Tektronix 7904 User manual

COMMI`T`TED TO EXCELLENCE
PLEAS CHECK SCR CHANGE
INPCRMATION
AT THE READ C THIS MANUAL
.
CILL
COP'
SN
E260000®UP
IN ~F~U~~IUN
MANUAL_
Tektronix, Inc .
P .O . Box 500
Beaverton, Oregon

97077

Serial Number ____
070-2390-00

First Printing SEP
1977
Product Group 42

Revised MAY
1983

7904 (SN
8260000-UP)
Operators
Safety Information

.............,....,...    ,...
iv
Service Safety
Information .......... ... . .................,..,.,,,,.,,..
.
vi
SECTION 1

GENERAL INFORMATION

Page
Introduction .......................................
.......... . . .... .1-1
Installation ....

............................
. . . . ................... 1-1
Initial
Inspection ..........................
....................... 1-1
Operating Power
Information ................ ................,.,, . , , . 1-1
Operating Voltage ....................
. . ........... . .... . . . . . . .... 1-2
Operating Position ............. . . ...
............. ..... . ........... 1-3
Operating Temperature

........ ................  
1-3
Repackaging for
Shipment ... ... . ................ ... . , .  ,
1-3
Specification ...... .... . . ....................
....................... .1-4
System Electrical Specification ............... . ... , . 
1-12
Standard Accessories

.............. . . . . ............... 
1-14
SECTION
2

OPERATING INSTRUCTIONS
Preliminary Operation

................... 
2-1
Plug-In
Units ...................................
. . . .............. . . . . 2-1
Installation
of Plug-In Units

................,., .    , 2-1
Controls and Connectors .....................,.. .,.,.        2-1
Functional Check

............................
........ . . . . . . .... . ....
.2-4
Set-Up Information ........... .
. . ... ........ . . . ................... 2-4
Display
Focus ............... ............
........................ 2-4
Trace Alignment

. . .... ... . ............... ..... . .................
.2-4
Graticule
Illumination

. ......... . . ... ..,.....  .  , 2-4
Controllllumination
..... . . . . .....  ,..  ,
.2-5
Vertical Deflection System ..............,...  .  
,
2-5
Horizontal Deflection System ..............,.....   , . 
2-5
Triggering .....................................................
.2-7
Readout ......................................................
.2-7
Beam Finder
.....................................
. ...... . ...... .2-7
Calibrator .....................................
. ................ 2-8
Z-Axislnput
................................ . ..................
.2-8
Simplified Operating Instructions
................. . ....,..,.,,,,,,,,,,,,,, 2-g
Single-Trace Display
........... . .....
. . . . . ........................
2-8
Dual-Trace Display ...........
. . . . . . .............................. 2-9
Dual-Sweep
Display ...... . ........................................
2-10
Dual-Trace--Dual-Sweep
Display . ............,.,.  .  , 2-10
Independent-Pairs
Display ...................... 
2-11
Delayed Sweep-Single Trace
Display ....................,,..,,.,,,,.,,
2-11
Delayed Sweep-Dual Trace .........,......,....   , .  
2-12
X-Y
Display ..............................
.... . .... . . . ..... . . . . . . 2-12

7904 (SN B260000-UP)
SECTION 2

OPERATING INSTRUCTIONS
(cont)

Page
Detailed
Operating Information
......................~~~-~~~-~-----~----~~
2-13
Intensity Controls

................................................
2-13
Crt
Phosphor Protection

.......................~~~~~~-~~--~~--~~...
2-13
Display
Focus
. . . . ..... .........................................
.2-13
Astigmatism Adjustment
......... . . ... .......~~~~~-~~---~----~--~~~.
2-13
Y'race Alignment
Adjustment

. .......... . .... ......~~~~~~~~~--~----~~
2-13
Graticule .............
. .... ............. ......................
.2-14
Light Filter .......................
.........
. . . ..................
2-14
Beam Finder ........................
.
... ......... . .... . . . .
. .... .2-14
Controllllumination
........................ .--~~~~~~----~------~~
.2-15
Readout . . . ....................................
..
.... .... . . ... .2-15
Remote Readout .. .
. ...........................................
. .2-16
Display
Photography ..... . .... ....................................
2-16
Vertical and
Horizontal Mode
Switch Logic

..... . ..........~~~~~~~--~~~- -
2-17
Vertical
Trace Separation ............... . . . . .....~~~~~~~--~--~~-~~~ ~
2-19
Trigger
Source

........ ..................
.......................
.2-20
X-Y Operation . . .............
... . . . .............
... . .............
2-21
Intensity
Modulation

