Tektronix 465 User manual

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-1861- 00
TEKTRONIX
465
OSCILLOSCOPE
WITH OPTIONS
(SN B250000 & UP)
SERVICE
INSTRUCTION MANUAL
First Printing AUG 1974
REPRINTED JULY 1975

WARRANTY
All TEKTRONIX instruments are warranted against
defective 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 ~) 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 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 .

@
465 Service (SN B250000 & up)
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
LIST OF TABLES
SECTION 1
SECTION 2
SPECIFICATIONS
Introduction
VERTICAL DEFLECTION SYSTEM
TRIGGERING
HORIZONTAL DEFLECTION SYSTEM
X-Y OPERATION
CALIBRATOR
Z-AXIS
INPUT
SIGNAL OUTPUTS
POWER SOURCE
CATHODE RAY TUBE (CRT)
SUPPLEMENTAL INFORMATION
Vertical Deflection System
Triggering
Horizontal Deflection System
Calibrator
External
Z-Axis Input
Output Resistances
Cathode Ray
Tube (CRT)
OPERATING INFORMATION
Introduction
Instrument Repackaging
Operating Voltage
CONTROLS
AND CONNECTORS
Introduction
Cathode Ray Tube (CRT) and Display
Vertical Deflection System
Channel 1 and Channel 2
A and B
Triggering
A and B Sweep
Calibrator and Power
Rear Panel
OBTAINING BASIC DISPLAYS
Introduction
Normal Sweep Display
Magnified Sweep Display
Delayed Sweep Display
Mixed Sweep Display
X-Y Dlsplay
Page
V
V
1-1
1-1
1-1
1-2
1-2
1-3
1-3
1-3
1-3
1-3
1-3
1-3
1-4
1-4
1-4
1-4
1-4
1-4
2-1
2-1
2-1
2-2
2-2
2-2
2-2
2-4
2-5
2-6
2-6
2-6
2-6
2-6
2-7
2-7
2-7
2-7

465 Service (SN B250000 & up)
TABLE OF CONTENTS (cont)
SECTION 3 CIRCUIT DESCRIPTION Page
Introduction
3-1
Digital Logic
3-1
BLOCK DIAGRAM 3-1
CHANNEL 1 PREAMP
3-3
Introduction
3-3
Scale Factor Switching
3-4
Input Coupling
3-4
Input Attenuator
3-4
Source Follower
3-4
First Cascode Amplifier
3-5
Second Cascode Amplifier
3-5
Third Cascode Amplifier
3-5
CHANNEL 2 PREAMP
3-5
Introduction
3-5
Second Cascode Amplifier
3-5
Third Cascode Amplifier
3-6
VERTICAL SWITCHING CIRCUIT
3-6
Introduction
3-6
Diode Gates 3-6
Switching Multlvlbrator
3-7
Delay Line Driver
3-9
Reference Feedback Amplifier
3-9
Normal Trigger Pickoff
3-9
VERTICAL OUTPUT AMPLIFIER 3-9
Introduction 3-9
Delay Line
3-9
Vertical Output Amplifier -Discrete Version 3-9
Vertical Output Amplifier-IC Version 3-10
A AND B TRIGGER GENERATORS 3-
10
Introduction
3- 10
Trigger Source
3-10
Tr i gger Coupling
3- 10
Input Source Follower
3-10
Paraphase Amplifier
3- 10
Tunnel Diode Driver 3-11
A AND B SWEEP GENERATOR 3-11
Introduction
3- 11
Disconnect Amplifier
3- 12
Output Buffer Amplifier
3- 12
Sweep Start Amplifier
3-12
Logic Multivibrator
3-12
B Sweep Differences 3-
12
SWEEP AND Z-AXIS LOGIC CIRCUIT 3-13
Introduction
3-13
A Sweep Gate
3-13
ii
@

@
465 Service (SN 8250000 & up}
TABLE OF CONTENTS (cont) Page
3-13
3-13
3-14
3-14
3-14
3-14
3-14
3-15
3-15
3-15
3-15
3-15
3-16
3-16
3-16
3-
17
3-17
3-17
3-18
3-18
3-18
3-18
3-19
3-19
3-19
3-19
3-19
3-20
3- 20
3-20
3-20
3-20
3-20
3-20
3-22
SECTION 3 (cont)
SECTION 4
B Sweep
Gate
Sweep Control Integrated Circuit
Holdoff Timing
A Sweep Holdoff Amplifier
B Sweep Holdoff Amplifier
B Sweep Latch
A Sweep Z Axis Gate
B Sweep Z Axis
A + Gate and B - Gate Emitter Followers
HORIZONTAL AMPLIFIER
Introduction
X-Axis Amplifier
Input Paraphase Amplifier
Gain Setting Amplifier
Output Amplif i er
CRT CIRCUIT
Introduction
High Voltage Oscillator
High Voltage Regulator
High Voltage Rectifier and Output
CRT Control Circuits
Z Axis Ampliflfer
DC Restorer Circuit
CALIBRATOR
Introduction
Multivibrator
Output Amplifier
A TRIGGER VIEW AMPLIFIER
Introduction
Amplifier
LOW VOLTAGE POWER SUPPLY
Introduction
Power Input
Secondary Circuit
FAN MOTOR CIRCUIT
MAINTENANCE
Introduction
Cabinet Removal
PREVENTIVE MAINTENANCE
Introduction
Cleaning
Visual
Inspection
Lubrication
Semiconductor Checks
Recalibration
4-1
4-1
4-1
4-1
4-1
4-2
4-3
4-3
4-3
iii

