Tektronix 7623A User manual

Tektronix
COMMITTED TO EXCELLENCE
7623A/R7623A
STORAGE
OSCILLOSCOPE
WITH OPTIONS
SERVICE
INSTRUCTION MANUAL

WARRANTY
Al TEKTRONIX insiruments are warranted against
defective materials and workmanship for one year.
Any questions with respect to the warraniy should
be taken up with your TEK TRONIX Field Engineer of
representative.
AU requests for repairs and replacement parts
should be directed to the TEKTRONIY Field Office
oc representative in your area. This will assure you
the fastest possible service. Please include the
instrument Type Number or Part Number and Serial
Number with all requests for parts or service.
Specifications and price change privileges reserved.
Copyright | 1974 by Tektronix, Inc., Beaverton,
Oregon. Printed in the United States of America. All
rights reserved. Contents of this publication may not
be reproduced in any torm without permission of
Tektronix, Inc.
ULS.A. and foreign TEKTRONIX producis covered
hy U.S. and foreign patents and/or patenis pending.
TEKTRONIX is a registered trademark of Tektronix,
inc.

7623A/R7623A Service
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
LIST OF TABLES PAGE
SECTION 1 OPERATING INFORMATION
PRELIMINARY OPERATION 1-1
AC POWER SOURCES 1-1
AC POWER CORD 1-1
OPERATING VOLTAGE 1-1
OPERATING TEMPERATURE 1-3
RACKMOUNTING 1-3
PLUG-IN UNITS 1-4
PLUG-IN INSTALLATION AND REMOVAL 1-4
CONTROLS AND CONNECTORS 1-5
FRONT PANEL CONTROLS AND CONNECTORS 1-6
REAR PANEL CONTROLS AND CONNECTORS 1-8
GENERAL OPERATING INFORMATION 1-10
INTENSITY CONTROL 1-10
DISPLAY FOCUS 1-10
GRATICULE 1-10
LIGHT FILTER 1-11
BEAMFINDER 1-11
READOUT MODES 1-12
DISPLAY PHOTOGRAPHY 1-12
STORAGE 1-13
CARE OF STORAGE SCREEN 1-14
VERTICAL MODE 1-15
TRIGGER SOURCE 1-16
X-¥ OPERATION 1-17
INTENSITY MODULATION 1-17
RASTER DISPLAY 1-18
CALIBRATOR 1-18
SIGNALS OUT 1-19
APPLICATIONS 1-20
SECTION 2 SPECIFICATIONS
INTRODUCTION 2-1
STANDARD ACCESSORIES 2-9

7623A/R7623A Service
SECTION 3
TABLE OF CONTENTS (cont.)
THEORY OF OPERATION
LOGIC FUNDAMENTALS
SYMBOLS
LOGIC POLARITY
INPUT/OUTPUT TABLES
NON DIGITAL DEVICES
BLOCK DIAGRAM
THEORY OF OPERATION
MAIN INTERFACE >
LOGIC CIRCUIT ®
Z-AXIS LOGIC
CLOCK GENERATOR
VERTICAL CHOPPED BLANKING
CHOP COUNTER
VERTICAL MODE CONTROL
VERTICAL BINARY
PLUG-IN BINARY
OUTPUT BUFFERS
TRIGGER SELECTOR ©@>
TRIGGER MODE AND ADD SIGNALS
TRIGGER CHANNEL SWITCH
TRIGGER OUTPUT AMPLIFIER
VERTICAL SIGNAL BUFFER
VERTICAL INTERFACE >
VERTICAL CHANNEL SWITCH
AUXILIARY Y-AXIS INPUT AMPLIFIER
DELAY-LINE BUFFER
DELAY LINE
VERTICAL AMPLIFIER <@>
CENTERING AND READOUT AMPLIFIER
INPUT AMPLIFIER
BEAMFINDER NETWORK
OUTPUT AMPLIFIER
HORIZONTAL AMPLIFIER <6>
HORIZONTAL CHANNEL SWITCH
RIGHT OUTPUT AMPLIFIER
LEFT OUTPUT AMPLIFIER
PAGE
3-2
3-2
3-5
3-5
3-5
3-5
3-9
3-9
3-9
3-11
3-12
3-15
3-17
3-18
3-20
3-21
3-21
3-21
3-23
3-24
3-25
3-25
3-25
3-26
3-26
3-27
3-27
3-27
3-28
3-28
3-28
3-29
3-29
3-30
3-30

