix 2230 Specifications

General IconGeneral
TypeOscilloscope
Bandwidth100 MHz
Channels2
Vertical Sensitivity2 mV/div to 5 V/div
Time Base5 ns/div to 0.5 s/div
Sample Rate1 GS/s
Rise Time3.5 ns
DisplayCRT
Input Impedance1 MΩ
Trigger ModesAuto, Normal, Single
Trigger SourcesCH1, CH2, Line
Power Supply100-120 V / 220-240 V
Weight14 lbs (6.4 kg)

Summary

GENERAL INFORMATION

INTRODUCTION

Provides a general description of instrument functions and the basic block diagram.

SPECIFICATION

Defines electrical characteristics, environmental conditions, and physical characteristics.

OPERATING INFORMATION

PREPARATION FOR USE

Details steps for preparing the instrument and proceeding with initial start-up.

SAFETY

General safety information for operating and servicing personnel.

LINE VOLTAGE

Specifies the acceptable input voltage and source frequency range for continuous operation.

POWER CORD

Describes the detachable three-wire power cord and its connection for electrical shock protection.

LINE FUSE

Explains the location and procedure for verifying or replacing the line-protection fuse.

INSTRUMENT COOLING

Details precautions to prevent instrument damage from overheated components and airflow obstructions.

START-UP

Describes the instrument's automatic power-up tests to verify functionality.

REPACKAGING

Provides instructions for repackaging the instrument for commercial transportation.

CONTROLS, CONNECTORS, AND INDICATORS

Familiarizes the operator with the location and function of instrument controls, connectors, and indicators.

THEORY OF OPERATION

SECTION ORGANIZATION

Describes the functional overview and detailed explanation of each major circuit.

INTEGRATED CIRCUIT DESCRIPTIONS

Explains digital logic conventions and linear device operations using waveforms.

GENERAL DESCRIPTION

Provides an overall functional description of the instrument, referring to block diagrams.

VERTICAL

Describes signals applied to CRT, coupling options, and attenuator switching.

HORIZONTAL

Explains horizontal deflection signals, preamplifiers, and mode switching.

Microprocessor

Details the microprocessor's role in controlling digital storage and display operations.

Storage Acquisition

Explains how input signals are selected, sampled, and digitized for storage.

Digital Acquisition

Describes the transfer of digitized waveforms to acquisition memory.

Triggering

Explains how the triggering circuitry develops trigger signals for sweep generation.

A Sweep

Describes how the A Sweep Generator and Logic circuits control sweep generation and timing.

B TIMING AND ALTERNATE B SWEEP

Explains the Alternate B Sweep circuitry and its control over Nonstore B Sweeps.

Horizontal

Details horizontal deflection signals, preamplifiers, and mode switching.

Microprocessor

Explains the microprocessor's control over digital storage and display.

Storage Acquisition

Describes how input signals are selected, sampled, and digitized for storage.

Digital Acquisition

Details the transfer of digitized waveforms to acquisition memory.

Digital Time Base

Explains the accurate frequency source for synchronizing the microprocessor with other digital devices.

Digital Display

Describes the custom IC that handles digital display generation, interfacing with display memory.

Vector Generator

Explains how X- and Y-Axis analog signals are converted into vector signals to drive CRT deflection plates.

Z-Axis

Details the Z-Axis Amplifier's input signals that control CRT intensity on a time-shared basis.

OPERATORS SAFETY SUMMARY

Terms in This Manual

Defines CAUTION and WARNING statements regarding equipment damage or personal injury.

Terms as Marked on Equipment

Explains CAUTION and DANGER indications marked on the equipment.

Symbols in This Manual

Indicates where cautionary or other information is found.

Symbols as Marked on Equipment

Defines symbols indicating DANGER (High voltage) and Protective ground.

Power Source

Specifies the power source requirements and essential protective ground connection.

Grounding the Product

Explains grounding through the power cord and the importance of a properly wired receptacle.

Danger Arising from Loss of Ground

Warns about electric shock hazard due to loss of protective ground connection.

Use the Proper Power Cord

Instructs to use only the specified power cord and connector, ensuring it is in good condition.

Use the Proper Fuse

Advises using only the correct type, voltage, and current rating fuse to avoid fire hazards.

Do Not Operate in Explosive Atmospheres

Caution against operating the product in an explosive atmosphere unless specifically certified.

Do Not Remove Covers or Panels

Warns against removing covers or panels to avoid personal injury.

SERVICING SAFETY SUMMARY

Do Not Service Alone

Recommends having another person present who can render first aid and resuscitation.

Use Care When Servicing With Power On

Warns about dangerous voltages and advises not to touch exposed connections or components.

Power Source

Specifies the power source requirements and essential protective ground connection.