465 Service (SN 8250000 & up)
TABLE OF CONTENTS (cont) Page
4-3
4-3
4-3
4-5
4-5
4-7
4-7
4-7
4-8
4-9
4-14
iv
SECTION 4 (cont) TROUBLESHOOTING
SECTION 5
SECTION 6
SECTION 7
SECTION 8
SECTION 9
Introduction
Troubleshooting Aids
Troubleshooting Equipment
Troubleshooting Techniques
CORRECTIVE MAINTENANCE
Introduction
Obtaining Replacement Parts
Soldering Techniques
Component Removal and Replacement
Recalibrat i on After Repair
Instrument Repackaging
PERFORMANCE CHECK
Purpose
Limits and Tolerances
Line Voltage Selection
Equipment Required
Special Fixtures
Test Equipment Alternatives
INDEX TO PERFORMANCE CHECK
VERTICAL
TRIGGERS
HORIZONTAL
CALIBRATION
Purpose
Limits and Tolerances
Step Titles
Line Voltage Selectlon
Internal Adjustments
Display
Test Equipment Required
Interactions
INDEX TO CALIBRATION PROCEDURE
POWER SUPPLY
DISPLAY AND 2-AXIS
VERTICAL
TRIGGERS
HORIZONTAL
GATES, CALIBRATOR AND EXT Z-AXIS
ELECTRICAL PARTS LIST
OPTIONS
DIAGRAMS
MECHANICAL PARTS
LIST
CHANGE INFORMATION
4- 14
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-3
5-7
5- 10
6-1
6-1
6-1
6-1
6-1
6-1
6-1
6-1
6-5
6-8
6-10
6-12
6-24
6- 35
6-43
7-1
TAB PAGE
8 -1
9-1
REV. A, JUNE, 1 975

465 Service (SN B250000 & up)
LIST OF ILLUSTRATIONS
Page
Fig. 1-1 465
Oscilloscope
Fig. 2-1
Power supply regulating range selector.
2-2
Fig. 2-2
Front and rear panel controls and connectors.
2-2
Fig.
3-1 Basic block diagram of the 465. 3-2
Fig. 3-2 Detailed
block diagram of the Channel 1 Preamplifier. 3-3
Fig. 3-3 Detailed
block diagram of the Channel 2 Preamplifier. 3-6
Fig. 3-4 Detailed
block diagram of the Vertical Switching Circuit.
3-7
Fig. 3-4 Effect
of Diode Gates on signal path (simplified Vertical
Switching diagram). Condit ions shown for CH 1 posi tion of
Vertical Mode switch.
3-8
Fig. 3-6 Detailed block diagram of the A Sweep Generator. 3-11
Fig. 3-7 Detailed
block diagram of the Horizonta l Amplifier.
3-16
Fig. 3-8 Detailed
block diagram of the CRT and Z- Axis circuits.
3-17
Fig. 3-9 Detailed
block diagram of the Calibrator circuit.
3-19
Fig. 3-10 Detailed
block diagram of the Trigger View Amplifier. 3-20
Fig. 3-
11 Detailed block diagram of the Low Voltage Power Supply.
3-21
Fig. 3-12
Foldover circu it action . 3-22
Fig. 4-1 Removing the wrap around cabinet. 4-1
Fig. 4-2
Color codes. 4-4
LIST OF TABLES
Page Page
2-1 REGULATING RANGES 2-1 6-1 ADJUSTMENT INTERACTIONS 6-2
6-2 TEST
EQUIPMENT REQUIRED 6-3
3-1
GAIN SWITCHING AND ATTENUATION 3-4 6-3 LOW
VOLTAGE POWER SUPPLY
LIMITS 6-8
6-4
TYPICAL LOW VOLTAGE POWER
5-1 DEFLECTION FACTOR
ACCURACY 5-5 SUPPLY RIPPLE 6-9
5-2
LOW FREQUENCY COMPENSATION 6-5 VERTICAL DEFLECTION
FACTOR
SETUP 5-5 ACCURACY
6-16
5-3 A
AND B TIMING ACCURACY
5-10 6-6 A AND B
TIMING ACCURACY
6-39
5-4
DELAY OR DIFFERENTIAL 6-7 A
AND B MAGNIFIED ACCURACY 6-39
TIME ACCURACY
5-11 6-8 DIFFERENTIAL
TIME ACCURACY 6- 40
@ V

1861-19
Fig. 1-1. 465 Oscilloscope.

