Tektronix Z Instruction Manual

IV l/X IN I U A L

Tektronix, Inc.

S.W. Millikan Way • P. O. Box 500 • Beaverton, Oregon • Phone Ml 4-0161 • Cables: Tektronix

Tektronix International A. G.

Terrassenweg 1A • Zug, Switzerland • PH.042-49192 • Cable: Tekintag, Zug Switzerland • Telex 53.574

070-251

WARRANTY

All Tektronix instruments are warranted
against defective materials and workman
ship for one year. Tektronix transformers,
manufactured in our own plant, are w ar

ranted for the life of the instrument.

Any questions w ith respect to the w a r
ranty mentioned above should be taken up
with your Tektronix Field Engineer.

Tektronix repair and replacement-part
service is geared directly to the field, there
fore all requests for repairs and replace
ment parts should be directed to the Tek
tronix Field Office or Representative in your

area. This procedure w ill assure you the
fastest possible service. Please include the

instrument Type and Serial number with all
requests for parts or service.

Specifications and price change priv
ileges reserved.

Copyright © 1960 by Tektronix, Inc.,
Beaverton, Oregon. Printed in the United

States of America. All rights reserved. Con
tents of this publication may not be repro
duced in any form w ithout permission of
the copyright owner.

CONTENTS

W arranty

Section 1

Specifications

Section 2

Operating Instructions

Section 3

Circuit Description

Section 4

Maintenance

Section 5

Calibration

Section 6

Accessories

Section 7

Parts List and Diagrams

® Type z

m

TYPE Z PLUG-IN UNIT

CALIBRATED DIFFERENTIAL CO MPACTO R

.1 0 0 0 CM. DYNAMIC SCALE LENGTH

/UUU V.f'l- " ■ ■ ’ — _

COMPARISON VOLTAGE -x

VOLTS/CM

(ATTE NUATION !

VAR. ATTEN

I PUSH TO j

0 I 5 C O N N E C T

SIGNAL j

ptSCO N N E d

signal

u n i a eh

ATTEN.

GAIN

ADJUST

b a ia n c e

'position

VOLTS/CM

{ A T T I N U A T I O N )

onto on.

PORTIA I

rlATEONIX,

Type Z

http://manoman.sqhill.com

O INI 1

SPECI F I CATION

General Information

The Type Z Plug-In Unit is a calibrated differential com

parator preamplifier designed for use in all Tektronix

Type 530-, 540-, 550-, or 580-Series Oscilloscopes. The

unit may be used for three different modes of operation:

(1) as a conventional plug-in preamplifier, (2) as a differential

input preamplifier, or (3) as a calibrated differential com-
pa rator.

As a conventional preamplifier, the Z Unit alone has a

risetime of 24 nanoseconds and a maximum sensitivity of

0.05 volt per centimeter of deflection. Table 1-1 summar
izes the risetimes and bandwidths available when the Z
Unit is used in combination with various types of Tektronix

oscilloscopes.

TABLE 1-1

Z Unit and

Type.-

Risetime in

Nanoseconds*

Bandwidth, —3 db,

Megacycles/Seconcl*

532

70 5

531 or 535

39 9

536

40

9

531 A, 533, or 535A

35

10

541, 543, 545,
541 A, 545A,
551, or 555

27 13

581 or 585**

27 13

*For signals which do not overscan the graticule.

**Type 81 Adapter must be used.

In differential input mode of operation, the dynamic
range of r'zlOO volts allows the application of common
mode signals up to 100 volts to be applied to the unit with
out attenuation. The common-mode rejection ratio of
40,000 to 1 at dc or low frequencies allows measurement

of differential signals less than 50 mv in amplitude on

7+c 100-volt common-mode signals.

As a calibrated differential comparator, the Z Unit has

an effective screen height of ih2000 cm at maximum sensi

tivity. Within the dynamic range of :J:100 volts, calibra'ed

±DC comparison voltages can be added differentially to
the input waveform to permit a maximum of 0.005% or
5 mv per mm to be accurately resolved.

Vertical Deflection Factors

0.05 to 25 volts per centimeter in nine calibrated steps;
also continuously variable (uncalibrated) between steps and
up to 60 volts per centimeter.

Input Impedance

1 megohm :Ul % paralleled by 24 pf.

Maximum Allow able Combined DC and Peak AC
Input

600 volts, ac-coupled.

Maximum Common-Mode Signal

r'rlOO volts at 0.05 volt per centimeter. Higher voltages

are permissible with larger vertical deflection factors.

Common-Mode Rejection Ratio

40,000 to 1 at 0.05 volt per centimeter with a 1-kc sine

wave, lower at other sensitivities and higher frequencies.

At 0.05 volt per centimeter, a 200-volt (p-p) 1-kc common

mode signal produces less than 1 mm of vertical deflection.

Comparison Voltages Available

Three voltage ranges are provided: 0 to r‘-l volt, 0 to

~10 volts, and 0 to : 100 volts. An accurate 10-turn
potentiometer is used to select the comparison voltages
over these ranges.

Comparison Voltage Regulator

A regulator circuit maintains comparison voltages es
sentially constant and independent of normal power supply
voltages supplied by the oscilloscope.

1-1

Specifications — Type Z

Comparison Voltage Accuracy

Within 5 millivolts (0.5%) on the ±l-v o lt range.
Within 20 millivolts (0.2%) on the ± 10-volt range.
Within 150 millivolts (0.15%) on the ±100-volt range.

Maximum Trace Shift

2 mm due to input grid or gas current.

Comparison Voltage Drift

Less than 0.1 % per 100 hours operation.

Temperature compensated over normally expected tem
perature range. Air filter in oscilloscope should be main
tained clean, particularly when using the Z Unit.

10-Turn Potentiometer Linearity

0.05%

Measurement Resolution

Resolution accuracy, at 100-volts comparison voltage—

0.005%
Maximum resolution—5 millivolts per millimeter.

Transient Response and Permissible Signal Volt
age Rate of Change

Rate of rise—1 volt per 6 nsec, maximum. If this rate

is exceeded, grid current will flow in the input stages.

Rate of fall—1 volt in 5 nsec, maximum. If this rate is

exceeded, the amplifier will momentarily cut off. If over

driven by a sufficiently fast pulse, the amplifier will ‘‘run
down" linearly at the above rate.

Because of the wide dynamic amplitude capabilities of the

Z Unit, transient response is a function of signal amplitude.

Mechanical Specifications

Construction—Aluminum-alloy chassis.
Front panel—Photo-etched.
Net weight—6 pounds.

Accessories

2—Instruction Manuals

1-2

®I

A front-panel view of the Type Z Unit is shown in Fig. 2-1.

In addition, a brief functional description is given of the
front-panel controls, input connectors, Securing Rod, and
Mechanical Lock.

Connecting the Z Unit to the Oscilloscope

Connect the Z Unit to the associated oscilloscope by

inserting the unit into the plug-in compartment and tighten

ing the Securing Rod. With the Intensity control of the
oscilloscope turned fully counterclockwise, switch on the
oscilloscope power. Normally it is necessary to wait a few

minutes for the oscilloscope and plug-in to warm up and
stabilize. Then turn up the intensity and set the oscilloscope
triggering controls to produce a free-running sweep. Posi
tion the trace on the screen using the POSITION control
and the oscilloscope beam-position indicators.

Preliminary Operational Adjustments

After the Z Unit has warmed up and stabilized, check

its operation to see if adjustment of one or more of the
following controls is necessary. Be sure that the oscilloscope

used in conjunction with the Z Unit is correctly calibrated in
the vertical-deflection circuit, and that the calibrator output
voltage is correct.

1. Amplifier DC Balance

If the trace cannot be centered on the screen when -he

POSITION control is set near midrange, the AMP DC BAL
adjustment (see Fig. 2-2) must be checked. Need for this
adjustment arises mostly when the Z Unit is transferred
from one oscilloscope to another. To make the adjustment,
set the POSITION control to midrange, remove the left
side panel from the oscilloscope, and adjust the AMP DC

BAL control to position the trace behind the horizontal
centerline of the graticule.

2. Differential Balance

Differential balance may be quickly checked by applying
100 volts of calibrator signal to both input connectors. Set
both VOLTS/CM switches to .05, the AC-DC switches to
DC, and the Mode switch to A-B DIFF. Ignoring the posit ve
and negative spikes, adjust the DIFF. BAL. control to elimin-

SECTION 2

O PERAT I N G

I NSTRUCTI ONS

ate any square-wave response (that is, to obtain a straight-

line appearance of the trace).

3. Variable Attenuator Balance

Any vertical shift of the oscilloscope trace when the VAR.
ATTEN. control is rotated, with no input signal applied,
indicates need for adjustment of the variable attenuator

balance. This adjustment must be made in conjunction
with the differential balance adjustment (step 2) due to
interaction between the circuits. Repeat the two adjust
ments until both are correct.

Set the Mode switch to A ONLY and remove any input
signals. Adjust the VAR. ATTEN. BALANCE control to
eliminate any vertical shift of the crt trace as the VAR.
ATTEN. control is rotated. Check to see if the trace can
be centered as described in step 1 (Amplifier DC Balance).
If not, repeat step 1.

4. Gain

The gain adjustment should be checked periodically to
assure correct vertical deflection factors. It should also be
checked when the Z Unit is transferred from one oscilloscope

to another. The adjustment is made using the calibrator

signal from the oscilloscope.

Set the Mode switch to A ONLY and apply 200 milli
volts of calibrator signal to the A input connector. Make
sure the VAR. ATTEN. control is set fully clockwise. Set
the A VOLTS/CM switch to .05 and rotate the GAIN AD
JUST control for exactly 4 centimeters of vertical deflection.

Input Signal Connections

It is often possible to make signal connections to the
Z Unit with short-length, unshielded test leads. This is par
ticularly true for high-level, low-frequency signals. When
such test leads are used, you must also use a ground con
nection between the oscilloscope and the chassis of the
signal source. (Note: Excessively long test leads may cause
parasitic oscillations.)

In many applications, however, unshielded leads are
unsatisfactory for making signal connections because of
pickup resulting from magnetic fields. In such cases, shielded
cables should be used. You must be sure that the ground
conductors of the cables are connected to the chassis of
both the oscilloscope and the signal source.

In high-frequency work it is usually necessary to terminate

signal sources and connecting cables in their characteristic

2-1

Operating Instructions — Type Z

VAR, ATTEN.— Varies the verti
cal d e fle ction factors betwee n
ranges o f the V OLTS/C M co n 
trols.

Po larity— Selects the co mpa r
ison voltag e p o la rity.

VOLTS/C M— Selects the
ca l d e fle ction factors.

verti-

A INPUT— Connecto r fo r coupl
ing input dc or ac vo lta g e s to
pream plifier.

AC-DC— Determines wheth e r
Inpu t signals are dc couple d or
ac coupled.

PUSH TO DISCONNECT
NAL— D isconnects signal

pream p lifier input.

DIF F. BAL.— A d justs the
am p lifier fo r maximum

fe re ntia l re jection ratio.

PUSH TO DISCONNECT SIG
NAL— Disconnects signal from
pream p lifier input.

AC-DC— Determ ines wheth er

inp u t signals are dc couple d or

ac coupled.

B INPUT— Connector fo r coupl
ing Inp u t dc or ac voltages to
pream plifie r.

Range— Selects the ap p rop ri
ate co m pariso n volta g e ra nge.

Mechanic al lock— Locks H eli-

dial when pressed dow n ward.

H e iid ial— Adju s ts the com 
parison voltag e ov er the range
selected by the Range switch.

VAR. ATTEN, BALANCE— A d
justed to preve n t v e rtical trace
shift as the VAR. ATTEN con
tro l Is ro tated.

POSITIO N— Sets the vertical
positio n of the trace on the
oscilloscope screen..

VOLTS/CM — Selects the ve rti
ca l deflec tio n factors.

GA IN ADJUST— Sets the de
flection factors o f the p re
am p lifie r to ag ree w ith the

fro nt panel m arkings.

Fig. 2 -1 . Functions of fro n t-p a ne l c o ntro ls, inp ut connectors. Securing Rod, and Mechanical Lock.

2-2

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Operating Instructions — Type Z

Fig. 2 -2 . Left rear side view of the Z U n it showin g location of the
AMP DC BAL adjustment.

impedances. Unterminated connections result in reflections
in the cables and cause distortion of the displayed wave

forms.

When input signal connections are made, consider the
effect of loading upon the signal source due to the input
circuit of the Z Unit. The input resistance of the Z Unit is 1
megohm which is generally adequate to limit low-frequency
loading to a negligible value. At high frequencies, however,
the input capacitance of the Z Unit and the distributed
capacitance of cables become important. Capacitive load
ing at high frequencies may be sufficient to adversely

affect both the displayed waveform and the operation of

the signal source. Both capacitive and resistive loading
can usually be limited to negligible values through use
of attenuator probes.

Use of Probes

Attenuator probes reduce loading of the signal source.
However, in addition to providing isolation of the oscillo
scope from the signal source, an attenuator probe also de

creases the amplitude of the displayed waveform by the
attenuation factor of the probe. When making amplitude

measurements with an attenuator probe, be sure to multi
ply the observed amplitude by the attenuation of the probe.
(Additional information concerning probe attenuation will
be found under Differential Preamplifier Operation and At
tenuator Test Point portions of this section of the manual.)

An adjustable capacitor in the probe body compensates

for variations in input capacitance from one instrument to

another. To assure the accuracy of pulse and transient meas
urements, this adjustment should be checked frequently.

To make this adjustment, set the oscilloscope calibrator
controls for a calibrator output signal of suitable amplitude.

Touch the probe tip to the calibrator-output connector and
adjust the oscilloscope controls to display several cycles

of the waveform. If the probe cable is connected to the
A input connector on the Z Unit, adjust the probe capacitor
for flat tops on the calibrator square wave. If it is connected
to the B input connector, adjust for a flat bottom on the
square wave.

Conventional Preamplifier Operation

When the Z Unit is used for conventional preamplifier
operation, the Mode switch should be placed in either
the A ONLY or the —B ONLY position. Input signals should
then be connected to the corresponding input connector.
Operation of the unit in the two positions is essentially the
same except that signals applied to the B input connector
are inverted on the display. Positive voltages produce an
upward deflection when applied to the A input connector

and a downward deflection when applied to the B input
connector (see Fig. 2-3).

Fig. 2 -3 . W ave form s a pplie d to the A Inpu t connector p roduce an
up righ t d isp lay , wh ile w aveform s ap p lied to the B Inpu t are in 
verted.

