Tektronix 2235 User manual

2235
OSCILLOSCOPE
SERVICE
INSTRUCTION
MANUAL

W A
RN I N G
7
e
Ictro
ηά
THE F O LL O W I NG S
ERV ICI N G I N ST RU CTIONS
A RE F O R US E BY Q
UA L I F I ED PER SO NNEL ONL Y .
T O A V OID PER
SO N A L I NJUR Y, DO NOT PER-
F ORM ANY SERV ICI N
GOTHERTHAN THAT
CO
N -
TAI NE D IN OPER ATI N
G I NST RU CTIONS UNLE
SS
YO U A RE QU A L I F I
ED TO DO SO . REFER TO OP-
ERATORS SA FE TY
S UMM A RY A N D S ERV
IC E
SA FE TY S UMM A
RY PR IO R TO PERF
O RM I N G
ANY SERV
IC E .
Te k tro n ix
N atio n al M ar k eting
Ce n ter
for P
ro d uct Or d er Information,
call
1-800-426-2200
ext 41
In O r ego n call
collect [phone] ext
41
Te k t r on ix N atio n
al M a rk eti ng Ce n te r
P .O . Box 500 D/S
Υ 6-088, B eaverto n ,
O R 97077
PLE
AS
E
C
HE
C K F O R C H A N G E I NF O RM ATIO
N
AT THE RE A R
O
F T
H IS M A NU A L .
2235
OSCILLOSCOPE
S ERV IC E
I N ST RU CTIO N
M A NU A L
Te
k
tronix, Inc .
Ρ .
Ο . Box 500
B
eaverto n , Oregon

97077

Serial
N
umber
CO MM ITT E D
TO
E
XC ELLEN C E
070-4206-00

F irst P
rinting D E C 1982
Pr o d
uct Gro up 46

R
evised MAY 1983

Copy r ig h t ύ
1982
Te k tro n ix, I n
c . All rig h ts rese r ved .
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not b e re pr oduce d in
any
form wit h out t h e w r itten pe r
missio n of Te k tronix, Inc .
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. and its sub sidia r ies are
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r
ed
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atents and /or pen ding p ate n
ts .
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O
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Ta
are
registered t r ad
emar k s of Tek t r o n ix, I n c . T ELE Q
U I PMEN T
is α registered
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imited .
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rice c h ange p rivileges
are reserved .
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eaverto n , O r ego n , USA
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
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erla nd s

TA BLE OF CO
N T EN TS
2235 Service
LIST OF
ILLUSTRATIONS

. ...................

iii

SECTION 3

THEORYOF OPERATION
LIST OF TABLES

. . . .... . ...................

iii

INTRODUCTION ........
..... ...

3-1
OPERATORS
SAFETY SUMMARY

.............

ί ν

GENERAL DESCRIPTION

........

3-2
SERVICING
SAFETY SUMMARY ............ ...

ν

DETAILEDCIRCUIT DESCRIPTION

3-3
VERTICAL ATTENUATORS .....

3-3
SECTION 1

SPECIFICATION

In p
ut
Coupling .... .........

3-3
INTRODUCTION ................

1-1

B
uffer
Amplifier and Gain
ACCESSORIES .............. ... 1-1

Switching Network .......... 3-4
PERFORMANCE CONDITIONS ....

1-1

Paraphase Amplifier ........ .

3-4
VERTICAL PREAMPLIFIERS

. . . 3-5
SECTION2

OPERATING INSTRUCTIONS

CHANNEL SWITCH A ND
PREPARATION FOR USE

.... ....

2-1

VERTICAL OUTPUT

........ . .

3-5
SAFETY ............... . .... 2-1

Delay
L ine Driver ......... . . 3-6
L INE VOLTAGE

......... . ....

2-1

V ertical Output Amplifier ... . .

3-6
POWER CORD ........ . . ..... 2-1

Α / Β Sweep Separation Circuit . 3-7
L INE FUSE ......... .... .....

2-1

TRIGGER AMPLIFIERS AND
INSTRUMENT COOLING .......

2-2

SWITCHING ......... . .......

3-7
CONTROLS,

CONNECTORS,

AND

Internal Trigger ..... . .......

3-7
INDICATORS ... ..... ...........

2-2

Internal Trigger Amplifier

.....

3-8
POWER, DISPLAY, AND PROBE

Α External Trigger Am p lifier ...

3-8
ADJUST

... . ................

2-2

L ine Trigger Amplifier ........

3-8
VERTICAL

. . .... . ...........

2-3

Α TRIGGER GENERATOR ......

3-9
HORIZONTAL ................

2-4

Α Trigger Level Circuit .......