Section 1- 465 Service (SN B250000 & up)
SPECIFICATIONS
Introduction
The 465 Oscilloscope is a wide-band, portable os-
cilloscope designed to op erate in a wide range of en-
vi ronmental conditions . The instrument is light in weight
and compact of design for ease of transporta tio n, yet
capable of performance necessary for
accurate high-
frequency measurements. Th e dual-channe l dc-to-
100 megahertz vertical defl
ect ion system provid es
calibrated def l ection factors from 5 mill ivolts to
5 volts/ division . The bandwidt h limit ing switch reduces
interference from signals above about
20 megahertz for
viewing
low-frequency , low-level signals.
The
trigger circ uits provide stable sweep trigge ring to
beyond the ba ndwidt h of th e vertical deflect ion system.
Separate
controls are provided to sele ct the desired mode
of triggering
for the A a nd B sweeps.The A sweep can be
operated in one
of three modes: automatic triggeri ng,
normal trigg ering , or single sweep. A variable tr igger
holdo ff co ntrol provides the abili ty for A sweep to tr igger
stably on
aperiodic signals or complex digital words .The
horizontal deflection system has cali brat ed sweep rates
from 0.5
second to 0.05 microseco nd/ division . A X10
magnifi er inc rea se s each sweep rate by a f actor of 10 to
provide a maximum sweep rate of 5 n ano-
seconds / division in the 0.05 µs positio n. The
delayed and mix ed sweep f ea tur es allow the start of the B
sweep to be
de layed a selected amount from the start of A
sweep to
provide accurate relative-time measurements.
Calibrated X-Y measurements can be made with Channel
2
pr oviding thevertical defle ction a nd Channel 1 providing
the horizontal deflection (TIME/DIV switch fully
c
oun _t ercloc kwis e and VERT MODE switch to CH 2) . The
regulated de power supplies ensure that instrument
performa nce is not affected by variations in line voltage
and
frequency . Maximum powe r consumption of the
instrument
is approximat ely 75 watts.
The
following instrument specificat ions a pply over an
ambie
nt temp erature range of - 15 °C to + 55 °C unless
otherwise specified. War m- up time for specified ac-
cu
ra cies is 20 minutes.The calibration procedure given in
section 6, if
performed comp letely, will allow an instru-
me
nt to meet the electrical characteristics listed below .
VERTICAL DEFLECTION SYSTEM
Deflection Factor
Calibrat ed range is from 5 millivolts to 5 volts/division
in 10 steps in a 1-2-5 sequence.
Accuracy is within 3%.
Uncalibrated VAR cont ro l prov ides deflect i on factors
continuously variable b et ween the cal ibr ated settings
and extends deflection factor to at least
12 .5 volts/division in the 5 VOL TS/DIV position .
REV . B, JUNE, 1975
Frequency Response
Ba ndwidt h in both Channel 1 and Channel 2 is de to at
least 100 megahertz from -
15 °C to ·l 40° C and de toat
least 85 megahertz from -l- 40 °C to -l- 55°C. Risetime is
3.5 nanoseconds or less from 0°C to +40 °C and
4
.2 nanosec onds or less from +40° C to + 55 °C. The ac-
coupled lower - 3 dB point is 10 hert z or less (1 hertz or
less when using a 10X probe) . Vertical system
bandwidt h with the BW LIMIT pushbutton pulled is
approximate ly 20 megahertz.
Chopped Mode Repetition Rate
Ap pr oxi mately 250 kiloh ertz.
Input Res istance And Capacitance
One me gohm within 2% paralleled by approximately
20 picofarads.
Maximum Input Voltage
De coupled : 25 0 V (de + peak ac) or 500 V p-p ac at
1 kHz
or le ss.
Ac coupled : 500 V (de + peak ac) or 500 V p-p ac at
1 kHz or less.
Cascaded Operation (CH 1 VERT SIGNAL OUT
Connected to CH 2 OR Y)
Ba ndw idth is de to at least 50 MH z with a sensitivity of
at least 1 millivol t/ division.
TRIGGERING
Sensitivity
DC Coupled:0.3 divis ion internal or 50 mi llivolt sexter-
nal
from de to 25 megahertz, increasi ng to 1.5 divisions
internal or 150 millivolts external at 100 mega her tz.
AC Coupled: 0.3 division interna l or 50 millivolts exter-
nal
from 60 h ertz to 25 megahert z, increasing to
1
.5 divisions internal or 150 millivolts external at
100 megahertz.
Att enuates all signals below about
60 her tz.
LF REJ Coupled: 0.5 di vision intern al or 100 millivol ts
external from 50 kil ohertz to 25 megahertz, increasing
to 1.5 divisions internal or 300 mill ivolts external at
1-1

Specifications-465 Service (SN B250000 & up)
100 megahertz. Blocks de and attenuates all signals
below about 50 kilohertz.
HF REJ Coupled: 0.5 division internal or 100 millivolts
external from 60 hertz to 50 kilohertz. Blocks de and
attenuates all signals bel
ow about 60 hertz and above
about 50 kil ohertz.
Trigger Jitter
0.5 nanosecond or less at5 nanos e conds / division with
100 megahertz
appl ied (X 10 MAG on).
External Tr igger Input
Maximum input voltage is 250 volts (de + peak ac) or
250 volts peak to peak ac (1 kilo hertz or less). Input
resistance is 1 me gohm wit hin 10%.
Level Range
EXT: At least + and -2 volts, 4 volts peak to peak.
EXT + 10: At least + and -20 volts. 40 volts peak to
peak.
HORI ZONTAL DEFLECTION SYSTEM
Calibrated Sweep Range
A Sweep: From 0.5 second / div ision to 0.05 micro -
second/
division in 22 steps in _a 1-2-5 sequence. X10
MAG extends maxim um sweep rate to 5 nano-
seconds/ ct ivision.
B Sw ee p: From 50 milliseconds /division to 0.05 micro -
second/
divisio n in 19 steps in a 1-2-5 sequence. X10
MAG extends maximum sweep rate to 5 nano-
seconds/division.
Calibrat ed Sweep Accuracy
Unma gnifi ed sweep a ccuracy is within 2% from + 20 °C
to +30°C (+
68 °F to +86° F) and within 3% from - 15 °C
to +
20 °C and +30° C to +55°C ( +5 °F to + 68° F and
+86° F to + 131 ° F) . For the s am e temperature rang es ,
magnified
sw eep accuracy is within 3% and within 4%
respectively.
Exclude the first and last 50 nanoseconds
of the 5 nanose conds , 10 nanose conds , and
20 nanoseconds magnified sweep rat es . Accuracy
specifications apply over full 10 divisions unless
otherwise specified.
Sweep
accuracy , over any 2 or less division portion of
the sweep, is within 5%. Exclude the first and last
magnified divisions of the 5
nanosecond and
1-2
10 nanosecond / division magnified sweep rates. Also
exclude the first and last 50 nanoseconds of the 5, 1O,
and 20 nanoseco nds/division sweep rates.
Mixed sweep
accuracy is within 2% plus the measured
A sweep
error when viewing the A sweep portion only .
The B sweep
portion retains its normal accuracy.
A Ti me /Division Variable Range
Provides continuous ly variable (Un calib rated) sweep
rates between the calibrated settings
of theA TIME /DIV
switch. Extends the slow
es t A sweep ra te to at least
1.
25 se conds /division.
A Trigger Ho ldoff
Increases A sweep ho l doff time by at least a factor of 10.
Delay Time And Differential Time Mea su rement
Accuracy
+10°c to +3 5°C
-1 5°C to +55°
(
+5 0° F to +95° F)
C
)(+S°F to +1 31 °F
Over 1 Or More ± 1% 1± 2.5%
Maior Dial Division
Over Less Than 1 ±0.
01 Maj or
± 0 03
Major
Major Dial Division Dial Division
Dial
Divis io n
Delay or Differenti al Time Jitter
Within 0.002% (less than one part in 50,000) of the
maximum available delay time when operating on
pow er line f re quencies other than 50 hertz.
Within 0.005% (less than one part in 20,000) of the
maximum available delay lime when operating on
50 hertz
power line frequency .
Maxi
mum available de lay time is 10 times the setting of
the A TIME /DIV switch.
Calibrated Delay Time (A VAR se t to calibra te d
posi
ti on)
Conti nuous from 5 seconds to 0.2 micros econd.
X-Y OPERATION
Sens iti vity
Same as vertical deflection system.
X Axis defl
ect ion ac cura cy within 4 %.
REV . 8 , APR. 1 975