The amount of vertical deflection produced by a signal

is determined by the settings of the VAR. ATTEN. control

and the VOLTS/CM switch. Calibrated deflection factors

indicated by the settings of the VOLTS/CM switch apply
only when the VAR. ATTEN. control is set fully clockwise.
Serious errors in display measurements may result if the
setting of this control is inadvertently moved away from

the fully clockwise position.

The range of the VAR. ATTEN. control is approximately

2.5 to 1 to provide continuously variable (uncalibrated)
vertical-deflection factors between calibrated settings of
the VOLTS/CM switches.

Voltage measurements may be made directly from the

oscilloscope screen by noting the deflection factor on the

appropriate VOLTS/CM switch dial, and the amount of

deflection on the screen. Then multiply the deflection on
the screen by the setting of the VOLTS/CM switch and the
attenuation factor, if any, of the probe.

Placing the AC-DC switch in the AC position inserts a dc
blocking capacitor in series with the input circuit. In the
AC position, the input time constant is 0.1 second and the
low-frequency response is —3 db at 2 cps. Thus some

attenuation exists even at 60 cps. Because the input dc
signal may be suppressed by means of the calibrated com

parison voltage feature, there are few occasions where the

ac-coupling mode will be needed. Two principle occasions

are: (1) When it is desired to get a quick look at the ac
component of a signal which has a large dc component

and (2) where there is a difference in dc levels of the two
signals to be observed during differential mode of operation.

The tolerances of the input circuit time constants (at

—3 db frequency) are nominally =h2%. When tighter

®T

2-3

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Operating Instructions — Type Z

matching between A and B input circuits is necessary, one
input dc blocking capacitor may be “ padded" with a small
additional capacitance, generally less than 0.001 /ifd.

The PUSH TO DISCONNECT SIGNAL buttons allow the
signal to be momentarily removed from the input without
the bother of disconnecting the probe or coaxial input con
nector. This provides an easy method for finding the base

line of zero voltage level on the crt. (When utmost ac
curacy in measurement is required, trace deviation from
exact zero due to gas or grid current must be considered.)
The POSITION control may then be adjusted to make the
zero level lie at any graticule mark desired.

Differential Preamplifier Operation

The primary purpose of differential operation is to elim
inate undesirable common-mode signals. The term “common-
mode signal" is defined as that signal which is common
to both inputs of a differential amplifier. It most commonly,
but not necessarily, represents unwanted hum or noise.

This feature can be used, for example, to observe the
signal across one circuit element while effectively eliminat
ing the remainder of the circuit from the observations. Tnis
is accomplished by connecting the signal at one end of
the element to one input of the Z Unit and the signal at
the other end of the element to the other input of the unit

Differential operation between the two inputs is obtained

when the Mode switch is in the A-B DIFF. position. Maximum

common-mode rejection is obtained when both input at
tenuators are set to XI. Common-mode rejection is a func
tion of frequency in practical amplifiers. It is 40,000 to 1
for dc common-mode signals in the Z Unit and remains
near that value through audio frequencies, decreasing as
the frequency increases.

The differential or common-mode rejection ratio of the
Z Unit describes the ability of the unit to reject common
mode signals. Common-mode rejection ratio is best defined

as the ratio of amplifier response to that part of the input

signal not common to both, with respect to the response

of the amplifier to any input signal which is common to

both inputs. It is defined numerically in the following ex

ample.

If an input signal consists of 100 volts (p-p) of 60-cps hum

and 0.1 volt of desired signal, the 100-volt hum would cause

-nr

----

;—7

-------

times 100 volts or 2000 cm of deflection, and

.05 volts/cm
the signal would cause an additional 2 cm of deflection.

If conventional preamplifier operation were used, the de

sired signal would be deflected off the screen and could
not be observed. However, if differential operation is

used and common-mode rejection were 2000 to 2 or
1000 to 1, then the hum and desired signal would each
produce 2 cm of deflection. The resulting combined wave-

i

r s r

i

/

/

la ) 100-volt, 6 0 ~ hum plus 0.1-volt, 1-kc square

wave. Vertical Sensitivity: 25 v/cm. Mode: A ONIY.
Sweep Rate: 5 miliisec/cm.

7

r

7

, V

L

j

\

/

V

/

\

u.

V /

(c) 100-volt 60 — hum only. Control settings similar

to (a) except Mode is — B ONLY.

(b) Top 4-cm of waveform (a ) at vertical sensitivity

of 0.05 v/cm. Mode: A-Vc, decoupled.

V c S i + S O v .

Sweep Rate: 0.5 millisec/cm.

++++

4+B ++++ t+H

W+

H + +

+-H4 ++++

m+

++++

id ) 60— hum is differentially suppressed and only the

1-kc square wave is displayed. Vertical Sensitivity:

0.05 v/cm. Mode: A-B DIFF., dc-coupled. Sweep Rate:

0.5 millisec/cm.

2-4

Fig. 2 -4. Com m on-mode rejection b y the Z U nit.

Operating Instructions — Type Z

form could be seen but not easily measured. With a
common-mode rejection of 40,000 to 1, the hum would be
reduced to 0.5 mm and the desired signal alone could be
accurately observed and measured.

The preceding example is shown pictorially in the series
of waveform photographs shown in Figs. 2-4(a), (c), and (d).
A combined 100-volt hum and 0.1-volt square-wave signal
is shown in Fig. 2-4(a). Although the square wave does
not seem to be present, it can be made visible by increasing
the sensitivity of the Z Unit to 0.05 volts/cm, which increases
the effective height of the waveform to 2000 cm. A dc com
parison voltage (using differential comparator operation
explained later in this section) of approximately 50 volts
is used to bring the top 4-cm portion of the combined
signals into view, shown by the waveform photograph in
Fig. 2-4(b). The 2-cm high square-wave signal, riding on
top of the hum but not synchronized with it, causes the
separated appearance of the hum signal. Fig. 2-4(c) shows
the 100-volt (p-p) hum signal which, by itself, is applied to
the B input connector. The resulting display using common
mode rejection is shown in Fig. 2-4(d).

The following five operational notes provide helpful in
formation to obtain optimum performance from the Z Unit
using this mode of operation.

1. Large signal response of the Z Unit as a differential am
plifier is shown in Table 2-1.

TABLE 2-1

Signal Handling Capabilities of the Z Unit

Attenua

tion

Maximum

Calibrated

Sensitivity

(volts/cm)

Minimum

Uncalibrated

Sensitivity

(volts/cm)

Maximum

Signal or

Common

Mode
(volts)

Magni ■
fication
Factor

XI

.05 .12

100

2000X

X2

.1

.24

200

1000X

X5

.25 .6

500 400X

X10

.5

1.2 1000*

200X

X20

1

2.4 1000*

100X

X50

2.5

6

1000*

40X

XI00

5

12

1000*

20X

fox

X200

10

24

1000*

X500 25

60

1000*

5X

^Maximum continuous dc input level with AC-DC switch set to DC: 800

volts; momentary maximum dc level should not exceed 1000 volts.

2. Any difference in attenuation factors of the two attenua
tors (VOLTS/CM switches) will decrease the differential
capabilities of the Z Unit to the extent shown in Table 2-2.

3. Both AC-DC switches should be in the DC position if
possible as explained under Conventional Preamplifier
Operation.

4. Differential balance may decrease slightly as the VAR.
ATTEN. control is adjusted away from the calibrated
(clockwise) position.

5. Either input signal alone may be viewed without switch
ing back to the A ONLY or —B ONLY positions of the
Mode switch by depressing the PUSH TO DISCONNECT
SIGNAL button of the other input channel.

TABLE 2-2

Attenuator Performance

Attenuation

Attenuator

Accuracy, ± %

Input Resistance

Tolerance, ± %

XI 0

1

X2

1

1

X5

1.5 1

X10 and up 2

1

If conventional probe is used, the probe resistor tolerance of 1 % de
creases the Z Unit attenuator accuracy. These inaccuracies can be ac
curately measured as explained later under Attenuator Test Point.

Calibrated Differential Comparator Operation

When the Mode switch is in the A-Vc or Vc-B position,
the Z Unit is a calibrated differential comparator or slide-
back voltmeter. The calibrated comparison voltage, which
has a range of 0 to 100 volts, may be added (differentially)
to either input signal.

In this mode a calibrated dc voltage is internally applied
to cancel out any unwanted dc component in the applied
signal, thereby allowing accurate measurements of relative
ly small ac signals riding on top of relatively large dc
signals.

When the Mode switch is in the A-Vc position, the com
parison voltage is applied internally to the amplifier input
where the B signal is ordinarily applied during differential
mode of operation. The switches and input connector in
the —B ONLY section of the front panel are not used.
Signals applied to the B input connector will not be ob
served.

In Vc-B position of the Mode switch, the comparison
voltage is applied to the amplifier input where the A input
signal is normally applied during differential mode of op
eration. All switches and the input connector in the A ONLY
section of the front panel are not used.

The dc comparison voltage is set by 3 controls: the COM
PARISON VOLTAGE Polarity, Range, and Helidial. The
Range control has ranges of 0 to 1, 0 to 10, and 0 to 100
volts. The Helidial varies the comparison voltages over
this range and indicates the precise comparison voltage at
any particular setting.

NOTE
The regulator circuit in the Z Unit maintains con
stant, accurate, comparison voltages as long as

the oscilloscope — 150- and + 225-volt power
supplies are in regulation and within their output
voltage tolerance ratings. Be sure these and other
regulated power supplies in the oscilloscope are

operating properly.

Differential comparator mode of operation may be used
to make the following voltage measurements: (1) dc volt
age measurements, (2) ac signal measurements superimposed
on dc, and (3) high-amplitude ac signal measurements.

2-5

Operating Instructions — Type Z

1. DC Voltage Measurements.

When the Z Unit is used to make any dc voltage measure
ments, it is first necessary to establish a reference line on
the screen of the oscilloscope. This line will usually be the
horizontal centerline of the graticule. To establish the
reference, set the COMPARISON VOLTAGE Polarity switch
to 0 and press the appropriate PUSH TO DISCONNECT
SIGNAL button to disconnect the input signal. (As noted

previously under Conventional Preamplifier Operation, slight
trace deviation from exact zero must be taken into account
to obtain best accuracy.) Use the POSITION control to
set the oscilloscope trace at the centerline of the graticule.

To measure a dc voltage component of ±100 volts or less,
apply the input signal to one of the connectors. For ex
ample, suppose the signal is applied to the A input
connector, then proceed as follows:

(a) Place the A VOLTS/CM switch to .05 and the Mode

switch to the A-Vc position.

(b) If the dc voltage component to be measured is posi
tive, place the COMPARISON VOLTAGE Polarity switch to
the + position. If it is between 10 and 100 volts, set the

COMPARISON VOLTAGE Range switch to 100 V.

(c) Rotate the COMPARISON VOLTAGE Helidial to bring
the desired portion of the trace onto the screen. Set the
trace exactly on the reference line with the Helidial.

(d) Recheck the reference as described in the first para
graph.

(e) When the zero reference line and signal trace appeiar
at the same place on the screen, the input voltage and
the comparison voltage are equal.

2. AC Signal Measurements Superimposed on DC

Small ac signals superimposed on a dc component can
be measured accurately by first using the comparison volt
age to effectively eliminate the dc component. The ac
signal can then be measured in the same manner as in con
ventional preamplifier operation. The VAR. ATTEN. control

must be kept clockwise to obtain correct results.

3. High-Amplitude AC Signal Measurements.

High-amplitude ac signals, subject to the rise rate and fall
rate limitations listed in the Specifications section, can also
be measured with the Z Unit at maximum sensitivity. This
type of measurement is very similar to dc measurements
except that it is not necessary to establish a zero voltage
reference line unless measurements of both ac and dc volt
age levels are to be made. To measure the voltage differ
ence between two points on the waveform, proceed as fol
lows:

(a) Set the Helidial to zero and position one point on the
waveform to the horizontal centerline of the graticule.

(b) Use the Helidial and Range controls to bring the other

desired point to the centerline.

(c) The voltage difference between the two points is

read from the Helidial and the setting of the Range switch.

AC-DC Voltage Measurements Exceeding ±1 0 0
Volts.

If ac, dc, or both ac and dc voltage components are
greater than ±100 volts, the .05 settings of the VOLTS/CM
switches cannot be used. It will be necessary to use a lower
sensitivity in order to prevent overdriving the preamplifier
and to prevent exceeding the comparison voltage available.
To obtain the correct voltage measurement, use the multi

plication factor which appears below the volts per centi
meter setting on the VOLTS/CM knob. The product of the
multiplication factor times the comparison voltage used

is the input signal voltage.

ATTENUATOR TEST POINT

Two applications included here show how the ATTEN
TEST PT connector, located on the left side of the Z Unit,
can be used to make attenuation factor or ratio checks on
probes used with the Z Unit and on the internal attenuators
of the unit. The test point, when connected to a voltage
divider network under test, forms a bridge circuit as shown
in Fig. 2-5. The crt is the null indicator and the Helidial
reading is used to determine the attenuation factor or ratio
of the divider resistors.

A third application describes how the unit may be used
to measure external resistors.

± 1 0 0 V

Fig. 2 -5 . S im plified diagra m o f the brid g e circuit fo rm ed durin g
use of the ATTEN TEST PT connector.

2-6

Operating Instructions — Type Z

Checking Attenuation Accuracy of VOLTS/CM
Switches

The attenuation accuracy of the X2, X5, XI0, and X20
positions of the VOLTS/CM switches can be determined by
utilizing the 100-volt comparison voltage available at the

ATTEN TEST PT connector. The following procedure ex

plains how to check the X2 position of the A VOLTS/CM
switch. The other positions are checked in the same manner,

1. Set the A VOLTS/CM switch to X2, the AC-DC switch to
DC, and the Mode switch to A-Vc.

2. Place the COMPARISON VOLTAGE Polarity switch to 0

and position a free-running trace to the center of the screen
for reference,

3. Remove the left side panel from the oscilloscope. Connect
a test lead from the A input connector to the ATTEN TEST
PT connector (see Fig. 2-6).

Fig. 2 -6. Left side vie w of the Z U nit sh o w ing the lo ca tion o f the
ATTEN TEST PT.

CAUTION

Use care in making the test lead connections to
prevent shorting the 100 volts at the ATTEN TEST
PT to ground. An accidental short circuit may
damage the CAL. 4 adjustment (R7684).

4. Set the COMPARISON VOLTAGE Polarity switch to +

and the Range switch to 100 V.

5. Rotate the Helidial to return the trace to the reference
level obtained in step 2. Use the vertical trace indicator
lights to aid in returning the trace. In this example the
Helidial should end up in the vicinity of 5.00 (or 50 volts).

6. Divide the Helidial reading into 10 to obtain the at

tenuation factor. (Assume the Helidial reading to be 5.02.