3-9
TRIGGER

...................

2-6

Α Trigger L evel Comparator

. .

3-9
REAR PANEL ................

2-7

Α Schmitt Trigger and TV
OPERATING CONSIDERATIONS ...

2-8

Trigger Circuit

.............

3-9
GRATICULE .............. ...

2-8

Α SWEEP GENERATOR AND
GROUNDING ............. ... 2-8

L OGIC ... .................. . 3-9
SIGNAL CONNECTIONS ... . ...

2-8

Α M iller Sweep Generator ... .

3-10
INPUT COUPLINGCAPACITOR

Α Sweep L ogic

......... . . .

3-11
PRECHARGING .......... . ... 2-8

ALTERNATE Β SWEEP ...... . . 3-11
OPERATOR'S ADJUSTMENTS . ...

2-9

Β M iller Sweep Generator ... .

3-12
INTRODUCTION

...... ... ....

2-9

Β Trigger L evel Comparator

. .

3-12
TRACE ROTATION ... .... .....

2-9

Runs After Delay ..... ..... .

3-12
PROBE COMPENSATION . . ....

2-9

Β Delay Time Position
OSCILLOSCOPE DISPLAYS ...... 2-10

Comparator ........ . ...... 3-12
INTRODUCTION

.... ......... 2-10

Β Swee p L ogic

. . ... ....... 3-12
B ASELINE TRACE .. ..........

2-10

Alternate Dis p lay Switching
SIGNAL DISPLAY

. . .......... 2-11

L ogic

........ . ........... 3-13
M AGNIFIED-SWEEP DISPLAY

. .

2-11

ΒΖ -Axis L ogic . ..... .......

3-13
DELAYED-SWEEP DISPLAY .... 2-11

HORIZONTAL ... . ............ 3-13
DELAYED-SWEEP

Horizontal Pream p lifier ....... 3-14
MEASUREMENTS ............

2-11

Χ - Υ Amplifier

. . . . . . ........

3-14
SINGLE-SWEEP DISPLAY ......

2-12

Horizontal Output Amplifier ...

3-15
Χ - Υ DISPLAY ............... .
2-12

Z-AXIS AMPLIFIER ........... 3-15
TV SIGNAL DISPLAYS

....... .
2-12

Dc Restorer ............... 3-16

2235 Service
Page

Page
SECTION 3

THEORYOF OPERATION
(cont)

SECTION 6

M AINTENANCE (cont)
POWER SUPPLY AND PROBE

I NTRODUCTION

........... . .

6-2
ADJUST ............. ..... . .

3-17

GENERAL CARE
........... . .

6-2
Power Input ........ ..... . . 3-17

INSPECTION AND CLEANING

. .

6-2
Preregulator ........ ..... . . 3-17

LUBRICATION ............ . . .
6-4
Inverter ............ ..... . . 3-18

SEMICONDUCTOR
CHECKS
. . .
6-4
Crt Supply ......... ..... . . 3-18

PERIODIC READJUSTMENT

. . . 6-4
Focus Circuit ....... ..... . .

3-18

TROUBLESHOOTING
......... . . .

6-5
L ow-Voltage Supplies

..... . .

3-19

INTRODUCTION

........... . .

6-5
Probe Adjust

...... . . . . . . . .

3-19

TROUBLESHOOTING AIDS

. . . .

6-5
TROUBLESHOOTING
EQUIPMENT ............. ...
6-6
SECTION 4

PERFORMANCE
CHECK

TROUBLESHOOTING
PROCEDURE

TECHNIQUES ............ . . .
6-6
INTRODUCTION .......... ..... . 4-1

CORRECTIVE MAINTENANCE . . . .
6-10
PURPOSE ............. ... . . 4-1

INTRODUCTION .......... ...
6-10
STRUCTURE .......... ..... . 4-1

M AINTENANCE PRECAUTIONS
.

6-10
TEST
EQUIPMENT ..... ..... . 4-1

OBTAINING REPLACEMENT
L IMITS
AND TOLERANCES ... .

4-1

PARTS

. . . . .............. . . .

6-10
PREPARATION
FOR CHECKS

. .

4-2

M AINTENANCE AIDS

...... ...

6-10
INTRODUCTION
Τ 0

I NTERCONNECTIONS ...... . . . 6-10
PERFORMANCE
CHECK STEPS

4-3

TRANSISTORS AND
VERTICAL

............
. .....

4-4

INTEGRATED CIRCUITS ... ....

6-11
HORIZONTAL
.......... .... . .

4-8

SOLDERING TECHNIQUES

....

6-12
TRIGGER

.............
..... .

