Tektronix 7B53A User manual

MANUAL SUPPLEMENT
TEKTRO N IX
7B53A/7B53AN
DUAL TIME BASE
OPTION 5
INSTRUCTION MANUAL
Tektronix, Inc.
070-1471-00
P.O. Box 500
Beaverton, Oregon 97005
772

WARRANT
This Tektronix product is warranted against defective materialsand
workmanship, under normal use, for a period of one year from date
of initial shipment. Tektronix will repair or replace, at its option,
those products determined to be defective within the warranty
period and returned, freight prepaid, to a Tektronix Service Center.
There is no implied warranty for fitness of purpose.
Please direct all requests for service or replacement parts to the
nearest Tektronix Service Center or Field Office; include the type or
part number of the product and its serial number.
Copyright ® 1972 by Tektronix, Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the permission of Tektronix, Inc.
Products of Tektronix, Inc. and its subsidiaries are
covered by U.S. and foreign patents and/or pending
patents.
TEKTRONIX, TEK, SCOPE-MOBILE, TELEQUIPMENT,
and are registered trademarks of Tektronix, inc.
Printed in U.S.A. Specification and price change
privileges are reserved.

7B53A/7B53AN OPTION 5
SPECIFICATION
General Information
The TV Sync Separa or permi s TEKTRONIX real- ime
oscilloscopes o display composi e video signals. The TV
Sync Separa or clips video informa ion from he incoming
video signal; hen, i amplifies and separa es he field or
ver ical rigger pulses from he line or horizon al rigger
pulses. Line ra e or field ra e rigger pulses are provided
depending on he posi ion of he fron panel swi ch.
This manual inser describes he special fea ures of he
7B53A/7B53AN OPTION 5 plug-in uni which has been
modified o enable riggering on composi e video signals
hrough he use of a Sync Separa or circui . The EXT ÷ 10
and LINE posi ions of he Main Triggering Amplifier
SOURCE swi ch have been replaced by he TV FIELD and
TV LINE swi ch posi ions, allowing he sweeps o be
riggered by he ou pu of he Sync Separa or circui a a
Field or Line Ra e. The delayed sweep circui has TV
LINE/EXT or INT/EXT SOURCE riggering capabili y,
depending on whe her he connec ion is made o P903 or
P904.
Compatability
The TV Sync Separa or can be used wi h 7400, 7500,
7600, 7700, and 7900-Series real ime TEKTRONIX
oscilloscopes.
External Graticules
Ex ernal gra icules for he main frame are available. Use
he following informa ion when ordering:
Main Frame External Graticule
7403N-7603 CCIR Composi e, Par No.
378-0684-04
NTSC Composi e, Par No.
378-0684-05
Main Frame External Graticule
7500,7700,7900 CCIR Composi e, Par No.
378-0625-05
NTSC Composi e, Par No.
378-0625-06
ELECTRICAL CHARACTERISTICS
Connector Input or Output Signal
COMPOSITE
VIDEO IN (2
Major Divisions)
Needs 2 major divisions peak- o-
peak sync nega ive composi e video
signal.
FIELD RATE
A group of one o six pulses, whose
minimum ampli ude is 2 V nega 
ive, shall re-occur a a field ra e.
The wid h of each individual group
of pulses shall no exceed 3H.
LINE RATE
The line rigger pulses available
shall have a clean leading edge and a
minimum ampli ude of 180 mV
nega ive.
S STEM CHARACTERISTICS
Compa ibili y
Compa ible wi h V and H sync
signals of s andard 405, 625, 819
Line/50 Hz, and 525 Line/60 Hz
broadcas sys ems; 405 o 1201
Line closed circui sys ems.
Trigger Sensi ivi y
2 major divisions or more will
provide s able V or H riggering.
1