................. ... . ~ ~~~~~~~-------- - ----
-~~~
2-21
Raster
Display ............................
.......................
2-22
Calibrator ......................................
. . . . . ..... . .
.... 2-22
Signal Outputs

........................................ .
. ...... . . 2-23
Probe Power
Connectors .... . ..................~~~~-~~~------~-~~~~
2-23
Applications
.......... . . . . . . ...................................
.2-24
THE REMAINING
PORTION OF THIS TABLE OF
CONTENTS LISTS THE
SERVICING INSTRUC-
TIONS
. THESE
SERVICING INSTRUCTIONS
ARE FOR USE BY QUALIFIED
SERVICE PERSONNEL
ONLY .
T
O
AVOID ELECTRIC SHOCK OR
OTHER PERSONAL INJURY, DO
NOT PERFORM
ANY
SERVICING OTHER THAN THAT
DESCRIBED IN THE
OPERATORS INSTRUCTIONS UNLESS
YOU
ARE QUALIFIED TO DO SO .
SECTION 3

CIRCUIT DESCRIPTION
Introduction ...............
. .... ........ . ...
.......................
.3-1
Logic
Fundamentals

. . ..............
. ...
..... . . . .....................
.3-1
Block
Diagram

..............................
........ . .
..... . ...... . .3-2
Main
Interface .................................
. . ..
.................. 3-2
Front-Panel
Interconnect .................. .~~~~--~~~~~~----~~--~---~~~
.3-5
Logic ........... .... . . ...........................................
.3-5
Trigger Selector

...........
. . . . ......................................
3-24
Readout System

............
. ..... . . . . . .............................
.3-27
Vertical Amplifier ....
... . . ................
.
.. .
........................
3-46
Horizontal
Amplifier ............... ...... .~~~~~~~~~~~---~~--~--~--~~
. .
.3-49

7904 (SN 8260000-UP)
SECTION
3

CIRCUIT DESCRIPTION (cont)

Page
Output Signals and Calibrator

...... ............. ........................
3-52
Converter/Rectifiers . . . . ..... ... . ......... .............................
3-54
Low-Voltage Regulators . . . . ......... . . ... ..............................
3-59
CrtCircuit . . . . . . . ............... . . ... ............................ . .3-62
SECTION 4

MAINTENANCE
Preventive Maintenance

. . . ............................. . .... . . ... .....
4-1
Cleaning ...... ... . .............................. . . . . ..... . ..... 4-1
Visual Inspection .
. . . ............   .  .,........
. . , . .  ,..,..  . 4-2
Semiconductor Checks

........................... ............... . .4-2
Periodic Electrical Adjustment

...................... ............... . .
4-2
Troubleshooting . . . ............................
. . . ............... ... .4-3
Troubleshooting Aids ........................ ....... . .... . . .... ....
4-3
Troubleshooting Equipment .................. ........ . . . . . ... ... ....
4-5
Troubleshooting Techniques

................ ......... ... . ... . .......
4-5
Troubleshooting the High-Efficiency Power-Supply Unit ...... . . . . ........... 4-8
Corrective
Maintenance ........................ ...... . . ................ 4-13
Obtaining Replacement
Parts ................ ... . . . .................. 4-13
Soldering Techniques

................. ...... ......................
4-73
Component Removal and Replacement .... ...... .......................
4-14
Adjustment After Repair .......... . ... ...... .............,..........
4-27
SECTION 5

PERFORMANCE
CHECK AND ADJUSTMENT
Preliminary Information ....... . .... ............ .......,,..,....,...,, ..
5-1
Adjustment Interval . . . . . . . . . .......... ........................,., .
5-1
Using this Procedure . ...... . ........ ............................ . .
5-1
Test Equipment Required . . . ......... . . . ............................ ....
5-1
Test Equipment Alternatives . ..... . . . . . ..........,.......... . . ... .... 5-2
Performance Check/Adjustment
Procedure Index ............... . ..... . .... .... 5-5
Setup Procedure . . .....
. . ... ..................... . . . . . .......... .5-6
SECTION 6