5.02 divided into 10 is 1,99 or an attenuation factor of XI.99.

The attenuation ratio is 1.99 to 1).

Checking Attenuation Accuracy of Probes

Passive attenuator probes can be checked for attenuation
accuracy by a method similar to that used for determining
the VOLTS/CM attenuation accuracy. Referring to Fig. 2-5,

divider resistor R1 is the 1-meg input resistor in the oscil

loscope, R2 is the resistor in the probe. The procedure which
follows describes a method for checking a 10X attenuator
probe.

1. Set the A VOLTS/CM switch to XI, the AC-DC switch to
DC, and the Mode switch to A-Vc.

2. Place the COMPARISON VOLTAGE Polarity switch to 0

and position a free-running trace to the center of the screen

for reference.

3. Remove the left side panel from the oscilloscope [if not
already removed). Connect the probe cable connector to

the A Input connector on the Z Unit and connect the probe

tip to the ATTEN TEST PT.

4. Set the COMPARISON VOLTAGE Polarity switch to -j-

and the Range switch to 100 V,

5. Rotate the Helidial to return the trace to the reference
level obtained in step 2. In this example the Helidial should
end up near a reading of 10 volts,

6. Divide the Helidial reading into 100 to obtain the at

tenuation factor of the probe.

Checking External Resistors

External resistors can be checked for value against the

1-megohm input resistance of the unit by using the bridge
circuit of Fig, 2-5. In this application, R2 is the resistance
to be measured and R1 is the internal 1-megohm resistor.

The following procedure can be used:

1. Set the A VOLTS/CM switch to XI, the AC-DC switch to

DC, and the Mode switch to A-Vc.

2. Place the COMPARISON VOLTAGE switches to 0 and

100 V. Position a free-running trace to the center of the
screen for reference.

3. Remove the left side panel of the oscilloscope. Connect
one end of R2 to the A input connector and the other end
to the ATTEN TEST PT (see Fig. 2-6) by using a jumper
wire.

4. Set the COMPARISON VOLTAGE Polarity switch to -f.

5. Adjust the Helidial to return the trace to the reference
level obtained in step 2. Use the vertical trace indicator

lights to aid you in returning the trace.

6. Let H be the Helidial reading. Then use the folowing
equation to find the value of R2.

R2 = R1 1 ^ - = — ^ Megohms.

If R2 is small compared to 1 megohm, the Helidial read
ing will be very close to 10,00 making it difficult to obtain
an accurate measurement. When this occurs, R1 can be
shunted by an accurate external resistor which will permit
Helidial readings around 5.00. The only restriction on the
shunting is that the total resistance to ground from the
ATTEN TEST PT should not be less than 20 k. This limits the
current drawn from the test point to a maximum of 5 ma. If
the 1-megohm resistor is shunted, R1 in the equation will
have to be changed to the new value of the 1-megohm
and shunt resistors in parallel.

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2-7

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Fig. 3-1. Type

Z

Plug-In Unit block diagram.

BLOCK DIAGRAM DESCRIPTION

SECTION 3

CI RCUI T

DESCRIPTI O N

DETAILED CIRCUIT DESCRIPTION

Fig. 3-1 shows the block diagram for the Type Z Unit.
Signals applied to A Input and B Input connectors pass
through the VOLTS/CM Attenuator switches to the grids
of the tubes in the Input Cathode Follower stage. The
VOLTS/CM switches insert frequency-compensated attenu
ators into the circuit. When properly adjusted the input
resistance and capacitance of the unit remains unchanged
as the attenuators are inserted.

Accurate ±DC comparison voltages are obtained from
the Comparison Voltage Regulator. These can be applied to
the grid of either Input Cathode Follower stage by means of
a Mode switch. These voltages add differentially to the
signal applied to the other Input Cathode Follower when
differential-comparator mode of operation is used.

The low-capacitance, high-impedance input of the Cath
ode Follower stage isolates the input circuitry from the
amplifier stages. The Input Cathode Followers are required
to handle input signal voltages as great as ±100 volts,
without distorting. Special Constant-Current circuits prevent
the cathode followers from cutting off or drawing grid
current with large signals. Screen Voltage Regulator circuits

maintain a constant voltage between the cathode and

screen grid of the cathode followers. The Constant-Current

and Screen-Regulator circuits permit the cathode followers

to handle large signals without operating nonlinearly.

The output of the Input Cathode Followers is applied to
the control grids of the Differential Amplifier stage. This
stage also employs a Constant-Current circuit and a screen
Voltage Regulator to permit the stage to handle large signals
without distortion.

The output of the Differential Amplifier stage is applied

to the bases of the transistors in the Output Amplifier stage

Signals from the Output Amplifier stage are applied
through voltage dividers to the Output Cathode Follower
stage. The voltage dividers provide the proper dc operating
voltages at the grids of the Output Cathode Follower stage.
Output signals from this stage are then applied to the in put
of the oscilloscope main vertical amplifier through pins

1 and 3 of the interconnecting plug. Overall gain of ihe
preamplifier is 2, push-pull.

You may wish to refer to the schematic diagram located

near the rear of the manual and the block diagram of
Fig. 3-1 during the following discussion.

Comparison Voltage Regulator

Regulation of both the + and — comparison voltages

is necessary to maintain specified voltage accuracy. This
regulation system makes the comparison voltage independent
of differences in regulated power supply voltages from one
oscilloscope to another.

The comparison voltage is developed across V7689, a
highly stable gas tube, type OG3. Because the drop across
the tube is less than 100 volts, three zener diodes are placed
in series to increase the reference voltage to slightly more
than 100 volts. In addition to increasing the total voltage
drop in the circuit, the zener diodes provide temperature
compensation for V7689.

A constant-current source of 6 ma is required to maintain
a constant voltage across the gas tube, V7689. For the
— 100-volt comparison voltage reference the 6 ma is pro
vided by a constant-current transistor, Q8674, which operates
as a common-base amplifier. The base voltage is estab
lished with respect to the —150-volt supply by zener diode
D8679. Since the base-to-emitter voltage of Q8674 is es

sentially constant, the current through the transistor is de

termined and maintained constant by the voltage across
resistors R8673 and R8674. By adjusting R8674, the current
through V7689 is set to the specified 6 ma. Transistor
Q8672, a diode-operated 2N1102, provides temperature
compensation for Q8674.

For the + 100-volt reference, a constant current of 6 ma
is furnished by Q7674 in conjunction with zener diode D7675
and resistors R7670 and R7671. This circuit operates similar
to the —100-volt reference previously explained.

As the COMPARISON VOLTAGE Polarity switch is moved
from + position to — position, it is important that the load
on transistors Q8674 and Q7674 remain the same. In the

+ and 0 positions, the current from the negative current
regulator, Q8674, passes through R8670 instead of the gas
tube and associated zener diodes. In the — position, the
current from the positive current regulator, Q7674, passes
through R8670. In calibration, the voltage at Test Point A
is set equal to the voltage at Test Point B in all positions
of the polarity switch, so that a constant load is always pre
sented to Q7674 and Q8674. The voltage is then applied
across the COMPARISON VOLTAGE potentiometer, R7686.

The voltage applied across potentiometer R7686 must

be exactly 100 volts. Since the voltage obtained by the

3-1

Circuit Description — Type Z

drop across V7689 and the zener diodes is slightly more
than 100 volts, R7684 and R7685 (if needed) reduce the
potential to the exact amount required.

The precision voltage dividers consisting of R7687A and
R7687B (XI0), and R7687C and R7687D (XI00), reduce the
comparison voltage from 100 volts to either 10 volts or

1 volt by means of the COMPARISON VOLTAGE Range

switch.

Input Cathode Follower Stage

Signals applied to input connectors A and B of the Type
Z Unit go to the AC-DC switches which either include,
or short across, the coupling capacitors. The signals then

pass through the PUSH TO DISCONNECT SIGNAL switches,
the VOLTS/CM switches, and the Mode switch, SW7611.
The signals are then impressed upon the grids of the input
cathode followers, V7613 and V8613.

The wide dynamic range of the Type Z Unit requires

constant-current operation of both the Input Cathode Pol-

lower stage and the Differential Amplifier stage. Another

requirement is that screen-to-cathode voltages remain con
stant in both stages. Transistor Q7618 is the constant-current
source for both V7618A and input cathode follower V7613.
This transistor operates as a common-base amplifier. Its

base is held approximately 6 volts above the -150-volt
supply by zener diode D8679 (see Note, below).

NOTE

When reference to the — 150-volt supply is made,
the actual typical voltage measurement is — 144
volts at pin 9 of the interconnecting plug in all
oscilloscopes using a decoupling network in the

main oscilloscope.

The base-to-emitter voltage is essentially constant, the

base being a few tenths of a volt more positive. With base
and emitter voltages fixed, Q7618 operates at a constant
current. Note that a variation in the -150-volt supply has

little or no effect on the transistor bias. Thus no change oc

curs in either the base-to-supply drop or the base-to-emitter
drop. Only the base-to-collector drop varies.

The voltage drop across zener diode D8679 sets the

voltage drop between emitter and the —150-volt supply.
A decrease in emitter resistance would require a greater

current to establish the same fixed drop. Hence R7619 is
the current control for Q7618, the constant-current source.

The collector current of Q7618 is slightly less than the
emitter current, very nearly constant, and independent of
the base-to-collector voltage. Such a circuit is very staole
with respect to transistor parameters and temperature.

To describe the constant-current circuit of the Inout

Cathode Follower stage during peak operation, assume

that an input voltage swing from —100 to +100 volts is
applied to the grid of V7613. The cathode of V7613 end
plate of V7618A follow the 200-volt swing. The cathcde

of V7618A varies

---------

— times the plate swing. In this

H + 1

circuit, the cathode swings about 1/30 of the plate swing.
Therefore the grid-cathode swing of V7618A is approxi
mately 6.6 volts. The voltage swing is now low enough
for direct coupling to the collector of Q7618 whose func
tion is to provide the constant-current source for this half
of the input stage. The voltage swing of 6.6 volts is easily
handled by the transistor at its operating current of ap
proximately 8 ma.

The effect of a transistor “long-tail” in the cathode circuit
of V7618A is shown in Fig. 3-2. The top curve displays
the constant-current characteristics of a 2N1302 transistor
when connected similar to Q7618. The lower curve displays
the constant-current characteristics of V7618A with Q7618
connected in its cathode circuit to control the current. For
practical purposes, no measurable change in current occurs
during these voltage excursions.

The grid of V7618A returns to the zener diode D8679
through a temperature-compensating diode-connected tran-

'c

1 m a/div

P

1 m a/div

1 volt/div

20 volti/div

Fig. 3-2. Top: consta nt-current co llecto r characteristics o f 2N 130 2
transistor having a 1-k resistor in the em itter circuit; botto m : con
stant-current pla te characteristics of 6DJ8 triode connected sim ilar to

V7618A. {Transisto r dis pla y obtaine d from Tektronix Type 575

Transistor-Curve Tracer; triode displa y o bta ined from Type 570
Characteristic-Curve Tracer.)

3-2

Circuit Description — Type Z

sistor, Q8672. The bias of V7618A is the collector-to-base
voltage of Q7618 plus the drop across Q8672.

The screen of the input cathode follower V7613 is con
nected back to its cathode through another cathode fol
lower, V7623A, and zener diode, D7621. The screen

voltage of V7613 will therefore follow variations in the
cathode voltage (because it is “bootstrapped" to the
cathode), approximately 105 volts above the cathode.
Capacitor C7626 bypasses high-frequency components of
the signal directly to the screen. C7621 and R7622 form
a low-pass filter to remove zener noise from the screen
of V7613.

The gain of the input CF's (V7613 and V8613 approaches
unity because the impedance of the constant-current cathode
“long-tail" approaches infinity, and because of the high

and constant grid-screen p. The grid-screen p remains
constant because of the constant screen-cathode potential.
The most significant factor which reduces the gain of the
stage below unity is the cathode-load resistors R7620,

R7621, and R8621.

Slight circuit imbalances, principally in triode p and

zener diode impedance, necessitate a balance control

R7620. For all practical purposes, this control, plus R7621

and R8621, form the cathode load for the input cathode
followers.

Differential Amplifier Stage

Signals from the input cathode followers are applied to
the grids of the Differential Amplifier stage, V7634 and
V8634. The cathode circuitry of the stage consists of a
constant-current circuit and a gain adjustment network.
The constant-current circuit is formed by Q8638 and V8o38
and is identical in principle, with one exception, to the
operation of the circuits in the Input Cathode Follower
stage. The exception is that one constant-current circuit
supplies both tubes in this stage.

The amount of current supplied by the constant-current
circuit is determined by the setting of the GAIN ADJUST
control R8639. As screen-to-cathode voltage is maintained
constant, R8639 controls the transconductance of V7634 and

V8634, thereby controlling the gain of the stage. The
control is set to provide the correct vertical deflection fac
tors when the VAR. ATTEN. control R7633 is set fully clock
wise. The VAR. ATTEN. control varies the gain of the Dif
ferential Amplifier stage by varying the cathode degenera
tion.

To prevent trace shift as the VAR. ATTEN. control R7633
is adjusted, the cathode potentials must remain equal. This
is accomplished by proper adjustment of the VAR. ATTEN.
BALANCE control R7619. Adjustment of R7619 varies the

grid (and the cathode) voltage of V7634 and V8634 in
opposite directions to compensate for slight differences in
operating characteristics of the two tubes. Proper adjust

ment of R7619 will result in equal voltages at the cathodes

of V7634 and V8634 for all positions of the VAR. ATTEIN.
controls.

As in the Input Cathode Follower stage, the screen volt

age for the Differential Amplifier stage is “bootstrapped"

140 volts above the cathode. Because total cathode current,

screen-to-cathode voltage, and the plate-to-screen current

ratio remain constant, the plate currents of the Differential

Amplifier stage respond only to differential signals.

The high-frequency response of the Differential Amplifier

stage is improved by the use of series-shunt peaking in the

plate circuits. This peaking is provided by L7632 and
L8632.

The AMPLIFIER DC BAL. control R7640 adjusts the base
voltage of Q7644 by forcing a small current through R7632.
The control is used to dc balance the Output Amplifier
Stage. Adjustment of R7640 forces the base of Q7644 to be
at the same voltage as the base of Q8644 when no signal

is applied to the unit.

Output Amplifier Stage

Output signals from the Differential Amplifier stage are
applied to the bases of Q7644 and Q8644, the Output
Amplifier stage. This stage has a gain of slightly more than
two. A large common emitter resistance provides a large
amount of emitter degeneration and a high degree of
stability and linearity. Transistors used in this stage have
an advantage over a vacuum tube stage in two respects.
The dc level is lowered instead of raised, and the swing
of the amplifier in the oscilloscope is limited to no more
than 12 centimeters deflection on the crt screen. The latter
is important since rapid recovery from very large input
voltages is essential. Series-shunt peaking in the collector
circuit improves the high-frequency response of the ampli
fier.