7623A/R7623A Service
TABLE OF CONTENTS (cont.)
PAGE
OUTPUT SIGNALS <> 3-31
VERT SIG OUT 3-31
+ GATE OUT 3-31
+ SAWTOOTH OUT 3-31
CRT CIRCUIT <7> 3-31
HIGH VOLTAGE REGULATION 3-31
AUTO FOCUS DC RESTORER 3-33
AUTO FOCUS 3-34
CONTROL GRID DC RESTORER 3-34
Z-AXIS AMPLIFIER 3-34
CRT CONTROL CIRCUITS 3-35
LOW-VOLTAGE POWER SUPPLY 3-35
POWER INPUT 3-35
—50-VOLT SUPPLY 3-38
—-15-VOLT SUPPLY 3-40
+5-VOLT SUPPLY 3-40
+15-VOLT SUPPLY 3-40
+50-VOLT SUPPLY 3-40
+130-VOLT SUPPLY 3-40
GRATICULE LIGHT SUPPLY 3-41
CALIBRATOR 0) 3-41
READOUT SYSTEM <> 3-43
INTRODUCTION 3-43
THREE-COMPARTMENT MAINFRAMES 3-43
DISPLAY FORMAT 3-44
DEVELOPING THE DISPLAY 3-44
TIMER 3-51
TIME-SLOT COUNTER 3-53
WORD TRIGGER 3-54
CHANNEL COUNTER 3-54
READOUT CONTROL 3-54
SINGLE-SHOT LOCKOUT 3-55
ENCODING THE DATA 3-56
COLUMN AND ROW DATA SWITCHES 3-59
DISPLAY-SKIP GENERATOR 3-60
COLUMN AND ROW DECODERS 3-60
ZEROS LOGIC AND MEMORY 3-61

7623A/R7623A Service
TABLE OF CONTENTS (cont.)
PAGE
CHARACTER GENERATORS 3-64
DECIMAL POINT LOGIC AND CHARACTER POSITION COUNTER
3-64
FORMAT GENERATOR 3-65
Y-OUTPUT AMPLIFIER 3-67
X-OUTPUT AMPLIFIER 3-67
DISPLAY SEQUENCE 3-67
STORAGE SYSTEM <> 3-68
Loic 3-68
OPERATIONAL AMPLIFIERS 3-73
SECTION 4 MAINTENANCE
PRELIMINARY INFORMATION 44
PANEL REMOVAL 4-4
POWER UNIT REMOVAL 4-2
PREVENTIVE MAINTENANCE 43
CLEANING 4-3
LUBRICATION 4-4
VISUAL INSPECTION 45
SEMICONDUCTOR CHECKS 45
RECALIBRATION 45
TROUBLESHOOTING 45
TROUBLESHOOTING AIDS 4-5
TROUBLESHOOTING EQUIPMENT 48
TROUBLESHOOTING TECHNIQUES 4-8
CORRECTIVE MAINTENANCE 4-13
OBTAINING REPLACEMENT PARTS 4-13
SOLDERING TECHNIQUES 4-13
COMPONENT REPLACEMENT 4-14
SEMICONDUCTOR REPLACEMENT 4-18
CATHODE-RAY TUBE REPLACEMENT 4-20
SWITCH REPLACEMENT 4-21
GRATICULE-BULB REPLACEMENT 4-22
POWER TRANSFORMER REPLACEMENT 4-22
HIGH VOLTAGE COMPARTMENT 4-22
FUSE REPLACEMENT 4-23
RECALIBRATION AFTER REPAIR 4-23
INSTRUMENT REPACKAGING 4-23