PERFORMANCE CHECK PROCEDURE

INTRODUCTION

Explains the purpose and usage of the Performance Check Procedure.

PURPOSE

States the procedure verifies Performance Requirements and determines calibration needs.

PERFORMANCE CHECK INTERVAL

Recommends checking performance after every 2000 hours or annually, with more frequent checks for harsh environments.

STRUCTURE

Describes the procedure's structure in subsections for checking individual sections.

TEST EQUIPMENT REQUIRED

Lists all test equipment necessary for performance checks and adjustment procedures.

LIMITS AND TOLERANCES

States that tolerances are valid for instruments operating within +20°C to +30°C after a 20-minute warm-up.

PREPARATION FOR CHECKS

Notes that instrument covers do not need removal for checks, using operator-accessible controls.

VERTICAL

Details the initial control settings and procedure steps for vertical checks.

HORIZONTAL

Outlines initial control settings and procedure steps for horizontal checks.

TRIGGER

Provides initial control settings and procedure steps for checking internal and external triggering.

EXTERNAL Z-AXIS, PROBE ADJUST, EXTERNAL CLOCK, AND X-Y PLOTTER

Details initial control settings and procedure steps for checking external Z-axis, probe adjust, external clock, and X-Y plotter.

ADJUSTMENT PROCEDURE

INTRODUCTION

Explains the purpose of the Adjustment Procedure for returning the instrument to Performance Requirements.

PURPOSE

States the procedure is for returning the instrument to conformance with Performance Requirements.

STRUCTURE

Describes the procedure's structure in subsections for independent adjustment of instrument sections.

TEST EQUIPMENT

Lists test equipment required for both Performance Check and Adjustment Procedures.

LIMITS AND TOLERANCES

Specifies tolerances are valid for instruments operating within +20°C to +30°C after a 20-minute warm-up.

ADJUSTMENTS AFFECTED BY REPAIRS

Identifies adjustments affected by repairs or component replacement, referencing Table 5-1.

PREPARATION FOR ADJUSTMENT

Instructs to remove the instrument cabinet and lift the storage circuit board.

POWER SUPPLY AND CRT DISPLAY

Details initial control settings and procedure steps for checking and adjusting power supply DC levels and CRT bias.

VERTICAL

Provides initial control settings and procedure steps for vertical adjustments.

HORIZONTAL

Details initial control settings and procedure steps for horizontal adjustments.

TRIGGER

Outlines initial control settings and procedure steps for trigger adjustments.

EXTERNAL Z-AXIS, PROBE ADJUST, EXTERNAL CLOCK, AND X-Y PLOTTER

Details initial control settings and procedure steps for external Z-axis, probe adjust, external clock, and X-Y plotter.

MAINTENANCE

STATIC-SENSITIVE COMPONENTS

Provides precautions for handling semiconductor components to avoid damage from static discharge.

PREVENTIVE MAINTENANCE

Covers cleaning, visual inspection, and performance checking to prevent instrument malfunction.

GENERAL CARE

Addresses cabinet dust accumulation and front cover protection for storage or transport.

INSPECTION AND CLEANING

Details instrument inspection for damage and cleaning procedures for exterior and interior.

LUBRICATION

States that potentiometers are permanently seated and periodic lubrication is not recommended.

SEMICONDUCTOR CHECKS

Recommends checking semiconductors through actual operation rather than periodic checks.

PERIODIC READJUSTMENT

Recommends checking performance every 2000 hours or annually, and after component replacement.

TROUBLESHOOTING

Provides information to facilitate fault location, referencing Theory of Operation and Diagrams.

TROUBLESHOOTING AIDS

Introduces diagnostic routines for digital storage portions and schematic diagrams.

Diagnostic Firmware

Explains power-up kernel tests and diagnostic routines for locating malfunctions.

Schematic Diagrams

Describes the location and identification of schematic diagrams and functional blocks.

INTERCONNECTIONS

Details replacement procedures for various types of mating connectors used for interconnecting pins.

End-Lead Pin Connectors

Explains pin connectors used to connect wires to interconnect pins, including replacement procedures.

Multipin Connectors

Describes removal, reinstallation, or replacement of grouped pin connectors.

TRANSISTORS AND INTEGRATED CIRCUITS

Advises on replacing transistors and integrated circuits only if defective and checking performance.

SOLDERING TECHNIQUES

Outlines general soldering techniques for maintaining instrument reliability and accuracy.

REMOVAL AND REPLACEMENT INSTRUCTIONS

Provides guidance for removing and reinstalling subassemblies or components, referencing exploded view drawings.

Cabinet

Provides steps for removing and reinstalling the instrument cabinet.

OPTIONS

INTRODUCTION

Provides a general description of instrument options available at the time of publication.