Output Cathode Follower Stage

Output signals from the Output Amplifier stage and

positioning voltages from the POSITION control are ap

plied to the grid circuits of the Output Cathode Followers.
Compensated voltage divider networks at the input to the
cathode followers lower dc levels to the proper level for
driving the vertical amplifier of the oscilloscope. The divid
ers consist of resistors R7655 and R7656, R8655 and R8656;
capacitors C7655 and C8655 compensate the attenuators
for high frequencies.

The OUTPUT CF BAL. adjustment R7658 is used to pro
vide dc balance for the output cathode followers. This
insures that the input signals to the push-pull sides of the
vertical amplifier of the oscilloscope are at equal average
dc potentials.

The output cathode followers provide the necessary low
impedance to drive the capacitance of the interconnecting
plug and the input of the oscilloscope vertical amplifier.
In addition, this stage isolates the plug capacitance from
the Output Amplifer stage. The signal from the Output
Cathode Follower stage is applied through the intercon
necting plug to the input of the oscilloscope vertical ampli
fier.

3-3

ON 4

The Z Unit is a stable instrument, and will require com
plete calibration very infrequently. However, to be certain
that the unit is operating properly at all times, the cali
bration of the unit should be checked after each 500-hour
period of operation (or every six months if the unit is used
intermittently). A complete step-by-step procedure for cali
brating the unit and checking its operation is given in the
Calibration section of this manual.

Visual Inspection

Many potential and existent troubles can be detected by
a visual inspection of the unit. For this reason, a complete
visual check should be performed every time the unit is
inoperative, needs repairs, or needs recalibration. Apparent
defects may include loose or broken connections, damaged
connectors, improperly seated tubes or transistors, scorched
or burned parts, and broken terminal strips. The remedy
for these troubles is readily apparent except in the case
of heat-damaged parts. Damage to parts due to heat is
often the result of other less apparent troubles in the unit.
It is essential that the cause of overheating be found before
replacing the damaged parts.

COMPONENT REPLACEMENT

General

Useful information concerning the replacement of im

portant parts in the Z Unit is given in this portion of the
manual. Because of its precision design, replacement of
close tolerance components will require calibration of the
unit to assure proper operation. Refer to the Calibration
section of this manual for a complete procedure. If the
steps in the procedure are to be performed out of sequence
to get the repaired portion of the Z Unit calibrated, refer
to the preceding portion of the procedure for more infor
mation about control panel settings and test equipment
used.

Switches

If a switch is found to be defective and needs to be

repaired or replaced, use normal care in unsoldering and

MAI N T ENAN CE

disconnecting leads from the terminals. To remove some
switches, such as the AC-DC, Polarity, and Range, the
front overlay panel must be removed first to obtain access
to the switch mounting screws.

Single wafers on wafer-type switches are not normally
replaced. If a wafer is defective, the entire switch should
be replaced. Some switches may be ordered from the
factory either unwired or with parts wired in place, as de
sired. Refer to the Parts List to find the wired and unwired
part numbers.

When soldering the leads to a wafer-type switch, do not
let solder flow around and beyond the rivet on the switch
terminal. Otherwise the spring tension of the switch con
tact may be destroyed.

Turret Attenuators

To remove or to replace a component inside one of the
VOLTS/CM turret attenuators, the following instructions are
given:

1. To remove the turret, loosen the 0.050" alien set screw
(see Fig. 4-1). Grasp the knob and pull it outward far
enough to let the shaft free the turret. Do not pull the
shaft too far out or it will not hold the detent wheel in
position.

2. Remove the turret. Remove the end caps from the body
of the turret to obtain access to the components.

NOTE

When replacing any of the components inside the
turret, the lead lengths and parts placement are
critical. Duplicate the original lead lengths and
the exact part placement. Use parts ordered from
the factory to assure correct physical size and
tolerance accuracy. Do not use excessive heat or

let the soldering iron touch the white plastic part

of the turret body. No attempt should be made

to replace button capacitors C413E, C414E, or
C415E. These parts are sweat-soldered in the
outer metal ring to secure a low inductance
grounding path. The ring is fitted to the body
of the turret before the inside components are
soldered into place. It is extremely unlikely that

these capacitors will become defective. How
ever, if a button capacitor needs to be replaced,
order a replacement wired turret body from the
factory.

4-1

Maintenance — Type Z

THRUST SPRING

(Shown rotated

FRAME CONTACTS 180° ,rom e0,r,“

Fig. 4 -1 . B V O LTS/C M turre t attenuator removed from the Z U nit.

3. To remount the turret body, align the holes in the end
caps with the index pins. Fit the end caps to the turret
body.

4. Note the setting of the knob and then rotate the knob
so the bent ends rather than the open ends of the thrust
spring will accept the turret.

5. Slide the turret into the frame. Make sure the contacts
(indicated in Fig. 4-1) are aligned with the contacts on the

turret.

6. Rotate the knob to its original setting. Slide the shaft

through the turret and through the rear hole in the frame.
Check alignment of contacts while carefully rotating the
turret. Tighten the set screw.

7. If the bent ends of the thrust spring are not located

between the roll pins, rotate the thrust spring around the
shaft until it is properly positioned. When this is done,
the bent ends of the spring will not strike the detent wheel
stop as the turret is rotated.

If the entire VOLTS/CM turret attenuator is to be re
moved or replaced, the complete switch can be removed
as a unit the same as a conventional rotary switch. When
ordering a replacement switch, refer to the Parts List lor
the wired switch part number.

Ceramic Terminal Strips

Damaged ceramic terminal strips are most easily removed

by unsoldering all connections and then using a plasric

or hard rubber mallet to knock the yokes out of the chassis.
This can be done by tapping on the ends of the yokes

protruding through the chassis. When a new strip is
ordered, the yokes are furnished with and are attached
to the strip. New spacers need not be ordered because
the original spacers can be used two or three times before
they become too loose to hold the yokes securely.

When the damaged strip and yoke assembly have been
removed, place the spacers for the new strip assembly
into the holes in the chassis. Using a plastic or hard rubber
mallet, tap the ceramic strip lightly above the yokes to
drive the yoke pins down through the spacers. Be certain
that the yoke pins are driven completely through. Using
a pair of diagonal cutters, cut off the excess length of the
yoke pins. Fig. 4-2 illustrates the way that the parts fit
together.

Ceramic Strip Yoke

Chassis Spacer Yoke Pin

4-2

Fig. 4 -2 . Installa tion of ceramic terminal strips.

Soldering Precautions

In the production of Tektronix instruments, a special
silver-bearing solder is used to establish a bond to the
ceramic terminal strips. This bond may be broken by the
repeated use of ordinary tin-lead solder, or by the appli
cation of too much heat. Occasional use of ordinary
solder will not break the bond however, if too much heat
is not applied.

If continued maintenance work is to be performed on
Tektronix instruments, it is advisable to have a stock of
solder containing about 3% silver. This type of solder is
used often for work on etched-circuit boards and should
be readily available. It may also be purchased directly

from Tektronix in one pound rolls (part number 251-514).

Because of the shape of the terminals on the ceramic
terminal strips, the soldering iron should have a wedge-
shaped tip. A tip such as this allows the heat to be ap
plied directly to the solder in the terminals and reduces

the amount of heat required. It is important to use as little

heat as is possible. Do not use force or twist the tip in

the slot as this may chip or break the ceramic strip.

REPLACEMENT PARTS

Standard Parts

Replacement for all parts used in the Type Z Unit can
be purchased directly from Tektronix at current net prices.

Many of the components, however, are standard electronic

parts that can generally be obtained locally in less time

than required to obtain them from the factory. Before

purchasing a part, be sure to consult the Parts List to de

termine the tolerances and rating required. The Parts List

gives the values, tolerances, ratings, and Tektronix part

number of all components used in the instrument.

Special Parts

In addition to the standard electronic components men
tioned in the previous paragraph, special parts are also
used. These parts are manufactured or selected by Tek
tronix to satisfy particular requirements, or are manu

factured especially for Tektronix by other companies. These

parts and most mechanical parts should be ordered directly

from Tektronix since they are normally difficult or impossi

ble to obtain from other sources. All parts may be obtained

through your local Tektronix Field Engineering Office.

TROUBLESHOOTING

General Information

This portion of the manual will aid you in troubleshoot
ing the Z Unit in the event that trouble develops. During

troubleshooting work, the information contained in this

Maintenance — Type Z

section should be correlated with information in other
sections of the manual.

No attempt is made to give complete step-by-step pro
cedures for finding the cause of each possible type of
trouble. Instead, an attempt is made to outline a general

troubleshooting guide. This guide provides a means for

determining the probable cause of a trouble from symptoms
observed before detailed checks are made.

A schematic diagram of the Z Unit is contained at the
rear of this manual. The reference designation of each
component is shown on the circuit diagram.

All wiring used in the Z Unit is color coded. This greatly
simplifies circuit tracing in the instrument.

Preliminary Troubleshooting

Before attempting any troubleshooting work, check all
front-panel controls for proper settings. If in doubt as to
the settings of the controls, refer to the Operating Instructions
section.

1. Visual Operational checks

A good procedure to follow when trouble occurs in the
Z Unit is to make a careful visual check of the instrument
and the input connections. A source of trouble can often

be detected by visual means. If no trouble is visible, apply
an input signal and observe the CRT for proper wave
shapes. Adjust the front-panel controls to see the effect
of each. The normal or abnormal operation of each con
trol will indicate what sort of trouble is encountered. Once
the symptoms are clearly established, the faulty circuit can

usually be isolated more readily.

2. Oscilloscope or Z Unit

When following a troubleshooting procedure, it is as

sumed that the oscilloscope used with the Z Unit is operat

ing normally. This is not always the case. If in doubt,
check the operation of the oscilloscope before attempting
to troubleshoot the Z Unit. Troubles occurring in the oscillo
scope can usually be detected by substituting another

plug-in unit for the Z Unit and checking for proper opera
tion.

Troubleshooting Procedures

The troubleshooting procedures that follow are divided

into sections according to trouble symptoms. When a trou

ble occurs in the unit, the proper troubleshooting section
can be quickly found.

1. Incorrect Gain

Improper gain may be caused by any of several condi

tions in the unit. However, as a first check, see if the

GAIN ADJUST control will correct the gain. Refer to the
Operating Instructions section which describes how to make
the adjustment. Then, if necessary, check the tubes and

®

4-3

Maintenance — Type Z

transistors in all cathode follower and amplifier stacks,
preferably by substitution. After substituting a part, vari
ous adjustments are affected. Use the Preliminary Pro
cedure in the Calibration section for a guide in setting up
the front-panel controls, and perform steps 2, 5, 6 and 7
in the Calibration procedure to determine if any of the
adjustments given in those steps require readjustment.

When a tube or transistor is replaced in a stage, imbal

ance may occur. Choose matched components or use Tek

tronix parts to get the trace onto the screen. To aid in
determining how well the stage balances, refer to the

Calibration section for the appropriate balance step to

perform and the location of jumper-connection test points

(see Fig. 5-3) to use.

If the trouble has still not been corrected, apply a known

input signal and use a test oscilloscope to check the gain
of each stage. The overall gain of the unit as measured
at the cathode of each output cathode follower should be

1 (single-ended); the push-pull gain should be 2. The input
cathode followers should have a single-ended gain of
approximately 0.99, the differential amplifier a gain of
approximately 0.7, the output amplifier a gain of approxi
mately 2.6, and the output cathode follower measured
from the input grid to output a gain of approximately 0.98.
The single-ended gain of the entire output cathode 'ol-

lower stage when measured from the collector of the out

put amplifier to the cathode of the output cathode fol

lower is approximately 0.6.

It should be remembered when measuring the gain tnat
the input of the differential amplifier is single-ended while
the output is push-pull. The input of the differential ampli
fier is measured at the grid of either V7634 or V8634, as
applicable. Output of the stage is measured at the plate
of each tube. Then the single-ended gain of each half
of successive push-pull stages should be checked for proper
gain as given in the previous paragraph. At the same
time check to see if the gain for each half of the push-pull
stage is approximately the same.

When the defective stage has been found, use voltage
and resistance measurements to determine the exact cause
of the trouble.

2. Nonlinearity

An improper setting of the OUTPUT CF BAL. adjustment
causes nonlinear operation and the trace to be deflec'ed
off the screen. An operator can easily correct for the de
flected trace symptom if the OUTPUT CF BAL. adjustment
had not been moved more than about 20° from eitner
side of the correct setting. As stated in the Operat ng
Instructions section for centering the trace, the AMP. OC
BAL. adjustment is used to position the trace behind the
horizontal centerline of the graticule when the POSITION
control is set to midscale. However, the nonlinearity will
not be corrected unless the OUTPUT CF BAL. is brought
back to its correct setting.

To check if nonlinearity exists, proceed as follows:

Apply a 100-mv calibrator signal to the A input con
nector. Set the A AC-DC switch to DC, the A VOLTS/CM

switch to .05, and the Mode switch to A-Vc. Set the Polar
ity switch to + , the Range switch to 1 V, the Helidial

control to 0.00, and the POSITION control to midscale.
Set the oscilloscope triggering controls to produce a stable
display. Rotate the Helidial slowly clockwise to position
the signal to the center of the graticule. Note the exact
amplitude of the signal (should be about 2 cm high.)

Rotate the Helidial slowly clockwise to position the signal
to the bottom 2 cm of the graticule. Note the amplitude
of the signal. Place the Polarity switch to — and position
the signal to the top 2 cm of the graticule. Note the ampli
tude again. If changes in signal amplitude are noted which
are greater than any slight inherent compression (if any)
due to the main oscilloscope vertical amplifier or crt, then
the Z Unit is operating in a nonlinear region.

To restore the Z Unit to proper operation, perform steps

2. 5 and 6 in the Calibration procedure. Use the Pre

liminary (Calibration) Procedure for a guide in presetting

the front-panel controls prior to making the adjustments.

3. Low Differential Rejection Ratio

The differential rejection ratio is highest on the .05 settings
of the VOLTS/CM switches; the ratio is lower on other
settings due to slight imbalances in the input attenuators.

If the differential rejection ratio seems normal on the .05
settings of the VOLTS/CM switches but abnormal on one or

more of the other ranges, the input turret attenuators

should be checked.

