Tektronix 7623 User manual

MANUAL
7623/R7623
STORAGE
OSCILLOSCOPE
SERVICE
MANUFACTURERS
OF CATHODE-RAY
OSCILLOSCOPES

WARRANTY
All TEKTRONIX instruments are warrante against
efective materials an workmanship for one year. Any
questions with respect to the warranty shoul be taken up
with your TEKTRONIX Fiel Engineer or representative.
All requests for repair an replacement parts shoul be
irecte to the TEKTRONIX Fiel Office or representative
in your area. This will assure you the fastest possible
service. Please inclu e the instrument Type Number or Part
Number an Serial Number with all requests for parts or
service.
Specifications an price change privileges reserve .
Copyright © 1973 by Tektronix, Inc., Beaverton, Oregon.
Printe in the Unite States of America. All rights reserve .
Contents of this publication may not be repro uce in any
form without permission of Tektronix, Inc.
U.S .A . an Foreign TEKTRONIX pro ucts covere by U.S.
an foreign patents an /or patents pen ing.
TEKTRONIX is a registere tra emark of Tektronix, inc.

7623/R7623 Service
TABLE OF CONTENTS
SECTION 1 OPERATING INFORMATION Page
Operating Voltage 1-1
Operating Temperature 1-1
Plug-In Installation An Removal 1-1
Operation 1-1
Non-Store Operating Set-Up Information 1-1
Front Panel Controls An Connectors 1-2
Rear Panel Controls An Connectors 1-3
Storage Mo es 1-4
Variable Persistence Operating Set-Up Information 1-4
Fast Operating Set-Up Information 1-4
Multi-Trace Fast Operating Set-Up Information 1-4
Bi-Stable Operating Set-Up Information 1-4
Save Mo e Operating Set-Up Information 1-4
SECTION 2 CALIBRATION
Calibration Interval 2-1
Tektronix Fiel Service 2-1
Using This Proce ure 2-1
General 2-1
In ex 2-1
Performance 2-1
Partial Proce ure 2-1
Complete Calibration Proce ure 2-1
TEST EQUIPMENT REQUIRED
Special Calibration Fixtures 2-1
Calibration Equipment Alternatives 2-1
Test Equipment 2-2
Preliminary Control Settings 2-4
CALIBRATION PROCEDURE 2-5
Intro uction 2-5
In ex To Calibration Proce ure 2-5
Power Supply 2-5
Display An Z-Axis 2-5
Vertical Deflection System 2-5
Trigger System 2-5
Horizontal Deflection System 2-5
Z-Axis An Auto Focus 2-5
Calibrator 2-5
Signals Out 2-5
Rea out Operation 2-6
Storage Operation 2-6
i

7623/R7623 Service
TABLE OF CONTENTS (cont)
SECTION 3 CIRCUIT DESCRIPTION Page
Block Diagram 3-1
Circuit Operation 3-1
Logic Fun amentals 3-3
Symbols 3-3
Logic Polarity 3-3
Input/Output Tables 3-6
Non-Digital Devices 3-6
MAIN INTERFACE 3-6
LOGIC CIRCUIT 3-6
Logic Block Diagram 3-6
Z-Axis Logic 3-6
Clock Generator 3-9
Vertical Choppe Blanking 3-10
Chop Counter 3-11
Vertical Mo e Control 3-13
Right 3-13
Chop 3-13
Alt 3-14
A 3-14
Left 3-14
Vertical Binary 3-14
Plug-In Binary 3-15
Output Buffers 3-16
TRIGGER SELECTOR 3-16
Trigger Mo e An A Signals 3-16
General 3-16
Vert Mo e 3-16
Left 3-16
Right 3-18
Trigger Channel Switch 3-18
Trigger Output Amplifier 3-18
Vertical Signal Buffer 3-18
VERTICAL INTERFACE 3-19
Vertical Channel Switch 3-19
Auxiliary Y-Axis Input Amplifier 3-20
Delay Line Buffer 3-20
Delay Line 3-20
VERTICAL AMPLIFIER 3-20
Input Balance 3-21
Output Amplifier 3-21
Beam Fin er Network 3-21
HORIZONTAL AMPLIFIER 3-21
Horizontal Channel Switch 3-21
Riÿit Output Amplifier 3-22
Left Output Amplifier 3-22
ii