OPTIONS
SECTION 7

REPLACEABLE ELECTRICAL PARTS
SECTION 8

DIAGRAMS and CIRCUIT BOARD
ILLUSTRATIONS
SECTION 9

REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION

7904 (SN 8260000-UP)
OPERATORS SAFETY
INFORMATION
The following general safety
information applies to all
operators and service
personnel . Specific warnings will be
found throughout the manual
where they apply and
should be
followed in each instance .
Grounding the Instrument
This
instrument is safety class 1
equipment (IEC
designation) . All accessible conductive
parts are directly
connected through the
grounding conductor of the power
cord to the grounding
contact of the power connector
.
WARNING

statements identify conditions or
practices which could result in personal injury or
loss of
I ife .
CAUTION

statements identify
conditions or prac-
tices which could result
in damage to the equipment or
other property .
The power-input plug must be inserted only
into
a
mating receptacle with a grounding contact
. Do not defeat
the grounding connection
. Any interruption of the groun-
ding connection can
create an electric-shock hazard .
Refer to qualified
service personnel for verification of
adequate
protective grounding system to which this
instrument
is to be connected .
The word DANGER on the equipment identifies areas
of immediate hazard which could result in personal injury
or loss of life .
For electric-shock protection, the
grounding connec-
tion must be made before
making connection to the
instrument's input or output
terminals .
The following safety symbols may appear on the
equipment .
CAUTION-Refer to manual
DANGER-High voltage
Protective ground (earth)
terminal
Do Not Remove Instrument Covers
To avoid electric-shock hazard,
operating personnel
must not remove the protective
instrument covers . Com-
ponent replacement and
internal adjustments must be
made by
qualified service personnel only .
Other warning symbols where they apply
.
WARNING
AC Power Source and Connection
Do Not Remove CRT° Implosion Shield
This instrument operates from a single-phase power
source . It has a three-wire power cord and a two-pole,
three-terminal
grounding-type connector
. The voltage to
ground (earth) from
either pole of the power source must
not exceed the maximum rated operating voltage, 250
vol ts .
Do not remove the clear
plastic implosion shield
covering the crt
face
plate . This crt implosion shield
provides protection to the operator from crt implosion .
Before making connection to the power source,
deter-
mine that the instrument is adjusted to
match the voltage
of the power source, and
has
a
suitable two-pole, three-
terminal grounding-type connector . Refer any changes to
qualified service personnel .
Do Not Operate in Explosive
Atmosphere
To avoid explosion, do not operate
this instrument in an
explosive atmosphere
unless it has been certified forsuch
operation
.
iv

7904 (SN 8260000-UP)
Use the
Proper Fuse
Refer fuse replacement to qualified service personnel
only
.
To avoid fire hazard, use only the fuse specified in
the
parts list for your instrument and which is identical in
the following
respects
:
Exercise Care with Intensity Level
Crt phosphor damage can
occur under adverse con-
ditions . Avoid any condition where an extremely bright,
sharply focused
dot exists on the crt . Also, remember that
fhe light filter reduces the apparent
light output from the
crt .
Prevent Instrument
Damage
A .

Type : Slow blow, fast blow, etc
.
B . Voltage rating : 250 V, etc .
C . Current rating .
Plug-in units should not
be installed or removed
without first turning the instrument power off, to prevent
instrument damage .
Operating-Power Consideration
To
prevent damage to the instrument always check
the
LINE VOLTAGE
SELECTOR switch, located on the rear of
the instrument,
before connecting the instrument to the
supply circuit .

7904 (SN 8260000-UP)
SERVICE SAFETY INFORMATION
The following are safety precautions which appear in
the servicing information sections of this manual . This
Service
Safety Information is in addition to the Operators
Safety Information given previously .
WARNING
Do Not Service
Alone
Do
not attempt internal service or adjustment
unless
another person, capable of rendering
first aid and
resuscitation, is present .
Exercise Care
When Operating Instrument with
Covers
Removed
Dangerous potentials
exist at several points
throughout this
instrument . When the instrument is
operated
with the covers removed, do not touch exposed
connections or components . Some
transistors have
voltages present on their cases . Disconnect
power before
cleaning the instrument or replacing
parts .
Disconnect the instrument from the
power source and
allow the line storage capacitors to
discharge before
removing the power-unit
cover . The line storage
capacitors remain
charged with high-voltage do for
several minutes
after the line power is disconnected
unless they
are manually discharged . A warning-indicator
neon bulb, located on the Power-Supply Inverter
board,
flashes when this stored voltage exceeds
about 80 volts .
Do not remove the power-unit
cover while this light is
flashing .
Use extreme
caution when troubleshooting in the
power-supply
unit, to avoid electric shock . Stored do
potentials on the Power-Supply Inverter circuit board
remain long after the instrument is
disconnected from the
power source . Verify
that the power-cord plug is dis-
connected and that the
line storage capacitors (C1216 and
C1217)
are completely discharged before attempting any
repairs or ohmic measurements . (A
warning-indicator
neon bulb, located on the Power-Supply
Inverter board,
flashes when this storage
voltage exceeds about 80 volts .
However, simply because the neon bulb is not flashing
does not mean that the capacitors are fully discharged .)
Disconnect Instrument Power
To avoid electric-shock hazard, always
disconnect the
7904 from the power source
before removing or replacing
components .
To avoid electric-shock hazard, disconnect
the instru-
ment from the power source
before soldering .
Silicone Grease Handling
Handle silicone grease with care . Avoid
getting the
silicone grease in your eyes . Wash hands thoroughly
after
use .
CRT Handling
Use care when handling a crt . Breakage of the
crt
causes a high-velocity scattering of glass
fragments
(implosion) . Protective clothing and safety
glasses should
be worn . Avoid striking the crt on any object
which might
cause it to crack or implode
. When storing a crt, place it in
a
protective carton or set it face down in a protected
location on a smooth surface with a soft mat under the face
plate .
Avoid Excessive Moisture
Exercise Care When Servicing Power Unit
The
power supply unit has been Tested at the
factory fo
ensure safe operation . Improper repair of
This unit can
result in hazardous potentials on
the instrument chassis .
Do not remove the plate insulator,
block insulator, or
transistor shield from
the heaf-sink . (See the exploded
view
drawing of the power supply unit for the location of
these components .)
Circuit boards and components must be dry before
applying power to prevent damage from electrical arcing .
Exercise Care When Checking Diodes
When checking diodes, do not use an ohm-meter scale
that has a high internal current, since high currents may
damage the diodes under test
.
vi