POWER CORD OPTIONS

Lists Tektronix part numbers for available power cords, with descriptive information in Section 2.

OPTION 33

Describes the Travel Line option providing impact protection for industrial and service environments.

OPTION 10 AND OPTION 12

Introduces Option 10 (GPIB) and Option 12 (RS-232-C) for communications interface and memory.

PERFORMANCE CONDITIONS

OPTIONS SIDE PANEL

Describes the standard side panel and options for Option 10 and Option 12 instruments.

GPIB PARAMETER SELECTION

Primary Address

Establishes primary talk and listen addresses for the oscilloscope, settable from 0 to 31.

Input End-of-Message Terminator

Allows selection of EOI interface signal or Line-Feed (LF) character as the end-of-message terminator.

RS-232-C PARAMETER SELECTION

Baud Rate

Establishes the baud rate used by the instrument for sending and receiving data.

Parity

Determines instrument response to received parity errors and parity of data sent by the instrument.

Line Terminator

Allows selection of carriage return (CR) or CR and Line-Feed (LF) characters for message termination.

MESSAGES AND COMMUNICATION PROTOCOL

Command Separator

Explains the possibility of using multiple commands in one message separated by a semicolon.

Command Formatting

Describes command format flexibility, accepting uppercase or lowercase ASCII characters.

Default Arguments

Explains that arguments in brackets are defaults and omitting them selects the default.

GPIB PARAMETER SELECTION

Allows selection of GPIB parameters like address, terminator, and talk/listen mode using the switch.

STATUS AND ERROR REPORTING

Each time the GPIB controller performs a serial poll...

Describes how SRQ is asserted for errors, and how EVENT? query returns specific error types.

DIAGNOSTICS

Introduction

Lists instrument diagnostic tests run automatically at power-up or manually via the menu.

PU TEST

Performs a quick check of dynamic RAM, ROM, and NMI circuitry; displays error codes if failures occur.

Diagnostic Test Routines

Explains how to select and use diagnostic routines from the front panel via the MENU.

Check Control Settings

Advises checking control settings to avoid false indications of instrument malfunction.

Check Associated Equipment

Recommends ensuring any connected equipment is operating correctly and signals are properly connected.

CORRECTIVE MAINTENANCE

INTRODUCTION

Describes component replacement and instrument repair procedures.

MAINTENANCE PRECAUTIONS

Lists precautions to reduce the possibility of personal injury or instrument damage during maintenance.

OBTAINING REPLACEMENT PARTS

Explains how to obtain replacement parts through Tektronix or local commercial sources.

Special Parts

Highlights special parts manufactured or selected by Tektronix for specific performance requirements.

Ordering Parts

Specifies required information for ordering replacement parts from Tektronix.

Selectable Components

Discusses components selectable for optimum circuit operation, usually adjusted during initial factory calibration.

MAINTENANCE AIDS

Lists items required for maintenance procedures and suggests equivalent product substitutions.

INTERCONNECTIONS

Describes replacement procedures for various types of mating connectors used for interconnecting pins.

End-Lead Pin Connectors

Explains pin connectors used to connect wires to interconnect pins, including replacement procedures.

Multipin Connectors

Describes removal, reinstallation, or replacement of grouped pin connectors.

TRANSISTORS AND INTEGRATED CIRCUITS

Advises on replacing transistors and integrated circuits only if defective and checking performance.

SOLDERING TECHNIQUES

Outlines general soldering techniques for maintaining instrument reliability and accuracy.

REMOVAL AND REPLACEMENT INSTRUCTIONS

Provides guidance for removing and reinstalling subassemblies or components, referencing exploded view drawings.

Cabinet

Provides steps for removing and reinstalling the instrument cabinet.

2230 Service

OPTIONS

Contains a general description of instrument options available at the time of publication.

POWER CORD OPTIONS

Lists Tektronix part numbers for available power cords, with descriptive information in Section 2.

OPTION 33

Describes the Travel Line option providing impact protection for industrial and service environments.

OPTION 10 AND OPTION 12

Introduces Option 10 (GPIB) and Option 12 (RS-232-C) for communications interface and memory.

PERFORMANCE CONDITIONS

OPTIONS SIDE PANEL

Describes the instrument's side panel, including auxiliary connectors, GPIB, and RS-232-C interfaces.

GPIB PARAMETER SELECTION

Primary Address

Establishes primary talk and listen addresses for the oscilloscope, settable from 0 to 31.

Input End-of-Message Terminator

Allows selection of EOI interface signal or Line-Feed (LF) character as the end-of-message terminator.

RS-232-C PARAMETER SELECTION

Baud Rate

Establishes the baud rate used by the instrument for sending and receiving data.

Parity

Determines instrument response to received parity errors and parity of data sent by the instrument.