4-12

REMOVAL A ND REPLACEMENT
EXTERNAL
Z-AXIS AND PROBE

I NSTRUCTIONS ......... . ....

6-13
ADJUST .............. .... . .
4-15

Cabinet .............. . ....
6-13
Cathode-Ray
Tube
...... ....

6-13
SECTION5

ADJUSTMENT
PROCEDURE

Power-Supply
Shield ... . ....

6-14
INTRODUCTION
................

5-1

F ilter Circuit B oard
. . .... ....

6-14
PURPOSE

..................

5-1

Alt Sweep Circuit B oard

. ....

6-15
STRUCTURE

................

5-1

Attenuator Circuit B oard

. ....

6-15
TEST EQUIPMENT
........... 5-1

Timing Circuit B oard ... . .... 6-16
L IMITS AND
TOLERANCES

....

5-1

B ottom Shield, Attenuator a nd
ADJUSTMENT INTERACTION

. .

5-1

Timing Circuit-Board M odule . .

6-17
PREPARATION FOR

Front-Panel Circuit B oard

....

6-17
ADJUSTMENT
............... 5-1

M ain Circuit B oard . . . ....... 6-18
INDEX
TOADJUSTMENT

REPACKAGING F OR SHIPMENT

6-20
PROCEDURE
STEPS

.........

5-3

SELECTABLE COMPONENTS

. .

6-20
POWER SUPPLY AND
CRT DISPLAY 5-4
VERTICAL . ....................

5-6

SECTION 7

OPTIONS
H ORIZONTAL ..................
5-14
TRIGGER

. ....................

5-20

SECTION8

REPLACEABLE ELECTRICAL PARTS
EXTERNAL Z-AXIS AND PROBE

SECTION 9

DIAGRAMS
ADJUST . . . ...................
5-24
SECTION 10 REPLACEABLE MECHANICALPARTS
SECTION 6

M AINTENANCE

Accessories
STATIC-SENSITIVE COMPONENTS

6-1
PREVENTIVE
MAINTENANCE ..... 6-2

CHANGE INFORMATION
ιι
TA BLE O F CO N T EN
TS (cont)

L IST O F I LLU ST R ATIO N S
F
ig
ur e

P age F igu r e

P age
T he
2235
Oscillosco p e
.........
..... . .

vi

2-7

R ear- p anel con n ector . ............. . . .

2-7
1-1

M aximum

inp u t

voltage

vs .

fre q ue n cy

2-8

Gratic
u le meas u reme n t mar k i ngs ...... ..

2-8
de
r ating
curve
for C H 1 OR Χ , C H2 O RΥ ,

2-9

P
ro
be com p en satio n
. ............. .
. . .

2-10
and
ΕΧ 7 I NPU T conn ecto r s ..... .. ... . .

1-7

3-1

B loc k d iagram of t he Ve r tical Atte n uators .

3-4
2-1

V
oltage, p
ower cord, an d fuse data .... . .

2-1

3-2

B loc k diagram of t he C h annel Switch ing
2-2

F
use
h
ol
d er and p ower co r d connector . . .

2-2

circ u itry ....... . ............ .....
...

3-6
2-3

P ower, dis p lay, and probe a dju st con trols

3-3

B loc k diagram of t he Α Sweep Generator
conn ector and in d icator ... . . . . . . .......

2-3

and L ogic Circuitry

........... . .......

3-10
2-4

V ertical controls an d co nn ecto r s . ........

2-4

3-4

B loc k diagram of t he H orizontal Am p lifier

.

3-14
2-5

H orizontal controls

...... ..... ........

2-5

3-5

Sim p lified diagram of t he Dc R estorer
2-6

Trigger controls, connector, and indicator

.

2-6

circuitry

...... . ............. ........

3-16
6-1

M ulti-co nn ector h older o r ientatio n

.......

6-6
L IST O FTA BLE S
2235 Service
Ta b le

P age Ta b le

P age
1-1

E lectrical C h aracte r istics . . ..... ........

1-2

5-4

Attenuator Compensatio n Ad ju stme n ts ...

5-9
1-2

E nvironmental C h aracteristics ... . .......

1-8

5-5

Settings for Bandwid t h C heck s

.........

5-12
1-3

Ph ysical C h aracte r istics

. . ..... ........

1-9

5-6

Settings fo r Timing Accuracy C hecks .....

5-17
4-1

Test E q ui p ment R e q uired

...... . .......

4-2

5-7

Setti ngs for Delay Time Acc u racy C hec k s .

5-18
4-2

Deflectio n Acc u racy L imits ..... . .......

4-4

5-8

Switch Combinations for Α Triggering
4-3

Setti ngs for B a nd wi d t h C heck s

. ........