Variable Range
Same as vertical deflection system.
X-Axis Bandwidth
De to at least 4 megahertz.
Y-Axis Bandwidth
Same as vertical deflection system.
Input Resistance
Same as vertical deflection system.
Input Capacitance
Same as vertical de flection system.
Maximum Usable Input Voltage
Same as vertical deflection system.
CALIBRATOR
Output
An approximate 1 kilo hertz. 30 milliampere (with in
2%) , 300 millivolt ( with in 1%). square-wave signal.
Z AXIS INPUT
Sensitivity
A 5-volt peak to peak signal causes noticeable modu la-
tion at n ormal intensity.
Usable Frequency Range
From de to 50 megahertz.
SIGNAL OUTPUTS
Ch 1 Vertical
@
Output voltage is at least 50 millivolts / division into a
1 megohm load (at least 25 millivolts/divi sion into a
50
ohm load).
Bandwidt h is from de to at least 50 megahertz into a
50 ohm load.
O
ut put de level is approximately zero vol ts .
Specifications-465 Service (SN B250000 & up)
A and B + Gate
Outp ut voltage is approximately 5.5 volts, positive-
going .
POWER SOURCE
Line Voltages
110, 115, 120,220, 230, or 240 Volts ac (all with in 10%),
dependi
ng on the settings of the Line Voltage Selector
sw it ch and the R egulat ing Range Selector assembly,
wit h a line f requency of 48 to 440 hertz. Maximum
power consumpt ion is 75 watts at 1 15 volts ac,
60 hertz.
CATHODE -RAY TUBE (CRT)
Graticule Area
Ei ght by 10 centimeters .
Phosphor
P3 1 is the sta nda rd phosphor with P1 1 offered as an
option .
SUPPLEMENTAL INFORMATION
NOTE
The following supplemental information represents
l
imi ts t hat , when m et , ensure optimum instrument
operation. T hey are, however , not instrument
specifications but are intended to be used only as
maintenance or operational aids.
VERTICAL DEFLECTION SYSTEM
Low-Frequency Linearity
There shou Id be no more than 0.1 division of compres-
sion or expansio n of a 2-division signal, at center
screen, when the signal is posit ioned to the upper and
lower extremes of the crt gr aticule area.
Bandwidth Limiter Switch
The - 3 dB point sh ou ld be between 15 and
25 megahertz with the 20 MHz BW switch pulled
(yellow showing).
Step Response Aberrations
Aberrations on a positiv e going 5 division step should
be +3%,- 3%or less
not to exc eed 3% peak-to-peak on
1-3

Speclfications-465 Service {SN 8250000 & up)
all ranges except at 5 VOLTS/DIV. Aberrations at
5
VOL TS/ DIV s hould be + 4 %, - 4% or less not to
exceed 4% p
ea k-to-p ea k. Posi tion effect should cause
aberrations to be no more than + 5 %, -5% not to exceed
5%
peak-to -peak.
Common-Mode Rejection Ratio (CMRR)
At least 10 :1 a t20 megahertz for common mode signals
of 6 divisions or
le ss w it h vertical gain adjusted for best
c
mrr at 50 kiloh ertz.
Step Attenuator Balance
Adjustable to 0.2 div ision or less of trace s hift when
switching between
adjacent deflection factors,
Trace Shift as Variable is Rotated
Adjus table to 1 div is ion or less.
Invert Trace Shift
Two div i sions or less when switch ing from normal to
inverted.
Input Gate Current
0.5 nanoampere or less (0.1 divisi on of deflectio n at 5
millivolts/
div ision) from + 20 °c to +30° C. Four
nanoamperes
or less (0.8 division of defl ect ion at 5
millivolts/
division) from -15°C to -1- 55 °C.
Channel Isolation
At least 100:1 at 25 megahertz.
Position Range
Twe l ve div isions up and 12 divisions dow n from
grat icule center.
TRIGGERING
External Trigger Input Capacitance
Twe nt y picofarads with in 30%.
HORIZONTAL DEFLECTION SYSTEM
A Sweep Length
10 .5 to 11 .5 divisions.
1-4
Magnifier Registration
The re should be 0.2 division or less difference at
graticu le cent er when switc hi ng from MAG on to MAG
off .
Position Range
Sh ould be able to posi tion the start of the sweep to the
right of graticule ce nter ,and the end of the sweep to the
left of
grat icule ce nter .
Phase Difference Between X And Y Axes Amplifiers
Typi cally 3° or less from de to 50 kilohertz.
CALIBRATOR
Repetition Rate
Repet it i on rate accuracy is 1 kilo h ertz within 25 %.
Output Resistance
Approx imately 9 .4 ohm s.
EXTERNAL Z AXIS I NPUT
Voltages appl ied to the EXT Z AXIS INPU T connector
s ho uld be limited to less than 100 vo lts {de+ peak ac)
or 100 volt s peak to peak ac at 1 kilohertz or less.
OUTPUT RESISTANCES
Outpu t re sis tanc e of the CH 1 VE RT SIG OUT connec-
tor is approx imately 50 ohms .
Outpu t resist ance of A+ and B+ GAT E outp uts is
approximately 500 ohms .
CATHODE -RAY TUBE
Resolution
Typi cally at least 15 lin es /divi sion hor i zontally and
vertically.
Geometry
0.1 division or less of tilt or bowing.
Raster Distortion
0.1 division or less.
Nominal Accelerating Potential
Approxima t ely 18 ,5 00 vol ts .
REV . B, APR . 1975

