Tektronix T921 User manual

Tektronix, Inc .
P .O . Box500
Beaverton, Oregon 97077
070-1982-01
TEKTRONIX
T921 /T922/T922
R
15
MHz
OSCILLOSCOPES
WITH OPTIONS
INSTRUCTION
MANUAL
Serial Number
First Printing JULY 1975

WARRANTY
All TEKTRONIX
instruments are warranted against de-
fective materials
and
workmanship for
one
year . Any
questions with respect
to
the warranty should
be
taken up
with your TEKTRONIX Field Engineer or representative .
All requests for repairs and replacement parts should be
directed to the TEKTRONIX Field Office or 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 © 1975, 1976 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 form without permission of Tektronix,
Inc .
U .S .A . and foreign TEKTRONIX products covered by
U .S .
and foreign patents and/or patents pending .
TEKTRONIX is a registered trademark of Tektronix, Inc .

REV . B JUL 1977
TABLE
OF
CONTENTS
T921/T922/T922R
Page THE FOLLOWING
SERVICING INSTRUCTIONS
AREFOR QUALIFIED SERVICE PERSONNEL
LIST OF ILLUSTRATIONS
ii
ONLY
SECTION 4 ADJUSTMENTS
Page
LIST OF TABLES
III
Limits and Tolerances 4-1
Adjustment Interaction 4-1
Partial Procedures 4-1
Test Equipment Required 4-1
Preliminary
Procedure 4-2
SECTION 1 SPECIFICATIONS
A . Display and Power Supply 4-4
Electrical 1-1
B . Vertical Amplifier 4-6
Environmental 1-3
C . Time Base 4-10
Physical 1-3
Standard Accessories 1-5
SECTION 5 SERVICE INFORMATION
Recommended Accessories 1-6
Cabinet Removal 5-1
Preventive
Maintenance 5-1
Troubleshooting 5-2
Corrective Maintenance 5-10
SECTION 2
OPERATING INSTRUCTIONS
T922R Line Voltage and
Range
Operating Voltage
2-1
Selection 5-21
Safety
Information 2-1
Repackaging For Shipment 5-21
Function of
Controls, Connectors
and Indicators, T921 and T922 SECTION 6 ELECTRICAL REPLACEABLEPARTS
A . Display 2-1
B . Vertical Amplifier 2-3
OPTIONS
C . Time Base 2-5
SECTION 7
CIRCUIT DESCRIPTION AND DIAGRAMS
Function of Controls, Connectors
and Indicators, T922R
Block Diagram
A . Display 2-7
CRT and Vertical Amplifier
B . Vertical Amplifier 2-8
Power Supply
C . Time Base 2-8
Vertical Input (T921)
First Time Operation 2-10
Vertical
Input (T922)
Probe Compensation 2-13
Vertical Switching (T922)
Applications
2-13
Trigger (Late)
T922R
Rackmounting 2-17
Trigger (Early)
Sweep & Horizontal Amplifier
T922R Single Sweep, Buffer, & Z Axis
T922R Scale Illum, +32 V P .S ., Vert Out,
SECTION 3 PERFORMANCE CHECK
F&R Sw
.
T922R
Circuit Board Interconnections
Limits and Tolerances 3-1
Test Equipment Required 3-1 SECTION 8 MECHANICAL REPLACEABLEPARTS
. Preliminary
Procedure 3-2
Performance Check Procedure 3-3 CHANGE INFORMATION

T921/T922/T922R
LIST OF
ILLUSTRATIONS
REV . A, JUNE 1976
Fig .
No .
Description
Page
No .
Fig .
No .
Description
Page
No .
1-1 T921/T922/T922R 15 MHz
oscilloscopes . Frontis
4-1 T922R
adjustment locations . 4-3
1-2 T922R
dimensional drawing . 1-4
4-2 Power supply adjustment location
1-3 T921/T922 dimensional
drawing . 1-5
(bottom of T921 and T922) . 4-4
2-1 Display front panel controls and 4-3 Interface board adjustment locations . 4-5
connectors . 2-2 4-4 Vertical amplifier adjustment locations
2-2 Rear panel controls and connectors . 2-3 (bottom view of T921 and T922) . 4-7
2-3 Left side of cabinet . 2-4 4-5 Display of correct (idealized) attenuator
2-4
Bottom of cabinet . 2-4
compensation .
4-8
2-5 Vertical
amplifier front panel controls . 2-5 4-6
Time base adjustment
locations . 4-11
2-6 Time
base front panel controls and
connectors .
2-6 5-1 Troubleshooting chart .
5-4
2-7 T922R display controls,
connectors, and 5-2 Color code for resistors and capacitors .
5-6
indicators .
2-7 5-3 Lead configuration for semiconductor
2-8
T922R vertical amplifier controls,
devices . 5-7
connectors
and indicators . 2-9 5-4
Multi-cohnector holder orientation . 5-8
2-9 T922R time
base controls, connectors
5-5 Pin connector replacement . 5-12
and indicators .
2-10 5-6 Shaft-knob removal .
5-13
2-10
Probe compensation . 2-14 5-7
T921 and T922 circuit board locations .
5-13
2-11 Effects
of probe compensation . 2-14 5-8
T921 and T922 circuit board locations . 5-15
2-12 Peak-to-peak
voltage measurement . 2-15 5-9
T922R circuit board locations . 5-17
2-13 Instantaneous voltage
measurement . 2-15 5-10 T922R
vertical module replacement . 5-18
2-14 Phase difference .
2-16 5-11 T922R horizontal
module replacement . 5-18
2-15 Time duration .
2-16 5-12 T922R interface
board replacement . 5-19
2-16 Risetime .
2-17 5-13 T922Rpowermodule replacement
. 5-19
2-17
T922R rackmounting methods .
2-19 5-14 T922R scale illum assembly
3-1 Deflection
accuracy and X gain check
replacement . 5-20
test setup .
3-3 5-15 T922R
line-voltage and range selection . 5-21
3-2 T922R rear input test
setup . 3-4
3-3 Bandwidth check test setup .
3-6
7-1
Foldback circuit action .
3-4 Triggering and Z-axis input check test 7-2
Timing diagram : sweep generatorand gate .
setup .
3-7 7-3
Timing
diagram of signals generated
3-5 Timing
accuracy check test setup . 3-8 ' during
a single-sweep display .
3-6 SWEEP RAMP
OUT display . 3-10 7-4 Bench
version T922+33voltpowersupply .
3-7 SWEEP GATE OUT
display . 3-10 7-5 Simplified block
diagram of the vertical
3-8
TV trigger check test setup .
3-11 output amplifier circuit .