7623A/R7623A Service
TABLE OF CONTENTS (cont.)
SECTION 5 PERFORMANCE CHECK/CALIBRATION
PRELIMINARY INFORMATION
CALIBRATION INTERVAL
TEKTRONIX FIELD SERVICE
USING THIS PROCEDURE
TEST EQUIPMENT REQUIRED
SPECIAL CALIBRATION FIXTURES
CALIBRATION EQUIPMENT ALTERNATIVES
SIGNAL CONNECTIONS
WARM-UP AND TEMPERATURE REQUIREMENTS
PART I--PERFORMANCE CHECK
INTRODUCTION
OUTLINE FOR PART I-PERFORMANCE CHECK
PART H—CALIBRATION
INTRODUCTION
OUTLINE FOR PART II--CALIBRATION
SECTION 6 OPTIONS
SECTION 7 ELECTRICAL PARTS LIST
SECTION 8 DIAGRAMS
SECTION 9 MECHANICAL PARTS LIST
CHANGE INFORMATION
PAGE
5-1
5-1
5-1
5-1
5-1
5-2
5-2
5-2
5-2
5-6
5-6
5-6
5-26
5-26
5-26

vi
7623A/R7623A Service
LIST OF ILLUSTRATIONS
Frontispiece
Figure 1-1. Location of voltage-selector jumper.
Figure 1-2. Front panel controls and connectors.
Figure 1-3. Rear panel controls and connectors.
Figure 1-4. Definition of measurement lines on the graticule.
Figure 1-5. Location of Readout Mode switch.
Figure 1-6. Location of Calibrator jumper on Storage circuit board.
Figure 3-1. Block diagram 7623A.
Figure 3-2. Logic circuit block diagram.
Figure 3-3. Z-Axis logic block diagram.
Figure 3-4. (A) Clock Generator stage of U55A. (B) Idealized waveforms from Clock
Generator stage.
Figure 3-5. (A) Input and output pins for Vertical Chopped Blanking stage. (B) idealized
waveforms for Vertical Chopped Blanking stage.
Figure 3-6. (A) Logic diagram for Vertical Chopped Blanking stage. (B) Table of input/output
combinations for Vertical Chopped Blanking stage.
Figure 3-7. Detailed togic diagram of Chop Counter stage.
Figure 3-8. Idealized input and output waveforms for Chop Counter stage
Figure 3-9. Logic diagram of Vertical Mode Control and Vertical Mode Buffer Amplifier
stages.
Figure 3-10. Logic diagram of Vertical Binary stage.
Figure 3-11. Idealized waveforms showing relationship between input and output waveforms
for Vertical Binary and Plug-In Binary stages when operating in ALT mode.
Figure 3-12. Logic diagram of Plug-In Binary and Plug-In Alternate Buffer stage.
Figure 3-13. Detailed block diagram of Trigger Selector circuit along with simplified diagram
of trigger source selection circuitry.
Figure 3-14. Input levels at pin 4 of U324.
Figure 3-15. Input/output table for Trigger Channel Switch stage.
Figure 3-16. Vertical Interface detailed block diagram.
Figure 3-17. Input/output table for Vertical Channel Switch.
Figure 3-18. Vertical Amplifier detailed block diagram.
Figure 3-19. Horizontal Amplifier detailed block diagram.
Figure 3-20. CRT circuit detailed block diagram.
Figure 3-21. Low-Voltage Power Supply detailed block diagram.
Figure 3-22. Schematic illustrating voltage drop between power supply output and load due
to resistance of interconnecting wire.
Figure 3-23. Calibrator detailed block diagram.
Figure 3-24. Location of readout words on the crt identifying the originating plug-in unit
and channel (one complete frame shown).
PAGE
1-2
1-5
1-9
1-11
1-13
1-20
3-8
3-10
3-11
3-16
3-17
3-17
3-19
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-26
3-27
3-29
3-32
3-36
3-39
3-41
3-44