Section 2- 465 Service (SN B250000 & up)
OPERATING INFORMATION
Introduction
This section of the manual is intended to a llow the
operator to become familiar with the instrume nt power
requirements , functions of controls and co nn ectors. and
how to obtain a few basic displays . For more comp lete
operating information , ref er to the 465 Operators Hand-
book .
Instrument Repackaging
If this instrument is to be shipped for long distances by
commercial means of transportat ion. it is recommended
that it be repackaged in the or iginal manner for maximum
protection . The original shipping carton can be saved and
used
forth is purpose . The Mechanical Parts List illustrates
how to repackage the 465 and gives the part number for
the packaging components . New shipping cartons can be
obtained from Tektronix, Inc. Contact your local
TEKTRONIX Field
Office or representative .
Operating Voltage
WARNING I
This instrument is de signe d for operation from a
power sou r ce with its neutral at or near earth
(ground) potential with a separate sa fety-e arth
conductor . It is not intende d for operation from two
phases of a multi-phase system. or across the legs of
a single-phase three-wire system.
This in strument can be operated from e ither a 115-volt
or 230-volt nominal line voltage so urc e, 48 to 440 hertz.
The Line Voltage Sel ecto r switch on the right si de panel
converts the instrument from one nomi nal operat ing
voltage to the other . The Regulating R ange Selector
asse mbly on the in strument rear panel selects one of three
regula
ting ra ng es for each nom inal line voltage; i also
co
nt ains the line fuse for over l oad pro t ect ion. To select
the
correct nominal line voltage and regulating range,
proceed as follows :
1.
Disconnec t the inst rument fr om the pow er source.
2. To convert from 115-volts no min;,I to 230-volts
nominal line voltage, set the s elec tor switch to the
230 vol ts position (toward th e rear of the instrument).
Change the li ne-cord plug to match the power source or
use a 115-to-230 volt adapter. Check for correc t fuse for
the line voltage selected (see Table 2-1 ).
REV. C, JUNE, 1975
NOTE
The power cord on T ektronix instruments may
conform to ei ther of the following tw o electrical
codes:
USA (NEC)
Conductor & Canada
IEC
Line
B la ck Brown
Neutral Wh ite
Light Blue•
Safety-Eart h Green w/ yellow Green w/yell ow
stripe
stripe
*Tinned copper conductor.
3. To change regulating ranges. loosen the 2 captive
screws which ho ld th e co ver onto the Regulating Range
Selector assembly, the n pull to remove the cover .
4. Pull
out the rang e sel ector switch bar (see Fig. 2-1).
Slide the bar to the desired position and plug it back in.
Select a ra nge which is centered about the average line
voltage to which the i nst rument is to be connected (see
Tab le 2-1 ).
TABLE 2-1
REGULATING RANGES
Regulating Range
Range Selector 115 V 230 V
Switch Position Nominal Nominal
Lo (sw itch bar in
99to121V 198 to 242 V
bottom holes)
M (switch
bar in 104
to 126 V 208 to 252 V
middle hol es)
HI (swit
ch bar in 108
to 132 V 216 to 264 V
top holes)
Fus,e Size 1.5 A
3AG 0.75 A 3AG
Fast-blow Fas t-b low
5. Re-instalI the cover and tighten the 2 cap tive screws.
6. Before app l ying power to the instrument. check that
the line voltage
selector sw it ch and the indicating tab on
the R
egulating Ran ge Sel ector assembly are in the correc t
position for the desired nominal line voltage and
regulat ing range.
~~
This instrument may be damaged if operated with
the line voltage selector switch or the Regul ating
Range Selec tor assembly set to incorrect positions
for the line volt age app li ed, or if the wrong line fuse is
used .
2-1

Operating lnformatlon-465 Service (SN B250000 & up)
fig . 2 -1 . Power supply regulating range selector.
The 465 is designed to be used with a three-wire ac
power system. If a 3 to 2 wire adapter is used to connec t
this
instrument to a 2 wire ac power system. be sure to
connect the ground lead of the adapte r to earth (ground) .
Fa i lure to complete the ground system may allow the
chassis of this instrument to be elevated above ground
potential and pose a shock hazard.
The fe et on the rear panel provide a conven ie nt cord
wrap to store the power cord when not in use.
CONTROLS AND CONNECTORS
Introduction
Th e major controls and connectors for operat ion of the
465 are l
ocated on the front panel of the i nstrument. A few
auxiliary functions are provided on the rear panel. Fig.2-2
shows the front and rear panels of the 465. A br ief
description of each control and connector is given here.
More detailed operating i nformat io n is given in the 465
Oscilloscope Operators Manual.
Cathode -Ray Tube (CRT) and Display
1. BEAM FINDER
2.
INTENSITY
2-2
Compresses the display to within
the graticule area, ind ependently
of disp l ay position or appl ied
signals.
Controls brightness of the display.
3. FOCUS
4. SCALE ILLUM
5. ASTIG
Provides adjustment for opti mum
disp lay definit io n.
Controls grat i cule brightness.
Screwdriver adjustment used in
conjunction with the FOCUS con-
trol to obtain a well-defined dis-
pl ay Do es not require readj ust-
ment in normal use.
6. TRACE
TION
ROT A- Screwdriver adjustment to a lig n
the tr ace with the h orizo ntal
graticule lines.
Vertical Deflection System (Channel 1 & Channel 2)
7. POSITION
8. CH 1 OR X
9.
CH 2 ORY
10. VOL TS / DIV
11. VAR
_I
Controls the vertical position of the
trace. In the X-Y mode of opera-
tion , the Ch 2 control positions on
the Y-axis (verti cally) and the
Horizontal POSITION control
posit i ons on \he X-axis (horiz on-
tally).
Input connector for Channel 1
deflection signals or X-axis deflec-
tion in the X-Y mode of operation .
Input connector for Channel 2
deflection signals or Y-a xis deflec-
tion in the X-Y mode of operation .
Selects vertical deflection factor in
a
1-2-5 sequence (VAR con trol
must be in the calibrated detent for
the indicated deflection factor ).
Prov i des continuously variable un-
ca librat ed def lectio n factors
between the calibrated settings of
the VOL TS / DIV switch.
12. UNCAL Light indicates that the VAR con-
trol is not in the calibrated position .
13.
Input Coupling Selects the method of coupling
signa l to the in put of the Ve rtical
Amp l ifier .
AC: Signa l is c apact ive ly coup led
to
the Vertical Amplifier . De com-
ponent of signal is blocked . Low-
freque nc y limit (lower - 3 dB
point) is about 10 hertz .
GND : In put signal is removed and
the input circui t is grounded . Does
not ground the input signal.
DC: All components of the input
signal are passed to the Vertical
Amplifier .
REV A, JAN 1975