7623/R7623 Service
TABLE OF CONTENTS (cont)
SECTION 3 CIRCUIT DESCRIPTION (cont) Page
CALIBRATOR An FRONT PANEL SWITCHING 3-22
Mo e Switch Logic 3-23
Calibrator 3-23
Oscillator 3-23
Output Amplifier 3-23
Output Divi er 3-23
CRT CIRCUIT 3-24
Z-Axis Amplifier 3-24
Auto Focus Amplifier 3-25
High Voltage Oscillator 3-25
High Voltage Regulator 3-25
High Voltage Supplies 3-26
CRT Control Circuits 3-26
LOW-VOLTAGE POWER SUPPLY 3-27
Power Input 3-27
- 50 Volt Supply 3-27
— 15 Volt Supply 3-30
+5 Volt Supply 3-30
+15 Volt Supply 3-30
+50 Volt Supply 3-30
+130 Volt Supply 3-31
Graticule Light Supply 3-31
SIGNAL OUT BOARD 3-31
Vert Sig Out 3-31
+Gate Out 3-31
+Sawtooth Out 3-31
READOUT SYSTEM 3-31
Display Format 3-32
Developing The Display 3-32
Circuit Analysis Of The Rea out System 3-35
Timer 3-35
Time-Slot Counter 3-40
Wor Trigger 3-40
Channel Counter 3-41
Single-Shot Lockout 3-41
Enco ing The Data 3-41
Column An Row Data Switches 3-43
Display-Skip Generator 3-44
Column An Row Deco er 3-44
Zeros Logic An Memory 3-44
Character Generators 3-47
Decimal Point Logic An Character Position Counter 3-47
Format Generator 3-48
Y-Output Amplifier 3-48
X-Output Amplifier 3-48
Display Sequence 3-48

7623/R7623 Service
TABLE OF CONTENTS (cont)
SECTION 3 CIRCUIT DESCRIPTION (cont)
Page
STORAGE CIRCUITRY
3-50
Erase An Timing Circuits 3-50
Sweep Lockout Circuit 3-50
Auto Erase Circuit
3-50
Rea out Shut Down Circuit 3-54
Persistence Pulse An Pump Pulse
Generator Circuits
3-54
Floo Gun Ano e An CE2 Circuits 3-55
CE3 An CE 2 Circuits 3-55
Collector Circuit 3-56
High Spee Mesh Circuit 3-56
Bi-Stable Mesh Circuit 3-56
SECTION 4 MAINTENANCE
Panel Removal 4-1
Cabinet Mo el 4-1
Rack Mo el 4-1
Power-Unit Removal 4-1
PREVENTIVE MAINTENANCE
General
Cleaning
Exterior
CRT
Interior
Lubrication
Semicon uctor Checks
Recalibration
4-1
4-1
4-1
4-2
4-2
4-2
4-2
4-2
4-2
TROUBLESHOOTING
Intro uction
Diagrams
Circuit Boar s
Multi-Pin Connector Color-Co e
Wiring Color-Co e
Resistor Color-Co e
Capacitor Marking
Dio e Color-Co e
Semicon uctor Lea Configuration
Troubleshooting Equipment
Troubleshooting Techniques
4-2
4-2
4-3
4-3
4-3
4-3
4-3
4-3
4-3
4-3
4-3
4-6
iv

7623/R7623 Service
TABLE OF CONTENTS (cont)
SECTION 4 MAINTENANCE (cont) Page
CORRECTIVE MAINTENANCE 4-10
Obtaining Replacement Parts 4-10
Special Parts 4-10
Or ering Parts 4-11
Sol ering Techniques 4-11
Component Replacement 4-11
General 4-11
Circuit Boar Replacement 4-11
Access To The Fan Motor 4-13
Access To The Fan Motor For The R7623 4-13
Semicon uctor Replacement 4-14
Access To The Power Transistors 4-14
Interconnecting Pin Replacement 4-14
Catho e Ray Tube Replacement 4-15
Switch Replacement 4-16
Graticule Bulb Replacement 4-16
Power Transformer Replacement 4-16
High-Voltage Compartment 4-16
Fuse Replacement 4-16
Recalibration After Repair 4-16
Instrument Repackaging 4-17
SECTION 5 ELECTRICAL PARTS LIST
SECTION 6 DIAGRAMS
SECTION 7 MECHANICAL PARTS LIST
CHANGE INFORMATION

The TEKTRONIX 76 3/R76 3 Storage Oscilloscope is a solid-state instrument designed for fast writing rate storage
applications. The 76 3 has four basic modes of operation: Fast, Bi-Stable, Variable Persistence, and Non-Store. The in 
strument is designed to accept TEKTRONIX 7-Series plug-in units to form a complete measurement system. The
flexibility of this plug in feature and the variety of plug-in units available allow this system to be used for many measure 
ment applications. The 76 3 features a large cathode-ray tube (CRT) screen, 8 X 10 divisions, with small spot size, and
fast stored writing rate.
76 3/R76 3 Service