7904 (SN 8260000-UP)
Exercise Care When Soldering on Multi-Layer
Boards
Several of the circuit boards
in
the 7904 are multi-layer
type boards with a conductive path laminated between the
top and bottom board layers . All soldering on these boards
should be done with extreme care to prevent breaking the
connections to this center conductor . Only experienced
maintenance personnel should attempt repair of these
boards
:
A2-Main Interface, A4-Logic, AS--Trigger
Selector, A7-Vertical
interface, A12-Cap-Rectifier .
Use Proper Cleaning Agents
Avoid the use of
chemical cleaning agents which might
damage the plastics used in this instrument . Use
a
non-
residue type of cleaner, preferably isopropyl alcohol,
totally denatured ethyl alcohol, or TP35 . Before using any
other type of cleaner consult your Tektronix Service
Center or representative .
Do Not Use Pin Sockets for Connection Points
Exercise Care When Handling CRfi Anode Lead
Do
not touch any components with the crt anode lead
until it is fully discharged .
The spring Pension of the pin sockets ensures a good
connection between the circuit board and the pin . This
spring
tension can be destroyed by using the pin sockets
as
a
connecting
point for spring-loaded probe tips,
alligator clips, etc .
Universal Euro
220 volt/50 Hz
Rated 16 ampere
North American
120 volt/60 Hz
Rated 15 ampere
(12 amp max ; NEC)
Australian
240 volt/50 Hz
Rated 10
ampere
North American
240 volt/60 Hz
Rated 15 ampere
(12 amp max ; NEC)
23617-01
Power plug options .
REV A DEC 1980

7904 (SN
B260000-UP)
2394 ~ 3
7904 FEATURES
The TEKTRONIX 7904 Oscilloscope is a solid-state, high
performance instrument designed for general purpose
applications . The 7904 features a crt with small spot size and high writing
rate . Graticule area is 8 X 10 cm . Additionally, the
instrument
includes a readout system providing crt display of alphanumeric
information from the plug-ins, including
deflectior7 factor, sweep
rate, and other encoded parameters .
The instrument's high vertical bandwidth (500 MHz),
and four plug-in compartments which accept 7-series plug-in
units, form
a
highly
flexible measurement system .