7623A/R7623A Service
LIST OF ILLUSTRATIONS (cont.)
PAGE
Figure 3-25. Character Selection Matrix for 7623A Readout System. 3-46
Figure 3-26. Typical readout display where only channel 2 of the Right Vertical and 3-47
Horizontal units is displayed.
Figure 3-27. Detailed block diagram of the Readout System. 3-48
Figure 3-28. Output waveforms of Timer stage. 3-50
Figure 3-29, Detail of output at pins 12, 13, 14, and 16 of U2126. 3-51
Figure 3-30. Timer stage operation when Display-Skip condition occurs. 3-52
Figure 3-31. Time relationship of the time-slot (TS) pulses produced by U2159. 3-53
Figure 3-32. Typical encoding scheme for voltage-sensing amplifier plug-in unit. Coding 3-57
shown for deflection factor of 100 microvolts.
Figure 3-33. Idealized current waveforms of: (A) Row analog data, (B) Column analog data. 3-58
Figure 3-34. Block representation of memory sequence in U2232. 3-61
Figure 3-35. Typical output waveforms for Zeros Logic and Memory stage operation (at pin 3-62
7 of U2232).
Figure 3-36. Readout word relating 10 possible character locations to the decimal point 3-65
instructions that can be encoded, and the resultant crt display.
Figure 3-37. Flow chart for character generation by the Readout System. 3-66
Figure 3-38. Storage circuit simplified block diagram. 3-68
Figure 3-39. Time relationship of Storage logic pulses. 3-69
Figure 3-40. BISTABLE mode Storage waveforms. 3-70
Figure 3-41. VAR PERSIST mode Storage waveforms. 3-71
Figure 3-42. FAST BISTABLE mode Storage waveforms. 3-72
Figure 3-43. FAST VAR PERSIST made Storage waveforms. 3-74
Figure 4-1. Power Unit removal. 4-2
Figure 4-2. Location of circuit boards in the 7623A. 46
Figure 4-3. Location of circuit boards in the R7623A. 4-7
Figure
4-4. Circuit isolation troubleshooting chart. 4-10
Figure 4-5. Location of screws holding Low Voltage sub-chassis. 4-17
Figure 4-6. Location of screws holding Signals Out rear panel. 4-18
Figure 5-1. Typical crt display when checking X-Y phase shift. 5-15
Figure 5-2. Location of Calibrator AC/DC jumper. 5-17
Figure 5-3. Location of High-Voltage Test Point. 5-30
Figure 5-4. Location of adjustments in High-Voltage cover. 5-32
Figure 5-5. Typical crt display when checking X-Y phase shift. 5-43
Figure 5-6. Location of Calibrator AC/DC jumper. 5-46
vii

7623A/R7623A Service
LIST OF ILLUSTRATIONS (cont.)
Section 8 figures are located near their associated diagrams on the foldout pages.
Figure 8-1.
Figure 8-2.
Figure 8-3.
Figure 8-4.
Figure 8-5.
Figure 8-6.
Figure 8-7.
Figure 8-8.
Figure 8-9.
Figure 8-10.
Figure 8-11.
Figure 8-12.
Figure 8-13.
Figure 8-14.
Figure 8-15.
Figure 8-16.
Figure 8-17.
Figure 8-18.
Figure 8-19.
Figure 8-20.
Figure 8-21.
Figure 8-22.
Figure 8-23.
Figure 8-24.
viii
Semiconductor lead configurations.
A1-Main Interface Board.
A2-Logic Board.
A3-Trigger Selector Board.
A4-Vertical Interface Board.
A5-Vertical Amplifier Board (front).
A5-Vertical Amplifier Board (rear).
A6-Horizontal Amplifier Board.
A7-Output Signals Board.
A8-Z-Axis Board.
A9-Anode Board.
A10-High-Voltage Board.
A11-Low-Voltage Rectifier Board.
A12-Low-Voltage Regulator Board.
A13-Readout Board.
A14-Storage Board.
Adjustment locations-Low-Voltage Regulator board.
Adjustment locations-Z-Axis board.
Adjustment locations-High-Voltage board.
Adjustment locations-Vertical Amplifier board.
Adjustment locations-Horizontal Amplifier board.
Adjustment locations-Signals Out board.
Adjustment locations-Readout board,
Adjustment locations-Storage board.