Section 1 — 76 3/R76 3 Service
OPERATING INFORMATION
Operating Voltage
The 76 3/R76 3 can be operated from either a 1 10-volt
line or 0-volt line source. In addition, three operating
ranges can be selected by a jumper located on the Rectifier
board. See Fig. 1-1. Select a range that is centered about
the average line voltage to which the instrument is
connected. See Table 1-1 for ranges and proper fuses.
Table 1-1
Pins
Regulating Range
Selected
1 10-volt nominal
0-volt nominal
Low
90 to 110 volts
180 to 0 volts
Med 99 to 1 1 volts
198 to 4 volts
Hi
108 to 13 volts
18 to 6 volts
Line Fuse
3. A Slow-blow 1.6 A Slow-blow
Operating Temperature
The 76 3/R76 3 can be operated where the ambient air
temperature is between 0 °C and +50° C. The 76 3 is cooled
by air drawn through the instrument. Maintain about
two-inches clearance for proper ventilation on all sides and
the top. The feet on the bottom of the instrument provide
the necessary clearance. The R76 3 is cooled by air drawn
through the air filter on the rear of the instrument and
blown out through the holes on the right side. Maintain
two-inches of clearance on the right side for proper
ventilation. A thermal cutout switch in the instruments
provides thermal protection, and interrupts the power to
the instrument if the internal temperature exceeds a safe
operating level.
Plug-in Installation and Removal
To install a plug-in unit into one of the plug-in
compartments, align the slots in the top and bottom of the
plug-in unit with the associated guide rails in the plug-in
compartment. Push the plug-in unit firmly into the plug-in
compartment until it locks into place. To remove the
plug-in unit, pull the release latch on the plug-in unit to
disengage it, and pull the unit out of the plug-in
compartment. Plug-in units can be removed or installed
without turning off the instrument power. Special purpose
plug-in units may have specific restrictions regarding the
plug in compartments in which they can be installed. This
information will be given in the instruction manual for
these plug-in units.
Operation
The following information provides the necessary
controls and control settings to obtain a display, which can
be used to verify basic operation or calibration without
removing the covers or making any internal adjustments. In
the NON STORE mode the 76 3 functions the same as a
conventional oscilloscope. The CALIBRATOR signal is a
convenient signal for verifying basic operation and
calibration. Use the Operating Set-Up Information as a
guide for setting the front panel controls.
Non-Store Operating Set-Up Information
INTENSITY
READOUT
GRATICULE ILLUM
FOCUS
TRIG SOURCE
VERT MODE
POWER
As desired (midrange)
As desired
As desired
Well defined display
VERT MODE
Selected for the plug-in
compartment with the
plug-in unit installed and
with signal input to be
displayed.
Pressed in
Spare jumper
Fig. 1-1. Location of Voltage-selector jumper, spare jumper, an
230 V fuse in power-unit (shown remove ).
1-1