If the differential rejection ratio (.05 volts/cm) is less than
the specified 40,000 to 1, check the setting of the DIFF.
BAL. potentiometer. Then check the tubes and transistors
in all cathode follower and amplifier stages (by substitu

tion). Apply the same signal first to one and then the

other input connector of the unit. The vertical deflection
produced should be the same in either case with only the
polarity reversed. If the deflection produced by the signal
applied to one input is different than the deflection pro
duced by the same signal applied to the other input, a
difference in gain exists between the two sides of the ampli
fier. Use a test oscilloscope to determine where this gain
imbalance is introduced. When the defective stage has
been determined, use voltage and resistance measurements
to find the cause of the trouble.

4. Large DC Imbalance

A large dc imbalance in the preamplifier will cause the
oscilloscope trace to deflect off the screen, and the POSI
TION control may not have sufficient range to bring the
trace back on the screen. If this occurs, set the Mode
switch to TEST, center the POSITION control, and use the
AMP. DC BAL. adjustment to attempt to bring the trace
back on the screen. If the trace does not appear, perform
steps 2 through 6 in the Calibration section of the manual.

When the adjustments and jumper connections are made

as instructed in the previous paragraph, there may be one

jumper-connection checkpoint where the trace cannot be
made to return to the screen. When this occurs, the stage

following the jumper (looking toward the output of the
unit) is producing the imbalance. Substitution of tubes and
transistors, whichever apply, plus voltage and resistance
measurements will determine the cause of the imbalance.

When substitutions are made, repeat steps 2 through 6 as

4-4

stated previously. Where necessary, use matched and se

lected parts obtained from the factory.

5. Waveform Distortion

If waveform distortion occurs, first check to see which
ranges of the VOLTS/CM switch have distortion. If the
distortion only occurs on one or two ranges, check the
compensation of the input turret attenuators. If the dis
tortion occurs on all ranges, first check the compensation
of the probe used. Use a calibrated, 30-mc-bandwidth,
test oscilloscope for signal tracing through the unit. The
test oscilloscope aids in determining which stage (or stages)
is introducing the distortion. In signal tracing for high-
frequency distortion, consider the loading effect of the
probe. When the defective stage has been determined,
check tubes and transistors (by substitution). Then check
the settings of frequency compensation components such as
L7632, L8632, L7645, L8645, C7655, and C8655. If none of
these checks determines the cause of the trouble, use volt
age and resistance checks on the defective stage.

6. Incorrect Comparison Voltages

This trouble can be detected only with a high precision,
infinite-impedance voltmeter such as described in the Cal
ibration section under Equipment Required. To check these
voltages, connect the voltmeter from test point C to ground,
set the Helidial at 10.000 and set the Range switch at
100 V. The voltage measured should be 100 (±0.15)
volts in both the + and — positions of the Polarity switch.
If both the + and — voltages are correct, check for 10
(±0.02) volts with the Range switch set at 10 V and 1
(±0.005) volt with the Range switch set at 1 V. If either
the 10 V or 1 V ranges are incorrect, check the Range
switch contacts and rotors, the precision attenuators, and
the setting of R7689 (CAL. 5 adjustment).

If voltages obtained on both the + and — 100 V ranges
are incorrect, check the settings of the CAL. 1, CAL. 2,

CAL. 3, and CAL. 4 adjustments. If only one polarity is
incorrect, check the settings of CAL. 1 or CAL. 2 as applica
ble, and the voltages on Q7674 or Q8674.

Maintenance — Type Z

Poor regulation of the comparison voltage may be caused
by defects in any of the following: D8679, Q8672, Q8674,
D7675, Q7672, Q7674, D7686, D7687, D7688, or V7689.

7. Short Circuit

If the oscilloscope must be turned off because the

Z Unit is the cause of resistors overheating in the oscillo
scope power supply, and possibly in the unit as well, re

move the unit from the plug-in compartment. Place the

COMPARISON VOLTAGE switch in the + Position. Make
the following resistance-to-ground checks at the 16-pin
interconnecting plug. The measurements listed in Table 4-1
are typical values obtained using a 20,000 Q/V VOM.

When the trouble is corrected, replace the overheated
resistors in the oscilloscope and check the Z Unit for any
other troubles under operating conditions. It may be desir

able to perform steps 1 through 11 in the Calibration section

of the manual. These steps provide a systematic approach
to important voltage measurements, balancing each stage,

and making operational checks.

TABLE 4-1

CIRCUIT

INTERCONNECTING

SOCKET

PIN NUMBER

RESISTANCE
TO GROUND

Output 1 & 3 9.8 k
Ground 2

0

No Connection

4, 5, 6, 7, 8, and 16

Infinite

-150 V 9

10.7 k

*17.0 k

+ 100 V

10 8.7 k

*7.7 k

+225 V 11 19.0 k

*14.0 k
+350 V 12 60 to 80 k
6DJ8 Filament

Transformer Primary

13 and 14

Infinite

Series Filament String

15 72 n

*W ith COMPARISON VOLTAGE Polarity switch at — position.

4-5

C AL I B RAT I O N

A complete procedure for checking the operational

standards and calibration of the Type Z Plug-In Unit is

provided in this section of the manual. The steps in the
procedure are arranged in correct sequence to avoid un

necessary repetition.

The step-by-step instructions also furnish an orderly ap

proach for isolation of malfunctions which may develop.
Consequently, this procedure should be used in conjunction
with any maintenance and troubleshooting system.

If an abnormal indication is obtained at some point in
the procedure, it is not usually necessary to locate its cause
before continuing to the next step. Additional symptoms
revealed by performing further steps will frequently simplify
the task of locating trouble. Obscure symptoms, if any,
usually show up when performing the first eleven steps of
the procedure.

For this procedure, the Z Unit should be used in con
junction with a properly calibrated Tektronix Type 540-
Series oscilloscope. Oscilloscope control settings for a
Type 541A Oscilloscope are listed in the procedure; cor
responding control settings should be used if a different

oscilloscope is used.

3. Sine-wave generator, Tektronix Type 190A Constant-
Amplitude Signal Generator or equivalent. Required spec
ifications are: frequency range of 50 kc to 13 me; output
amplitude of 0.14 volt or more; output must be adjustable
(manually or automatically) for constant amplitude within
the above frequency range.

4. Precision dc voltmeter. Required specifications are:
accuracy of 0.05% or better; resolution of 50 /i.volts or less;

must be of the nulling type with infinite impedance at null.
If a John Fluke Differential Voltmeter is available, use

Model 803 or equivalent.

5. Calibrated volt-ohm meter (VOM). Sensitivity of 20,000
12/v at full deflection.

6. 24-/i,/i,f Input Capacitance Standardizer, Tektronix Type

CS24 (Part No. 011-029) or equivalent.

7. Plug-in cable extension, Tektronix Part No. 012-038.

8. Plug-in extension. Type EP54, Tektronix Part No. 013-019.

9. 52-ohm coaxial cable, Tektronix Part No. 012-001.

10. 52-ohm 5-to-l "L" attenuator, Tektronix Part No. 011-

002.

11. 52-ohm cable termination, Tektronix Part No. 011-001.

Test equipment used in a particular step should be eft

connected at the end of that step unless instructions state
otherwise. Similarly, controls not mentioned are assumed
to be in the positions they were in at the conclusion of the

preceding step.

If information explaining the normal operation of front-

panel controls is needed before starting the procedure,
consult the Operating Instructions section of this manual.

12. Suggested tools: screwdriver, shank 2" long x 1/8"
dia.; 0.050" alien wrench; low-capacitance screwdriver,
Tektronix Part No. 003-000; alignment tool consisting of
a handle (Tektronix Part No. 003-007), a low-capacitance
screwdriver insert with a metal bit (Tektronix Part No.
003-334, and a hexagonal core insert (Tektronix Part No.

003-310).

EQUIPMENT REQUIRED

The following equipment or its equivalent is required to

perform a complete calibration of the Type Z Plug-In Unit.

1. Square-wave generator, Tektronix Type 105 or equiva
lent. Required specifications are: 13-nsec risetime or less;
output frequencies of approximately 1 kc and 10 kc; output
amplitude variable from 10 to 100 volts across 600-ohm
internal load.

2. Square-wave generator, Tektronix Type 107 or equiva
lent. Required specifications are: 3 nsec risetime or less;
output frequency of approximately 1 me; output amplitude
variable to at least 0.35 volt.

PRELIMINARY PROCEDURE

NOTE— Make certain the — 150-, + 100-, +2 25-,
and + 350-volt power supplies in the oscilloscope
are regulating and witl
ances before attempting

Preset the Type 541A Osci

panel controls as follows:

Horizontal Display
Time/cm
Variable Time/cm
Triggering Mode
Triqqer Slope
Stability

in rated voltage toler-
to calibrate the Z Unit.

loscope (or equivalent) front-

Normal
.5 Millisec
Fully Clockwise
AC
+ Internal
Fully Clockwise

5-1

Calibration — Type Z

Preset the Z Unit front-panel controls as follows:

POSITION Midrange
A VOLTS/CM .05
B VOLTS/CM .05
Both AC-DC switches DC
Mode TEST
VAR. ATTEN.
COMPARISON VOLT

AGE Polarity

COMPARISON VOLT

AGE Range

Fully Clockwise

0

100 V

Check to see that the COMPARISON VOLTAGE Helidial
reads exactly zero when the control is rotated fully counter
clockwise. Rotate the control fully clockwise. The dial
should read about one half a minor division over 10.000

or a reading of 10.005. If the Helidial does not read ex
actly as described, loosen the set screw with 0.050" alien
wrench and set the Helidial for correct readings. Tighten
set screw.

Remove the left side panel from the oscilloscope. Con
nect the plug-in cable extension between the Z Unit and

the oscilloscope vertical plug-in connector. Connect the os

cilloscope power cord to the nominal voltage source for
which it is wired and turn on the power.

WARNING

Do not touch transistors! Dangerous potentials
exist on transistor cases. If a transistor needs to
be replaced, turn off the power.

CALIBRATION PROCEDURE

1. Check Voltage Measurements.

Use the VOM to make the following measurements:
(a) Measure the voltage drops across the 105-volt zener

diodes, D7621 and D8621 (see Fig. 5-1). The drops must be

0 8 6 7 2 D 8 A 7 9

BASE OF

D8621

JUNCTIO N S OF

R7645 A N D

R8645

PIN 4,
V7618

D7621

Fig. 5 -1. Location of com ponents ond test p o ints w he re some of
the step 1 volta g e measurements ore m ade.

PIN 7,
V7613

PINS PIN D 7675 Q 767 2

1 A N D 3 15 .

'

-----------------------------

1 JUNCTIO N OF V8 6 2 3

INTERCONNECTING FILAMENT AND R8691

PLUG

Fig. 5 -2. A n oth er view o f the Z U nit showin g lo c a tion o f rem ain

ing com ponents a n d test points describe d in step 1.

within the range of 95-115 volts and within 3 volts of each
other.

(b) Connect the VOM between pin 7 of V7633 (see Fig.

5-2) and ground. Place the COMPARISON VOLTAGE Po

larity switch to the + position. The meter should read

approximately 100 volts. Place the COMPARISON VOLT

AGE Polarity switch to the — position. The meter should
now be reading approximately —100 volts. Set the COM
PARISON VOLTAGE Polarity switch back to 0.

(c) Check the voltage readings listed in Table 5-1. Those

listed from -f 12.2 volts and on are obtained by connecting

the VOM between the given location and ground.

TABLE 5-1

READ

LOCATION

FIG. NO.

0.3 to 0.6 V

Emitter-to-base drop across
Q7672.

5-2

0.3 to 0.6 V

Emitter-to-base drop across
Q8672.

5-1

5.7 to 6.7 V

Drop across RT-6 zener diode
D7675.

5-2

5.7 to 6.7 V

Drop across RT-6 zener diode
D8679.

5-1

+ 12.2 V

Junction of V8623 filament
lead (blue and orange tracer)
and R8691.

5-2

+ 65 to +70 V

Terminals 1 and 3, intercon
necting plug.

5-2

+75 V

Terminal 15, interconnecting
plug.

5-2

-9 8 V Pin 4 of V7618.

5-1

-138 V

Base of Q7618.

5-1

+210 V

Junction of R7645 and R8645.

5-1

5-2

®

http://manoman.sqhill.com

Calibration — Type Z

JU N C TION OF

R7653 AND R7652

PINS 1 AND 3, COLLECTOR PIN 1,

INTERCONNECTING OF Q 8 644 V863 4

PLUG

Fig. 5 -3 . Location o f jum per te st points used fo r makin g steps 2, 3,
and 4 pu sh -p u ll balance checks.

2. Output Cathode Follower Balance

Remove the plug-in cable extension and insert the Z Unit
directly into the oscilloscope plug-in compartment. Tighten
the securing rod to hold the unit fully plugged in.

(a) Connect a short jumper between pins 1 and 3 at the
interconnecting plug (see Fig. 5-3 for location). The posi
tion of the free-running trace on the crt is the "vertical-
system electrical center". Note the position of the trace for
future reference in the procedure. Remove the jumper.

(b) Connect the VOM between the wiper arms of the
POSITION control (R7653) and adjust the control for a zero
reading on the meter. Connections can be made at the
junction of R7653 and R7652 and the junction of R7653
and R8652 (see Fig. 5-3). Disconnect the VOM.

CAUTION

Use care when connecting jumper leads in the
following steps. An incorrect connection can

quickly damage transistors. Also, if parasitics are

produced when a jumper is connected, they can
be suppressed with a ferrite toroid. Wind the
jumper lead through the toroid two or three times.

(c) Connect a jumper between the collectors of Q7644

and Q8644 (see Fig. 5-3). Rotate the OUTPUT CF BAL ad

justment (R7658) to bring the trace back to the "vertical-
system electrical center" position established in step 2 (a).
Remove the jumper.

Fig. 5-4 shows all internal adjustments not accessible from

the front of the unit.

3. Output Amplifier Balance

Connect the jumper between the bases of Q7644 and
Q8644 (Fig. 5-3). With balanced transistors the trace will
not shift more than 1 cm from the "vertical-system electrical
center" position. Disconnect the jumper.

4. Differential Amplifier Tube Balance Test

Connect the jumper between pins 1 of V7634 and V8634
(Fig. 5-3). The trace should not shift more than 3 cm from
"vertical-system electrical center". Disconnect the jumper.

5. Variable Attenuator Balance

Position the trace onto the screen using the POSITION,
AMP DC BAL, and VAR. ATTEN. BALANCE controls. Set
the VAR. ATTEN. BALANCE control so the trace no longer
shifts as the VAR. ATTEN. control is rotated. During ad
justment of the VAR. ATTEN. BALANCE control, it may
be necessary to reposition the trace to keep it centered
on the crt by using the POSITION and AMP DC BAL con
trols.