7B53A/7B53AN OPTION 5
OPERATING INSTRUCTIONS
Introduction
This sec ion describes using he TV Sync Separa or
por ion of he ime base plug-in uni .
Using the TV Sync Separator Plug-In
a. Connec a coaxial cable from he oscilloscope ver ical
signal inpu connec or o a composi e video signal source of
such ampli ude as o produce a leas 2 major divisions of
ver ical deflec ion.
Se he 7B53A/7B53AN OPTION 5 con rols as follows:
Main Triggering Amplifier
SLOPE
MODE
COUPLING
SOURCE
AUTO
DC
TV FIELD
TIME/DIV
MAG
Main Time Base
2 ms
X1
b. Se he oscilloscope Main Triggering Amplifier
SOURCE swi ch o TV FIELD and he SLOPE swi ch o — .
c. Refer o he informa ion under Ob aining a Display
in his sec ion o ob ain a display.
Adjusting the CLIPPING LEVEL Control (R914)
NOTE
If the input amplitude of the composite video
changes, it may be necessary to readjust the CLIP 
PIN LEVEL control (R914).
a. Connec he composi e video as described under he
heading Using he TV Sync Separa or Plug-In.
b. Turn he CLIPPING LEVEL con rol (R914) fully
clockwise.
c. Se he oscilloscope con rols o ob ain he desired
video display.
d. Slowly ro a e he CLIPPING LEVEL con rol (R914)
coun erclockwise un il a poin is found where he mos
s able video display resul s.
TWO FIELD DISPLA
To ob ain a wo field display, adjus he LEVEL con rol
o ob ain a riggered display. The TIME/DIV VARIABLE
con rol may be adjus ed o ob ain a display of sligh ly less
han wo fields.
LINE DISPLA S
1. Variable Line Selector. To ob ain Variable Line
Selec or capabili ies, he DLY'D TRIG con rol mus be se
o he RUNS AFTER DLY TIME posi ion. Pull he
TIME/DIV knob ou ward and ro a e he knob o he
desired ime/div posi ion (10 µs). Ro a e he DELAY TIME
MULT con rol o he desired por ion of he waveform.
Push he TIME/DIV knob in and he desired por ion of he
waveform will be displayed. The delayed sweep is free
running in his mode of opera ion.
2. Discrete Line Selector. For Discre e Line Selec or
capabili y, place he Delayed Sweep Triggering SOURCE
swi ch in TV LINE posi ion. Ro a e he DLY'D TRIG
con rol ou of he RUNS AFTER DLY TIME posi ion and
se he con rol o ob ain a riggered sweep. Ro a e he
DELAY TIME MULT con rol un il he desired line is
displayed. When ro a ing he DELAY TIME MULT con rol,
he display will jump from line o line.
3. Main Triggering Amplifier TV Line. Se he TIME/
DIV swi ch o 10 µs and check ha he Main Triggering
Amplifier SOURCE swi ch is se o TV LINE. Adjus he
LEVEL con rol o ob ain a s able display a he H ra e.
Obtaining a Display
Ins all he TV Sync Separa or Plug-In in he oscilloscope
as described under Using he TV Sync Separa or. The
following ins ruc ions apply for he 7B53A/7B53AN OP 
TION 5 plug-in uni .
DELA ED INTERNAL TRIGGER OPTION
The Delayed Sweep Triggering SOURCE selec ion may
be changed from TV LINE/EXT o INT/EXT or vice versa.
For INT/EXT riggering source capabili y, move he coaxial
connec or from P903 o P904 and change he pushbu on
o read INT/EXT. The pushbu on is s ored on he TV
Sync Separa or board.
2