Operating Information — 7623/R7623 Service
1. INTENSITY — Controls the brightness of
the isplay.
2. READOUT — Turns on the Rea out is 
play, an controls the brightness of the
Rea out isplay.
3. FOCUS — Screw river a justment provi es
a justment for optimum isplay efinition.
4. GRATICULE ILLUM — Controls graticule
illumination.
5. BEAM FINDER-When presse the isplay
is limite to within the graticule area.
6. Camera Power-Three pin connector on the
CRT bezel, (top) +15 volt power source,
(mi le) receives remote single sweep reset
signal from compatible camera system, an
(bottom) groun pin.
7. VERT MODE — Selects vertical mo e of operations.
o
«X
10. NON-STORE — Non-store operation.
LEFT: Signals from the left plug-in compartment are is 
playe .
ALT: Signals from both vertical plug-in compartments are
isplaye ( ual trace). Display is switche from one vertical
to the other after each sweep.
ADD: Signals from both vertical plug-in compartments are
algebraically a e , an the sum is isplaye .
11. VAR-PERSIST-Variable persistence storage mo e. The AUTO
VIEW TIME or PERSISTENCE control setting, controls the
retention of the store isplay.
12. FAST — For storing fast signals.
13. MULTI-TRACE-IMULTI-FAST in early instruments)-For stor 
ing multiple fast signals. For each new signal to be store the
ERASE (PREP IN MULTI TRACE FAST) must be presse .
CHOP: Signals from both vertical compartments are is 
playe ( ual trace). Display switches from the left vertical
compartment signal to the right vertical compartment signal
at a one megahertz rate.
RIGHT: Signals from the right plug-in compartment are
isplaye .
8. TRIG SOURCE — Selects the source of the internal trigger signals
for the horizontal compartment.
LEFT: Trigger signals are from the left vertical plug-in
compartment only.
VERT MODE: Trigger signals are from the vertical compart 
ment being isplaye except in the CHOP an ADD mo es;
then the trigger signal is the algebraic sum of the trigger
signals from the left an right plug-in compartments.
RIGHT: Trigger signals are from the right vertical plug in
compartment only.
14. INTEG — For storing very fast repetitive signals.
15. BI STABLE — For storing slow signals for long perio s of time.
16. SAVE — Prevents acci ental erasure of the store isplay.
17. SAVE INTEN (STORED INTEN in early instruments)-Controls
the brightness of the store isplay in the Save Mo e.
18. AUTO ERASE-Automatically erases the store isplay. AUTO
VIEW TIME setting controls the time between erase cycles.
19. AUTO VIEW TIME-IVIEW TIME in early instruments)-
Controls the time between erase cycles in the Auto Erase Mo e.
20. MAN ERASE — Erases the store isplay.
21. STORAGE LEVEL-(LEVEL in early instruments) — Controls
the writing rate in the FAST an BI STABLE storage mo es.
Controls the writing rate an brightness of the store isplay
in the Variable persistence Mo e.
9. POWER — Switch an in icator; switch turns on instrument, an
the in icator is on when the instrument is connecte to a power
source an turne on.
22. CALIBRATOR — Positive going square wave or DC voltage
selecte by changing an internal jumper. Output voltage at pin
jacks (4 V. 0.4 V an 40 mV).
Fig. 1-2. Front Panel Controls an Connectors.
1-

Operating Information — 7623/R7623 Service
1. FUSE — Line voltage fuse.
2. REMOTE ERASE IN — Provi es external connection for remote
erase.
3. EXT S S RESET IN — Remote single sweep reset.
4. EXT Z AXIS IN — Input for intensity mo ulation of the CRT
isplay.
5. VERT SIG OUT-Vertical signal selecte by TRIG SOURCE
switch (LEFT. RIGHT. ALT an ADD).
6. +GATE OUT — Gate signal selecte by gate selector switch
(Main, Auxiliary, an Delay).
7. +SAWTOOTH OUT-Positive-going sawtooth from time-base
unit.
Fig. 1-3. Rear Panel Controls an Connectors.
1-3

Operating Information — 7623/R7623 Service
After obtaining a display in the NON Store mode
continue to the Storage modes.
Storage Modes
Set the controls as given in the Operating Set-Up
Information for the Non-Store mode. Set the storage
controls as given for Variable Persistence, Fast, Bi-Stable
and Save mode.
MULTI TRACE In
ERASE Pressed and released. (Only one
sweep is stored, press the ERASE
button and another sweep will be
stored without erasing the original
display.)
SAVE Out (released).
Variable Persistence Operating
Set-Up Information
Bi-Stable Operating Set-Up Information
VAR PERSIST In (Pressed in)
BI-STABLE In (pressed in)
NON STORE
Out (released)
FAST Out (released)
STORAGE LEVEL
PERSISTENCE
SAVE
As desired (no fading positive of
the display)
As desired (counterclockwise in the
detent is maximum retention; in
the clockwise direction the
retention decreases.)
Out (released).
ERASE
Press ERASE button
SAVE Mo e Operation Set-Up Information
Obtain a stored display in any storage mode.
SAVE
In (Pressed in)
ERASE
FAST Operating Set-Up Information
Press ERASE button
SAVE INTEN
FAST
VAR PERSIST
AUTO ERASE
STORAGE LEVEL
In (pressed in).
Out (Released).
Out. Pressed and released. (Only
one sweep is stored. Press the MAN.
ERASE button to erase the display,
and to start another sweep for
storing.)
As desired (adjusted so stored
display does not fade into the
background).
Turning the SAVE INTEN control
clockwise increases the intensity of
the stored display. There is no erase
signal generated, and all sweep
signals are locked-out. Press the
SAVE button out (release).
Auto ERASE
Pressed in
Auto VIEW TIME
As desired (counterclockwise
position maximum display time
before erase cycle starts. Clockwise
direction decreases time that a
stored display is present before an
erase cycle).
AUTO ERASE
Pressed and released (out).
MULTI TRACE FAST Operating
Set-Up Information
Obtain one stored display in the fast mode.
For more detailed operating instructions, see the
76 3/R76 3 Operators Manual.
1-4

