Tektronix 7623 User manual

STORAGE
SCILLOSCOPE
SERVICE

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SECTION 2

CALIBRATION
CONTENTS
SECTION 1

OPERATING INFORMATION

Page
Operating Voltage

1-1
Operating Temperature

1-1
Plug-In Installation And Removal

1-1
Operation

1-1
Non-Store Operating Set-Up Information

1-1
Front Panel Controls And Connectors

1-2
Rear Panel Controls And Connectors

1-3
Storage Modes

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 Mode Operating Set-Up Information

1-4
Calibration Interval

2-1
Tektronix Field Service

2-1
Using This Procedure

2-1
General

2-1
Index

2-1
Performance

2-1
Partial Procedure

2-1
Complete Calibration Procedure

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
Introduction -

2-5
Index To Calibration Procedure

2-5
Power Supply

2-5
Display And Z-Axis

2-5
Vertical Deflection System

2-5
Trigger System

2-5
Horizontal Deflection System

2-5
Z-Axis And Auto Focus

2-5
Calibrator

2-5
Signals Out

2-5
Readout Operation

2-6
Storage Operation

2-6
7623/R7623
Service

7623/R7623 Service
OF
CONTENTS (cont)
SECTION 3 CIRCUIT
DESCRIPTION
Page
Block
Diagram
3-1
Circuit Operation
3-1
Logic Fundamentals
' 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 Chopped Blanking
3-10
Chop Counter
3-11
Vertical Mode Control
3-13
Right
3-13
Chop
3-13
Alt 3-14
Add
3-14
Left
3-14
Vertical Binary
3-14
Plug-In Binary
3-15
Output Buffers
3-16
TRIGGER SELECTOR
3-16
Trigger Mode And Add Signals
3-16
General
3-16
Vert Mode
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 Finder Network
3-21
HORIZONTAL
AMPLIFIER
3-21
Horizontal
Channel Switch
3-21
Right Output Amplifier
3-22
Left Output Amplifier
3-22

TA
O
CONTENTS
(cont)
SECTION 3

CIRCUIT DESCRIPTION (cont)

Page
7623/137623 Service
CALIBRATOR And FRONT PANEL SWITCHING 3-22
Mode Switch Logic 3-23
Calibrator 3-23
Oscillator 3-23
Output Amplifier 3-23
Output Divider
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 Readout System 3-35
Timer 3-35
Time-Slot
Counter
3-40
Word Trigger 3-40
Channel
Counter 3-41
Single-Shot Lockout 3-41
Encoding The Data 3-41
Column And Row Data Switches 3-43
Display-Skip Generator 3-44
Column And Row Decoder 3-44
Zeros Logic
And Memory 3-44
Character Generators 3-47
Decimal
Point Logic And Character Position Counter 3-47
Format Generator 3-48
Y-Output Amplifier 3-48
X-Output Amplifier 3-48
Display Sequence 3-48

7623/137623
Service
TABLE
®F CONTENTS (confi)
SECTION 3

CIRCUIT
DESCRIPTION (cont)

Page
SECTION 4 MAINTENANCE
Panel Removal
4-1
Cabinet Model
4-1
Rack Model
4-1
Power-Unit
Removal
4-1
PREVENTIVE MAINTENANCE
4-1
General
4-1
Cleaning
4-1
Exterior
4-2
CRT 4-2
Interior 4-2
Lubrication 4-2
Semiconductor Checks
4-2
Recalibration 4-2
TROUBLESHOOTING 4-2
Introduction
4-2
Diagrams
4-3
Circuit Boards
4-3
Multi-Pin Connector Color-Code
4-3
Wiring Color-Code
4-3
Resistor Color-Code
4-3
Capacitor Marking
4-3
Diode Color-Code
4-3
Semiconductor Lead Configuration
4-3
Troubleshooting Equipment
4-3
Troubleshooting Techniques
4-6
STORAGE CIRCUITRY
3-50
Erase And Timing Circuits
3-50
Sweep Lockout Circuit
3-50
Auto Erase Circuit
3-50
Readout Shut Down Circuit 3-54
Persistence Pulse And Pump Pulse
Generator Circuits
3-54
Flood Gun Anode And CE2 Circuits
3-55
CES And CE2 Circuits 3-55
Collector Circuit
3-56
High Speed Mesh Circuit 3-56
Bi-Stable Mesh Circuit
3-56

CHANGE INFORMATION
OF CONTENTS (cont)
SECTION 4

MAINTENANCE (cont)

Page
7623/137623 Service
CORRECTIVE MAINTENANCE
4-10
Obtaining Replacement Parts
4-10
Special Parts
4-10
Ordering Parts
4-11
Soldering Techniques
4-11
Component Replacement
4-11
General
4-11
Circuit Board Replacement
4-11
Access To The Fan Motor 4-13
Access To The Fan Motor For The 137623 4-13
Semiconductor Replacement
4-14
Access To The Power Transistors
4-14
Interconnecting Pin Replacement 4-14
Cathode 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