6. Amplifier DC Balance

Set the POSITION control to midrange and adjust the
AMP DC BAL control to position the trace directly behind
the center horizontal graticule line.

7. Gain

Set the Mode switch to A Only. Apply a 0.2-volt square-

wave signal from the oscilloscope calibrator to both input

AMPLIFIER

DC BAL.

TURRET

ATTENUATOR

OUTPUT

CF BAL

10033

LO OH J

LO O J 4

TURRET

ATTENUATOR

Fig. 5 -4 . Location of internal adju stments accessible from left side
of Z Unit. Turre t atte n uator com pe nsation adjustm ents a re acces
sible th ro u gh fron t p a n e l a fte r o u ter V O LTS /CM knobs are re 
moved.

®

5-3

http://manoman.sqhill.com

Calibration — Type Z

connectors. Make certain the VAR. ATTEN. control is set
fully clockwise. Set the GAIN ADJUST control (R8639) to
obtain exactly 4 cm of vertical deflection. Place the Mode
switch to —B ONLY. Check to see that there are exactlv 4
cm of vertical deflection.

8. Operational Checks

Perform the following Z Unit operational checks:

(a) Disconnect the calibrator signal from the input con
nectors. Check to see that the baseline does not shift
more than 2 mm after switching the Mode switch from
A ONLY to —B ONLY. Reconnect the calibrator signal
to the input connectors.

(b) With the Mode switch at —B ONLY, check the opera
tion of the B AC-DC switch by setting it to the AC posi

tion. Observe the signal to see that it shifts to its average

voltage level. The shifting of the signal indicates that fhe

AC-DC switch and the blocking capacitor function properly.
Set the Mode switch to A ONLY and check the A AC-DC
switch for the same waveform shift indication. Place both

AC-DC switches back to the DC position.

(c) Check operation of the VAR. ATTEN. control. When

the control is rotated fully counterclockwise, the vertical de
flection of the signal should not exceed 1.6 cm. Rotate the
control back to the fully clockwise position.

9. Turret Attenuation Ratios

With the Mode switch at A ONLY, check for 2 cm of
vertical deflection at each position of the A VOLTS/CM

switch by following the information in Table 5-2.

TABLE 5-2

VOLTS/CM Switch Calibrator Output

Setting

Volts

.05 .1

.1

.2

.25

.5

.5 1

1

2

2.5

5

5 10

10

20

25

50

After checking the A VOLTS/CM turret attenuator, set
the Mode switch to —B ONLY and check the B VOLTS/CM
attenuator in the same manner.

10. Differential Balance

Set the Mode switch to the A-B position and both
VOLTS/CM switches to .05. Set the calibrator switch lor

a 100-volt output signal. Set the oscilloscope triggering

controls for a stable display. Ignoring the spikes on the

waveform, adjust the DIFF. BAL. control for minimum square-
wave amplitude. The maximum allowable amplitude is

0.5 mm. When the control is correctly adjusted and the Z
Unit balances properly, the waveform appears as a straight
line with positive and negative spikes.

An ac mismatch between two tubes or components can

cause the straight line segments of the waveform to tilt
diagonally to form a zigzag pattern. The amplitude of the
tilt at its highest point should not exceed 1 mm. To check

the amplitude, free run the sweep at 20 millisec/cm and
observe the width of the trace. It should not exceed 1.5 mm

(amplitude of tilt and square wave together). After com

pleting this check, repeat step 5. Then go on to step 11.

11. Characteristic Unbalance

Disconnect the signal from the Z Unit inputs, and set
the Mode switch to the TEST position. Set the oscilloscope
Time/cm switch to .5 millisec/cm. While observing the
trace, move the COMPARISON VOLTAGE Polarity switch
to the + , 0, and — positions several times. The overall
baseline shift should not exceed 1 cm. Leave the COM

PARISON VOLTAGE Polarity switch in the 0 position at

the conclusion of this step.

12. Input-Capacitance Standardization

Loosen the set screws in both VOLTS/CM knobs with a

0.05" alien wrench and remove the knobs. This allows ac
cess to the attenuator adjustments through slots in the front

panel. Each position of the VOLTS/CM control has a
SHUNT and a SERIES adjustment. The only exception is the
.05 position which has only an input-capacitance trimmer
accessible through the SERIES side of the slot.

Connect the 52-ohm cable to the Type 105 Square-Wave
Generator, or equivalent. Connect the other end of the
cable to the 5-to-l “L" pad. Connect the other end of the
“L" pad through the 24-/ipf capacitance standardizer to
the A input connector on the Z Unit. Set the Mode switch
to A ONLY and both VOLTS/CM switches to .05.

To make this adjustment, set the square-wave generator

to produce about 3.5 cm of deflection at a frequency of

1 kc. Set the oscilloscope front-panel controls for 'double

triggering" as follows:

Triggering Mode
Trigger Slope
Trigger Level
Stability
Time/cm

AC Fast

+ Internal
0
Fully clockwise
.5 Millisec

Rotate the Variable Time/cm control slowly counterclock
wise until you obtain a stable display of overlapping square
waves as shown in Fig. 5-5.

Adjust the input-capacitance trimmer in the A VOLTS/CM
attenuator for best flat top on the displayed waveform

(see Fig. 5-5), disregarding any fast-rise leading edge spikes.

Set the Mode switch to —B ONLY. Disconnect the signal

from the A input connector and connect it to the B input.
Adjust the input-capacitance trimmer in the B VOLTS/CM

attenuator for best flat bottom, disregarding the spikes.

13. Output Voltage Divider Compensation

Increase the square-wave generator frequency to lOkc.
Set the oscilloscope Time/cm switch to 50 /isec and re
adjust the Variable Time/cm control to obtain a stable
display of several overlapping waveforms. Adjust the out
put voltage divider compensations C7655 and C8655 for

5-4

Calibration — Type Z

REGION OF

OVERLAP

« i i i

\ I I I-

-4-444-

"TTTT

T t 1 ♦

1 1 11

1111

Fig. 5-5. “ Double trigge rin g ” the wa ve form permits attenuator
com pensation adjustm ents to be m ade qu ickly a n d accurate ly. Wave
form p h o tograph shows result w hen the A VOLTS /CM input-cap a c i
tance trim m er is correctly adjusted.

f..T

1 r

f r 1 f r

-jiii

It t 1

Till.

I 1 i I ; : | 1 i

i .

■ 1 11,

i i

i

i

f TTT

I ll t t il l

r

.....

-

r

i

i

Fig. 5-6. Effect o f the outp u t v o ltage divid er compensation a d just
ments w hen incorrectly adjusted. When adjustm en ts a re correct,
waveform should a ppear sim ilar to Fig. 5 -5 .

adjust the Variable Time/cm control to obtain a stable

display of several overlapping waveforms. Adjust the out

put voltage divider compensations C7655 and C8655 for

best square leading corner at the bottom side of the square
wave. The capacitors should be adjusted in equal incre
ments so they will be at approximately the same physical
setting. Fig. 5-6 shows typical appearance of waveforms
when C7655 and C8655 are not correctly adjusted. When
adjustments are set correctly, the waveform should look
like Fig. 5-5. Set the Mode switch to A ONLY. Disconnect
the signal from the B input connector and connect it to the

A input. Check to see if C7655 and C8655 are adjusted

to give the best possible square leading corner at the top

of the displayed square waves. If the capacitors need to
be readjusted, adjust them for the best compromise between
the two displays. Keep the capacitors at approximately
the same physical settings in relation to each other. Be

cause of adjustment interaction, repeat steps 12 and 13
before going on to step 14.

14. Turret Attenuator Compensation

Place the A VOLTS/CM control to the .1 position. Set
the oscilloscope Time/cm switch to .5 millisec. Decrease the
square-wave generator frequency to 1 kc and adjust the
generator output amplitude for approximately 3.5 cm de
flection on the crt. Adjust the SERIES trimmer for the most
nearly square corner on the leading edge. Then adjust the
SHUNT trimmer to make the flat tops of the waveform as
level as possible. Recheck the SERIES adjustment for the best
square leading corner. Set the attenuator to the next posi
tion. Continue in this manner until the rest of the attenu
ator positions have been adjusted. Throughout this step,
adjust the generator output amplitude to keep about 3.5
cm of deflection for each position of the attenuator as long

as sufficient output can be obtained. Remove the "L” pad

for more amplitude during the higher attenuation posi
tions of the turret. After completing all the turret adjust
ments, check each position again to see if any "touching
up" is necessary. Place the turret attenuator in its most
clockwise position and remount the outer knob to read .05.

Disconnect the signal from the A input connector and

apply it to the B input connector. Set the Mode switch to

—B ONLY and repeat the above procedure to adjust the
B VOLTS/CM attenuator compensation. Disconnect the gen

erator cable, “L” pad, and capacitance standardizer.

15. Amplifier High-Frequency Compensations

Connect the 52-ohm cable to the Type 107 Square-Wave
Generator (or equivalent) output connector. Connect the
other end of the cable through a 52-ohm termination to
the B input connector on the Z Unit. Set the generator
output frequency to approximately 1 me and adjust the
amplitude for about 3.5 cm of vertical deflection. Set the
oscilloscope Time/cm switch to .1 /asec. Display the nega-

(a)

r

11 11

iJ"11 1

ti ll

■ f i t 1

T il l

u

(b)'

Fig. 5-7. ( a ) Appearance o f in put B w av e form w h en L7632 and
L86 3 2 are im pro perly ad justed, (b) A ppearance of waveform when
all high-freq u e ncy com pensations are correctly made.

5-5

Calibration — Type Z

five half cycle of the waveform by using the -f- Internal

position of the Triggering Mode switch. Adjust L7645, L8645,
L7632, and L8632 to obtain the sharpest negative leading
corner on the displayed waveform without introducing any

overshoot (see Fig. 5-7). Adjust each pair of variable in
ductors (for example, L7645 and L8645) in equal increments
so the slugs are positioned the same depth in the coil forms.

Disconnect the signal from the B input connector and

apply it to the A input connector. Set the Mode switch

to A ONLY. Set the oscilloscope Trigger Slope switch to

—Internal to display the positive half cycle of the wave

form. Check to see if the leading corner of the positive

going waveform is as square as possible without overshoot.

If it is not, adjust the coil slugs for a compromise between

the best display obtained with signal applied to the B

input connector and that obtained when connected to the

A input connector. The compromise setting assures that

the best possible high-frequency differential operation will be

attained.

Disconnect the square-wave generator cable and the

termination.

16. Bandwidth Measurement

Apply a 50-kc sine-wave from the Type 190A Constant-
Amplitude Signal Generator (or equivalent) to B input
connector. Set the oscilloscope Time/cm switch to the .1
millisec position and free run the sweep. Adjust the gen
erator amplitude control so that the signal produces exactly
28 mm (2.8 cm) of deflection on the crt. Center the display
vertically on the screen.

Increase the sine-wave generator frequency to 13 me,
keeping the generator output level constant. (The Type
190A Generator maintains a constant-amplitude signal auto
matically.)

After the generator frequency has been increased to

13 me, (3 db point), there should be at least 20 mm (2 cm)

of deflection.

If another type of Tektronix oscilloscope is being used
with the Z Unit to make a bandwidth check, consult the
Specifications section of this manual for the upper frequency

limit. That is the frequency at which 20 mm of deflection
or more should be obtained. For instance, if a Type 535A
Oscilloscope is used in conjunction with the Z Unit, 20 mm
or more should be obtained with the sine-wave generator
set at 10 me.

Disconnect the generator from the B input connector
and apply the signal to the A input connector. Set the
Mode switch to A ONLY and repeat this step. Disconnect
the sine-wave generator.

17. Precision Voltage Adjustments

Remove the Z Unit and connect an EP54 plug-in extension

between the unit and oscilloscope. Set the COMPARISON
VOLTAGE Polarity switch to +. Make certain the COM
PARISON VOLTAGE Range switch is set to 100 V. Before
proceeding with this step, be sure the regulated power

supply voltages measured in the oscilloscope are within

specifications as noted in the preliminary calibration in
structions. Refer to Fig. 5-8 for locations of all test points
and internal adjustments given in this step.

CAL. 1 CAL. 2 CAL. 3 CAL. 5 CAL. 4

Test Point Test P oint Test Point

A B C

Fig. 5-8 . Top v iew o f the Z Unit showing lo ca tio n of step 17 test

points and inte rn al adjustm ents.

(a) Adjust CAL. 1: Set the precision voltmeter for
—107.70 volts and connect it between Test Point A and
ground. Adjust CAL. 1 (R8674) for a null reading on the
meter.

(b) Adjust CAL. 2: Set the precision voltmeter for

+ 107.70 volts. Place the COMPARISON VOLTAGE Polar
ity switch in the — position. Adjust CAL. 2 (R7671) for a
null reading on the meter.

NOTE

When adjusting CAL. 1 and CAL. 2 wirewound
controls, it is more important that the voltage
readings be identical, than that they be exactly

107.7 volts. For instance, readings of — 107.90

and + 107.95 are better than — 107.70 and

+ 107.85. Keep the two voltage readings within

the range of 107.3 to 108.1 volts, however.

(c) Adjust CAL. 3: With the precision voltmeter set for

+ 107.7 volts, connect it between Test Point B and Ground.
Set the COMPARISON VOLTAGE Polarity switch to the

+ position. Adjust CAL. 3 (R7681) for a null indication on
the meter. (If CAL. 1 and CAL 2 adjustments are set at

107.9 or any other voltage reading within limitations given

in step 17b, then CAL. 3 should set at the same voltage).

(d) Adjust CAL. 4: Set the precision voltmeter for

+ 100.00 volts and connect it between Test Point C and
ground. Adjust CAL. 4 (R7684) for a null reading on the
meter.

(e) Adjust CAL. 5: Set the COMPARISON VOLTAGE

Range switch to 10 V and the precision voltmeter for

10.000 volts. Adjust CAL. 5 (R7689) for a null reading on
the meter. Because of interaction between CAL. 4 and CAL.
5, repeat these adjustments until readjustment is no longer
necessary.

(f) Check 1 Volt Range: Set the COMPARISON VOLT

AGE Range switch to 1 V and the precision voltmeter for

1.0000 volts. The meter should be within 5 millivolts of

null. Or conversely, null the voltmeter by turning the

5-6

®

http://manoman.sqhill.com

Calibration — Type Z

COMPARISON VOLTAGE Helidial. At null, the Helidial
dial reading should not be further than V2 minor division
(which is 5 millivolts) from the 10.000 position.

Disconnect the voltmeter, remove the plug-in extension

and insert the Z Unit directly into the oscilloscope plug-in

compartment. Install the left side panel on the oscilloscope.