Section 2 — 7623/R7623 Service
CALIBRATION
Calibration Interval
To assure instrument accuracy, check the calibration of
the 76 3 every 1000 hours of operation, or every six
months if used infrequently. Before complete calibration,
thoroughly clean and inspect this instrument as outlined in
the Maintenance section.
Tektronix Field Service
Tektronix, Inc. provides complete instrument repair and
recalibration at local Field Service Centers and the Factory
Service Center. Contact your local Tektronix Field Office
or representative for further information.
Using This Procedure
General. This section provides several features to facili 
tate calibration of the 76 3. These are:
In ex. An index is given preceding the calibration
procedure to aid in locating a step.
Performance Check. The performance of this instrument
can be checked by performing only the VCHECK steps.
The V preceding a step indicates that performing this step
checks the instrument against the tolerance listed as a
Performance Requirement (see Specification Section in the
Operators Manual).
Partial Proce ure. A partial calibration is often desirable
after replacing components, or to touch up the adjustment
of a portion of the instrument between major recalibra 
tions. To calibrate only part of the instrument, set the
controls as given under Preliminary Control Settings and
start with the nearest Equipment Required list preceding
the desired portion. To prevent unnecessary recalibration of
other parts of the instrument, re-adjust only if the tolerance
given in the CHECK- part of the step is not met. If
re-adjustment is necessary, also check the calibration of any
steps listed in the INTERACTION — part of the step.
Complete Calibration Proce ure. Completion of each
step in the following calibration procedure ensures that this
instrument is both correctly adjusted and performing
within all given tolerances.
TEST EQUIPMENT REQUIRED
The test equipment and accessories, or the equivalent,
given in the Test Equipment table is required for complete
calibration of the 76 3. Specifications given for the test
equipment are the minimum necessary for accurate calibra 
tion. Therefore, the specifications of any test equipment
used must meet or exceed the listed specifications. All test
equipment is assumed to be correctly calibrated and
operating within the listed specification. Detailed operating
instructions for the test equipment are not given in this
procedure. Refer to the instruction manuals for the test
equipment for more information.
Special Calibration Fixtures
Special Tektronix calibration fixtures are used in this
procedure only where they facilitate instrument calibration.
These special calibration fixtures are available from
Tektronix, Inc. Order by part number through your local
Tektronix Field Office or representative.
Calibration Equipment Alternatives
All of the listed test equipment is required to completely
check and adjust this instrument. This calibration pro 
cedure is based on the first item of equipment given as an
example of applicable equipment. When other equipment is
substituted, control settings or calibration setup may need
to be altered slightly to meet the requirements of the
substitute equipment. If the exact item of test equipment
given as an example in the Test Equipment table is not
available, first check the Specifications column carefully to
see if any other equipment is available which might suffice.
Then check the Usage column to see what this item of test
equipment is used for. If used for a check or adjustment
which is of little or no importance to your measurement
requirements, the item and corresponding step(s) can be
deleted.
The following procedure is written to completely check
and adjust the 76 3 to the limits given in Section of the
Operators Manual and to allow interchanging 7000-series
plug-in units between 7000-series mainframes without the
need to recalibrate the instruments each time. If applica 
tions for which you will use the 76 3 do not require the
full available performance from the 76 3 and plug-in units,
this procedure and the required equipment list can be
-1