Section 1-7904 (SN B260000-UP)
INTRODUCTION
INSTALLATION
The Instruction Manual contains both operating and
servicing information for the 7904 Oscilloscope .
Section 1-General Information
;
contains safety infor-
mation, instrument description, electrical specifications,
environmental
characteristics, standard and recommend-
ed accessories, and packaging for shipment instructions .
Section 2-Operating Instructions ; contains informa-
tion relative to operating and checking the instrument
operation
.
Initial Inspection
This instrument was inspected
both mechanically and
electrically before shipment . It should be free of
mars or
scratches and should
meet or exceed all electrical
specifications . To confirm this,
inspect the instrument for
physical damage incurred in transit and test the electrical
performance by following the Operating Instructions in
Section 2 and
Performance Check Procedure in Section 5
of the
Instruction Manual
.
If there is damage or deficiency,
contact your local
Tektronix Field Office or represen-
tative .
Section 3~-Circuit Description ; contains basic and
general circuit analysis that may be useful for servicing or
operating the instrument
.
Operating-Power Information
Section 4--Maintenance ; describes routine and correc-
tive maintenance procedures with detailed instructions for
replacing assemblies, subassemblies, and individual com-
ponents .
This instrument can
be operated
from either a 115-volt
or 230-volt nominal supply source, 48 to 440 Hz .
Section 5-Performance Check and Adjustment ; con-
tains procedures to check the operational performance
and electrical characteristics of the instrument .
Procedures also include methods for adjustment of the
instrument
to meet specifications .
Section 6-Instrument Options ; contains a description
of available
options and locations of incorporated infor-
mation for those
options .
To prevent damage to the instrument, always
check
the LINE VOLTAGE
SELECTOR switch located on
the rear of the instrument
before
connecting
the
instrument to the supply circuit .
Section 7-Replaceable Electrical Parts ; contains in-
formation necessary
to order replaceable parts and
assemblies related to the electrical functions
of the
instrument
.
Section
8-Diagrams and Circuit Board Illustrations
;
includes detailed
circuit schematics, locations of
assembled boards
within the instrument, voltage and
waveform information, circuit
board component locators,
and locations of adjustments to aid
in performing the
Adjustment procedure .
WARNING
AC POWER
SOURCE AND CONNECTION . This
instrument
operates from a single-phase power
source
. It has a three-wire power cord and two-pole,
three
Terminal
grounding-type plug . The voltage to
ground (earth) from either pole of
the power source
must not exceed the maximum
rated operating
voltage, 250 volts .
Section
9-Replaceable Mechanical Parts ; includes
information necessary
to order replaceable mechanical
parts and shows exploded
drawings which identify
assemblies .
Before making connection to the power
source,
determine
that the instrument is adjusted to match
the
voltage of the power source, and has a suitable
two-pole, three-terminal
grounding-type plug . Refer
any changes to qualified
service personnel .

General Information-7904 (SN B260000-UP)
WARNING
GROUNDING . This instrument is safety class I
equipment (IEC designation) . All
accessible con-
ductive parts are directly connected through the
grounding conductor of the power cord
to
the
grounding contact of the power plug .
Operating Voltage
The 7904
can be operated from eithera 115 V or a 230 V
nominal line voltage
source . The Line Selector assembly
on
the rear panel converts this
instrument from one
operating voltage
to the other . This assembly
also in-
cludes fuses to provide
protection for the line-input
portion of this instrument
. Use the following procedure to
obtain correct instrument operation
from the line voltage
available . Refer to Table 1-3 .
The power input plug must only
be inserted in a
mating receptacle with
a grounding contact . Do not
defeat the grounding connection . Any
interruption
of the grounding connection can create an electric
shock
hazard .
Table 1-3
REGULATING RANGE LIMITS
Line Selector
Switch Position
Regulating
Range
For electric shock
protection, the grounding con-
nection muss be made before making connection to
the instrument's input or output terminals .
115 V
230 V
_

_90_ to 1_32 volts___
a

180 to 264 volt s
1
.

Disconnect
the instrument from the power source .
Table 1-1
POWER-CORD
CONDUCTOR IDENTIFICATION
Conducto r
U ngrou nded (Line)_
_Gr_o_un
ded _

(N eutral)
Grounded
(Ear thing)
Color Alternate Color
Brown
_Blue _ _ _
Green-Yellow
B
lac
k__  ____ .______
White
-"______ .__
Green-Yellow
2 .
Loosen the two captive screws which hold the cover
onto the selector
assembly ; then pull to remove the cover .
3 . To convert from 115 V to 230 V nominal line voltage,
or
vice versa, pull outthe Line Selectorswitch bar (see Fig .
1-1) and
plug it back into the remaining hole . Change the
line-cord
power plug
to match the power source recep-
tacle or use a 115 V to 230 V adapter .
The power-cord plug required depends upon the ac
input voltage and the country in which the instrument is to
be used . Should you require a power-cord plug other than
that supplied
with your instrument, refer to the standards
listed in Table 1-2
.
Table 1-2
POWER-CORD PLUG CONFIGURATION
Nominal Supply Voltage
115
Vac
`IEC 83

_
aANSI C73 .20 230 Vac
`IEC 83
a
BS 1363
`CEE 7, sheets IV, VI, and VII
`AS
C112
b NEMA 6-15-P
'ANSI-American
National Standards Institute
b NEMA-National Electrical
Manufacturer's Association
`IEC-International
Electrotechnical Commission
d BS-British Standards Institution
`CEE-International Commission on Rules for the Approval
of
Electrical Equipment
`AS-S
Reference Standards
aANSI C73 .11

_
b
NEMA
5-15-P
4 .