®

5-7

HO W TO ORDER PARTS

Replacement parts are available through your local Tek

tronix Field Office.

Improvements in Tektronix instruments are incorporated as
soon as available. Therefore, when ordering a replacement
part it is important to supply the part number including any
suffix, instrument type, serial number, plus a modification
number where applicable.

If the part you have ordered has been improved or re
placed, your local Field Office will contact you if there is a
change in part number.

PARTS LIST

C U fve C

DIAGRAMS

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MANUFACTURERS OF CATHODE—RAY OSCILLOSCOPES

http://manoman.sqhill.com

PARTS LIS T

Capacitors

Values fixed unless marked variable.
Tolerances ±20% unless otherwise indicated.

Tektronix

Part Number

C7600t

.1 /if PTM

600 v

*295-054

C7601

XI 950-up

1.5 pf Cer.

500 v

±.5 /t/if

281-526

C7602

.2 /if Cer.

25 v

283-026

C7614

.2 /if Cer.

25 v

Use 283-026

C7621

.01 /if Cer.

250 v

283-005

C7626 .001 /if Cer.

500 v

283-000

C7631

.005 /if

Cer. 500 v

283-001

C7635 .01 /if

Cer. 250 v

283-005

C7655 3-12 pf Cer. Var.

281-007

C7686 101-1149

.01 /if

Cer.

150 v GMV

283-003

C7686

1150-up .1 /if

PTM

200 v

285-572

C86001

.1 /if PTM

600 v

*295-054

C8601

XI 950-up 1.5 pf

Cer.

500 v ±.5 /i/if

281-526

C8602

.2 /if Cer.

25 v

283-026

C8614

.2 /if

Cer.

25 v

Use 283-026

C8621

.01 /if Cer.

250 v

283-005

C8626 .001 /if

Cer.

500 v

283-000

C8655

3-12 pf

Cer. Var.

281-007

t Note: C7600 and C8600 matched within 1 %

each other. Furnished as a unit.

Diodes

D7621t

105Z10

Selected

*153-003

D7635 140Z10

Selected

Use *153-006

D7675

RT-6

152-016

D7686

1N753

152-034

D7687

1N753

152-034

D7688

RT-6

152-016

D8621t

105Z10

Selected

*153-003

D8679

RT-6

152-016

tD7621 & D8621 are a matched pair, furnished as a unit.

Inductors

L7632

2-2.7 /th

Var. core 276-506

*114-085

L7645 5.2-8.3 /ih

Var.

core

276-506

*114-056

L7664

.18 /ih

Fixed

*108-009

L8632

2-2.7 /ih

Var. core

276-506

*114-085

L8645 5.2-8.3 /ih

Var.

core

276-506

*114-056

L8664 ,18/ih

Fixed

*108-009

Resistors

Resistors are fixed, composition, ±10% unless otherwise indicated.

R7604 101-260X

47 a

V2 w

302-470

R7608

1 meg

Vl W

Prec.

1%

309-148

R7610

47 n y 4 w

316-470

R7614

33 on

% w

316-331

R7615

47Q y4 w

316-470

R7618 101-2509

750 a

y 2 w

Prec.

1%

309-327

R7618 251 Oup 700 a

Vi w

Prec.

1%

309-083

©

PARTS LIST — TYPE Z

6-1

Resistors (continuedJ Tektronix

Part Number

R7619

ioo a

Var. VAR. ATTEN. BAL. 311-003

R7620

500 k

.2 w

Var. DIFF. BAL.

311 -068

R7621

470 k

’A w

Fixed

Comp.

5%

301-474

R7622

100 k

’A w

316-104

R7623

47Q

’Aw

316-470

R7626

1 k ’Aw

316-102

R7630

47 a

’Aw

316-470

R7631

47 a

y2 w

302-470

R7632

500 a y2 w

Fixed

Prec.

1%

309-250

R7633

1.3 k

Var.

WW

VARIABLE Use *311-289

R7634

1.582 k

y2 w

Fixed Prec.

1%

309-029

R7635

470 k

y2 w Fixed

Comp.

5%

301-474

R7636

100 k

’A w

316-104

R7637

47 a

’A w

316-470

R7640 500 k

Var.

Vert. Pos. Range

311-229

R7641

220 k

y2 w

Fixed

Comp.

5%

301-224

R7645

600 a y2 w

Fixed

Prec.

1%

309-097

R7648

220 a y2 w Fixed

Comp.

5%

301-221

R7649

33 k

1 w

Fixed

Comp.

5%

303-333

R7650 X770-up 5.6 k y2 w Fixed

Comp.

5%

301-562

R7652

10 meg

’/2 w

Fixed

Prec.

1 %

309-095

R7653

2 x 500 k Var.

Vert. Position

311-152

R7655

101-383 100 k

y2 w

Fixed

Prec.

1%

309-045

R7655 384-up 100 k y2 w Fixed

Prec.

1%

309-334

R7656

101-383 143 k 1 w Fixed

Prec.

1%

310-088

R7656 384-up 143 k 1 w Fixed

Prec.

1 %

310-582

R7658 5k

Var. WW Output CF Bal.

311-203

R7660 47 a

’A

W

316-470

R7662

47 a

’A w

316-470

R7664

9.1 k 1 w

Fixed

Comp.

5%

303-912

R7670 101-2509

808 a y2 w Fixed

Prec.

1%

309-103

R7670 2510-up 750 a

y2 w Fixed

Prec.

1%

309-327

R7671

500 a

Var.

Cal Adj. #2

311-214

R7672

15k 2 w

Fixed

Comp.

5%

305-153

R7678

470 a

y2 w Fixed

Comp.

5%

301-471

R7679 12k 2 w

Fixed

Comp.

5%

305-123

R7681 2k

Var.

WW Cal. Adj. #3 311-209

R7682 3.3 k

y2 w

302-332

R7684 10k

Var.

WW Cal. Adj. #4 311 -204

R7685 14k 3 w

1%

*310-577

R7686

400 k

Var.

WW

COMPAR. VOLTS

311-205

R7687A 270 k J

1

R7687B

R7687C

33.33 k '
297 k (

r Encapsulated

1%

307-067

R7687D 3.0303 k 1

1

R7688 990 k

1 w Fixed

Prec.

1%

310-098

R7689 500 k

Var.

WW Cal. Adj. #5 311-210

R8604 101-260X 47 0

Vi w

302-470

R8608 1 meg

y2 w Fixed

Prec.

1%

309-148

R8610 47 a

’A w

316-470

R8614 330 a

’Aw

316-331

R8615

47 a

’A w

316-470

R8618

101-2509 750 0

y2 w Fixed

Prec.

1 %

309-327

R8618 2510-up 700 a

’A w Fixed

Prec.

1%

309-083

R8621

470 k

’A w

Fixed

Comp.

5%

301-474

R8622

100 k

’A w

316-104

R8623 47 a

’A w

316-470

6 -2

PARTS LIST — TYPE Z

©

Resistors (continued) Tektronix

Part Number

R8626 1 k

Vi

W

316-102

R8630

47 a

Vi

W

316-470

R8632

500 a

Vi

W

Fixed Prec.

1%

309-250

R8634

1.582 k

y 2

w

Fixed Prec.

1%

309-029

R8635

47 a

Vi

W

316-470

R8636

47 a

Vi

W

316-470

R8638

101-2509 470 a

Vi

W

Fixed Comp. 5%

301-471

R8638

2510-up 430 a

Vi

W

Fixed Comp. 5%

301-431

R8639

500 a Var.

GAIN ADJUST 311-005

R8640

220 k

Vi

W

Fixed

Comp.

5%

301-224

R8645

600 a

Vi

W

Fixed Prec.

1%

309-097

R8648

220 a

Vi

W

Fixed

Comp.

5%

301-221

R8652

10 meg

Vi

W

Fixed Prec.

1%

309-095

R8655 101-383

100 k

Vi

W

Fixed

Prec.

1%

309-045

R8655 384-up

100 k

Vi

W

Fixed

Prec.

1%

309-334

R8656 101-383

143 k 1 w Fixed

Prec.

1%

310-088

R8656 384-up

143 k 1 w Fixed

Prec.

1%

310-582

R8660

47 a

Vi

W

316-470

R8662

47 a

Vi

W

316-470

R8664 9.1 k

1 w

Fixed Comp.

5%

303-912

R8670

17k 3 w

Fixed Mica Plate

1%

*310-578

R8672

3.6 k

Vi

W

Fixed

Comp.

5%

301-362

R8673

101-2509

808 a

Vi

W

Fixed Prec.

1%

309-103

R8673 2510-up

750 0

Vi

W

Fixed

Prec.

1%

309-327

R8674

500 a

Var. WW Cal. Ad). #1

311-214

R8676

12k 2 w Fixed

Comp.

5%

305-123

R8677

4.7 k 1 w

304-472

R8691

9.1 k 2 w Fixed

Comp.

5%

305-912

Switches

Wired Unwired

SW7600

Slide AC-DC

Use 260-408

SW7602

Pushbutton PUSH TO DISCONNECT SIGNAL

260-324

SW7610

Turret Atten. complete VOLTS/CM "A ’

*

*263-004

X3564-up

Turret Body, wired!

*204-128

SW7611

Rotary INPUT SELECTOR

Use

*262-481 *260-344

SW7670

Lever COMPARISON VOLTAGE (Polarity)

*260-345

SW7680

Lever

COMPARISON VOLTAGE

*260-346

SW8600 101-1829

Slide

AC-DC

260-145

SW8600 1830-up

Slide AC-DC

*260-408

SW8602

Pushbutton

PUSH TO DISCONNECT SIGNAL

260-324

SW8610

Turret Atten. complete VOLTS/CM “ B1

*263-005

X3564-up

Turret Body, wired!

*204-128

Transformer

T8695

Power

*120-177

Transistors

Q7618 101-2509

2N1302

151-040

Q7618 2510-up

RT5204

151-058

Q7644

2N1517

151-031

Q7672 2N1102

151-026

Q7674 101-2509 2N1303

151-041

Q7674 2510-up

J3138

151-087

Q8618 101-2509

2N1302

151-040

Q8618

2510-up RT5204

151-058

Q8638 101-2509 2N1302

151-040

Q8638 2510-up RT5204

151-058

t Below S/N 3564 order for wired turret body *263-004 or *263-005.

©I

PARTS LIST — TYPE Z

6-3

Transistors (continuedj

Tektronix

Part Number

Q8644

2N1517

151-031

Q8672

2N1102

151-026

Q8674

101-2509 2N1302

151-040

Q8674

2510-up

RT5204

151-058

Electron Tubes

V7613t

6AK5 Selected

*157-063

V7618

6DJ8

154-187

V7623

12AT7

154-039

V7634T

12AU6 Selected

use *157-038

V7663

12AT7

154-039

V7689

OG3

Selected

*157-064

V8613+ 6AK5

Selected

*157-063

V8623 12AT7

154-039

V8634*

12AU6

Selected

use *157-038

V8638

6DJ8

154-187

C O

J \

>

& V8613. Furnished as a unit.

t V7634 and V8634. Furnished as a unit.

NOTE: Four ferrite beads {ferramic suppressors) are found in the Type Z Unit, two ahead of each turret attenuator. If re
placement of these becomes necessary, order by the Tektronix Part Number 276-507.

6-4

PARTS LIST — TYPE Z

PARTS LIS T

“Z” Turret Attenuators

Values are fixed unless marked Variable.

Capacitors

Tolerance ±20% unless otherwise indicated.
Ckt. No. S/N Range Description

Tektronix

Part Number

C407

Adjusting Slug

214-084

C408A

Selected Nominal Value 1.5 pf

281-529

C408B

Adjusting Slug

214-084

C408C

Adjusting Slug

214-084

C408D

5.6 pf

Cer. 500 v

281-544

C409A

Selected Nominal Value

3.3 pf

281 -534

C409B

Adjusting Slug

214-084

C409C Adjusting Slug

214-084

C410A

Selected Nominal Value 3.3 pf

281-534

C410B

Adjusting Slug

214-084

C410C

Adjusting Slug

214-084

C410E 12 pf Cer. 500 v

281-508

C411A

Selected Nominal Value 3.3 pf

281-534

C411B

Adjusting Slug

214-084

C411C

Adjusting Slug

214-084

C411E 47 pf

Cer. 500 v

281-519

C412A

Selected Nominal Value 3.3 pf

281 -534

C412B Adjusting Slug

214-084

C412C

Adjusting Slug

214-084

C412E

100 pf

Cer. 500 v

281-530

C413A

Selected Nominal Value

3.3 pf

281-534

C413B Adjusting Slug

214-084

C413C

Adjusting Slug

214-084

C413E 200 pf Mica 500 v

10%

1-283-557

C414A

Selected Nominal Value 3.3 pf

281 -534

C414B Adjusting Slug

214-084

C414C

Adjusting Slug

214-084

C414E 400 pf

Mica 500 v

10%

-f-283-556

C415A Selected Nominal Value

4.7 pf

281-501

C415B Adjusting Slug

214-084

C415C

Adjusting Slug

214-084

C415E 625 pf

Mica 500 v 10%

-f-283-547

Resistors

Resistors are fixed, composition, ±10% unless otherwise indicated.

R407C

X261-up 47 a y4 w

10%

316-470

R408C 500 k

y2 w Prec.

1%

309-140

R408E

1 meg

Vs W

Prec.

1%

318-004

R409C

800 k

% W

Prec.

1%

309-288

R409E 250 k

Vs W

Prec.

1%

318-032

® I

PARTS LIST — TYPE Z 6-5

Resistors (c on tin u e d )

R410C

900 k

'A W

Prec.

1%

R410E

111 k

Vs W

Prec.

1%

R411C 950 k

'A w Prec.

1%

R411E

52.6 k

Vs w

Prec.

1%

R412C

980 k

'A w

Prec.

1%

R412E

20.4 k

Vs W

Prec.

1%

R413C 990 k 'Aw Prec.

1%

R413E

10.1 k

'/e w

Prec.

1%

R414C 995 k

'A w

Prec.

1%

R414E 5.03 k

'/s w

Prec.

1%

R415C 998 k

'A w

Prec.

1%

R415E

2k

Vs w

Prec.

1%

Tektronix

Part Number

309-142
318-006
309-143
318-007
309-277

318-033
309-145
318-009
309-146
318-010

309-278
318-034

Turret Assemblies

SW7610
SW8610

VOLTS/CM "A” Turret Attenuator Complete

Turret Body, Wired

VOLTS/CM "B" Turret Attenuator Complete

Turret Body, Wired

*263-004
*204-128

*263-005
*204-128

Miscellaneous Hardware

QUANTITY

DESCRIPTION

PART NO.

