Tektronix 507 User manual

CATHODE- RAY OSCILLOSCOPE
TYPE 507
INSTRUCTION
MANUAL
TEKTRONIX, INC.
MANUFACTURERS OF CATHODE-RAY AND VIDEO TEST INSTRUMENTS
IM -507-1
Sunset Highway and Barnes R ad • P.O.B x 831 • P rtland 7, Oreg n, U. S. A.
Ph ne: CYpress 2-2611 • Cables: Tektr nix
TYPE 507 SERIAL NUMBER _________

Copyrig t © 1959 by Tektronix, Inc.,
Portland, Oregon. Printed in t e
United States of America. All rig ts
reserved. Contents of t is publica 
tion may not be reproduced in any
form wit out permission of t e copy 
rig t owner.

CONTENTS
Vertical Deflection System. Sweep Circuit. Power Sup 
plies. Miscellaneous. Functions of Controls and Con 
nectors.
GENERAL DESCRIPTION
SECTION 1
Sweep. Vertical Deflection System. Cathode-Ray Tube
Circuit. igh-Voltage Power Supply. Time Mark Gen 
erator. External Power Supply.
CIRCUIT DESCRIPTION
SECTION 2
Preventive Maintenance. Analyzing Trouble.
MAINTENANCE
SECTION 3
ADJUSTMENT PROCEDURE
SECTION 4
PARTS LIST
SECTION 5
SCHEMATIC DIAGRAMS
SECTION 6
ACCESSORIES
SECTION 7
507 ®

GENERAL DESCRIPTION
T e Tektronix Type 507 Oscilloscope is a specialized instrument
designed primarily for ig -voltage surge testing as applied to
power transformers, ig -voltage insulators, lig ting arrestors and
allied components, and t eir associated design and acceptance
tests.
T e use of a 24-kv accelerating potential on a new type cat ode
ray tube permits p otograp ic recording of single sweeps at t e
maximum writing-rate permitted by t e vertical deflection and
sweep circuits. T e vertical deflection system provides a risetime
of approximately 5 millimicroseconds and a sensitivity of approx 
imately 50 v/cm. An external lengt of delay cable can be inserted
into t e vertical-input signal circuit to permit viewing of t e lead 
ing edge of t e waveform w ic triggers t e sweep. Time markers
are available for convenient calibration of t e sweep.
T e Type 507 consists of two units, indicator and power supply,
mounted on a Scope-Mobile, t us making a convient mobile unit.
If desired, t e units may be lifted off t e Scope-Mobile for benc
use.
VERTICAL DEFLECTION SYSTEM
Transient Response
Risetime between 10-percent and 90-percent
amplitude points is about 5 millimicroseconds
(.005 microseconds). A passive damping network
inserted in t e deflection leads is adjusted for
optimum transient response wit out overs oot
or ringing.
T e maximum vertical sensitivity wit a Type
T507P cat ode-ray tube operated at 24-kv ac 
celerating is 50 v/cm.
Attenuator
A step attenuator wit a c aracteristic imped 
ance of 72 o ms is provided in t e vertical-input
signal circuit. T e attenuator is composed of
ten equal resistors of 7.2 o ms eac , mounted
on a tap switc . T e percentage of input signal
applied to t e deflection plates can be selected
by t e tap switc from 10 percent to 100 per 
cent in 10-percent steps.
Signal Mode
A t ree-position switc reverses t e deflection 
plate polarity; t e center position of t e switc
is used in conjunction wit a trigger-selector
switc to apply markers for p otograp ing time
references.
Positioning Switc
T e Type 507 as a seven-step vertical-posi 
tion switc wit 50-volt steps of — 150v, — 100 v,
— 50 v, 0, +50 v, +100 v and +150 v. A sep 
arate two-position switc selects eit er 50-volt
steps or continuously variable adjustment.
External Voltmeter Connections
Terminals are provided for a ig -impedance
(5000Ω/v) de voltmeter, permitting vertical cali 
bration w en using t e variable positioning.
GENERAL DESCRIPTION — TYPE 507
1-1

Signal Delay
Two standard UHF connectors are provided on
t e rear of t e instrument for insertion of an
external lengt of delay cable into t e vertical 
input signal circuit. C oice of t e appropriate
lengt and type of cable is at t e discretion of
t e user; no delay cable is furnis ed wit t e
instrument. A signal delay permits t e sweep to
be triggered and under way before t e signal is
applied to t e vertical deflection plates.
SWEEP CIRCUIT
Type
Triggered, ard-tube bootstrap sweep circuit
wit inverter to produce balanced deflection.
Rates
An eleven-position switc selects rates of .02,
.05, .1, .2, .5, 1, 2, 5, 10, 20 and 50 MICRO-
SECONDS/CM, wit a maximum displacement
error of 2 percent over t e center 8 cm of t e
10-cm sweep lengt .
Sweep Starting Time
T e orizontal sweep starts approximately
100-m/zsec after t e signal or triggering pulse
arrives at t e rear-panel connector. An inserted
signal delay of approximately 150 m µ sec permits
t e sweep to be triggered and under way before
t e signal is applied to t e vertical deflection
plates.
Duty Cycle Limitation
A duty-cycle limiting control automatically
limits t e duty cycle of t e sweep circuit to about
10 percent to avoid exceeding t e dissipation
limits of some of t e circuit components. T e
limiting system serves purely a protective func 
tion and does not provide a frequency dividing
operation.
T e following table s ows t e maximum per 
missible repetition rate for eac of t e avail 
able sweep times per centimeter.
SWEEP TIME
MAXIMUM
REPETITION RATE
50 µ sec/cm 600 c/s
20 µ sec/cm
1.5 kc
10 µ sec/cm
3 kc
5 µ sec/cm
6 kc
2 µ sec/cm
10 kc
1 µ sec/cm
20 kc
.5 µ sec/cm 50 kc
.2 µ sec/cm
50 kc
.1 µ sec/cm
50 kc
.05 µ sec/ cm
50 kc
.02 µ sec/cm
50 kc
Triggering
A triggering p ase-inverter amplifier in con 
junction wit a selector switc permits t e sweep
circuit to be triggered from eit er positive- or
negative-going portions of t e observed signal,
or from positive or negative triggers from an
external source. A trigger voltage range of 100
volts to 3000 volts amplitude will be adequate
for stable triggering. T e MARKER position on
t e selector switc must be used w en time
markers are desired.