7B53A/7B53AN OPTION 5
CIRCUIT DESCRIPTION
A composi e video signal from 0.1 vol peak o peak o 4
vol s peak o peak mus be supplied o P900 (COMPOSITE
VIDEO IN) connec or o ob ain he required riggers from
he main frame ins rumen . From TP900 he composi e
video signal passes hrough a clipping circui composed of
emi er follower Q904, clipping amplifier Q90.8 and associ 
a ed circui ry. The clipping circui , whose clipping level is
se by R914 (CLIPPING LEVEL), clips only he video from
he composi e video signal.
From he clipping circui he remaining pulses of he
composi e video signal are amplified by Q920. The nega ive
(line or horizon al sync) pulses presen a he collec or of
Q920 pass hrough CR921 and C920 o P902 and P903.
When he Main Triggering Amplifier SOURCE swi ch is se
o TV LINE, he nega ive (line or horizon al sync) pulses
are available in main rigger or delayed rigger.
The posi ive (field or ver ical sync) pulses presen a he
collec or ,of Q920 canno pass hrough CR921; however,
hey and he nega ive (line or horizon al sync) pulses will
pass hrough CR918 o he base of Q924. The nega ive
pulses will pass hrough CR918 since, during he grea er
percen age of heir du y cycle, he line or horizon al sync
pulses are posi ive and will appear o CR918 as posi ive
pulses.
The line or horizon al sync pulses are kep from ge ing
hrough Q924 by he RC ne work of C926 and R926.
During he line or horizon al sync pulse ime, Q924 is kep
cu off by he bias provided by C926. The charge across
C926 is kep high by he high repe i ion ra e of he line or
horizon al sync pulses.
During he field or ver ical sync pulse in erval, C926
biases Q924 o cu off only par of he ime due o he
rela ively low repe i ion ra e of he field or ver ical sync
pulses. The ime ha Q924 is allowed o conduc is such
ha every o her field or ver ical sync pulse will be
amplified by Q924. The nega ive field or ver ical rigger
pulses presen a he collec or of Q924 are supplied hrough
emi er follower Q932 and C932 o P901 (FIELD RATE)
connec or and o he TV FIELD pushbu on. The field or
ver ical rigger pulse group are available cons an ly a P901
for he Main Triggering Amplifier only.
C924, loca ed in he collec or circui of Q924 and he
base circui of Q932, serves o fil er ou any line or
horizon al sync pulses which may s ill be presen . CR932
se s he bias on Q932.
3

7B53A/7B53AN OPTION 5
CALIBRATION PROCEDURE
Optional Test Equipment
067-0601-00 Calibra ion Fix ure (Television Tes Signal
Genera or)
Plug-In Cards for 067-0601-00 Generator
067-5001-00
Sys em A
405/50
067-5002-00
Sys em M
525/60
067-5003-00
Sys em B
625/50
067-5004-00
Sys em E
819/50
067-5005-00
Sys em F
819/50
067-5006-00
EIA S andard
729/60
067-5007-00
EIA S andard
875/60
067-5008-00
EIA S andard 945/60
067-5009-00
EIA S andard
1029/60
067-5010-00
EIA S andard
1201/60
CHECK/ADJUST PROCEDURE
1. Check TP900 Waveform
a. Connec a composi e video signal o he ver ical
plug-in uni .
b. Se he 7B53A/7B53AN OPTION 5 con rols as
follows:
Main Triggering Amplifier
SLOPE
MODE
COUPLING
SOURCE
MAIN TIME BASE
AUTO
DC
TV FIELD
NOTE
If the trigger pick-off circuit is overdriven or the
piug-in Vertical Position control is rotated to its fully
clockwise or counterclockwise position, the wave 
form may become distorted. If so, the sync separator
will not function properly unless the display ampli 
tude is 2 major divisions as described in part c of this
step and the Vertical Position control is moved away
from its extreme position.
2. Check TP926 Waveform and Adjust R914
a. Connec he 10X probe o TP926. Se he es
oscilloscope con rols o ob ain a s able display.
b. Adjus he Clipping Level con rol R914 by ro a ing
he con rol fully clockwise. Then, ro a e he con rol
coun erclockwise un il one or more nega ive-going pulses in
a group are displayed on he es oscilloscope during he
ver ical sync pulse in erval. The exac number of pulses is
dependen on he elevision s andard of he composi e
video signal being applied o he ver ical plug-in uni . Fig. 1
shows a normal display ob ained for he 525/60 elevision
s andard. The pulse ampli ude is approxima ely 4 vol s
nega ive below he H pulses. If R914 is improperly
adjus ed, he H ra e rigger will no be normal during he
ver ical sync pulse in erval.
3. Check TP932 Waveform
a. Connec he 10X probe o TP932.
MAG X1
TIME/DIV
2 ms
c. Adjus he ver ical deflec ion fac or of he oscillo 
scope o ob ain a 2 major division display. Adjus he
7B53A/7B53AN OPTION 5 Main Triggering Amplifier
LEVEL con rol o ob ain a riggered display.
d. Connec a 10X probe from he es oscilloscope o
TP900 on he TV Sync Separa or board. Connec a field
drive signal from he signal genera or o he es oscillo 
scope Ex Trig Inpu connec or for use as an ex ernal
rigger source.
e. Check for a normal video signal display on he es
oscilloscope (same as signal from genera or). Ampli ude of
he signal will vary wi h changes of inpu signal level.
Fig. 1. Normal 525/60 waveform at TP926. Vertical deflection
factor is 2 V/div; time/div is 50 µs.
4