7623A/R7623A Service
LIST OF TABLES
PAGE
TABLE 1-1. Power Cord Color-Coding 1-1
TABLE 1-2. Regulating Range and Fuse Data 1-3
TABLE 2-1. ELECTRICAL 2-1
TABLE 2-2. ENVIRONMENTAL 2-8
TABLE 2-3. PHYSICAL 2-8
TABLE 2-4. 7623A SYSTEM SPECIFICATIONS 2-10
TABLE 3-1. Basic Logic Reference 3-2
TABLE 3-2. Standard Readout Format 3-45
TABLE 3-3. Channel Address Code 3-55
TABLE 4-1. Power Supply Tolerances 4-9
TABLE 4-2. Fuse Rating 4-23
TABLE 5-1. Test Equipment 5-3
TABLE 5-2. Power Supply Toierances 5-30
TABLE 5-3. High-Frequency Compensation Adjustments 5-38

The Tektronix 7623A/R7623A Storage Oscilloscope is a solid-state instrument designed for fast writing rate storage
applications. The 7623A operates in three display modes—NON STORE, STORE, and SAVE, and has four storage modes—
BISTABLE, VAR PERSIST, FAST BISTABLE, and FAST VAR PERSIST. This instrument has three plug-in compartments
that accept any 7-series plug-in units to form a highly flexible measurement system.
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7623A/R7623A Service

Section 1--7623A/R7623A Service
OPERATING INFORMATION
PRELIMINARY OPERATION
To effectively use the 7623A/R7623A Storage Oscilloscope, the operation and capabilities of the instru-
ment must be known. This section provides preliminary operating information, describes operation of con-
trols and connectors, and provides an operating checkout procedure.
AC POWER SOURCES
This instrument is intended to be operated from a single-phase, earth-referenced power source having
one current-carrying conductor (the Neutral Conductor) near earth potential. Operation from power sources
where both current-carrying conductors are live with respect to earth (such as phase-to-phase on a three-wire
system) is not recommended since only the Line Conductor has over-current (fuse) protection within the
instrument.
AC POWER CORD
This instrument has a three-wire power cord with a three-terminal polarized plug for connection to
the power source and safety-earth. The safety-earth terminal of the plug is directly connected to the in-
strument frame. For electric-shock protection, insert this plug only in a mating outlet with a safety-earth
contact or otherwise connect the frame to a safety earth system. The color-coding of the cord conductors
is in accordance with recognized standards as shown in Table 1-1.
TABLE 1-1
Power Cord Color Coding
Conductor USA & Canada IEC
Line Black Brown
Neutral White Blue
Safety-Earth Green with Green with
Yellow stripe Yellow stripe
OPERATING VOLTAGE
The 7623A/R7623A can be operated from either a 110-volt or a 220-volt nominal line-voltage source.
In addition, three operating ranges can be selected within each nominal line voltage source. Use the follow-
ing procedure to obtain correct instrument operation from the line voltage available:
1. Disconnect the instrument from the power source.
2. Remove the six screws securing the power unit (nine screws in the R7623A; see Figure 1-1).
3. Slide the power unit out of the rear of the chassis.
1-1

Operating Information—7623A/R7623A Service
% { j POWER UNIT
= ee SECURING
- 3 SCREWS
ALT SPARE VOLTAGE-SELECTOR
FUSE JUMPER JUMPER:
*
DO “4 e
Figure 1-1. Location of voltage-solector jumper.
4, Toconvert from 110-volts to 220-volts nominal line voltage, or vice versa, remove the voltage-
selector jumper and replace it with the spare jumper stored on the pins adjacent to the voltage selector
area (see Figure 1-1). The jumpers are color coded to indicate the nominal voltage for which they are in-
tended; brown for 110-volt nominal operation and red for 220-volt nominal operation. Change the fuse to
provide protection for the selected nominal line voltage. Use the fuse located in the Alt Fuse holder on the
Rectifier board (see Figure 1-1 for fuse location and Table 1-2 for fuse type). Also, change the line-cord
plug to match the power-source receptacle or use a suitable adapter.
1-2