4-6

C h ec ks . . ............. . . . . . .........

5-21
4-4

Setti ngs for Timi ng Acc u racy C hecks .....

4-9

6-1

R elative S u sce p tibility to Static-Disc ha r ge
4-5

Setti ngs for Delay Time Acc ur acy C hec k s .

4-10

Damage . .................. .........

6-1
4-6

Switch Com b i n atio ns fo r Α T r igge r i n g

6-2

E xternal Ins p ection C heck list . . .........

6-3
C heck s ................ ..... ........ 4-12

6-3

Inte r nal Inspection C heck list ...
.........
6-3
5-1

Ad j ustme n t I n teractio n s

. . ..... ........

5-2

6-4

P ower Supply L imits and R ip p le .........

6-8
5-2

P ower Supp ly L imits ..... ..... ........

5-4

6-5

M ai n te n ance Aids ...... ..... .........

6-11
5-3

Deflection Accuracy L imits ..... ........

5-8

6-6

Trigge r B an d wi d t h Alteration

. . . ........

6-20

2235 Service
Te r ms as M ar k ed on E q u i p me n t
Symbols in T h is Manual
O PER ATO R
S SA FE TY S UMM A R Y
Th e gener al safety information in t h is p
art of t
h
e s u mmary is for bot h operating an d se r vicing perso n nel . Specific
warnings
and cautio n s will be fo u nd t h roug h o u t t h e man u
al w
here
t hey apply an d d o not appea r i n t h is su mmary .
Terms i n T h is Manual

Groun d ing t h eP ro d uct
CA U TIO N stateme
n
ts

i d en tify

con d itio n s or p ractices

T h is produ ct is gro un d e d t hr ough t he g r oun
d
ing
co nd uctor
t h at coul d res u lt in
d amage to t he e qu i p me n t or othe r of
t
he p
ower cor d . To avoid elect r ical s hock , pl u g t h e
pr op erty .

p owe r cor d
into α pr operly wi r e d rece p ta b le b efore
con-
necting
to t he p r
oduct i
npu
t o r outpu t termi n als . Α
W
A RN I NG state
m
en ts i d entify cond itio n s or pr
actices

p rotective grou nd co nn ection
b y way of t he gro und ing
t
h
at coul d
r
es u lt i n personal injury o r loss of life .

co ndu ctor i n t he power cord is esse n tial
fo
r
safe o p eratio n .
CA U TIO N i nd icates α p erso n
al injury h aza rd n ot imme-
d iately accessi b le as o ne r ea d
st
he
ma rk i n gs, o r α h azar d to
pr o p erty, incl ud i ng t h e equ i pm en t
itself
.
DA N G ER in d icates
α p ersonal i
nju ry
h aza rd imme d iately
accessi b le as o n e rea d s t he
ma
rk i ng .
T h is symbol in d icates w h e r eapp
lica b le
cautio n ary o r ot h er info r mation
is to be
fo u nd
.
F
o r maxim u m inp u t voltage see
Ta b le
1-1 .
Symbols as M ar k e d on Equ i p me n t
114

DA N G ER - H ig h voltage .
Ο

P rotective g r oun d (eart h ) termi n
al
.
Danger A r isi ng Fr om
L oss of Groun d
Up on loss of t he protective-g
r oundconn ectio n , all acces-
si
b le co ndu
ctive parts (incl ud i ng knob s a nd con t r ols t h at
m ay a pp ea r to be i n
s
u
lati n g) can r end er an electric s hock .
Use t he Pr o p er P ower Co r d
U se
only
t he power cor
d
and co nn ector
s p ecifie d fo r
your p ro du ct .
U se only α
power
cor d t
h
at is i n goo d co nd itio n .
F o r
detaile d i nformation on power cor d s an d conn ectors
see F ig ur e 2-1 .
Use t he P ro p er F use
To avoi d
fire
h aza rd , use only α f u se of t he correct ty p e,
voltage rating
a nd cu r rent rating as specifie d in the parts
list for yo ur p r odu
ct
.
ΑΤΤΕΝΤΙΟΝ - R efe r to ma n ual .
To avoi d exp losion, d o n ot o p erate t h
is
produ
ct i
n
an
exp losive atmosp h ere un less it h as b een s p ecifically cer-
P
ower Source

tifie d for
s
uch o p e r
atio
n .
Do N ot O p erate in E xp losive Atmos
ph
eres
T
h
is pro d u ct is inten d e d to operate from
α power so urce
t h at does n ot apply more t han 250 volts rms
betwee n t h e
s u pply con d uctors o r b etween eit h er
s
up
ply cond u ctor and

Do
N
ot
R
emove Covers Or P anels
gro un d . Α protective groundcon
nectio n by way of t he

To avoi d p erso n al i nj ury,
d
o n
ot remove t he pr odu ct
gro u n d i ng co n d u ctor i n t he powe r
cord is essential for safe

covers
or
p a n els
. Do not
o
p e
r
ate t he
p
ro du ct withou t t h e
operation .

covers and pan els properly i n
stalle d .