LIST OF TABLES
T921/T922/T922R
Table Title Page
No . No .
1-1 Electrical Characteristics 1-1
1-2 Environmental Characteristics 1-3
1-3 Physical Characteristics
1-3
3-1 Test
Equipment 3-1
3-2 Deflection Accuracy 3-3
3-3 Normal Sweep Timing Accuracy 3-9
3-4 Magnified Sweep Timing Accuracy 3-9
4-1 Test Equipment
4-1
5-1 Power Supply
Tolerance 5-3
7-1 Attenuator and Gain Switching
Sequence
7-2 Attenuator and Gain Switching

T921 /T922/T922R
Fig . 1-1
. T921/T922/T922 R 15 MHz oscilloscopes .
REV . A, JUNE 197 6

This manual includes
instructions for the T921, T922
and T922R portable
oscilloscopes . The T922 is a 15
MHz,
dual trace,
oscilloscope and the T921 is a 15 MHz, single
trace oscilloscope
. The Vertical Amplifier,
either single
trace or dual trace, provides calibrated
deflection factors
from 2 mV to 10 V/div .
The TimeBase provides stable
triggering over the
full bandwidth of the Vertical
Amplifier(s) and
provides calibrated sweep rates from
0 .5 s/div to 0 .2 Ns/div
. A variable X1 to X10 magnifier
extends the
maximum sweep rate to 20 ns/div .
The T992R is a
rackmount verison of the T922 os-
cilloscope which
takes 5-1/4 inches of rack space .
Characterist ic
Probe Adjust Output
Voltage
(0°Cto
+40° C)
Repetition Rate
Z-Axis Input
Sensitivity
Signal Polarity
T921 and T922
T922R
REV . C APR
1977
PerformanceRequirement
A . DISPLAY
Approximately
0 .5
V .
Approximately 1 kHz .
5 volt
signal causes a noticeable
decrease in intensity .
Positive going from ground .
Either polarity of signal can be
applied, depending upon internal
jumper connections
.
SPECIFICATIONS
TABLE 1-1
Electrical
Features
added to the rackmount version
include : single
sweep ; rear panel outputs for Sweep Gate,
Sweep Ramp,
and Vertical Signal ; internally
selectable Z Axis polarity ;
user selection of the CHOP or
ALT dual trace modes ; and
switch-selectable
front-panel or rear-panel inputs for
CH 1, CH 2,
and EXT TRIG signals .
The following instrument specifications
apply over an
ambient temperature range of
0°C to +45°C unless
otherwise specified .
The Adjustment Procedure in Section
4, when
performed completely, allows the T921/T922/
T922R to
meet the electrical specifications listed in
Table
1-1 .
Characteristic
Line Frequency

1 50 to 60 Hz .
Maximum Power
Consumption
CRT Display
Display Area
Trace Rotation
Range
Standard
Phosphor
Nominal Accel-
erating Potential
Section 1-T921/T922/T922R
36 W, 0 .35
A
at 60 Hz, 120
V
line .
8 x 10 cm .
Adequate to
align trace with
horizontal
center line .
P31 .
PerformanceRequirement
12,400 V .
B . VERTICAL AMPLIFIER
Usable Frequency
Range
Dc to 5 MHz .
Deflection Factor
Maximum Input
30 V
(dc
+
peak ac) 30 V p-p at
Range 2
mV/div
to
10 V/div ;12steps in a 1-
Voltage 1 kHz or less
.
2-5
sequence .
Input Impedance Approximately 10 kit .
Accuracy
Power Source (T922R 120 V-240
V Range and
Line Voltage
HI-LO adjustments are not exter-
+20° C to Within 3% .
Ranges (ac,rms)
nally accessible) .
+30° C
120 V Range HI-108 to 132 V .
O' C to +45 1 C Within 4% .
LO-90 to 110 V .
Uncalibrated Continuously variable between
240 V Range HI-216
to 250
V . (VAR) Range settings . Extends deflection
factor
LO-198 to 242
V .
to at least 25
V/div (at least 2 .5 :1) .

