Tektronix 2A63 Instrument Reference Book

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INSTRUMENT REFERENCE BOOK

for the Tektronix Type

2A63

differential amplifier unit

For all serial numbers

µ

• TEK 2A63 IRB

1-25-64

1

©, 1964, Tektronix, Jnc., P. 0. Box 500

Beaverton, Oregon. All ri,:htr, rG§Cfvcd,

2

1-25-64

TEK 2A63 !RB

MPI EXTRACT

MPI May 1964

2A63 (also see Interim IRB)

~C Stabilized neon, insufficient sustaining voltage

Accessories included

* Calibration procedure

Compatibility with 560 Series

*Demo tips

FEN

FEN
FEN

8-10-62
061-499
061-209
5-11-62
6-16-61

* Designation change

*Instruction Manual
*Q454 and Q464 sockets must be rewired to accommodate

new transistors

Test specifications

*Tube 157-066 suitable for 63 (see 503 story)

*Tubes, use 157-066 6DJ8

*!nduded within IRB.

1

s for easier balancing

SPR-131

FEN

FEN

FEN

8-15-62
070-266

9-29-61
061-209
1-12-62

3-8-63

TEK 2A63 IRB

9-25-64

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CATALOG

Catalog #25 corrections
Change in plug-in type designation, 8-15-62

DEMO

Demo tips, 6-16-61

Modified products

CONTENTS-SALES

TEK 2A63 PRB 1-17-67

1

9-3l9

INSTRUMENT PERFORMANCE CHARACTERISTIC

CHANGE NOTICE

Instrument Type: ____ 2_A6 .... 3 ____________________________ _

Change No.

2A63-l

-----

Publication affected: Catalog No. 25

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

Page: 148

~add:

Item

AC LF -3 dB

Bandwidth (AC LF -3 dB)

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

Dated Apr

0

'66

Reason for change:

Addition to catalog information

Approved by : __ (.=?........,,_V_.---"~'--· .,..'/ _...,· ____________ Effective date __ l_l_/_

(Project Manager)

2

_9/_6_6 __ _

.

CATALOG

CHANGE IN PLUG-IN TYPE DESIGNATION

Sometime in the next few months Type 63 will be­come Type 2A63.

The primary reason for the change is to make the
type-designations consistent with the new system.

SPR-131 8-15-62

Examples; 3S76, 3T77, 3A74, 3Al, 3Bl, 3B3.
Except for the 2B67, there will be no electrical dif­ferences. Grey knobs instead of black knobs
be a distinguishing mechanical difference on the

2A63.

will

TEK

2A63 IRB

1-25-64

DEMO

Jerry Racanelli (Union) points out that there are
some traps
560 or 561. A few new and unusual design features
in these instruments, plus some old familiar traps
await the field engineer who hasn'tthoroughlyfam­iliarized himself with the instruments before the
demo.

1. The low rep-rate on the 560/561 calibrator
provides a much wider pulse (8.3 msec) than
the more familiar (500µsec) cal waveform-­meaning much more tilt with AC-coupling.

2. The calibrator being driven by60 cycles means
that any pickup in test leads between Cal Out
and Vert input will be locked into a calibrator
display, distorting the waveform badly.

3. The AC-stabilized feature of the Type 63 pro­vides different coupling time constants in the

l-2-5-10-20mv/cm settings where it is in the

circuit.

4. ·The DC balance control in the Type 63 is a 10
turn pot--a planetary-drive job, for easy ad­justment, but which feels a little like a normal

pot that has slipped its moorings.

to avoid in demoing the Type 63 in the

FEN 6-16-61

So here's the good word from Jerry:

A. Use a shielded lead (P52 cable or probe), not

a red patch cord, to demo the high-sensitivity
ranges of the 63. Otherwise, you'll see some­thing like Fig. 1.

-

-

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w·

Fig. 1. 561 with Type 63.

1 MV/DIV, AC Stabilized,

input via red patch lead.