7
CHANNEL2
REV A, JAN 1975
Operating lnformation -465 Service (SN B250000& up)
CRT
A&B
SWEEP
@
,. CALIBRATOR
Fi g. 2-2. Front and rear panel controls and connectors.
B TRIGGERING
A TRIGGERING
1861-23
2-3

Operating lnformatlon-465 Service (SN B250000 & up)
14 . 20 MHz BW /
TRIG VIEW
15. INVERT
16. VER T MODE
Dual-purpose switch that , when
pulled out, limits the
bandwidth of
the
complete Vertical Deflection
System to approximately 20
megahertz,
or when pressed
causes signal present in A
Trigge r
Gene
rator circuit to be display ed
on
the CRT .
Pushb
utton switch that inverts the
Chann el 2 display .
CH 1: Displays Channel 1 only .
ALT:
Dual-trace display of signals
on
both channels. Display is
switche d between channels at the
end
of each sweep.
ADD: Signals applied
to the CH 1
OR X and CH 2 OR Y connec tors
are algebraically added and the
sum is
disp layed on the CRT . Th e
INVERT
switch in Channel 2 allows
the display to be CH 1 +CH 2 or
CH 1 - CH 2.
CHOP : Dual-trace display of
signa ls on both channels. Display
isswit
ched between channels at an
approximate repetition rate of
250 kilohertz .
CH 2 OR X-Y: Displays Chan nel 2
only . Must be pushed when
operat ing in X- Y mode .
A and B Triggering (both where applicable)
17 . COUPLING
2-4
Determines the me thod used to
couple signa l to input of trigger
circu it s.
AC: Rejects de and attenuates
si
gnals be low about 60 hertz.
Accepts signals above about
60 hertz .
LF REJ: Rejects de and attenuates
si
gnals below about 50 kilohertz.
A
ccep ts s ign als above about
50 kilohertz.
HF REJ: Accepts signals between
60 hertz and 50 kilohertz . Rejects
de and attenuates all signals
out-
side the above range.
DC: Acc epts all trigger signals
from de to 100 megahertz
or
greater.
18. SOU RCE
19. SLOPE
Selects so
urc e of trigger signal.
NORM: Int ernal tr igger signal ob-
tained from Vertical Defle ction
System. Actua l source is signal(s)
displayed on crt .
CH 1: A sample of the signal con-
nected to the CH 1 OR X input
. connector is used as a trigger
signa l.
CH 2: A sampl e of the si gnal con-
nected to the CH 2 OR Y input
connector is used as a trigg er
signal.
EXT:
Trigger signal is obtained
from signal connec ted to the Ex-
ternal T
rigger Input connector .
EXT -;- 10 (A trigger circuit only):
Ext erna l trigge r signal is
attenuated by a factor of 10.
STARTS AFTER DELAY (B trig-
ger circuit only): B sweep star
ts
immedi at ely after th e delay time
se lected by the DELAY-TIME
POSITION dial and the DELAY-
TIME switch .
LINE (A trigger circuit only):
Trigger si gnal is obtained from a
sample of
the line voltage applied
to the in
strument.
Selects the slope of the trig ger
signal
which starts the sweep.
+:Sweep can be tr igg ered from the
positive
-g oi ng portion of the
trigger signal.
- :Sweep can be
triggered from the
negative-going por tion of the
trigg er signal.
20 . LEVEL Selects th e amplitude point on the
trigger signal at which thesweep is
triggered.
21. A
TRIG MO DE Determines the operating mode for
the A Trigg er Circuit.
AUTO: With the proper trigger
control se tt i ng s, A Sweep can be
initiated by signals that have
repetition rat
es above about
20 hertz and are within the fr e-
quency range selected by the
@

22. A TRIG HOLD-
OFF
COUPLING switch . In theab se nce
of an adequate trigger signal or
when the trigger controls are mis-
adjusted, the sweep free:runs to
produce a reference trace.
NORM: With the proper trigg er
control settings, A Sweep can be
initiated by signals that are wi thin
the fr eque ncy range selected by
the
COUPLING switch . In the
a
bs ence of an adequate trigger
signal or when the trigger contro ls
a
re misadjusted, there is no trace.
SINGL SWP: After a sweep is dis-
played, further sweeps cannot be
pr esented until the SINGL SWP
pushbutton is pressed again. The
display is tr iggered the same as for
NORM operation using the A
Tr i gger ing con tr ols.
Provides
control of holdoff time
between sweeps to obtain stable
displays when tr iggering on
aperiod ic signals (such as com-
plex digital words). Variable can
increase
hold off time up to at least
10
times the hold off time of the
NORM
position . In the BENDS A
position (fully clockwise), the A
sweep
is reset at the end of the 8
sweep
to provide the fastest possi-
ble sweep repetition rate
for
delayed sweep presentations.
23 . External Tr igger In put conneetors for external
tri
gger signals.
24. TRIG
A and B Sweep
25 . DELAY-T IM E
POSITION
26. A
AND B
TIME /DIV
REV A, JAN 1975
Light that indicates A sweep is
trigger ed.
Provides variable sweep delay
between O20 and 10.20 times the
delay time indicated by
the DELAY
TIME sw itch.
A
TIME /DIV switch (clear plastic
outer flange) se lects the sweep
rate
of the A sweep circuit and
selects the basic delay
tim e (to be
multipli ed by DELAY- TIME POSI-
TION dial setting) for del ayed-
sweep operation . 8 TIME /DIV
switch (i
nner dark knob ) selects
sweep rate
of the B sweep circuit
tor delayed sweep opera ti on o nly .
VAR
control must be in calibrated
detent for calibrated A sweep
rates.
Operating lnformatlon-465 Service (SN B250000 & up)
27 . VAR Provides con ti nuously variable A
sweep rates between the
cali-
brated sett ings of the A TIME/DIV
switch . The A sweep rate is
calibrated
wh en the VAR co nt rol is
fully clo ckwise into the cal ib rated
detent.
28.
UNCAL Light that i nd icates when the VAR
TIME /DIV contr ol is out of the
calibrated detent and the
horizon-
tal sweep rate is u nc a libr ated.
29. X10
MAG ln di - Light that indicat es when the X10
cator MAG is turned on .
30. READY Lig
ht that indi cates that A Sweep
has been prepared to present a
si ngle sweep upon rece ipt of an
adequate
trigg er signal.
31 . HOR IZ DISPLAY Selects the horizontal mode of
oper ation.
32.
Horizontal
33. FINE
34. X10
MAG
A: Horizont al deflection provid ed
by A Sweep. B Sweep
inoperative .
MIX: The first part of the hor izontal
sweep is
disp layed at a rate set by
the A TIME/DIV s witch and the
l atter part of the sweep at a rate set
by the 8
TIME /DIVswitch.Re lativ e
amounts of the display allocated to
each of the two rates are det er-
mined by the se tting of the DELAY -
TIME POS ITION dial.
A INTEN: Displayed sweep rate
determined
by the A TIME /DIV
switch . An intensified port ion
appears
on the display during the
B sweep
time . This switch position
provides a check of the dura tion
and
posit ion of the B sweep
(delayed sweep)
with respect to
the
delaying sweep (A).
B DLYD: Sweep ra te determined
by the B TIM E/ DIV switch wit h the
delay
time det er mined by the set-
ting of the DELAY TIME (A
TIME /DIV) swi tch and the DELAY-
TIME POSITION dial.
Positions
the display h orizo nt ally.
Provides fine horizontal
position-
ing.
Increases
the displayed sweep rate
by a
factor of 10 .
2-5