Sweep Mode
A two-position switc provides for eit er re 
petitive or single-sweep operation. W en t e
switc is in t e single-sweep position, pressing
t e RESET button arms t e sweep circuit. T e
sweep can t en be triggered internally, by MAN 
UAL TRIGGER, or by an external trigger. T e
1-2 GENERAL DESCRIPTION — TYPE 507

MANUAL TRIGGER switc is primarily for p oto- t e calibrated vertical position lines, to create,
grap ing a zero reference line and any or all of in effect, a parallax-free graticule.
POWER SUPPLIES
Cat ode-Ray Tube Accelerating Voltage
An oil-sealed supply of t e a-f oscillator type
provides 24 kv (+20 kv and — 4 kv) for t e ac 
celerating potentials. T e — 4-kv supply is reg 
ulated to compensate for load c anges and line 
voltage c anges.
Low-Voltage Supply
A separate power unit provides regulated d c
voltages for t e indicator unit of +750, +475,
+225 and — 250 volts. T e unit also provides
an unregulated voltage of +360 volts for t e
oscillator in t e ig -voltage supply for t e c rt
circuit.
Power Requirements
600 watts at 117 volts. Voltage range 105-125
or 210-250 volts, 60-cycle, single-p ase ac. Two
primary circuit fuses are provided for protection
against sustained over-load conditions.
MISCELLANEOUS
Cat ode Ray Tube
A Type T507P ca ode-ray tube wit P11 p os 
p or is furnis ed wit t e Type 507 unless an 
ot er p osp or is specified.
Construction
Contained in two separate units of convenient
size, normally mounted on a Tektronix Type
500A Scope-Mobile. T e anodized c assis and
t e blue wrinkle-finis ed cabinets are made of
an aluminum alloy. P oto-etc ed anodized pan
els are employed.
Dimensions
Indicator unit: 16-¾" ig , 13" wide, 23-
¾" deep.
Power unit: 10 ½" ig , 13" wide, 17½"deep.
Weig t
Indicator unit ................................................ 50 lbs.
Power Unit ................................................. 39 lbs.
Type 500A Scope-Mobile .......................... 35 lbs.
FUNCTIONS OF CONTROLS AND CONNECTORS
6.3V 1A. AC
Tip jack from eater bus.
SCALE ILLUM.
Variable resistor controlling brig tness of lamps illuminating graticule over
face of cat ode-ray tube.
ASTIGMATISM
Potentiometer controlling t e voltage at t e astigmatism anode of t e cat 
ode-ray tube. Proper setting of t e voltage at t is anode, wit respect to
t e deflection plates, permits t e spot to be focused s arply in bot dimen 
sions simultaneously.
INTENSITY
Potentiometer controlling de grid voltage of t e cat ode-ray tube and t ere 
by t e brig tness of t e trace.
FOCUS
Potentiometer controlling t e voltage applied to t e focusing anode of t e
cat ode-ray tube for focusing t e trace.
GENERAL DESCRIPTION — TYPE 507
1-3

HORIZONTAL
POSITION
Twin differentially-connected potentiometer controlling average potential of
cat ode-ray tube orizontal deflection plates, t ereby adjusting orizontal
position of sweep.
SWEEP MODE
Two-position toggle switc to select eit er repetitive or single-sweep opera 
tion.
RESET
Button-switc arms t e sweep circuit w en t e SWEEP MODE switc is in t e
SINGLE SWEEP position. T e READY lig t indicates t at a single sweep will
be produced upon reception of a trigger pulse from t e signal to be ob 
served (or p otograp ed), from an external trigger source, or from t e man 
ual-trigger circuit (obtained by depressing t e MANUAL TRIGGER switc ).
STABILITY
Potentiometer controlling grid bias of negative multivibrator tube. Deter 
mines optimum point of triggering.
MICROSECONDS/CM
Gang switc controlling sweep duration and sweep rate. Selects appropri 
ate multivibrator pulse lengt , and sweep generator c arging capacitor and
resistor. Switc also selects TIME MARKERS for convenient calibration of t e
sweep.
TRIGGER SELECTOR
Switc selecting source and polarity of sweep-triggering voltage.
MANUAL TRIGGER Button-switc provides manually-controlled trigger for sweep generator.
MANUAL TRIP PULSE
Button-switc provides pulse of approximately 700 volts amplitude and 5
µsec. widt at TRIP PULSE OUT connector on rear panel of instrument.
VERTICAL
ATTENUATOR
SIGNAL MODE
Switc selects percentage of input-signal voltage applied to vertical deflec 
tion plates.
T ree-position switc reverses deflection-plate polarity wit respect to signal
being observed. T e center position on t e switc connects t e output of t e
Time-Mark Genrator to t e vertical deflection plates.
VARIABLE DEFLECTION Switc connects arm of VARIABLE positioning control to EXTERNAL VOLT 
SENSITIVITY MONITOR METER connectors on front panel of instrument to monitor t e variable d c
positioning voltage. Polarity of voltage may be reversed.
POSITIONING
50 VOLT STEPS
Seven-position switc to control voltage at cat ode-ray tube vertical deflec 
tion plates in 50-volt steps. Eac position of t e switc causes t e beam to
s ift approximately 1 centimeter in t e vertical plane. T is switc is con 
nected into t e circuit w en t e toggle switc immediately below it is in t e
50 VOLT STEPS position.
POSITIONING
VARIABLE
Potentiometer controlling average potential of cat ode-ray tube vertical
deflection plates, providing continuous adjustment of vertical position of
beam. T is control is connected into t e circuit w en t e toggle switc
immediately below it is in t e VARIABLE position.