Re-install the cover and tighten the captive screws .
Fig . 1-1 . Line Selector assembly on rear panel (shown with cover
removed) .

General
Information-7904 (SN B260000-UP)
5 . Before applying
power to the instrument,
check that
the
indicator tab on the switch bar
is protruding through
the correct
hole for the desired nominal
line voltage .
This
instrument may be damaged if
operated with
the Line Selector
assemblyset to incorrectpositions
for the line voltage applied .
A thermal
cutout in this instrument
provides thermal
protection and disconnects
the powerfrom the instrument
if the
internal temperature
exceeds a safe operating level .
Power
is automatically restored when
the temperature
returns to a
safe level . Operation of this
instrument in
confined areas or in
close proximity to
heat-producing
instruments may cause the
thermal cutout to open
more
frequently .
REPACKAGING FOR
SHIPMENT
Operating
Position
A
bail-type
stand is mounted
on the bottom of this
instrument . This
stand permits the 7904
to
be
tilted up
about 10° for
more convenient viewing .
If the Tektronix
instrument is to be shipped
to a
Tektronix Service Center for
service or repair, attach a tag
showing :
owner (with address)
and the name of an
individual at
your firm that can
be contacted . Include
complete instrument
serial number and a
description of
the service
required
.
Operating
Temperature
The
7904 can be operated
where the ambient air
temperature
is between 0°C and -X50°C . This instrument
can be stored
in ambient temperatures between
--55°C
and i-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 7904 is
cooled by convection air flow
through the
instrument . 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 .
Maintain the clearance provided by the
feet on the
bottom and
rear and allow about two inches
clearance on
the top and sides (more
if possible) .
Save and re-use the
package in which your
instrument
was
shipped . If the original
packaging is unfit for use
or
not
available, repackage the instrument as
follows :
Surround the instrument
with polyethylene
sheeting to
protect the finish of the
instrument . Obtain a carton
of
corrugated
ca " dboard of the
correct carton strength
and having
inside dimensions of
no less than six inches
more than the
instrument dimensions .
Cushion the
instrument by tightly
packing three inches of dunnage
or urethane
foam between carton
and instrument, on all
sides .
Seal carton with shipping
tape or industrial
stapler .
The carton test strength
for your instrument
is 3'75
pounds .
1- 3

General Information-7904
(SN B260000-UP)
SPECiFIC,ATI~JN
The electrical characteristics listed in Table 1-4 apply when
the following conditions are met : (1)
Adjustment of the
instrument
must have taken place at an ambient
temperature between -+20°C and +30°C ;
(2) the instrument must be
allowed a 30-minute warm-up period
; (3) all specifications are valid at an ambient
temperature of 0° to +50°C,
unless
otherwise stated ;
(4) the instrument must be in an environment
that meets the limits described in Table 1-5 .
Any applicable
conditions
not listed above are expressly stated as part of that
characteristic .
Items listed in the Performance Requirements
column are verified by completing the
Performance Check in this
manual . Items listed in the
Supplemental Information column are not verified in
this manual ; they are either explanatory
notes or performance
characteristics for which no limits are specified .
Characteristic
Deflection Factor
Accu racy
Low-frequency linearity
Bandwidth
Table 1-4
ELECTRICAL CHARACTERISTICS
Performance Requirement
Supplemental Information
VERTICAL SYSTEM
Compatible with all 7-series plug-in units
.l
T i_
Less than 1% difference between vertical
compartments .
0 .1 div or less
compression or ex-
pansion of
a center-screen two-division
signal when positioned anywhere vertically
within the graticule area .
Varies with amplifier
plug-in selected . -
See Table
1-7, Vertical System Specification .
Isolation Between Vertical Com-
partments (eight-division
reference signal)
At least 100 :1 from do to 250 MHz ;
decreasing to at least 40 :1 from 250 MHz
to
500 MHz .
1- 4
Chopped Mode
Repetition rate
1 MHz t20% .
_ _ _
Time segment from eac
__ .
~ .~ 0 .4 to 0 .6 Ns .
compartment
_^
' ~
_ __
Delay Line
___
Permits viewing of leading edge of
y
triggering signal .
Difference in Delay Between
0 .1 ns or less .
Compartments
~ ._____ _ _
Vertical Display
Modes
_
Selected by front-panel VERTICAL
MODE switch .
LEFT : Left vertical unit only .
ALT :
Dual-trace, alternates between vertical units .
ADD :
Added algebraically .
CHOP : Dual-trace, chopped
between vertical units .
RIGHT :
Right vertical unit only .
Trace Separation Range for
_ .__ ._
B trace can be positioned approxi-
Dual-Sweep Modes
mately -f-4 and --4 div from
the A trace .