Calibration — 7623/R7623 Service
shortened accordingly. For example, the basic measurement
capabilities of this instrument can be verified by checking
vertical deflection accuracy, vertical square-wave response,
and basic horizontal timing with 7000-series real-time
plug-in units and an accurate square-wave signal. Also, if the
76 3 is to be used in a fixed system without the need to
interchange plug-in units, all tests can be made by substi 
tuting vertical plug-in units and applicable test signals for
the 067-0587-01 mainframe standardizer calibration fix 
ture.
TEST EQUIPMENT
Description Minimum Specifications
Usage
Examples of Applicable
Test Equipment
1. Precision DC Voltmeter
Range, zero to 150 Volts;
accuracy, within 0. %.
Calibrator output accuracy
check and adjustment.
a. Tektronix 7D13 Digital Multi 
meter (test oscilloscope must have
Readout System).
b. Fluke Model 8 5A Differential
DC Voltmeter.
. DC Voltmeter (VOM)
Range, zero to 4000 Volts;
accuracy, checked to with 
in 1% at 1500 Volts.
High voltage power supply
check. Z-Axis DC levels
adjustment.
a. Triplett Model 630-NA.
b. Simpson Model 6 .
3. Time-Mark Generator
Marker outputs, 10 nano 
seconds to 0.1 second;
marker accuracy, within
0.1%; Trigger output, one
millisecond.
CRT geometry check and
adjustment. Horizontal
timing check and adjust 
ment.
a. Tektronix 901 Time-Mark Gen 
erator.
b. Tektronix 184 Time-Mark Gen 
erator.
4. Medium frequency con 
stant amplitude signal gen 
erator
Frequency, 50 to 100
megahertz; reference fre 
quency, 50 kilohertz; out 
put amplitude, variable
from 5 millivolts to 5
Volts peak-to-peak into 50
ohms; amplitude accuracy,
constant within 3% of ref 
erence as output fre 
quency changes.
External Z-axis operation
check. Horizontal and Ver 
tical bandwidth check.
Vertical amplifier isolation
check and storage writing
rate.
a. Tektronix 191 Constant Ampli 
tude Signal Generator.
b. General Radio 1 15-C with
1 63-C Amplitude Regulating
Power Supply.
5. Low frequency signal
generator
Frequency, 35 kilohertz;
output amplitude, variable
from 50 to 100 millivolts.
X-Y phase shift check and
storage writing rate.
a. General Radio 1310-B Oscillator
with a binding post to BNC adapter
( 74-QBJ General Radio).
6. Test oscilloscope system
(dual-trace)
Bandwidth, DC to 50
megahertz; minimum de 
flection factor, 10
m illi volts/div; accuracy,
within 3%.
Horizontal limit centering
adjustment and + GATE
OUT.
a. Tektronix 7503 or 7504 oscillo 
scope with two 7A15A or 7A16
Amplifier and 7B50 and 7B53A
Time Base plug-in units and two
P6053 Probes.
b. Tektronix 453A oscilloscope
with two P6054 Probes.
-

Calibration — 7623/R7623 Service
TEST EQUIPMENT (cont)
Description
Minimum Specifications
Usage
Examples of Applicable
Test Equipment
7. Vertical plug-in unit
(two identical units re 
quired), and a dual display
vertical unit.
Tektronix 7A-series 65
megahertz bandwidth re 
quired for complete pro 
cedure as written.
Used throughout pro 
cedure to provide vertical
input to the instrument
under calibration. Identi 
cal units required for only
X-Y phase shift check.
a. Tektronix 7A15A and an 7A18
Amplifier (may be shared with an
7000-series test oscilloscope).
b. Any 7A-$eries plug-in unit (tol 
erances in some stpes may be lim 
ited if low-frequency units used).
8. Time-base plug-in unit
Tektronix 7B-series. Used through procedure to
provide sweep.
a. Tektronix 7B53A or 7B5 Time
Base.
b. Any 7B-series plug-in unit.
9. Mainframe standardizer
calibration fixture
Produces gain-check and
pulse-response waveforms.
Used throughout pro 
cedure to standardize in 
strument so plug-in units
can be interchanged with 
out complete recalibra 
tion.
a. Tektronix Calibration Fixture
067-0587-01.
b. Calibrated 7000-series plug-in
units with suitable signal sources
may be substituted if lower per 
formance is acceptable.
10. 1 0X passive probe Compatible with 7B-series
external trigger input.
Chopped mode operation
check (adjustment pro 
cedure).
a. Tektronix P6053 or P6054
Probe (may be shared with test
oscilloscope).
11. T connector Connectors, BNC.
External Z-axis operation
check.
a. Tektronix Part No. 103-0030-00.
1 . Termination
Impedance, 50-ohms;
accuracy, ± %; connec 
tors, BNC.
Horizontal timing check
and adjustment. X-Y phase
shift check.
a. Tektronix Part No. 011 0049-01.
13. Dual-input coupler Connectors, BNC.
Added operation check.
X-Y phase shift check.
a. Tektronix Calibration Fixture
067-05 5-00.
14. Cable (two required)
Impedance, 50 ohms;
type, RF-58/U; length, 18
and 4 inches; connectors,
BNC.
Used throughout pro 
cedure for signal intercon 
nection.
a. Tektronix Part No. 01 -0076-00
(18-inches). Tektronix Part No.
01 -0057-01 (4 -inches).
15. GR in-line termination
Impedance, 50 ohms;
accuracy, ± %; connec 
tors, GR874 input with
BNC male output.
External Z-axis operation
check. Vertical bandwidth
check. Vertical amplifier
isolation check. Horizontal
bandwidth check.
a. Tektronix Part No. 017-0083-00.
16. Cable
Impedance, 50 ohms; type
RG- 13/U; electrical
length, five nanoseconds;
connectors, GR874.
External Z-axis operation
check. Vertical bandwidth
check. Vertical amplifier
isolation check. Horizontal
bandwidth check.
a. Tektronix Part No. 017-050 -00.
-3