50 VOLT STEPS
VARIABLE
Toggle switc determines w et er vertical positioning is continuously variable
or in 50-volt steps.
1-4
GENERAL DESCRIPTION — TYPE 507

REAR-PANEL CONNECTORS
SIGNAL IN
UHF connector to TRIGGER SELECTOR switc and to SIGNAL OUT DELAY
LINE connector.
SIGNAL OUT TO
DELAY LINE
UHF connector receives signal internally from SIGNAL IN connector. An
external lengt of delay cable may be connected between t is connector
and t e SIGNAL IN FROM DELAY LINE connector.
SIGNAL IN FROM
DELAY LINE
UHF connector to vertical ATTENUATOR switc .
EXTERNAL TRIGGER
INPUT
UHF connector to TRIGGER SELECTOR switc .
TRIP PULSE OUT
UHF connector to t yratron in Trip Pulse circuit to make available external 
ly a pulse of approximately 700 volts amplitude and 5 µsec. duration.
EXTERNAL POWER SUPPLY
DC SUPPLIES
POWER
ON-OFF switc on power supply unit controlling ac line voltage to primary
of plate-supply transformer; pilot lamp indicates ON position.
AC HEATERS
ON-OFF switc on power supply unit for controlling ac line voltage to unit;
pilot lamp indicates ON position,
GENERAL DESCRIPTION — TYPE 507
1-5

CIRCUIT DESCRIPTION
SWEEP
A linear triggered sweep is available wit
eleven fixed, accurately timed sweeps ranging
from .02 microseconds per centimeter to 50 mi 
croseconds per centimeter. T e basic waveform
is generated by a pentode clamp wit a cat 
ode-follower bootstrap linearity corrector. Pus -
pull deflection is accomplis ed at output level by
addition of a plate-output unity-gain p ase 
inverter stage, s own on t e Horizontal Ampli 
fier circuit diagram.
Trigger P ase C anger
A trigger selector switc selects t e source of
trigger signal and V4 and V 1 4 reverse t e p ase,
if necessary, to provide t e trigger amplifier wit
t e required negative signal.
Trigger Limiter Amplifier
T e trigger limiter stage V24 operates wit
zero bias. T e negative pulse from t e trigger
inverter-amplifier drives t is tube to plate-cur 
rent cutoff. C oice of t e proper value of quies 
cent plate current and t e use of a plate-load
resistance of low value results in a very steep
positive pulse limited in amplitude to about 10
volts. T is positive pulse is t en used to drive
V34.
Trigger Switc Tube
T e resulting negative pulse at t e plate of
V34, coupled t roug t e coupling diode V 1 02
to t e plate of t e minus multivibrator V 1 05, trig 
gers t e sweep.
Trigger Coupling Diode
T e trigger-coupling diode V 1 02 serves to dis 
connect t e plate of t e trigger-switc tube V34
from t e plate of t e negative multivibrator tube
V 1 05 w en t e plate voltage of V1 05 drops be 
low t at of V34.
Multivibrator
V 1 05 and V 1 15 operate as a plate-coupled
monostable multivibrator for t e purpose of
converting a triggering pulse into a pulse of con 
trollable duration suitable for operating t e
sweep generator and unblanking circuits. T e
SWEEP STABILITY control, by varying t e bias
on t e grid of V 1 05, determines t e optimum
point of triggering.
Duty Cycle Limiter
T e duty-cycle limiting circuit is designed as
a protective circuit to prevent t e orizontal
amplifier V324 from exceeding its dissipation
rating. T is is accomplis ed by sampling t e out 
put of t e plus multi cat ode-follower V 1 33 and
feeding t is voltage t roug an integrating net 
work (R125-C125) to t e grid of t e difference
amplifier V 1 16 (pentode section). A rise in t e
voltage at t is grid forces t e grid of t e minus
multi V 1 05 toward cutoff w ic results in a multi 
vibrator waveform s orter t an normal for t e
sweep speed being used. Since t e lengt of t e
multivibrator waveform determines t e sweep
lengt , as t e duty cycle is increased t e sweep
lengt is s ortened.
A compensated divider located at t e grid of
t e triode section of V 1 16 provides a second
means of controlling t e multivibrator. T is cir 
cuit is not duty-cycle conscious, but rat er sam 
ples t e trigger lock-out circuitry. During t e
trigger locked-out configuration t e grid of t e
triode section is pulled down sufficiently to lock
out t e multivibrator until t e trigger-lockout cir 
cuit is reset.
Sweep-Trigger Lockout
W en t e SWEEP MODE switc is in t e
SINGLE SWEEP position t e t yraton V49 con 
ducts and its plate drops. T is action produces
two results: (1) It pulls down t e grid of t e
triode section of V 1 16 and switc es all of t e
current to t e pentode section. T is cuts off V 1 05
and forces t e multivibrator to remain in its
quiescent state; (2) It pulls down t e screen of
V34 t roug t e cat ode follower V63A and V34
cuts off. Wit V34 cut off, t e triggers are pre 
vented from reac ing plate of V 1 05 and initiat 
ing a sweep.
CIRCUIT DESCRIPTION — TYPE 507
2-1

W en t e RESET button is depressed, C48 dis 
c arges and t e resulting negative pulse at t e
plate of V49 extinguis es t e t yratron. T e re 
sulting rise in voltage at t e plate of t e t yra 
tron t en pulls up t e screen of V34 and permits
t is tube to conduct. It also pulls up t e cat ode
of V63B and ignites t e READY lig t. T is in 
dicates t at t e trigger circuit is now armed and
t e next trigger to arrive at t e grid of V34 will
produce a sweep.
As t e multivibrator switc es to its unstable
state, and t en reverts back to its stable state,
a negative pulse is produced at t e plate of
V 1 05. T is pulse is differentiated in t e grid cir 
cuit of V49 and t e resulting positive pulse fires
t e t yratron; t is action locks out t e trigger
circuit again and prevents t e sweep from being
started from t e next trigger. Depressing t e
RESET button will t en arm t e trigger circuit
again and permit one sweep to be produced up 
on reception of a trigger.