General
Information-7904 (SN 8260000-UP)
Trigger Source
VERT MODE :
LEFT VERT :
RIGHT VERT :
Table 1-4 (cont)
ELECTRICAL
CHARACTERISTICS
Determined by vertical
mode .
From left vertical unit only .
From
right vertical unit only .
Selected by front-panel A
TRIGGER SOURCE AND B
TRIGGER
SOURCE switches .
VERT MODE
position auto-
matically
provides opti-
mum trigger
source for
each vertical display mode .
Deflection
Factor
_
Deflection Accuracy
DC Linearity
Bandwidth
_ .______ .__ .~
._

._
10 div reference
Fastest Calibrated
Sweep Rate
Horizontal Display Modes
A :
ALT :
HORIZONTAL SYSTEM
Compatible with all
7-series plug-in units .
____
Less than 1% y difference
between

_ .~

_
compartments .
0 .1 div or less error at each graticule
line after adjusting for no error at
the second and tenth graticule lines .
do to at least 1 MHz .
0 .5 ns/div
A horizontal unit
only .
Dual-sweep,
alternates between
hori-
zontal
units .
With 7B92A time-base unit only . A
Other 7B-series units are uncal-
ibrated for first 60 ns of sweep
time when
used with 7904 .
Selected by
front-panel HORIZ-~
ONTAL MODE
switch .
CHOP :
Dual-sweep,
chopped between hori-
zontal units .
_
B :

_~ ._-L_~__-~^rv`~ B ho rizontal unit o nly . _
Phase
Shift Between Vertical
and
Horizontal Deflection
Systems
Without
phase correction
With phase
correction
(Option 2)
Chopped Mode
Repetition
rate
Time segment
from each
compartment
Display
Factor '
2° or less from do to at
least
35 kHz
.
Adjustable
to less than 2° from do to~
1 MHz .
200 kHz ±20% .
2 .0 to
3 .0 ~s .
At least 75% .

General Information--7904
(SN 8260000-UP)
Table
1-4 (cont)
ELECTRICAL CHARACTERISTICS
Characteristic
_ .. .__-_~--_- _ ._u_____~= ._
Performance
Requirement
- ...
-~
~~w~~ .=A
CALIBRATOR
Supple menta l Inf orm ation
-
- -_- _ . ._
._~__~~~____
Wave
Shape Square wave and dc .
~ ~ Polarity_
_
Positive-going
with baseline voltage at
zero .
Output Voltage
~
Selected by front-panel CALIBRATOR
switch .
Open circuit 4 mV, 40
mV, 0 .4 V, 4 V, 40 V .
_____
~
__
~~- Into 50 ohms
__
2 mV, 20 mV, 0 .2 V, 0 .4
~ _ __ _
Output Curren
40 mA through front-panel current
loop .
_
Amplitude Accuracy (Voltag
and Current)
+15°C to +35°C
Within 1% .
0°C to
+50°C Within 2% .
_
.__
Repetition Rates
1 kHz .
Selected by front-panel
RATE switch .
1/2 repetition
rate of B Sweep gate .
Dc .
1 kHz Accuracy (Voltage
and Current)
+15°C to -+-35°C Within 0
.25% .
0°C to +50°C
Within 0 .5% .
~~ ~~
Dual Cycle
50% within 0 .1% .
Risetime and Falltime
4 mV through 4V and 40 mA Less than 0 .25 us .
40 V Less than 2 Ns
with 10 pF load .

General Information~7904
(SN 8260000-UP)
Characteristic
Sensitivity
Polarity of Operation
Response to positive-going
input
Propagation delay
Recovery time in response
to positive input step
Recover time in response
to negative input step
Input Resistance at Dc
Maximum Safe Input Voltage
+-Sawtooth
Sou rce
Table 1-4 (cont)
ELECTRICAL CHARACTERISTICS
Intensity Circuit Pulse
Performance
(Between
Rear-
Panel
Connector and crt)
Low-frequency limit
Response to negative-going
input
Performance
Requirement
___ ~____
EXTERNAL Z-AXIS
INPUT
'I
2 V p-p~provides trace modulation_