Calibration — 7623/R7623 Service
Examples of Applicable
Test Equipment
TEST EQUIPMENT (cont)
Description
Minimum Specifications Usage
17. BNC to pin jack cable
Adapts pin jacks to BNC
male connector.
18. Screwdriver
19. Low-capacitance screw 
driver
Three-inch shaft,
inch bit.
1 1/ -inch shaft.
3/3 -
Added operation check.
Trigger source operation
check. Astigmatism adjust 
ment.
Used throughout adjust 
ment procedure to adjust
variable resistors.
Used throughout adjust 
ment procedure to adjust
variable capacitors.
a. Tektronix Part No. 175-1178-00
(one supplied as standard acces 
sory).
a. Xcelite R-33 3.
a. Tektronix Part No. 003-0000-00.
0. Adapter
Connector, GR to BNC
male.
Vertical bandwidth check.
Storage writing rate check.
a. Tektronix Part No. 017-0064-00.
NOTE
This instrument should be adjusted at an ambient
temperature of +25° C ±5°C for best overall accuracy.
1. Remove the sides and bottom covers from the 76 3
or the top cover and side panel from the R76 3.
. Connect the instrument to a power source that meets
the voltage and frequency requirements. The applied
voltage should be near the center of the voltage range
marked on the rear panel (see Section 1 for information on
converting this instrument from one operating voltage to
another).
NOTE
f correct line voltage is not available, use a variable
autotransformer to provide the correct input voltage.
3. Set the controls as given under Preliminary Control
Settings. Allow at least 0 minutes warmup before pro 
ceeding.
NOTE
Titles for external controls of this instrument are
capitalized in this procedure (e.g., NTENS TY ).
nternal adjustments are initial capitalized only (e.g.,
CR T Grid Bias).
Preliminary Control Settings
Set the 76 3 controls as follows:
INTENSITY
Midrange
FOCUS
Adjusted for well-
defined display
BEAM FINDER
Out
GRATICULE ILLUM
As desired
VERT MODE
Left
TRIG SOURCE
VERT MODE
READOUT
Midrange
NON-STORE In
VAR PERSIST
Out
FAST
Out
BI-STABLE
Out
MULTI FAST
Out
INTEG
Out
SAVE
Out
MANUAL ERASE
Out
AUTO ERASE
Out
STORAGE LEVEL Counterclockwise
STORED INTEN Counterclockwise
AUTO VIEW TIME Counterclockwise
(Persistance)
in detent
POWER ON
-4

Calibration — 76 3/R76 3 Service
CALIBRATION PROCEDURE
76 3 Serial No. _____________________________________
Calibration Date _____________________________________
Calibrated By ______________________________________
Introduction
The following procedure returns the 76 3 to correct
calibration. All limits and tolerances given in this procedure
are calibration guides, and should not be interpreted as
instrument specifications except as listed in Section .
Index to Calibration Procedure
Power Supply
1. Adjust -50 Volt Power Supply Page -7
. Check Remaining Power-Supply Voltages Page -7
3. Check High-Voltage Power Supply
Page -8
Display and Z-Axis
4. Adjust CRT Grid Bias
Page -9
5. Adjust Astigmatixm
Page -10
6. Adjust Trace Rotation
Page -10
7. Adjust Y-Axis Alignment
Page -10
8. Adjust Geometry
Page -10
9. Check External Z-Axis Operation
Page -11
10. Check Beam Finder
Page -11
Vertical Deflection System
11. Adjust Bias Adjustment
Page -1
1 . Adjust Vertical Centering
Page -1
13. Check Vertical Gain
Page -1
14. Check Vertical Linearity Page -13
15. Adjust Vertical High-Frequency Com 
pensation
Page -13
16. Check Vertical Amplifier Bandwidth
Page -13
17. Check Vertical Amplifier Isolation Page -14
18. Check Added Operation
Page -14
19. Check Alternate Operation
Page -14
0. Check Vertical Chopped Mode Opera 
tion
Page -15
Triggering System
1. Check Trigger Source Operation
Page -16
Horizontal Deflection System
. Adjust Horizontal Amplifier Gain and
Low Frequency Linearity
Page -17
3. Adjust Horizontal Amplifier Centering
Page -17
4. Adjust Horizontal Amplifier Limit
Centering
Page -18
5. Adjust High Frequency Timing
Page -18
6. Check X-Y Phase Shift
Page -19
7. Check Horizontal Bandwidth
Page -19
Z-Axis and Auto Focus
8. Adjust Z-Axis Compensation
Page - 0
9. Adjust Auto Focus Compensation and
Operating Levels
Page - 0
Calibrator
30. Adjust Calibrator Output Voltage
Page - 1
31. Check Calibrator Repetition Rate
Page - 1
Signals Out
3 . Check SINGLE SWEEP READY OUT
Page -
33. Check EXT SS RESET IN
Page -
34. Check VERT SIG OUT
Page -
35. Check + SAWTOOTH OUT
Page -
-5