Manual Trigger
T e sweep may be triggered manually, if
desired, by depressing t e MANUAL TRIGGER
button. C25 is c arged to about +20 volts from
t e divider R25-R26. W en t e MANUAL TRIG 
GER switc is depressed C25 disc arges into C22,
creating a negative pulse at t e top of C25. T e
negative pulse is coupled t roug t e diode V22
and C26 to t e grid of V24 w ere it activates
t e trigger circuitry to initiate a sweep.
Sweep Generator Clamp Circuit
In t e quiescent state, t e parallel clamp tubes
V 1 64 and V 1 74 conduct eavily and t eir plates
are down. W en t e multivibrator is triggered,
t e resulting negative pulse at t e plate of V 1 05
is coupled to t e grids of t e clamp tubes and
interrupts t e flow of plate current very rapidly.
T e plate voltage of t e clamp tubes t en begins
to rise at a rate determined by t e c arging
rate of C 1 77. T is c arging rate is determined
by t e value of C 1 77 and R176, bot of w ic
are selected by t e MICROSECONDS/CM timing
switc . T e small c oke L 162 in t e grid circuit
of t e clamp tubes provides a 10-millimicrosec-
ond delay to enable t e unblanking circuit to
reac full voltage before t e sweep starts.
Bootstrap Circuit
For C177 to c arge linearly rat er t an ex 
ponentially t e voltage across t e timing resistor
R1 76, and ence t e c arging current, must re 
main constant. T is action is accomplis ed by
t e sweep cat ode-follower V 1 73 and t e boot 
strap tubes V183-V193. T e rise in voltage at t e
cat odes of V173, as C 1 77 c arges, pulls up t e
cat odes of t e bootstrap tubes. T is rise in
voltage is coupled to t e top of R176A and
keeps t e voltage across t e timing resistor more
nearly constant.
Decoupling Diode
A decoupling diode V 1 72, in series wit t e
+475-volt supply to t e plates of t e clamp
tubes, offers low resistance to t e quiescent
plate current of t e clamp tubes but disconnects
t e upper end of t e timing resistor from t e
+475-volt supply w en t e bootstrap action
raises t e cat ode of t e diode above +475
volts.
Sweep Cat ode Follower
T e sweep cat ode-follower V 1 73 provides t e
positive-going sweep sawtoot voltage for t e
rig t- and deflection plate in t e cat ode-ray
tube. T is stage also drives t e grid of t e
sweep p ase inverter to provide t e negative 
going sweep sawtoot voltage for t e left- and
deflection plate.
Sweep Inverter
T e p ase-inverter V324 (Horizontal Amplifier
diagram) operates as a unity-gain amplifier to
supply t e negative-going sawtoot sweep volt 
age to t e left- and deflection plate of t e cat 
ode ray tube. T e gain of t is stage is kept low
by virtue of t e frequency-compensated feed 
back network between plate and grid. V313A
and V313B provide a low-impedance bias and
screen voltage, respectively, for t e p ase 
inverter tube V324.
DC Restoration
T diodes V332A and V332B remove t e accu 
mulated c arge from t e sweep-coupling capac 
itors C324 and C325, permitting t e sweep to
start at t e same position on t e cat ode-ray
tube regardless of t e repetition rate of t e
sweep.
Unblanking Amplifier
During t e waiting period, between sweeps,
t e bias on t e cat ode-ray tube is suc t at t e
2-2
CIRCUIT DESCRIPTION — TYPE 507

beam current is completely cut off. As soon as
a trigger pulse appears and a sweep starts, a
positive pulse of approximately 100 volts is re 
quired at t e grid of t e cat ode-ray tube to
turn t e beam on. T is pulse must ave a very
fast risetime and a very flat top to insure fast
unblanking and uniform image brig tness. Bot
conditions are accomplis ed by t e unblanking
amplifier V144-V154 and t e associated cat ode
follower V 1 53.
T e negative pulse at t e plate of t e minus
multivibrator VI 05 is coupled to t e grids of t e
unblanking amplifier via a frequency-compen 
sated voltage divider. T e s unt-compensated
plate-load impedance of t e amplifier circuit
produces a positive pulse aving a very fast
risetime. T e cat ode-follower circuit V 1 53 pro 
vides a ig -impedance, low-capacitance load
to t e amplifier, at t e same time providing a
low-impedance driving source for t e grid of t e
cat ode-ray tube. T e cat ode-follower VI 43
provides a low-impedance source of screen
voltage for t e amplifier tubes. T e UNBLANK 
ING ADJ. R146 provides a means of adjusting
t e screen voltage to obtain t e desired 100-volt
unblanking pulse.
Trip Pulse
A t yratron pulse generator produces a man 
ually-initiated pulse at a rear-panel connector
for triggering a trip-pulse generator. In t e
quiescent state t e divider R52-R53 olds t e grid
of t e t yratron below cutoff. W en t e MAN 
UAL TRIP PULSE switc is depressed C50 c arges
and t e positive pulse developed at t e grid fires
t e t yratron. Since t e t yratron is connected
as a cat ode follower, t e cat ode pulls up
s arply to develop t e output pulse of approxi 
mately 700 volts. In producing t e output pulse,
owever, t e cat ode voltage approac es suf 
ficiently close to t e voltage at t e plate to
extinguis t e t yratron and return t e circuit to
its quiescent state.
VERTICAL DEFLECTION SYSTEM
Since t e Type 507 does not contain a vert 
ical amplifier, t e vertical defection circuit con 
sists mainly of an attenuator and a positioning
network.
T e input signal is developed across t e 72-o m
attenuator resistance. T e desired percentage of
t e input signal is selected from a tap on t e div 
ider by means of t e ATTENUATOR switc , from
w ere t e signal is coupled to one of t e ver 
tical-deflection plates in t e cat ode-ray tube.
T e ot er vertical deflection plate is connected
to ground to accommodate t e single-ended
input signal.