_ ____ _
over full
intensity range .
Positive-going signal decreases trace
intensity ; negative-going signal increases
trace intensity .
A
HORIZ
time-base
unit
or
B HORIZ
time-base unit .
Supplemental Information
Approximately 0 V input produces
no intensity change .
Dc
Approximately 10 ns .
Approximately 20 ns .
~, Approximately 25 ns .
Approximately 50 ns .
Approximately 0 ns .
500
f2
f10% .
15 V (dc +
.
peak ac)
Selected by internal Sweep
switch .
Polarity
Output voltage
Rate
of rise
Into 50 O
Into 1 Mfg
(parallel with 150 pF)
50 mV/unit of time selected by the
time
base
T _IM_E/D_IV
s
witch, _ within 15% .
100 ns/div maximum .
1 V/unit of time selected by the
time-base TIME/DIV switch, within 10% .
1 Ns/div maximum .
Positive-going with baseline at 0 V
within 1 V (into 1 Mf2) .
Peak
voltage
Into 50 f2
Into 1 Mfg
At least 500 mV .
At least 10 V .
1-7

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~~~~~~ ~~
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horbontu!oompa~monU~
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~~~~~~~_
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'
xsp~eru

General Information-7904 (SN 8260000-UP)
Characteristic
Table 1-4 (cont)
ELEGTRICAL CHARACTERISTICS
Performance Requirement

Supplemental
Information
READOUT DISPLAY (cont)
Zero Display
Total characters
(Each row)
Horizontal
Centering
40 zeros displayed, no overlap,
at least 9 .5 div in width .
Left side
within
0
.25 div
of
0
graticule line .
With Q2225 removed
Right side within 0 .25 div of 10th
graticule line .
Vertical
Centering
Top Row CH 1 characters located within
upper graticule line .
Bottom Row CH 2 characters located within
lower graticule line .
Cathode
Ray Tube
Graticule
Type
DISPLAY
Internal, illuminated with variable edge
lighting .
Area
Standard
instrument 8 div vertical by 10 div
horizontal . Each division equals 1 cm .
Option 4 8 div vertical by 10 div
horizontal . Each division equals 0 .5 cm
.
Phosphor
Beam Finder
Minimum Photographic Writing
Speed with Polaroide Type
410 Film (without film fogging
techniques)
Standard instrument
Tektronix
C-51 R camera
with f1 .2 lens and 1 :0 .5
object-to-image ratio
P31 standard .
Others available on special order .
Limits display within graticule area
when actuated .
P31 :
2 .81 cm/ns
P11 :
6 .1 cm/ns
Option 4
Tektronix C-51 R
camera
with,fl .2 lens and 1 :0 .5
object-to-image ratio
P31 :
5 .0 cm/ns
P11 :
10 .0 cm/ns
'Registered trademark of the Polaroid Corporation .
1-9

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~~~1~~on~
~~~~~R!~~~~~~R~~T~R!~T!~~
~hm~c~d~~
~~e1~
~~~nR~~~KM~~T~~
NOTE
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Roqu~omen~uo/umn o~ Teb/o /'4ovor0ho /u8o~~g
onvknnmente/@n/~y~
Tompom~unoRango
Opomdng
Nonopenging
A!0~do
~~~~C~
-55°Cto+75°C~
Opom~ng
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Conduo~~!nte~ononoe
Trunoporu~ion <paokuged in~~mmen~
.
v,iMhoutp!ug-ine)
L_
~~~~
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add~~na//n/onna~on~
!n~n~nnonoorudiu~od~vum~hoin~~numen~under~oa
vvithin
~h~givon !imito~nom 150 kHz~o 1000 NiHz~
!nVa~orenoeoondumedou~o~~hoinu~numon~undor~m~
~hvuugh
~ho poworoovd vvi~hin tho givon !imitx ~rom
150kHztn25~Hz~
{~uu!i~iooun~orN~uiona!Go~Tmnoi~Commiuon*yo
proooduno1~ .Ca~~~nry11~
1'~~
~~~~~~~
~@~~~~WPP~~

General Information-7904
(SN 8260000-UP)
Ventilation
Warm-up Time
Finish
Overall Dimension (measured
at maximum points)
;
See Fig . 1-2 for
dimensional drawing
.
Characteristic
Table 1-6
PHYSICAL
Information
Convection cooling .
Automatic resetting thermal
cutout protects instrument from overheating .
20 minutes for rated accuracy .
Anodized front- and rear-panel with blue-vinyl painted
aluminum cabinet .
Height 13
.5 in .
Width
34 .2 cm
12 .0 in .
Length
Net
Weight (Instrument Only)
30 .5 cm
23 .8 in .
69 .5 cm
30 .0 lbs .
13 .5
kg
NOTE :
DIMENSIONS ARE GIVEN WITH
TOP FIGURE
IN INCHES AND BOTTOM
FIGURE IN CENTIMETERS
.
Fig . 1-2 . 7904 dimensional
drawing .