S ERV ICI
N
G SA
FE TY S UMM A R
Y
F ORQU A L I F I E
D
S
ERV IC E PER SO NNEL O
NL Y
R efer also to t
he
prece
d ing Operato r s Safety S u mmary .
Do
N
ot
Service Alo n e

Disco n nect power b efore
removing protective pa n els, sol-
Do
not p erform internal se r vice or ad j ustme
n t
of
t h is p r od-

deri n g, or re p lacing com
p
o
n ents .
uct unless
a n ot h e r personcapable of
r
ende
r i n g first aid a nd
resuscitatio n is prese n t .

P
owe r So ur ce
2235
Service
Th is product is inte
n
de
d to ope r ate from α power source
U se Ca r eWh e nServicin
g W it h P owe r On

t h at does not apply
mo r e t h a n 250 volts r ms between t
h
e
supp ly co nd ucto
r
s or
between eit h e r supply co n ductor a
n
d
Dangerous voltages exist at seve
r
al
points i n t h is p roduct .

grou n d . Α p
rotective groun d co nnectio n b y way of t
he
To avoi dpe r so n al i nj ury, d o not touc
h
exposed
conn ectio n s

gro u n d i n g con
n
ecto
r in t h e power cor d is essential fo r safe
or com p o n ents w h ile power is on .

ope r ation .

2235 Service
Th e 2235
Oscillosco p e
ατο 6- ο 1

The instr u me n t is sh i pp e d wit h t h e following sta nd a rd
accessories :
S PE CI F ICATIO N
Sectio n1-2235 Service
I NTR OD U CTIO N

PERF O RM A N C E CO N DITIO NS
T h e T EK TR O N IX 2235 oscillosco pe is α rugge d , lig h t-

T he following electrical c ha r acte r istics (Ta b le 1-1) a r e ναΙ -
weigh t, d ual-c h annel, 100- MH z i n strument t h at feat u res
α

id for t he 2235 w hen it h as b een
a dju sted at an am b ient
b rig h t, sh arply defined t r ace on an 80- by 100-mm cat h
ode-

tem p erat u re b etween +20°C and +30°C, h as h ad α warm-
ray tu be (crt) . Its vertical system p r ovi d es calibrated deflec-

up period of at least 20 minutes, and is o p e r ati ng
at an
tion facto r s f r om 2 m V p er divisio n to 5 V p er division .

am b ie n t temperature between 0°C and +50°C (u n less ot h
Trigger circuits enab le stable triggering over t he full band-

erwise noted) .
widt h of t he vertical system . T he h o r izo n tal system provi d es
cali b rated swee p s p eeds from 0 .5 s perd ivisio n to 50 n s per
division along wit h delaye d -sweep features for acc u rate
relative-time meas u rements . Α Χ 10 magnifie r extends t he

Items listed in t h e " P erformance R e qu ireme n ts" col u m n
maxim
u
m
swee p s peed to 5 ns pe r d ivision .

are verifia b le qualitative or quantitative limits, w h ile items
listed i n t h e "S upp lemental I n formatio n " col u m n are eit h er
explanatory notes, cali b ration setup descriptions, p erfor
ACC E SSO R I ES

mance ch aracteristics for w h ic h no absolute limits are s p eci-
fied, or ch aracteristics t h at are impractical to c h eck .
1 O p erators Manual

2 Pr o b e pac kages

E nvironmental ch aracteristics are give n i n Ta b le 1-2 . The
1 Service Manual

2235 meets t h e re qu ireme n ts of
MIL-T-288000,
p aragra ph s
4 .5 .5 .1 .3, 4 .5 .5 .1 .4, and 4 .5 .5 .1 .2 .2 for Type III, Class 5
F or part nu m be r s a nd f u rt he r i n fo r mation about both

e q uipment, except w h ere ot h erwise noted .
sta n dard and o p tional accessories, refer to t h e "Options
and Accessories" section (Section 5) of t h is man u al . Your
Tek tronix re p resentative, local Tek tronix F iel d Office, or
Tek tronix prod u ct catalog can also p rovi de accessories

Ph ysical c h aracteristics of t h e i n st ru me n t are liste
d
i n Τα -
information .

b le 1-3 .