Line Terminator

Allows selection of carriage return (CR) or CR and Line-Feed (LF) characters for message termination.

MESSAGES AND COMMUNICATION PROTOCOL

Command Separator

Explains the possibility of using multiple commands in one message separated by a semicolon.

Command Formatting

Describes command format flexibility, accepting uppercase or lowercase ASCII characters.

Default Arguments

Explains that arguments in brackets are defaults and omitting them selects the default.

GPIB PARAMETER SELECTION

Allows selection of GPIB parameters like address, terminator, and talk/listen mode using the switch.

STATUS AND ERROR REPORTING

Each time the GPIB controller performs a serial poll...

Describes how SRQ is asserted for errors, and how EVENT? query returns specific error types.

REMOTE-LOCAL OPERATING STATES

Local State (LOCS)

Instrument parameters are set manually; only option interface messages are executed.

Remote State (REMS)

Oscilloscope executes all commands addressed via communication options bus.

INSTRUMENT RESPONSE TO INTERFACE MESSAGES

Explains effects on the oscilloscope of standard interface messages received from a remote controller.

Local Lockout(LLO)

Local Lockout is not supported; response to LLO via GPIB generates an SRQ error.

Remote Enable (REN)

Asserting REN places oscilloscope in Remote State (REMS); changing front-panel controls returns it to Local State.

Go To Local (GTL)

Instruments that are already listen-addressed respond to GTL by assuming a local state.

My Listen and My Talk Addresses (MLA and MTA)

Explains primary Talk/Listen address establishment and the effect of UNL and UNT messages.

Unlisten (UNL) and Untalk (UNT)

When UNL is received, oscilloscope's listen function is placed in an idle state; UNT places talk function in idle state.

Interface Clear (IFC)

When IFC is asserted, Talk and Listen functions are idled, and ADDR indicator is turned off.

Device Clear (DCL)

Reinitializes communication, clears messages, unexecuted settings, and power-on events.

Selected Device Clear (SDC)

Performs the same function as DCL, but only instruments that have been listen-addressed respond.

Serial Poll Enable and Disable (SPE and SPD)

SPE enables instrument to transmit serial-poll status byte; SPD switches it back to normal operation.

2230 Service

PERFORMANCE CHECK PROCEDURE

Covers GPIB Option and RS-232-C performance check procedures against Table 7-4 requirements.

Limits and Tolerances

States limits and tolerances are instrument specifications from Table 7-4, valid under specific ambient conditions.

Test Equipment Required

Lists required test equipment and their minimum specifications from Table 7-37.

1. GPIB Performance Check

Details steps for setting RS-232-C parameters, front panel controls, and connecting the controller via GPIB cable.

2. RS-232-C Performance Check

Outlines steps for setting RS-232-C parameters, front panel controls, and sending an ID query from the controller.

ADJUSTMENT PROCEDURE

States there are no adjustment procedures for the GPIB and RS-232-C Options.

OPTION MAINTENANCE INFORMATION

Provides information on battery replacement and maintenance procedures applicable to Options.

Diagnostics

Discusses additional diagnostics for Option 10 or 12, describing each diagnostic separately.

COMM_RAM

Tests the Option RAM and microprocessor interface, filling memory with a checkerboard pattern.

REPLACEABLE ELECTRICAL PARTS

PARTS ORDERING INFORMATION

Provides information on ordering replacement parts from Tektronix or local representatives.

LIST OF ASSEMBLIES

Lists assemblies in numerical order to identify the assembly containing a known component number.

CROSS INDEX-MFR. CODE NUMBER TO MANUFACTURER

Provides an index of manufacturer codes to names and addresses for component sourcing.

ABBREVIATIONS

Lists abbreviations conforming to American National Standard Y1.1.

COMPONENT NUMBER (column one of the Electrical Parts List)

Explains the numbering method used to identify assemblies, subassemblies, and parts.

TEKTRONIX PART NO. (column two of the Electrical Parts List)

Indicates the part number to be used when ordering replacement parts from Tektronix.

SERIAL/MODEL NO. (columns three and four of the Electrical Parts List)

Indicates serial numbers at which parts were first used or removed.

NAME & DESCRIPTION (column five of the Electrical Parts List)

Provides item names separated from descriptions by a colon.

MFR. CODE (column six of the Electrical Parts List)

Indicates the code number of the actual manufacturer of the part.

MFR. PART NUMBER (column seven of the Electrical Parts List)

Indicates the actual manufacturer's part number.

INDENTATION SYSTEM

Assembly and/or Component

Attaching parts for Assembly and/or Component.

Detail Part of Assembly and/or Component

Attaching parts for Detail Part.

Parts of Detail Part

Attaching parts for Parts of Detail Part.

ABBREVIATIONS

Related product manuals