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TEK 2A63 IRB

1-25-64

B. Be prepared to explain the operation of the AC-

stabilized circuit, and the procedure called out

in the Type 63 manual (070-266) for setting
DC balance. With a shileded lead and good DC
balance (save the balancing and DC-coupling
demo until after a few minutes' warm-up), a
waveform like Fig. 3 at 1 mv /cm will be easy
as pie.

-

J...-

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,·

,:

j_.-

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r--

=L.-

Fig. 2. AC-stabi Ii zed display.
Note approx. 50 msec time­constant.

i--_

-- ---

1--..

-

Fig. 3. DC-coupled, AC-stabi
"off." About 50µv of 120-cycle
ripple is normal in 2mv calibrator
waveform.

Ii zed

1-25-64 TEK 2A63 IRB

MODIFIED PRODUCTS

Product

2A63/RM565/3A75
2A63
2A63
2A63
2A63

2A63
2A63

2A63

Mod

2170
217F

236G
237E
243C

802G
802K

803E

Description

Oversized panel. Panel must be anchored at top.
2 inputs paralleled to rear, oelrin. Tek ident removed.

Paint 24660.

2 vertical inputs paralleled to rear, BNC. Long tail and

internal release.
Letter of certification, Tek ident removed. Name plate, new
panel.

Tek ident and type number removed. Cannon miniature coax

rear connector.
subpanel.
Two vertical inputs switchable to rear.

Two vertical inputs paralleled to rear through blue-ribbon

connector.

Two vertical inputs paralleled to rear, BNC.

RFI.

No inputs. New panel. Iridite panel and

New panel.

TEK 2A63 PRB

10-12-66

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Inter-City Mfg. Co ., Inc

St. Louis II, Mo.

CONTENTS-ENGINEERING

PERFORMANCE

AC-stabilized time-constants
Power drain, 5-21-65
Environmental characteristics, 1-23-65

TECHNOLOGY

Operating instructions

Circuit description

(Troubleshooting)
( Calibration)

TECHNIQUES

Diodes

hilp with ground-loop problems, 10-11-63

TEK 2A63 RB 2-12-68

AC-STABILIZED TIME-CONSTANTS

PERFORMANCE

These are not a "spec", as the tolerances in the
250 µf nonpolarized electrolytic are too wide to
allow a specification. The following are typical
values:

POWER DRAIN -- 560 SERIES PLUG-INS

The power supply loading indicated below will vary
somewhat with line-voltage and front-panel control
settings. Where series-regulator shunts are indi­cated, the shunt consists of 2 k in the indicator unit
in series with 0 to 6 k in the plug-in, the series

combination connected between the unregulated sup­ply and the regulated supply (in the -100 v supply,
between the unregulated +supply and ground). The

shunt supplies the extra current drawn bytheplug­in beyond that which can be handled by the series
regulator. The actual amount of shunt current varies
with line-voltage, so if a positive power-supply bus
in the plug-in is opened to take a current reading,
the reading will be in error unless the bus is opened
on the load side of the shunt connection (with the

shunt still connected). The -100 v bus carries the

entire load current, so a current measurement at

Sensitivity

Setting

20mv/cm

lOmv/cm

5mv/cm
2mv/cm
lmv/cm

the plug-in connector is always correct for this
supply. There is no shunting for the -12.2 v supply.

CAUTION: The values below should not be used to
determine if there is any "extra" power available
in the compartment for other purposes or plug-in

modifications. The values of the shunts, the total

dissipation in the plug-in, the limitations of the in-

dicator (transformer and series regulators) and the
characteristics of the other plug-ins with which a
given plug-in may be used all limit the amount of
power "available" in a given plug-in compartment;
in most cases, there is little or no margin allowed
for extra current drain without modification of the

shunts or circuitry. See 040-0245-00 instructions
and power drain discussioninPRB'sforindicators.