W en t e SIGNAL MODE switc is in t e EX 
TERNAL NORMAL position, positive-going por 
tions of t e input signal produce upward deflec 
tion in t e cat ode-ray tube; in t e EXTERNAL
REVERSED position, positive-going signals pro 
duce downward deflection. In t e INTERNAL
MARKER position of t e switc , time markers
from t e Time-Mark Generator are coupled to
t e lower deflection plate and t e upper plate is
connected to ground.
Eit er of two positioning circuits may be con 
nected into t e vertical deflection circuit. W en
t e toggle switc SW435 is in t e 50 VOLT
STEPS position, a tapped divider connected be 
tween + 150 volts and — 150 volts is connected
into t e circuit. By means of t e POSITIONING
switc , t e positioning voltage may be selected
in 50-volt steps between t ese two limits. Test
points and adjustments are provided to accur 
ately set t e upper and lower voltage for t e
divider.
W en SW435 is in t e VARIABLE position,
a continuously variable positioning control is
connected into t e circuit. T e VARIABLE posi 
tioning control is part of a divider connected
between +225 volts and — 250 volts. T e resis 
tance values in t e divider are suc t at t e
range of positioning voltage is about 325 volts,
a bit greater t an t e 300-volt range provided
by t e 50 VOLT STEPS control. Front-panel EX 
TERNAL VOLTMETER connections are provided to
monitor t e VARIABLE positioning voltage. T e
VARIABLE DEFLECTION SENSITIVITY MONITOR
switc may be used to reverse t e voltmeter
connections, or to disconnect t e VARIABLE
position control from t e front-panel voltmeter
connections if desired.
CIRCUIT DESCRIPTION — TYPE 507
2-3

CATHODE-RAY TUBE CIRCUIT
I 1
EXTERNAL POWER SUPPLY
T e NE2 neon glow lamps across t e INTEN 
SITY control potentiometer and MAX. INTENSITY
variable resistor maintain t e INTENSITY poten 
tiometer terminal voltage constant regardless of
cat ode-ray tube cat ode current, t ereby
stabilizing t e intensity adjustment.
T e purpose of t e MAX. INTENSITY control
is to adjust t e minimum grid bias setting avail 
able by t e INTENSITY control to a safe value
t us preventing damage to t e cat ode-ray tube
screen in case t e INTENSITY control is ad-
HIGH-VOLTAGE
All accelerating potentials for t e cat ode 
ray tube are provided by a ig -voltage supply
employing an audio oscillator operating at a
frequency of approximately 1500 cycles. Four
ig -voltage rectifier tubes in a voltage-quad-
HIGH-VOLTAGE OSCILLATOR AND REGULATOR CIRCUIT
T e screen voltage of t e ig -voltage oscil 
lator V820 is regulated to maintain a con 
stant — 4000 volts of rectified output so t at
t e deflection sensitivity of t e cat ode-ray
tube will not be affected by line-voltage
or load c anges. A sample of t e — 4000-volt
output, obtained from a tap on t e divider con 
sisting of R212 and R213, is compared to t e
regulated — 250-volt supply t roug V814A. Any
“ error ” voltage t at may exist is amplified by
V814A and V814B and is applied to t e screen
of t e oscillator tube V820. T is will c ange t e
output of t e oscillator in a direction to compen 
vanced too far.
T e FOCUS control potentiometer varies t e
voltage at t e focusing ring to focus t e trace;
t e ASTIGMATISM control potentiometer varies
t e voltage at t e astigmatism anode to focus
t e spot in bot dimensions simultaneously.
T e GEOM. ADJ. potentiometer varies t e
field as t e beam emerges from t e deflection
system to control t e linearity at t e extremes
of deflection.
POWER SUPPLY
rupling circuit provide 4-20,000 volts; a single
a If-wave rectifier tube provides — 4000 volts.
T e ig -voltage rectifiers, capacitors, resistors
and transformers are all oil-immersed.
sate for t e error. T e — 4KV ADJ. R814 controls
t e bias on V814A and is adjusted so t at t e
output voltage is exactly — 4000 volts. T is same
circuit indirectly regulates t e 4-20,000- volt sup 
ply since t e oscillator furnis es energy for bot
supplies.
T e time-constant network associated wit t e
V804 circuit delays t e application of screen
voltage to t e oscillator tube slig tly w en t e
power is first turned on. T is permits t e oscil 
lator circuit for t e eaters (V830) to bring t e
eaters up to emission before t e application of
plate voltage in t e rectifier tubes.
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— 250-Volt Supply
T e -250-volt supply employs a full-wave
rectifier tube V612 and a capacitor-input filter
system. T e supply is regulated by comparing
t e voltage across V619, a gas-diode voltage-reg 
ulator tube, to t at obtained from a divider con 
nected across t e output, t roug a comparator
tube V614. T e — 250V ADJ. control R625 de 
termines t e percentage of total voltage t at
appears at t e grid of V614 and t us determines
t e total voltage across t e divider.
If line-voltage or load fluctuation tend to
c ange t e output voltage, an error signal
exists between t e grid and cat ode of V614.
T e error signal is amplified by V614 and
V627A. T e resulting c ange in voltage at t e
plate of \6'27K, w ic will be in a direction to
compensate for any c ange in output voltage,
is coupled t roug t e rectifier to t e output to
keep t is voltage constant.
4-225-Volt Supply
T e 4-225-volt supply employs selenium recti 
fiers in a full-wave, bridge circuit. T is supply is
regulated by comparing to ground (t e cat ode
of V634) t e voltage of a point near ground
potential obtained from t e divider R644-R645'
connected between t e 4-225-volt bus and t e
regulated — 250-volt supply. Any error signal
t at exists is amplified and inverted in polarity
by V634 and coupled t roug t e paralleled
cat ode-followers V647A, V647B and V627B to
t e output to prevent t e output voltage from
c anging. C644 improves t e response of t e cir 
cuit to sudden c anges in output voltage. T is
supply also provides a 4-360-volt unregulated
output for t e oscillator tube in t e ig -voltage
supply.
A small sample of t e unregulated bus ripple
appears at t e screen of V634 t roug R637.