Specifications-T921 /T9~2/T922R
Chara cteristic

Performance Requirement
B . VERTICAL AMPLIFI ER (co nt)
TABLE 1-1 (cont)
Characteristic
Sweep Rate
Calibrated Range
Accuracy
+20° C to
+30° C
X-Y
Operation
Unmagnified
Magnified
O' C to +45° C
Unmagnified
Magnified
Variable
Magnifier
Deflection Factor
Variable
Magnifier
X10
X1
X-Axis Bandwidth
T921 & T922
T922R
Input Resistance
Input Capacitance
T921 &T922
T922R
Phase Difference
Between X- and
Y-Axis
Amplifiers
C
.
TIME
BASE
0 .5 s/div to 0 .2,us/div ; 20 steps in a
1-2-5 sequence . Variable X1 to X10
magnifier
extends maximum
sweep rate to
20 ns/div .
Accuracy specification applies
over center 8 divisions . Exclude
first
50 ns of sweep for both
magnified and
unmagnified sweep
rates and anything beyond the
100th magnified division .
Within 3% .
Within
5%
.
Within 4% .
Within 6% .
PerformanceRequirement
Approximately 100 mV/div .
Approximately 1
V/div
.
DC to at least 1 MHz with 10 div
reference signal .
DC to least 1 MHz with 5 div
reference signal .
Approximately 1 MO .
Approxiamtely 30 pF .
Approximately 40 pF (front input
only) .
5°
or less from do to 50 kHz .
REV . B, DEC
. 197 6
Frequency
Response
Bandwidth
Dc to at least 15 MHz (5 division
reference signal
centered vertical-
ly from a 25 S2
source with
VOLTS/DIV VAR control
in
calibrated detent) .
Risetime 23 ns
or less .
ChoppedMode Approximately
250 kHz .
Repetition Rate
(T922)
Input Resistance Approximately
1 MO .
Input Capacitance Approximately 30 pF .
(T921 and
T922)
Input Capacitance
(
T922R )
CH 1
and CH 2, Approximately
40 pF .
(front only)
Maximum Input
Voltage
DC Coupled 400 V (dc +
peak ac) .
800 V (p-p ac) at 1 kHz or
less .
AC Coupled 400 V (dc + peak ac) .
800 V (p-p ac) at 1 kHz or less .
Vertical Output
(T922R)
Amplitude
High Im- At
least 0 .5V/div of display .
pedance Load
50 S2 Load Approximately 50 mV/div of dis-
play .
Bandwidth Approximately 1 MHz .

Ch a r acteristic
_
Performance Requirement
REV . B, DEC . 197 6
TABLE
1-1 (cont)
C .
TIME BASE (cont)
TABLE 1-2
Environmental
Characteristic
Altitude
Storage
Operating
Specifications-T921 /T922/T922R
TABLE 1-2 (cont)
PerformanceRequirement
To 50,000 ft .
To 15,000 ft . Maximum operating
temperature decreases 1°C/1,000
ft . above 5,000 ft .
TABLE 1-3
Physical
Triggering
Sensitivity 0 .5 div internal or 100 mV external
from 2 Hz to 1 MHz, increasing to
1 .5 div internal or 150
mV external
at 15
MHz .
TV Sync
Composite sync 1 div internal or
100 mV external (approximately
2 .3 div or 230 mV of composite
video) .
External Trigger Input
Maximum Input 400 V (dc + peak ac) .
Voltage 800 V (p-p ac) (1 kHz or less) .
Input Resistance Approximately 1 Mfg .
Input Capacitance Approximately 30 pF .
(T921 and T922)
Input Capacitance Approximately 40 pF
.
(T922R, front only)
Level Range
EXT +0 .5 V to -0 .5 V .
EXT +5 V to - 5 V .
10
Characteristic PerformanceRequirement
Weight
T921 and T922
With Panel 15 .5 Ibs (7 .0 kg) .
Cover,
Accessories
and
Accessory
Pouch
Without Panel 15 .0 lbs . (6 .8 kg) .
Cover,
Accessories
and Accessory
Pouch
T922R
Without 19 .0 Ibs (8 .6
kg) .
Accessories
Domestic 33 .0 Ibs (15 .0 kg) .
Shipping Wt
Overall
Dimensions
(T921 and T922)
Refer to Fig . 1-3 .
Overall Dimensions
(T922R) Refer to Fig . 1-2 .
Characteristic
Temperature
Storage
Performance Requirement
-55 0 C to +75 0 C .
Operating
T921 & T922
0° C to
+45° C .
T922R 0° C to
+50° C .

Specifications-T921 /T922/T922R
Fig . 1-2 . T922R dimensional drawing .
REV .
B, DEC . 197 6