17 Teflon Tubing-Shrink-on

162-027

2 End Caps

200-191

18

Capacitor Barrels

Use 204-127

1

Body Rear

204-025

1 Body Front

204-026

18

Hair Pin Cotter

214-085

1

Ground Ring

354-080

fButton capacitors part numbers 283-547, 283-556 and 283-557 are installed at the factory by a special process. If replace

ment is necessary, order a wired turret body, part number 204-128 (S/N 3564-up). Below S/N 3564 order 263-004 or 263-005

for wired turret body.

6-6

PARTS LIST — TYPE Z

Type Z

Mechanical Parts List

Part Number

Tektronix

BODY, CAP. BARREL FOR TURRET ATTEN. SN 101-3563 204-024
BODY, CAP. BARREL FOR TURRET ATTEN. SN 3564-up 204-127
BRACKET, ALUM., POT, .064 x 1 % x 2% x '/2 406-584
BRACKET, ALUM., TRANSISOR MTG., .050 x 7/ u x 1% 406-585

BRACKET, ALUM., SWITCH, .040 x 2% x 1 ’/2 406-586
BRACKET, RESISTOR MTG., .063 x 1 % x 15/u x 9/ u 406-593
BUSHING, ALUM., 3/8-32 x 9/u x .412 358-010
BUSHING, BRASS, HEX 3/8-32 x 13/32 x .25 2 3 58-029
BUSHING, BANANA JACK, '/4-32 x 13/32 x .159 x .375 358-054
CABLE, HARNESS SN 101-260 179-429
CABLE, HARNESS SN 261-up 179-505

CAP, BLACK PUSH BUTTON 200-114

CAP POT, POLY., 1" dia. 200-247
CHASSIS 441-321
CONNECTOR, CHASSIS MT„ 16 contact, male 131-017

CONNECTOR, CHASSIS MT„ 1 contact, female SN 101-3709 131-081

CONNECTOR, CHASSIS MT., 1 contact, BNC SN 3710-up 131-126
DIAL, DUODIAL FOR HELIPOT 331-003
GROMMET, RUBBER ' / a

348-002

GROMMET, RUBBER 3/8 348-004

KNOB, LARGE BLACK 366-029
KNOB, SMALL RED 366-031
KNOB, SMALL BLACK .780 x.591, ’/„ hole part way 366-044

KNOB, ASS’Y of 366-239 & 366-240 use 366-244

KNOB, INNER (101-3175) use 366-244

KNOB, INNER (3176-up) 366-240

KNOB, OUTER use 366-239

KNOB, PLUG-IN SECURING 366-125

LOCKWASHER, STEEL INT. # 2 210-001
LOCKWASHER, STEEL INT. # 4 210-004
LOCKWASHER, STEEL INT. # 6 210-006
LOCKWASHER, STEEL INT. V4 210-011
LOCKWASHER, STEEL INT. POT, 3/8 x ’/2 210-012
LOCKWASHER, STEEL INT. % x 1 '/,* 210-013

LOCKWASHER, INT. 210-046

LUG, SOLDER SE4 210-201
LUG, SOLDER SE6, long 210-203
LUG, SOLDER POT, plain, % 210-207
LUG, GROUND .025 x'5/14 210-241
NUT, HEX 2-56 x 3/,6 210-405

®

PARTS LIST— TYPE Z

6-7

Mechanical Parts List (continued)

Tektronix

Part Number
NUT, HEX 4-40 x 3/^ 210-406
NUT, HEX 6-32 x '/4 210-407
NUT, HEX 3/8-32xy2 210-413
NUT, HEX 'A-28 x % x 3/32 210-455

NUT, HEX 6-32 x s/u 210-457

PANEL, FRONT 333-575
PLATE, SUB PANEL 387-225
PLATE, FRAME BACK 387-226
POST, BINDING 129-051

RING, RETAINING 354-025
ROD, EXTENSION 2’ 3/14x.210 384-194
ROD, FRAME 3/8 x 8% 384-508
ROD, SECURING 3/,6xl0y2 384-510
ROD, SPACING Vs x 39/14 384-559

ROD, HEX, ALUM., y2xiy4, TAP %-32 (replaced by 385-158) 385-148
ROD, HEX, ALUM., y2xls/I4, TAP %-32 (see 385-148) 385-158
SCREW 4-40 x 3/u BHS 211-007
SCREW 4-40 x y4 BHS 211-008
SCREW 4-40 x% RHS 211-017
SCREW 2-56x1% PHS 211-059
SCREW 6-32 x '/4 BHS 211-504
SCREW 6-32 x 5/u BHS 211-507
SCREW 6-32 x% FHS, 100°, Phillips 211-559
SCREW 8-32 x '/j FHS, 100°, Phillips 212-043
SCREW 8-32 x y 2 RHS, Phillips 212-044
SCREW, THREAD CUTTING, 4-40 x % PHS, Phillips 213-035
SCREW, THREAD CUTTING, 5-32x3/,4 PAN H STEEL, Phillips 213-044
SCREW, 2-32 x s/16 RHS, Phillips 213-113

SHIELD, ATTENUATOR, BRASS 337-374
SOCKET, STM9G 136-015
SOCKET, 7 PIN UHF MIN. 136-071
SOCKET, 9 PIN UHF MIN. 136-072

SOCKET, 4 PIN, TRANSISTOR 136-095

SOCKET, TIP, JACK, BLACK NYLON 136-098
SPACER, NYLON '/u (for ceramic strip) 361-007
SPACER, NYLON 5/,4 (for ceramic strip) 361-009

6-8 PARTS LIST— TYPE Z ® I

Mechanical Parts List (continued)

STRIP, CERAMIC 7/ 1lSx5 notches, clip mounted
STRIP, CERAMIC 7/ i6x7 notches, clip mounted
STRIP, CERAMIC 7/# x 9 notches, clip mounted
STRIP, CERAMIC 7/ 1l5xl1 notches, clip mounted
TAG, SERIAL NO. INSERT
TUBING, PLASTIC INSUL., #20 black (skein)
WASHER, STEEL, .390 x 9/u x .020
WASHER, STEEL, .093 x */32 x .020
WASHER, POLY

Tektronix

Part Number

124-093

124-094

124-095
124-106
334-679

162-504
210-840
210-850
210-894

®

PARTS LIST— TYPE Z

6-9

0407

X I

t

7 "

—W v—

R 407

47

X 2

1 C408D

S.fe

X 5

r4o®gL |y

y800K> -*■

7Tc 409b

R409E>

*150R<

04I0 A

C 4 0 9C SEL. -T-

C4IO C

X 20

r041IA

S E L. 'T ~ /

_ 7 c.411 &

R 4 II O

950K-

R4IIE

5 2 . 6 R -

04110

041*14.

S E L ."

X 50

R4I2.C

_ ^990K-<
7 C-4I1B

R4I2E

2.0.4 |C

X loo

C4I1C

_1_C4I*1E

IOO

C4I3C

C4I3E

*

2.00

X 200

T

C4I4A

S E L . " p

R4I4CJ

y995|t<

7 C4I4&1

X 5 0 0

7 ^ 0 4 1 4 0

R4I4E

& .O B R

_L C 4 I4 E

400

C 4 I5 C

C4IS E

E2S

N O TE :-

ALL VARIABLE CAPAOITORS ARE

2 TUR.R.ET ATTENUATOR. a p p ro x . . 3 - i o » s .

INPUT
STAGE. OTHER HALF

|^ ~ NOT U5ED (

lA i OA_ ^

J r

R7623 R7622 <

/2 l? A T 7 +-7 IOOK •

DIFFERENTIAL

AMPLIFIER

+ 27.6V

OUTPUT

AMP LIF IER

i--------5W7 600

5W76Q 2

PUSH TO

-- DISCONNECT
SIGNAL

X s

. CT<600/
‘ O.l /

R7g

t r

9 J llFtRCm

VOL TS/C M

(ATTEN.)

-E>

ONLY-

\

N + I06

R7608<

> R767I
I 500

\2 FERRITE K

C 7 6 0 2 V & L A DS ^ T U R R E T i A v /

\ A T T E N U A T O R — A “ V c

MO VE D I N S ID E T U R R E T T E S T

' AT T E N . S / N 261 £ U P

VC-B«

I V 7 6 I 5

6A K 5/

56B4 <

“ Q7672.

T-Nl 102.

+225V

^*5.5

+ 2! I

2,7

-AAA/—1 +108

f t

D7621
105V

__

C 7621

'.Ol

<R763I
>47

+350 V ,

-------

R 7 M I I X COC

2ZOK >R74,AO X - ° C

------

^ 7 / 500 K -

Q j V +226V

I \ (d ec.)

+ IOOV

OUTPUT

CP'S

+ 225V

aAMP-

DC BAL.

------------------------------

(

L763 2 |

2.0 - 2.7/uA j
— j-

R76 14

3 30

>R7672 <R7679
>I5K > I2K

TO ALL POINTS
MARKED AS INDICATED

. C 7614

‘

0.22

R7630

4 7 2

i

—Wv—

V 76 3 4

12AU6

TEST PT. B

R86 70 O

------

I 7 K

IOOV

R76QI ^ C A L . 3
2 K

J O

+103 +

TEST PT

A

R76 82

3. 3K

COMPARISON

VOLTAGE

(p ol ar it y;

l !

D76 86I
IN 753 .

; +97

D7687
IN 75 3

‘ +91

D7686 ’

RT-O

us^ +e s

V7689/

0G3

)

\ y

r

' o A

7K

IC

T "

L

IF ^R

. V76I8 A
1 ' /2 6 D J8

-13+

iQ7 61 8

R768S

5W 76 80

H

COMPARISON

I VOL TAGE I

(RANGE.)

I—SW76II

( I N PU T \
^S E L E C T O F .

VAR. ATTEN.

BALANCE

>R7619

IOO

>R7620

• SOOK

V8 62 3B
'/2I2AT 7

R7637 R7636

+ 7 IOOK

> R765S

>+-70 K

I J > R7662

R7655 < _i C 7055 > 47

----------

7p 3-12

V76 63 A

R7 660 \l—» ‘/z ^ A T T

+ 7

R765 6-:

I43 K>

o—xi o —o
o- xio o -o

2,4,7

ATTEN.

TES T PT-

R7688

9 9 OK

DIFF.
BAL.

, I + 3 '

IVAR.ATTEhij

R76 52

!OM

+ 45

3 5 i

.Ol AA

D76 35
l + OV

TO X

X<R7fe+S

•^ 2 2 0

OUTPUT CF

BAL,

[pos itio n]

/+IOOV

R7664 <

9.1 K r

—''TOP—^-4 I

L7664 I

0.1 s M

V8 6 3 &

6DJ 8

R7 64 9

33 K

^—'\AAj- ' 1 »

RS6 34

1.582K

R8 65 5

+-7

R8(b 36 +

47 r

:R8676
* I 2 K

R867 7

■4.7 K

R76&9

500K

R7686
400 K

WV ——

-----

R8CIS

47

D

TEST

PT.

(VARIABLE-) \

COMPARISOUL

VOLTAGE

V 76 I 8B

•/2 6 D J 8

r ^ ;

“ l 38V

V8 6 3 4

I2AU6

GAIN

ADJUST!

J

r

R6630

47

>R8G74
] 50 0

TO A LL POINTS
MARKED AS INDICATED

k 0.8 672.

Ir N H 0 2

-138V

V8 6 I3

6A K 5 /

5654

D8679
RT-6

2,7

-I BOV

J_c 8601

I® ® DC

SW8 6Q2

PUSH TO

DISCONNECT

SIGN AL

. C8 626

.OOI

0 ^ ° 0 /^ 0 4
* ' “

Q 8 6 4 4

OCPZU

L8 63 2>

2. 0- ^. 7/aA

+ 222

~ \ ( Y

'

i

8.6V,

R86 48

22.0

R7658
R7653 *
2X5°OK

150 V

R8664;

9.i k :

+ 45

>R86 52

IO M

R8632< R 8 64 0

5 0 0 > 2 2 0 K

IL 86 4 5 "
| 5.a-8.3>JLh c

R8655

IOOK

+12.5V

+ 12.2

> • vQ 0 Q r——4 3

LS66 4I

0.18/iA

>4

1 >5

1

47

+ 68

1 >8

- 150V

-U-9

- 14+ 4 4
+ IOOV

-41 0

+9 8 44

+ 2 25V «*-

j4 l l

+ 2 244 4
+ 350V

-j-412

+3 4 2 44

+

210

+ 100V

H-- J

+ r- 1

-I^R86 + 5
>600

V76 63 B

i/al2AT.7

S W 8 6 0 0 _ _j

CSSOl j .

O . Z J^

I o— I 9 0 -1/ / V.

TU

V8 62 3 A *

'/ e I 2A T7

R8 6 23 R 8 62 2i p o<i? i

/"2. FERRITE

BE A DS

RRET

ATTENUATOR

;R8608

I M

, ENCAPS ULATE D

ATTENUATORS
R76B 7

> R8691

>9. I K

V7618

4I

< V 8 6 3 © < 6 . ^

W

----------

— i }

---------

MOVED INSIDE TURRET
ATTEN. S/N 261 4/ UP

R76 87A I

270K <

R7687B

33.33K

> R7687D
>3.03 K

* MATCHED

TO 1%

tt ^ A T C H E D T O W IT H IN

W O VE R R A N G E O F

9 5 V T O 116 V

SE E P AP .TS L IS T FO R E A R L IE R
VA LU E S A ND S / N C HA NG E S OF
PA RT S MA R K ED W IT H R E D
T IN T BL O CK S

34"'495 + 3 +

5 5 9 4 5 9

VO L TAGE R EA D IN G S

wer e

OBTAINED
WITH X UNIT IN OSCILLOSCOPE
WAVING DECOUPLED REGULATED

SUPPLY VOLTAGES
MODE TEST
POLA RITY

O

VAR. ATTE-N .

CLOCKWISE

—> 13

->14

-415

^(■DECOUPLED

REGULATED SUPPLY
VOLTAGES

M R H

9-21 “ 61

type z PLUQ-m Omit a calIb. oiff. comp

C A L IB R A T ED D IF F E R E N TI A L C O M P AR A T O R

+

+

68

IN T E R C O N N E C T I N G

/• P L U G

TYPE Z PLUG-IN UNIT

MANUAL CHANGE INFORMATION

At Tektronix, we continually strive to keep up with

latest electronic developments by adding circuit and

component improvements to our instruments as soon

as they are developed and tested.

Sometimes, due to printing and shipping require

ments, we can't get these changes immediately into

printed manuals. Hence, your manual may contain new

change information on following pages. If it does not,

your manual is correct as printed.