T is produces a ripple component at t e grids of
t e cat ode followers t at is opposite in polarity
to t e ripple appearing at t e plates, and tends
to cancel t e ripple at t e cat odes and ence
on t e 4-225-volt bus. T is same circuit also im 
proves t e regulation in t e presence of line 
voltage variations.
4-475-Volt Supply
Rectified voltage from terminals 9 and 10 of
t e power transformer is added to t e voltage
supplying t e 4-225-volt regulator to supply
power for t e 4-475-volt regulator. T e reg 
ulator circuit of t is supply functions in t e same
manner as t at of t e 4-225-volt supply.
+ 750-Volt Supply
A full-wave rectifier \672 is employed in t e
4-750-volt supply. T e rectified output of t is
tube is added to voltage supplying t e 4-475-
volt regulator to supply power for t is supply.
T is supply is regulated by comparing to t e
regulated 4-475-volt bus (t e cat ode of V674) a
voltage near 4-475 volts obtained from t e
divider R684-R685 connected between t e 4-750-
volt bus and ground. Any error signal is am 
plified by V674 and is applied to t e grid of t e
cat ode-follower V687. T e cat ode of V687
t en acts to prevent t e voltage on t e +750-
volt bus from c anging.
TIME-MARK GENERATOR
An electron-coupled Colpitts oscillator V250B
is gated off and on by a free-running multi 
vibrator circuit V225A and V225B t roug t e
cat ode-follower V250A. T e gated time markers
are t en amplified in V264 and are coupled to
t e cat ode-ray tube vertical deflection circuit
w en t e SIGNAL MODE switc is in t e MARK 
ER position.
T e time markers are also coupled t roug
C267 to t e grid circuit of t e cat ode-follower
V243A, w ere t ey are superimposed on t e
multivibrator waveform and fed to t e trigger
circuitry so t at t e sweep can be triggered by
t e markers w en t e TRIGGER SELECTOR switc
is in t e MARKER position. T e diode V242
clamps t e grid of V243A to prevent t e nega 
tive pulses of t e differentiated multivibrator
waveform from producing a trigger.
2-4 CIRCUIT DESCRIPTION — TYPE 507
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CIRCUIT DESCRIPTION — TYPE 507
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MAINTENANCE
PREVENTIVE MAINTENANCE
Ventilation
Care must be taken to assure free ventilation
of bot units inasmuc as some of t e compo 
nents are operated at dissipation levels suc t at
excessive temperatures will result wit out ad 
equate air circulation.
To assure free passage of air t e units s ould
be placed so t at t e air intakes are not blocked
by ot er apparatus or furniture, and t e filters
s ould be kept clean.
Was able “ E-Z KLEEN ” air filters are used
at t e air intake ports of bot units. T e follow 
ing filter cleaning instructions are given by t e
filter manufacturer:
(1) If grease or dirt load is lig t, remove filter
from installation and flus dirt or grease out
of filter wit a stream of ot water or steam.
(2) If load is too eavy for treatment in (1)
above, prepare mild soap or detergent solu 
tion in pan or sink deep enoug to cover
filter w en laid flat. Agitate filter up and
down in t is solution until grease or dirt is
loosened and carried off filter.
(3) Rinse filter and let dry.
(4) Dip or spray filter wit fres Filter Coat, or
ot er approved ad esive. Filter Coat is
available from local representative of Re 
searc Products Corp, in t e one-pint Handi-
Koater wit spray attac ment or one-gallon
and five-gallon containers.
Transformer Connections
Unless we are instructed ot erwise we s ip
t e Type 507 Oscilloscope connected for 105 to
125 volts, 50 to 60 cycles ac. However, provi 
sions are made for easy conversion to operation
at 210 to 250 volts, 50 to 60 cycles. T e t ree
transformers T601, T602 and T701 are provided
wit split input windings w ic are normally
connected in parallel for 1 17-volt operation, but
w ic can easily be connected in series for 234-
volt operation. Eac of t ese split windings ter 
minates in a nest of four terminal lugs arranged
in a square on a bakelite terminal board, on t e
underside of t e c assis, and are numbered 1, 2,
3 and 4 in clockwise rotation.
Terminals 1 and 3 are connected to one wind 
ing, and terminals 2 and 4 are connected to t e
second winding. T e ac input leads are connected
to terminals 1 and 4 w et er for 1 17-volt or 234-
volt operation, so t at t ese leads do not ave
to be moved w en conversion is made from one
to t e ot er operating input-voltage level.
W en wired for 1 17-volt operation terminals 1
and 2 are joined by a bare bus wire, and ter 
minals 3 and 4 are similarly joined. To convert
to 234-volt operation, remove t e bare bus wires
between t ese terminals and substitute a single
connecting wire between terminals 2 and 3.
T e fuses mounted at t e front of t e Power
Unit s ould be c anged to accommodate t e
reduction in input current. Refer to t e circuit
diagram for t e correct rating of fuses to be used
for eit er 1 17-volt or 234-volt operation.
ANALYZING TROUBLE
A good percentage of t e troubles t at occur
are likely to be found in t e tubes and it is
t erefore advisable to c eck tubes before exten 
sive tests are made on ot er components. Tube
c ecks s ould preferably be made by direct sub 
stitution. Tube failures may result in failure of
ot er components or may be caused by failure
of ot er components so t at it is advisable to
examine all components associated wit an
offending tube.
CAUTION: VOLTAGES HIGH ENOUGH TO BE
DANGEROUS ARE PRESENT AT SEVERAL PLACES
IN THIS INSTRUMENT, AND INASMUCH AS
MAINTENANCE MUST BE PERFORMED WITH
MAINTENANCE — TYPE 507
3-1

THE POWER CIRCUITS ENERGIZED, THE UT 
MOST CAUTION MUST BE OBSERVED. BOTH
THE +750-VOLT AND THE +475-VOLT SUP 
PLIES ARE POTENTIALLY MORE DANGEROUS
THAN THE 4-KV AND 20-KV SUPPLIES. THE
+750-VOLT AND THE +475-VOLT SUPPLIES
HAVE MUCH LOWER INTERNAL IMPEDANCE.