7B53A/7B53AN OPTION 5
b. Check for a es oscilloscope display of one or more
nega ive-going pulses in a group during he ver ical sync
pulse in erval. The number of pulses is dependen on he
elevision s andard composi e video signal being applied o
he plug-in uni . The pulse is very fas ; approxima ely
0.1 µs in wid h a he 50% ampli ude level. Full pulse
ampli ude is approxima ely 2.8 vol s.
4. Check TP920 Composite Sync Waveform
a. Connec he 10X probe o TP920.
b. Check es oscilloscope display. The waveform should
be nega ive-going composi e sync occurring a he H ra e;
ampli ude should be approxima ely 180 mV. All video,
excep burs , should be clipped off.
5. Check Sync Separator Operation
a. Apply various elevision s andard composi e video
signals (domes ic and closed circui ) o he plug-in uni .
NOTE
If desired, apply only those composite video signais
that will be used at your facility.
b. Wi h he 10X probe connec ed o TP920, check he
es oscilloscope display for a proper waveform as described
in s ep 4.
d. Pull he DLY TIME knob ou ward and se he DLY
TIME swi ch o he desired posi ion (10 µs). Ro a e he
DELAY TIME MULT con rol o in ensify he desired
por ion of he display. Then, push he DLY TIME knob in
o view he in ensified por ion.
NOTE
In this mode of operation the delayed sweep is free
running.
7. Check Discrete Line Selector Operation
a. Se he 7B53A/7B53AN OPTION 5 Main Triggering
Amplifier SOURCE swi ch o TV LINE. Adjus he LEVEL
con rol o ob ain a riggered display.
b. Ro a e he DLY'D TRIG con rol ou of he RUNS
AFTER DLY TIME posi ion and adjus his con rol o
ob ain a riggered delayed sweep. Ro a e he DELAY TIME
MULT con rol o display he desired por ion of he signal.
NOTE
in this mode of operation the displayed portion of
the signai will jump from line to line as the DELAY
TIME MUL Tcontrol is slowly rotated.
c. Disconnec he 10X probe.
6. Check Variable Line Selector Operation
a. Apply he desired composi e video signal o he
ver ical plug-in uni .
b. Check ha he 7B53A/7B53AN OPTION 5 Main
Triggering Amplifier SOURCE swi ch is se o TV FIELD
and he TIME/DIV swi ch is se o 2 ms. Se he TIME/DIV
VARIABLE con rol o display sligh ly less han wo fields.
Adjus he Main Triggering LEVEL con rol o ob ain a
riggered display.
c. Se he 7B53A/7B53AN OPTION 5 DLY'D TRIG
con rol o RUNS AFTER DLY TIME posi ion. Se he
Delayed Sweep Triggering con rols as follows:
SLOPE
COUPLING DC
SOURCE TV LINE
8. Check Main Triggering Amplifier TV Line Oper 
ation
a. Se he TIME/DIV o 10 µs. Check ha he Main
Triggering Amplifier SOURCE swi ch is se o TV LINE.
b. Adjus he Main Triggering Amplifier LEVEL con rol
o ob ain a s able display a H ra e.
9. Check Delayed Internal Trigger Operation
Move he coaxial cable connec or from P903 o P904 on
he TV sync separa or board and change he Delayed Sweep
Triggering SOURCE TV LINE pushbu on. The INT/EXT
pushbu on is s ored inside he 7B53A/7B53AN OPTION 5
plug-in uni on he TV Sync Separa or board.
5