Operating Information--7623A/R7623A Service
5. To convert the instrument from one regulating range to another, remove the voltage selector
jumper and re-install it on the set of pins corresponding to the desired regulating range. The proper reg-
ulating range will center about the average tine voltage to which the instrument is to be connected (see
Table 1-2).
TABLE 1-2 ‘
Regulating Range and Fuse Data
Pins Regulating Range
Selected
_ 110-volts (nominal) _220-volts (nominal)
LOW 90 to 110 volts 180 to 220 volts
MED 99 to 121 volts 198 to 242 volts
HI 108 to 132 volts 218 to 262 volts
Line Fuse 3.2 A slow-blow 1.6 A slow-blow
OPERATING TEMPERATURE
The 7623A can be operated where the ambient air temperature is between 0°C and +50°C. This in-
strument can be stored in ambient temperatures between 55°C and +75°C. After storage at temperatures
beyond the operating limits, allow the chassis temperature to come within the operating limits before power
is applied.
The 7623A is cooled by air drawn in through the top, side, and bottom panels and exhausted through
the rear panel. Components that require most cooling are mounted externally on a heat radiator. Adequate
clearance must be provided on all sides to allow heat to be dissipated from the instrument. Do not block or
restrict the air flow through the holes in the cabinet or the heat radiator. Maintain the clearance provided
by the feet on the bottom and allow about two inches clearance on the top, sides, and rear (more if possible).
The R7623<A is cooled by air drawn in through the air filter on the rear panel and exhausted through
ports on the right side of the instrument. Adequate clearance must be provided at these locations. Allow
at least one and one-half inches clearance behind the air filter and at least one inch on the right side.
A thermal cutout interrupts power to the instrument if the internal temperature exceeds a safe oper-
ating level. Power is automatically restored when the temperature returns to a safe level. Operation in
confined areas or close to a heat source may cause the thermal! cutout to open.
RACKMOUNTING
Instructions and dimensional drawings for rackmounting the R7623A are given in the Operators manual,

Operating Information—7623A/R7623A Service
PLUG-IN UNITS
The 7623A will accept up to three 7-series plug-in units. This plug-in feature permits a variety of
display combinations and also allows selection of bandwidth, sensitivity, display mode, etc. to meet many
measurement requirements. In addition, it allows expansion of the oscilloscope system to meet future
measurement requirements. The overall capabilities of the resultant system are in farge part determined
by the characteristics of the plug-in selected. For complete information on plug-ins avaitable for use with
this instrument, see the current Tektronix, Inc., catalog.
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 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 a plug-in, 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 in-
stalled without turning off the instrument power.
It is not necessary that all of the plug-in compartments be filled to operate the instrument; the only
plug-in units needed are those required for the measurement to be made. However, at environmental ex-
tremes, excess radiation may be radiated into or out of this instrument through the open plug-in compart-
ments. Blank plug-in panels are available from Tektronix, Inc., to cover the unused compartment; order
Part No. 016-0155-00.
When the 76234 is calibrated in accordance with the calibration procedure given in Section 5,
the vertical and horizontal gains are standardized. This allows calibrated plug-in units to be changed from
one plug-in compartment to another without recalibration. However, the basic calibration of the individual
plug-in units should be checked when they are installed in this system to verify their measurement accuracy.
See the plug-in unit instruction manual for verification procedure.
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.
1-4

Operating Information—7623A/R7623A Service
CONTROLS AND CONNECTORS
The major controls for operation of the 7623A are located on the front panel of the instrument. These
are illustrated in Figure 1-2. Figure 1-3 shows the location of rear panel controls and connectors. The follow:
ing is a brief description of the controls and connectors shown in Figures 1-2 and 1-3. More detailed operat-
ing information is given under General Operating Information.
Figure 1-2. Front panel controls and connectors.
1-5

Operating Information--7623A/R7623<A Service
FRONT PANEL CONTROLS AND CONNECTORS
The following descriptions are referenced to Figure 1-2.
(1) vert MODE:
LEET:
ALT:
ADD:
CHOP:
RIGHT:
(2) TRIG SOURCE:
LEFT:
VERT MODE:
RIGHT:
Selects vertical mode operation.
Selects signals from the left vertical amplifier compartment for display.
Selects signals from both vertical compartments for display on alternate
sweeps (dual trace).
Algebraically adds the signals from both vertical compartments and dis-
plays the sum.
Selects signals from both vertical compartments for display (dual trace).
The display switches between both vertical compartrnent signals, during
the sweep, at a one megahertz rate.
Selects signals from the right vertical amplifier compartment for display.
Selects the source of the internal trigger for the plug-in unit in the hori-
zontal compartment.
Selects the left vertical compartment as the internal trigger source.
Internal trigger signals are determined by the VERT MODE switch.
Selects the right vertical compartment as the internal trigger source.
(3) INTENSITY-Controls the brightness of the display
READOUT~—Turns on the Readout system and controls the brightness of the Readout display.
(Option 1 deletes this function.)
(5) BEAMFINDER-—When pressed, this switch limits the display to within the graticule area.
(6) GRATICULE ILLUM~—Controls the illumination of the graticule.