Operating lnformation-465 Service (SN B250000 & up}
Calibrator and Power
35. CALIBRATOR A combina ti on current l oop and
square
-w ave vo lt age output de-
vice. Provides a 30 milliampere
square-wave current, 300 millivolt
square-wave voltage signal wi th a
repeti
tion rate of approximately 1
kilohertz .
36 . POWER
37. LOW LINE
Rear Panel
38. A +GATE
39. B + GATE
40. CH 1 VERT
41 . EXT Z AXIS
42 . Regulating
Range Selector
Turns instrument power on and
off.
Light that indicates the applied line
voltage is below the l ower l imit of
the regu la ting range selected by
the Regulating Range Selector
assembly.
Output connector providing a
positive-going rectangular pulse
coincident with the A sweep time .
Output connector providing a
positive-going rectangular pulse
co
in ci dent with the B swe ep time .
Output connector providing a
samp le of the signal applied to the
CH 1
input connector.
Input connector for intensity
modu l ation of the crt display.
Sel ects the regulating rang e of the
internal power supplies (low ,
medium , high : determined by
speci fic line voltage applied to in-
strument).
OBTAINING BASIC DISPLAYS
Introduction
The following instructions will allow the operator who
is unfamiliar with the operation of the 465 to obtain th e
basic
displays c ommonly used. Before proceeding with
these instructions , preset the in strument contro ls as
follows :
Vertical Controls
VERT MODE Switch CH 1
VOL TS / DIV Switches
2-6
Proper posit ion deter-
mined by amplitude of
signal to be applied .
VOL TS /DIV VAR Controls
Input Coup l ing Switches
Vertical POSITION Controls
20 MHz BW Switch
INVERT Switch
INTENSITY Control
FOCUS Control
SCALE ILL UM Control
Calibr ated detent
AC
Mi
drange
Not limited
Button out
Fully counterclockwise
Midrange
Midrange
Trigger Controls lboth A and B if applicable)
SLOPE Switch
LEVEL Control
SOURCE Switch
COUPLING Switch
TRIG MODE Switch
+
0
NORM
AC
AUTO
A TRIG HOLDOFF Control NORM
Horizontal Sweep Controls
TIME /DIV Switches
A TIME /DIV VAR
HORIZ DISPLAY Switch
X10 MAG Switch
POSITION Control
Normal Sweep Display
Locked together at 1 ms
Calibrated detent
A
Off (button out)
Midrange
1. Set the POWER switch to on ( button out). Allow
several minutes f or instrume nt warmup .
2. Connect the ext ernal signal to the CH 1 input
connector.
3. Advance the INTENSITY control u ntil the display is
visible . If the disp l ay is not visible with the INTENSITY
control at midrange, press the BEAM FINDER pushbutton
and adjust the CH 1 VOL TS / DIV sw it ch until the display is
reduc ed in size vertically. Then, cent er the comp ressed
di
splay with the vertical and horizontal POSITION con-
tro ls, and release the BEAM FINDER pushbutton.
4. Set the CH 1 VOL TS/DIV switch and CH 1 POSI-
TION control for a display which remains in the display
area vertically.
5. Adjust the A Trigger LEVEL control for a stable
display.
6. Set the A TIME / DIV swi tch and the horizontal
POSITION contro l for a display which remains in the
display area horizontally .
@