7B53A/7B53AN OPTION 5
PARTS LIST
The following changes should be made o he appropria e par s lis for his modified ins rumen . When ordering
replacemen par s specify ins rumen ype, serial number, and mod number. Include he circui number, par number, and
descrip ion of he desired i em.
*Par s iden ified by an as erisk are unique o his modified produc and are no normally s ocked.
Electrical Parts List
Capacitors
C900
Add 283-0092-00 0.03 µf
cer 200 V +80% -20%
C904
Add 290-0517-00 6.8 µf em 35 V
C908
Add 281-0550-00
120 pf
cer
500 V
10%
C920
Add 283-0092-00
0.03 µf
cer
200 V
+80%-20%
C924
Add 281-0511-00
22 pf
cer
500 V
10%
C926
Add 281-0605-00
200 pf
cer 500 V
C929
Add
283-0010-00 0.05 µf cer 50 V
C932
Add
283-0092-00
0.03 µf
cer
200 V
+80% -20%
Diodes
CR908 Add
152-0075-00
Germanium Tek Spec
CR909
Add 152-0141-02 Silicon
1N4152
CR912
Add 152-0141-02
Silicon
1N4152
CR913
Add 152-0141-02 Silicon 1N4152
CR916
Add 152-0195-00 Zener 1N751A 0.4 W, 5.1 V,5%
CR917
Add 152-0075-00 Germanium Tek Spec
CR918
Add
152-0141-02 Silicon 1N4152
CR920
Add
152-0195-00 Zener 1N751A 0.4 W, 5.1 V, 5%
CR921
Add
152-0075-00
Germanium Tek Spec
CR932
Add
152-0075-00
Germanium Tek Spec
Transistors
Q904
Add
151-0188-00 Silicon
2N3906
Q908 Add
151-0188-00 Silicon 2N3906
Q920
Add
151-0192-00
Silicon
Replaceable by MPS-6521
Q924
Add
151-0192-00
Silicon Replaceable by MPS-6521
Q932
Add
151-0188-01 Silicon Replaceable by 2N3251
Resistors
R900
Add 315-0221-00
220  1/4 W
5%
R904
Add 315-0563-00
56 k 1/4 W
5%
R905
Add
315-0471-00
470  1/4 W
5%
R907
Add
315-0681-00
680  1/4 W
5%
R908
Add
315-0203-00 20 k
1/4 W
5%
6

7B53A/7B53AN OPTION 5
Resistors (cont)
R909
Add
315-0334-00
330 k 1/4 W 5%
R910 Add
315-0105-00 1 m
1/4 W
5%
R912 Add
315-0182-00 1.8 k 1/4 W
5%
R913 Add
315-0182-00
1.8 k 1/4 W 5%
R914 Add
311-1226-00
2.5 k
var
R918 Add 315-0112-00
1.1 k 1/4 W
5%
R920 Add 315-0303-00
30 k 1/4 W
5%
R921 Add
315-0513-00 51 k 1/4 W
5%
R922 Add
315-0274-00
270 k
1/4 W
5%
R923 Add
315-0242-00
2.4 k 1/4 W 5%
R924 Add
315-0103-00
10 k 1/4 W 5%
R926
Add 315-0154-00
150 k 1/4 W
5%
R928 Add
315-0822-00
8.2 k 1/4 W
5%
R929
Add 315-0123-00
12 k 1/4 W
5%
R932 Add
315-0822-00
8.2 k
1/4 W
5%
R940
Add
315-0102-00 1 k
1/4 W 5%
R941 Add
315-0102-00 1 k
1/4 W 5%
S10 Change
Switch
670-1969-00
Main T rigger Source
Test Point
TP900 Add
214-0579-00
TP920
Add 214-0579-00
TP926 Add
214-0579-00
TP932 Add
214-0579-00
Mechanical Parts List
Pos , Me allic Add
5
129-0339-00
Fron Panel
Change
1
333-1542-00
Iden ifica ion Tag
Add
1
334-1377-00
Knob Add
1
366-1257-00
Swi ch Trigger Source
Change
1 670-1969-00
E.C. Board, T.V. Sync
Separa or
Add
1 670-1970-00
Accessories
Manual, Op ion 5
Supplemen
Add
070-1471-00
1
7