Operating Information—7623A/R7623A Service
FRONT PANEL CONTROLS AND CONNECTORS (cont.)
@
@)
©®
©
©
®
©
ERASE~Initiates erase cycles; either MANual or PERIODIC.
MANual: When pressed, initiates an erase cycle to erase the stored display and
provide a single-shot reset command to the plug-in time-base unit.
Operation is locked out in SAVE display mode.
PERIODIC: Controls the time between automatic erase cycles. If the erase period
ends during a sweep, the erasure is delayed till the end of that sweep.
This control has a counterclockwise OFF detent position. Operation
is locked out in the SAVE display mode.
PERSISTENCE—Controls the view time of the VAR PERSIST and FAST VAR PERSIST
stored displays. Operation is locked out in the SAVE display mode.
FAST—Used in conjunction with the VAR PERSIST and BISTABLE storage selections to choose
the fast transfer storage modes of either FAST VAR PERSIST or FAST BISTABLE.
VAR PERSIST~Selects the Variable Persistence storage mode. The stored display is of variable
intensity dependent upon the setting of the STORAGE LEVEL, density of charge deposited
when storing, etc. The stored display can be erased at acontrollable, continuous rate determined
by the setting of the PERSISTENCE control. When not being erased, the view time is limited by
the natural bright fading of the storage target.
BISTABLE-Selects the BISTABLE storage mode. The stored display is substantially of two
fixed intensity levels; written (bright) and unwritten (background). An erase cycle returns the
display to the unwritten state.
POWER --Switch and indicator. Switch applies power to the instrument and the indicator illumi-
nates to indicate the power is on.
CALIBRATOR —Positive going square wave or dc voltage selected by an internal jumper. Output
voltage at pin jacks (4 V, 0.4 V, and 40 mV).
STORAGE LEVEL-Controls the voltage level on the storage targets. Adjusts writing speed in
FAST BISTABLE, VAR PERSIST, and FAST VAR PERSIST.
SAVE INTEN-—Used in conjunction with SAVE to control the storage viewing intensity. At
reduced intensity, the view time of the stored VAR PERSIST display is proportionately ex-
tended.
SAVE-~Selects the SAVE display mode. The stored display is retained at a controllable SAVE
INTENSITY and the erase functions are Jocked out. The time-base unit is inhibited except
when the SAVE mode is entered from STORE before a sweep occurs. If this is done, the dis-
play will wait in the STORE mode and enter SAVE automatically at the end of the next
1-7

Operating Information--7623A/R7623A Service
FRONT PANEL CONTROLS AND CONNECTORS (cont.}
occuring sweep. This is referred to as the ‘babysitting’ mode.
FAST LEVEL CENTER—Adjusts the voltage level of the FAST target relative to the viewing
target and, therefore, the tracking of the STORAGE LEVEL for the two targets.
©
STORE-Selects the STORE display mode.
NON STORE—Selects conventional display mode. Storage system is inoperative.
TRACE ROTATE--Adjusts alignment of the trace with the horizontal graticule line.
FOCUS--Provides adjustment for display definition.
®®®®®
22) CAMERA POWER—Three-pin connector on crt bezel provides power output and receives
remote single-sweep reset signal from compatible camera systems.
REAR PANEL CONTROLS AND CONNECTORS
1-8
The following descriptions are referenced to Figure 1-3.
(23) FUSE-—Line voltage fuse.
REMOTE ERASE IN--Provides external connection for remote erase.
(25) EXT SS RESET IN-~Remote single sweep reset.
EXT Z AXIS IN—Input for intensity modulation of the crt display.
(21)
VERT
SIG
OUT—Vertical
signal
selected
by
TRIG
SOURCE
switch
(LEFT,
RIGHT,
ALT,
and
ADD).
(28) + GATE OUT—Gate signal selected by gate selector switch (Main, Auxiliary, and Delay).
+ SAWTOOTH OUT-—Positive-going sawtooth from time-base unit.