USE ONLY INSULATED TOOLS. STAND ON A
DRY FLOOR AND DO NOT LEAN WITH THE
BARE ARMS ON THE FRAMEWORK OF THE IN 
STRUMENT. IF POSSIBLE, KEEP ONE HAND IN
YOUR POCKET.
Fuses
T e fuses located on t e front panel of t e
power supply provide over-current protection.
If t e DC SUPPLIES fuse blows, t e first step in
locating t e trouble s ould be to determine
w et er t e trouble is in t e power unit or t e
indicator unit. T is can be determined by dis 
connecting t e inter-unit power cable. If a new
fuse blows wit t e cable disconnected, t e
trouble is in t e power unit and t e usual types
of c ecks for capacitor failure and tube s orts
s ould be made until t e trouble is isolated.
If t e fuse does not blow except w en t e in 
ter-unit cable is connected, owever, t e trouble
is likely to be found in t e indicator unit. In t is
case, first measure t e resistance to ground at
eac de voltage bus to determine if any are be 
low 15,000 o ms. T e de voltage buses can be
located at t e plugs w ic connect to t e inter 
unit cable as follows:
Pin 1 +750 volts
Pin 2 +475 volts
Pin 3 +360-volt unregulated
Pin 4 +225-volts
Pin 8 — 250 volts
If no low-resistance circuits are found to exist,
it is possible t ere is a type of tube s ort t at
occurs only w en bot eater and plate volatges
are applied. By lifting individual bus wires from
t e power plug in t e indicator unit, and turning
t e power on t e offending circuit can be
isolated to one drawing current from one of t e
regulated supplies. T en, by tracing t e color-
coded bus wire, or by referring to t e circuit dia 
gram, t e circuits drawing current from t is
supply can be determined and you can t en
troubles oot in t ese circuits until t e one at
fault is identified.
If t e regulated voltages are off in value, look
for trouble in t e power supply. If all voltages
are off in value look for trouble in t e — 250-
volt supply to w ic all ot er supplies are com 
pared. If all voltages are low V612 may be low
in emission or V619 may not be conducting. It
all voltages are ig V619 may be s orted, in
w ic case t e — 250-volt bus s ould indicate
about — 350 volts.
It individual voltages are off c eck t e volt 
age at t e plate of t e series regulator tube
involved for evidence of low cat ode emission.
C eck t e resistance and voltage at t e grid of
t e reference tube for evidence of failure in
t e voltage divider.
Sweep
If a spot can be made to appear at left center
under normal operating conditions, but no sweep
occurs advance t e STABILITY control full clock 
wise. If a sweep occurs wit t is control adjust 
ment, t e difficulty may be in t e trigger circuit.
Turn t e TRIGGER SELECTOR to MARKER and
t e SIGNAL MODE switc to INTERNAL MARK 
ER; t en back off on t e STABILITY control and
attempt to trigger t e sweep rat er t an permit
it to free run. If t e sweep can be triggered by
t e internal marker, but you were not able to
trigger t e sweep wit an external trigger or by
t e signal, t en c eck tor failure of t e divider
at t e SIGNAL IN or EXTERNAL TRIGGER INPUT
connectors.
If t e sweep can not be triggered by t e mark 
er generator, measure t e amplitude of t e multi 
vibrator waveform at t e cat ode of V243A
wit anot er oscilloscope. T e peak-to-peak
amplitude of t e multivibrator waveform (not
t at of t e superimposed markers) s ould be
about 5 volts at t is point. If adequate output is
obtained, look for low gain in t e trigger ampli 
fier.
Cat ode-Ray Tube Power Supply
In case of failure of t e 20-kv power supply,
determine w et er t e oscillators supplying ac
input voltage to t e ig -voltage and filament
supplies are functioning properly. T is can be
determined by measuring t e de grid voltages of
t e two oscillator tubes using 20,000-Ω/v meter.
T e voltage at t e grid of V820 s ould be about
— 27 volts, and t e voltage at t e grid of V830
s ould be about — 23 volts. Or alternately, t e
ac voltages may be observed on anot er oscil 
loscope.
If it is determined t at failure as not occured
in t e oscillator circuits, it is recommended t at
your Tektronix field engineer be consulted in
regard to repair of t e supply in t e nearest
Tektronix field maintenance office.
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ADJUSTMENT
1. Power Supply Unit
— 250 VOLTS: Connect voltmeter to pin 8 of
power plug on underside of power unit or on
underside of indicator unit. Adjust R625 labeled
— 250 V ADJ. as accurately as possible.
NOTE: Be sure your meter is accurate; many
portable voltmeters are in error by as muc as
t ree percent.
2. Cat ode-Ray Tube Voltage Supply
— 4 KV: Turn INTENSITY control full counter 
clockwise. Connect 20,000-Ω/v voltmeter to un 
grounded end of C841 (t e junction of C841,
C840 and R840, located in t e vicinity of t e four
ig -voltage neon glow lamps, near t e panel
supporting t e — 4 KV ADJ., GEOM. ADJ. and
MAX. INTENSITY controls). Make sure your volt 
meter is set for negative polarity and to t e
proper scale. Adjust R814 labeled — 4 KV ADJ.
as accurately as possible.
3. Cat ode-Ray Tube Intensity
Maximum intensity is adjusted by means of
R851 labeled MAX. INTENSITY. Turn STABILITY
control full counterclockwise and INTENSITY con 
trol full clockwise; adjust R851 until a spot just
appears on t e screen.
4. Cat ode-Ray Tube Unblanking
Set t e MICROSECONDS/CM control to 10,
turn STABILITY control full counterclockwise, and
connect a 20,000-Ω/v voltmeter across R154, t e
plate-load resistor for V 1 44 and V 1 54. R154 is
t e large 25-watt resistor located near t e panel
t at supports t e DUTY CYCLE LIMITED and UN 
BLANKING controls. Adjust R146, labeled UN 
BLANKING, for 100-volt drop across R154. T e
UNBLANKING adjustment controls t e screen
voltage of V 1 44 and V 1 54 to adjust t eir plate
current.