7623/137623
Service
The TEKTRONIX 7623/137623 Storage Oscilloscope is a solid-state
instrument designed for fast writing rate storage
applications . The 7623 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 7623 features
a large cathode-ray tube (CRT) screen,
8 X 10 divisions, with small spot size, and
fast stored writing rate .
O

Operating Voltage
Operating Temperature
Plug-in Installation
and Removal
OPERATING INFORMATION
The
7623/R7623 can be operated from either a 110-volt
line or 220-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
The 7623/R7623 can be operated where the ambient
air
temperature is between 0 ° C and +50 ° C . The 7623 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 R7623 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 .
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 7623
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

As desired
GRATICULE ILLUM

As desired
As desired (midrange)
FOCUS

Well defined display
TRIG SOURCE

VERT MODE
VERT MODE

Selected

for the plug-in
compartment with the
plug-in unit installed and
with signal input to be
displayed .
POWER

Pressed in
Section 1-7623/R7623 Service
+15 V Fuse

ALT fuse

Spare jumper
Fig . 1-1 . Location of Voltage-selector jumper, spare jumper, and
230
V fuse in power-unit (shown removed) .
Pins Regulating Range
Selected 110-volt
nominal
220-volt
nominal
Low 90 to 110 volts 180 to 220 volts
Med
99 to 121
volts
198 to
242 volts
Hi I 108 to 132 volts I 218 to 262 volts
Line Fu s e 3 .2
A
Sl o w-bl o w 1 .6
A
Sl o w-blow

Operating
Information-7623/R7623 Service
1 . INTENSITY-Controls the brightness of
the display .
2 . READOUT-Turns
on the Readout dis-
play, and controls the
brightness of the
Readout
display .
3 .
FOCUS-Screwdriver adjustment provides
adjustment for optimum display definition .
4 .
GRATICULE ILLUM-Controls graticule
illumination .
5 . BEAM
FINDER-When
pressed the display
is limited to within the graticule area .
6 . Camera Power-Three pin connector on the
CRT bezel, (top) +15 volt power source,
(middle) receives remote single sweep reset
signal from compatible camera system, and
(bottom) ground pin .
7 . VERT MODE-Selects vertical mode of operations .
LEFT : Signals from the left
plug-in compartment are dis-
played .
ALT : Signals from both vertical
plug-in compartments are
displayed (dual trace)
.
Display is switched from one
vertical
to the other after each sweep .
ADD : Signals from both
vertical plug-in compartments are
algebraically added, and
the sum is displayed .
CHOP : Signals from both vertical compartments
are dis-
played (dual 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
displayed .
8 . TRIGSOURCE -Selects the source of the internal trigger signals
for the horizontal compartment .
9 . POWER-Switch and indicator ; switch
turns on instrument, and
the indicator is on when the instrument
is connected to a power
source and turned on .
LEFT : Trigger signals are from
the left vertical plug-in
compartment only .
VERT MODE : Trigger signals are from the vertical compart-
ment being displayed except in the CHOP and ADD modes ;
then the trigger signal is the algebraic sum of the trigger
signals from the left and right plug-in compartments .
RIGHT : Trigger signals are from the right vertical plug-in
compartment only .
10 . NON-STORE-Non-store operation .
Fig . 1-2
. Front Panel Controls and Connectors .
11 . VAR-PERSIST-Variable persistence storage mode . The
AUTO
VIEW TIME or PERSISTENCE control setting, controls the
retention of the stored display .
12 . FAST-For storing fast signals .
13 . MULTI-TRACE-(MULTI-FAST in early instruments)-For stor-
ing multiple fast signals . For each new signal to be stored the
ERASE (PREP IN MULTI TRACE FAST) must be pressed .
14
.
INTEG-For storing very fast repetitive signals
.
15 . BI-STABLE-For
storing slow signals for long periods of time .
16 . SAVE-Prevents accidental erasure
of
the stored display .
17 . SAVE INTEN-(STORED INTEN in early instruments) -Controls
the brightness of the stored display in the Save Mode .
18 . AUTO ERASE-Automatically erases the stored display, AUTO
VIEW TIME setting
controls the time
between erase
cycles
.
19 . AUTO VIEW TIME-(VIEW TIME in early instruments)-
Controls the time between erase cycles in the Auto Erase
Mode
.
20 .
MANE RASE-Erases the stored display .
21 . STORAGE LEVEL-(LEVEL in early instruments)-Controls
the writing rate in the FAST and BI-STABLE storage modes .
Controls
the writing
rate and brightness of the stored display
in the Variable persistence Mode .
22 . CALIBRATOR-Positive going square wave or DC voltage
selected by changing an internal jumper . Output voltage at pin
jacks
(4
V, 0 .4 V and 40 mV)
.