Magnified Sweep Display
1. Preset the instrum ent cont rols and follow steps 1
throu gh 6 for obtaining a Normal Sw ee p Display.
2.
Adju st the hor izontal POS ITION co ntrol to move the
area to be magnif ied to wi thin the ce nt er graticule division
of the crt (0.5 division on each side of the center ve rtical
gra
ticule line). If necessary, chang e the TIME / DIV switch
setting so the comple te ar ea to be magnif ied is within the
center div isio n.
3. s
e't th e X1 O MAG sw it ch to the on pos it ion (button
in) and adjus t the horizont al POSITION and FINE contro ls
for preci
se position ing of the magnified disp lay .
Delayed Sweep Displays
1. Preset the instrument controls and fol low steps 1
th
rough 6 for obtaining a N orma l Sweep Display.
2. Set the HORIZ DISPLAY switch to A INT and the B
Trigger SOURCE switch to STARTS AFTER DELAY .
3. Pull out the B TIM E/ DIV switch knob and turn
clockwise so the inte nsif ied zone on the di splay is the
desired l
ength . Adjust the INTENSITY control to achie ve
the d es ir ed di splay brightness .
4. Adjust the DEL
AY-TIME POSITION dial to position
the intensified zone to the
po rtion of the display to be
delayed.
5. Set the
HORIZ DISPLAY switch to B DL YD. Th e
i
nt ensified zone on the dis play noted in step3 is now being
displayed in delay
form . The delayed sweep rate is
indicated by the dot on the B TIME/ DIV switch knob .
6. F
or a delayed sweep di s pl ay that will ex hibit less
j
itt er , set the B Trigger SOURCE s witch to the same
posi
tion as the A Tri gger SOURCE s witc h and adjust the B
Trigger LEVEL
con trol for a stable display. Ifthe A Trigger
@
Operating lnformation-465 Service {SN 8250000 & up)
SOURCE switch is in the LINE position , a sample of the
line voltage will have
to be suppl ie d to the B Trigger ci rcuit
th ro ugh the B EXT trigger inp ut with the B SOURCE
sw itch in the EXT posit ion .
Mixed Sweep Displays
1. Preset the i nst rume nt controls and follow s tep s 1
through 6 for obtaining a Normal Sw ee p Di splay .
2. Pull
out on the B TIM E/DIV switch kn ob and tL1rn
cl ockwise to the desired sweep rate. Adjust the INTEN-
SITY control to a chi eve the des ir ed di splayfor brightne ss.
3. Set the HORIZ DISPLAY switch to MIX. The CRT
display now co ntains mo re than on e time factor on the
ho ri zonta l axis. Th e left portion of the display is at the A
Time Base sweep rate and the rig ht pa rt is at the B Time
Base sweep rate Th e s tar t of the B Tim e Base port ion of
th e display can be changed bya djusting the DELAY-TIME
POSITION co ntrol.
X-Y Display
1. Preset the in strument contro ls and turn the ins tr u-
m
en t power on . All ow several minut es f or insturment
warm-up.
2. Set the TlME/ DIV switch to X-Y a nd the VERT
MODE to CH 2. Ap ply the vertical signal to the CH 2 or Y
in
put co nne ctor and the ho rizontal signal to the CH 1 or X
inp ut co nnector. The CH 2 POSITION c ontro l will provide
vertical positi onin g and the Horizontal POSITION control
will provide horizontal posit ioning.
3. Advanc e the INTENSITY control until the display is
visibl
e. If the display is not visible with the INTENSITY
contro l at midrange, press the BEAM FINDER pushbutton
and adjust the CH 1 and CH 2 VOL TS /DIV switches until
the disp l ay is reduced in size both vertically and horizon-
tally. The n. center the compr essed display wit h the CH 2
POSITION and hor izontal POSITION co ntro ls, and
releasethe BEAM FINDER
pushbutton .Adjust the FOCUS
control for a well-def ined display .
2-7

Section 3- 465 Service (SN B250000 & up)
CIRCUIT DESCRIPTION
Introduction
This section of the manual contains a description of the
circuitry used in the 465 Oscilloscope. The descr i pt i on
begins with a discussion of the instrument, using the basic
block dia gram shown in Fig. 3- 1. Then, each circuit Is
described in detail using detailed block diagrams to show
the interconnections between the stages in each major
circuit and the relationship of the front panel controls to
the indivi dual stages.
A
complete block diagram is located in the Diagrams
Section at the back
of this manual. This blo ck diagram
shows the overall relationship between all
of the circu its.
Complete schematics
of each circuit are also given in the
Diagrams Section. Refer to these diagrams throughout the
following circuit description for electrical values and
relationships.
Digital Logic
Digital logic techniques are used to perform many
functions within this instrument. The function and opera-
tion
of the logic circuits are described using logic
symbology and terminology . All l ogic functions are
described using the positive logic convention. Positive
logic is a system of notation where the more positive of two
levels (HI) is called the true or 1state; the more negative
level (LO) is called
the false or Ostate.The HI-LO method
of notation is used in this logic description . The specific
voltages
which constitute a HI or LO state vary between
individual devices.
It should be noted that not all of the integrated circuit
devices in this instrument are digital lo gic devices. The
function of non-digital devices will be described in-
dividually using operat ing waveforms or other techniques
to illustrate
the ir function.
REV A, JAN 1975
BLOCK DIAGRAM
The following discussion is provided to aid in un-
derstanding the overall concept of the 465 Oscilloscope
before the individual
circuits are discussed in detail. A
basic block diagram of the 465 Oscilloscope is shown in
Fig.
3-1 . Only the basic interconnections between the
individual
blocks are shown on this diagram. Each block
represents a major circuit within the instrum ent. The
number on each block re fers to the complete circuit
diagram, which is locat ed at the rear of this manual.
Signals to be displayed
on the crt are applied to the CH
OR X and/
or CH 2 ORY conn ectors. The in put signals
are then
amplified by the Preamp circuits . Each Preamp
circuit includes separate vertical deflection factor, input
coupling , balance, gain and variable attenuation controls .
A trigger pickoff stage in each Vertical Preamp circu it
supplies a sample
of the channel signals to the Trigger
Generat or circuit. A sample of the Channel 1signal is also
s
upp lied to the CH 1VERT SIGNAL OUT connector on the
instrument rear pane l. In the X-Y mode of operation the
Channel 1 signal
is connec ted to the input of the
Horizontal Amp li fier circuit to provide the X-axis deflec-
tion. The Channel 2 Vertical Preamp
circuit contains an
invert feature to invert the Channel 2 signal as displayed
on the crt. The outputs of both Vertical Preamp circuits are
connected
to the V ertic al Switching circu it. This circu it
selects the channel(s) to be displayed. An
outp ut signal
from this circuit is connected to the Z-Axis Amplifier
circuit to blank out the switching transients between
channels when in the
chopped mode of operation. A
tr igger pi ckoff stageat theoutputof the Vertical Switching
circuit provides a sample of the displayed signal(s) to the
Trigger Generator circuit.
The output of the Vertical Switching circuit is con-
nected to the Vertical Output Amp li fier through the Delay
Line. The Vertical
Output Ampl i fier circuit provides the
final
amplification for the signal before it is connected to
3-1