Remove t e voltmeter leads from R154, set t e
MICROSECONDS/CM control to 2 and turn t e
STABILITY control full clockwise. Connect t e
probe from anot er oscilloscope to t e cat ode
of V 1 53, and adjust L 1 54 (next to R1 54) for maxi 
mum overs oot at t e leading edge of t e posi 
tive pulses displayed; t is will occur w en LI 54
is adjusted for maximum inductance.
5. Cat ode-Ray Tube Geometry Adjust
T e operating voltages required for best
linearity at t e extremes of deflection may vary
somew at between cat ode-ray tubes. T e
GEOM. ADJ. control R861 accommodates t is
variation.
Free run t e sweep by turning t e STABILITY
control full clockwise, and position t e trace
to t e top line of t e graticule. Adjust t e
GEOM. ADJ. control for best linearity. Position
trace at bottom of graticule and c eck linearity;
a compromise setting of t e GEOM. ADJ. con 
trol may be necessary for best overall linearity.
6. Sweep Duty Cycle Limit
Set t e MICROSECONDS/CM switc to 2 and
free run t e sweep by turning t e STABILITY con 
trol full clockwise; set t e SIGNAL MODE switc
to EXTERNAL NORMAL. Connect t e probe from
anot er oscilloscope to t e cat ode of VI 33, and
adjust t e test oscilloscope for a sweep speed of
50 µsec/division. Adjust t e DUTY CYCLE LIMIT 
ED control R137 so t at t e duration between
pulses, on t e ert of t e test oscilloscope, is
about ten times t e pulse duration. Jitter in t e
rig t and pulse displayed on t e test oscillo 
scope is normal, since t e sweep is free running
rat er t an triggered.
Set t e MICROSECONDS/CM control on t e
Type 507 to .05, and adjust t e sweep speed of
t e test oscilloscope so t at t e positive pulse
of t e displayed square wave is approximately
10 centimeters (or divisions) in lengt . At t is
fast sweep rate t e rise and fall of t e positive
pulse will be spread out considerably; make t e
10-centimeter (or divisions) measurement from
t e start of t e rise to t e start of t e fall. T en
turn t e MICROSECONDS/CM switc to .02
and adjust C112L, located on t e MICROSEC 
ONDS/CM switc , for a 9-centimeter (or div 
ision) lengt of t e positive pulse.
7. Time-Mark Generator
Before adjusting t e timing of t e markers or
t e sweep circuit (next step), be sure t e power
supply voltages are correct. Also make sure t e
t e instrument is t oroug ly warmed up; eaters
s ould be on t irty minutes and plate voltage
s ould be on for five minutes before any adjust 
ments are made.
ADJUSTMENT PROCEDURE — TYPE 507
4-1
3-2
MAINTENANCE — TYPE 507

To adjust t e timing of t e markers anot er
accurately-timed oscilloscope is required; pre 
ferably one wit a fast enoug sweep so t at
t ere is a calibrated rate of .05 microseconds/
division. Any Tektronix oscilloscope of t e 530,
540 or 550 series, or t e Type 517 oscilloscope,
may be employed for t is purpose.
Set t e SIGNAL MODE switc to t e INTER 
NAL MARKER position, and set t e MICROSEC-
ONDS/CM switc to t e lOµSEC marker posi 
tion. Connect t e probe of t e test oscilloscope
to t e junction of C267 and C268, and adjust t e
test oscilloscope for a triggered sweep rate
of 10 microsconds/division. Adjust L258A for
one marker per division on t e test oscilloscope.
L258A is one in a row of four coils located next
to t e MICROSECONDS/CM switc near t e
front panel; L258A is t e coil furt est from t e
front panel.
Set t e MICROSECONDS/CM switc to one
of t e 5 µSEC marker positions, and adjust t e
test oscilloscope for a sweep speed of 5 micro-
seconds/division. Adjust L258E, located just a-
ead of L258A, for one marker per division.
Set t e MICROSECONDS/CM switc to one of
t e .5 µSEC marker positions, and adjust t e
test oscilloscope for a sweep speed of 5 micro-
seconds/division. Adjust L258J, located just a-
ead of L258E, for one marker per division.
Set t e MICROSECONDS/CM switc to one
of t e .05 µSEC. marker positions, and adjust
t e test oscilloscope for a sweep speed of .05
microseconds/division. In t ose oscilloscopes
aving a HF SYNC mode, it may be more con 
venient to operate in t is mode wit a sync ro 
nized sweep t an to trigger t e sweep. Adjust
L258N for one marker per division.
Wit t e set up unc anged from t e previous
step, adjust L253 and L264 for maximum ampli 
tude of t e displayed pulses. L264 tunes very
s arply and its adjustment is critical; L253 is
broadly tuned and will ave less affect on t e
pulse amplitude.
8. Sweep Timing
To adjust t e timing of t e sweeps, display
t e time markers on t ee cat ode-ray tube of t e
507 by setting t e SIGNAL MODE switc to t e
INTERNAL MARKER position and t e TRIGGER
SELECTOR switc to t e MARKER position. For
eac setting of t e MICROSECONDS/CM control
listed in t e following table it may be necessary
*C177E and R304 interact; it will be necessary to
work back and forth between these two adjustments
for best results.
♦*C177L and C303 interact; it will be necessary to
work back and forth between these two adjustments
for best results.
MICROSECONDS/CM
CONTROL
ADJUST ADJUST
FOR
2
*C177E for timing
*R304 for linearity
4 markers/cm
.02
**C303 for linearity
**C177L for timing
4 cycles/ 10 cm.
.05
C177K
1 cycle/cm
.1
C177J
2 cycles/cm
.2
C177H
4 cycles/cm
.5
Cl 77G
1 marker/cm
1
C177F
2 markers/cm
2
Rec eck settings listed above
5
R176J
1 marker /cm
10
R176G
2 markers/cm
20
R176E
4 markers/cm
50
R176C
5 markers/cm
or
1 marker/minor
division
4-2
ADJUSTMENT PROCEDURE — TYPE 507