Calibration — 7623/R7623 Service
36. Check + GATE OUT
Rea out Operation
37. Check READOUT SYSTEM Operation
38. Check READOUT Gate Triggered Oper 
ation
Storage Operation
39. Check AUTO ERASE Function
40. Check SAFE Function
41. Check Readout Storage Operation
4 . Check Storage Test Points
43. Adjust Bi-Stable Operating Level
44. Check Storage Test Points
Page - 3 45. Check ERASE and FAST Transfer
Pulses
46. Check High Speed Mesh Pump Pulses
Page - 4
47. Check Pump Pulse Frequency
Page - 4
48. Check/Adjust STORAGE LEVEL
Range
49. Check FAST Writing Rate
Page - 5
50. Check/Adjust FAST Stability
Page - 5
51. Check/Adjust Variable Persistence Mode
Page - 6 and Voltage Levels
Page - 7 5 . Check/Adjust Variable Persistence Pulse
Amplitude
Page - 8
53. Check/Adjust CE and CE 3 Voltage
Page - 9 Levels
Page -30
Page -30
Page 30
Page -30
Page -31
Page -31
Page -31
Page -31
Page -3
-6

Calibration — 76 3/R76 3 Service
POWER SUPPLY
Equipment Required
. DC voltmeter (VOM)
1. Precision DC voltmeter
3. Three-inch screwdriver
Control Settings
Set the controls as given in the Preliminary Control
Settings.
1. Adjust — 50 Volt Power Supply
a. Set the INTENSITY control fully counterclockwise.
Fig. 2-1. (A) Location of low-voltage an high-voltage test points
(right si e of instrument) (B) Location of — 50 V a justment (Low
Voltage Regulator boar ).
b. Connect the precision DC voltmeter between TP -50
(see Fig. -1 A) and chassis ground.
c. CHECK-Meter reading; -50 volts ±0.1 volt.
d. ADJUST- — 50 volts adjustment R881 (see
Fig. -1 B) for a meter reading of exactly -50 volts.
e. INTERACTION — Change in setting of R881 may
affect the operation of all circuits within the 76 3.
. Check Remaining Power-Supply Voltages
a. CHECK — Table -1 lists the low-voltage power
supplies in this instrument. Check each supply with the
precision DC voltmeter for output voltage within the given
tolerance (connect meter ground lead to chassis ground).
Power supply test points are shown in Fig. -1 A.
NOTE
Ripple and regulation of the individual power
supplies can be checked using the procedure given
under Troubleshooting Techniques in Section 4.
TABLE -1
Power Supply Tolerance
Power Supply
Test Point
Output Voltage
Tolerance
-50 Volt
Pin 8 P1 170 ±0.1 Volt
-15 Volt
Pin 7 P1170
±0.1 Volt
+5 Volt
Pin 5 P1 170
±0.07 Volt
+15 Volt
Pin 4 P1170 ±0.1 Volt
+50 Volt
Pin 3 P1 170
±0.3 Volt
+130 Volt
Pin P1 170
±5. Volt
-7

Calibration — 7623/R7623 Service
3. Check High-Voltage Power Supply
a. Push in the power switch (turn off the instrument).
b. Set the DC voltmeter (VOM) to measure at least
1500 volts. Then, connect it between the high-voltage test
point (see Fig. 2-1 A) an chassis groun .
c. Pull out the power switch (turn on the instrument).
Check meter rea ing; — 1475 volts ±45 volts.
. Push in the power switch (turn off the instrument).
Disconnect the DC voltmeter.
e. Pull out the power switch (turn on the instrument).
-8