Time

Constant

270msec
200msec
120msec

55msec

17-35 msec

3db

Point

0.6 cps
1 cps

l.5cps

3cps

5-l0cps

Geoff Gass, 5-21-65

Plug-In

(2A)63

-l00v, shunt -12.2
45-55

FS

365

V +125v, shunt +300 v, shunt 6.3v AC 117v

6

--

22

--

0.9A 0

TEK 2A63 IRB

1-23-68

1

Performance - continued

ENVIRONMENTAL CHARACTERISTICS

The 2A63 was engineered before design goals for environmental characteristics

were established. The performance requirements given in the environmental

characteristic sheet are the most accurate figures available without performing
extensive environmental tests. They are to be used as a guide not as an
instrument specification.

Characteristic

Performance Requirement Supplemental Information

Temperature

Nonoperating

-40 to +65°C

Operating Same as

display

Altitude

Nonoperating

50,000 ft.

Operating 10,000 ft.

Vibration

Operating 0.015

10-50-10 cps
each axis,
resonance or 50 cps,

minutes total

oscilloscope used to
signal

inch pk-pk

(1. 9G), 15 min

three minutes

55

Derate maximum operating

temperature by 1°C/1000 ft

above 5000 ft.

at

Shock 30G's, 1/2 sine, llms;

Nonoperating shock

three

in each direction of the

axes;

total of six shocks

Humidity

Nonoperating

Transportation

Package Vibration
Package Drop

Qualifies under NSTC test
procedure lA, Category II

(24 inch drop)

I

2

1-23-68

one

TEK 2A63 RB

TYPE 2A63 DIFFERENTIAL AMPLIFIER

INTRODUCTION

The Type 2A63 Differential Amplifier module, Fig. 1, is
designed for use with Tektronix Type 560-Series Oscillo­scopes. It has a bandpass of de to -3 dB at 300 kc or
greater and a common-mode rejection ratio of 50 to 1
better, at .2 V / cm with a 50 kc sine wave. Common-mode
rejection ratio is higher at lower frequencies. Sensitivity is
variable in 14 calibrated steps from 1 millivolt to 20 volts per
division of deflection, and is continuously variable (uncali­brated) between steps and up to 50 volts per division. Accu­racy is within 3
to differential operation, the module can also be used for
single-ended operation. The input impedance at both inputs

% at each of the calibrated steps. In addition

*, or

Operating Instructions

Throughout the instructions that follow, it is assumed,
unless otherwise noted, that the Type 2A63 module is in­serted in the Y-axis opening of a Type 560-Series Oscillo­scope, thereby providing vertical deflection of the oscillo-

scope trace. If the module is inserted in the X-axis opening
of the oscilloscope, it will provide horizontal deflection and
the instructions must be interpreted accordingly. It is fur­ther assumed throughout the discussion that there is a time­base module in the X-axis opening of the oscilloscope.

Signal Connections

When a single signal input is used with the Type 2A63

module, it may be applied to either the + INPUT connector

or the -INPUT connector.
the + INPUT connector, the -INPUT AC-DC-GND switch
should be placed in the GND position and the +INPUT
AC-DC-GND switch should be placed in the AC or DC
position, depending upon the type of coupling desired. If
the signal is connected to the -INPUT connector, the

+INPUT AC-DC-GND switch should be placed in the GND
position and the -INPUT AC-DC-GND switch should be
placed in the AC or DC position. If the signal is applied
to the -INPUT connector, the display on the oscilloscope
screen will be opposite in polarity to a normal presentation.
Conventionally, a normal display places the more positive

If the signal is connected to

is one megohm paralleled by 47 picofarads. Maximum allow­able signal voltage at the INPUT connectors is 600 volts (de
plus peak ac).

A Type 2A63 module can be used with a Type 2A60 or
Type 3A75 module, or another Type 2A63, in the same Type
560-Series Oscilloscope to measure the phase relationship
between two sine waves. Phase measurements accurate to

within 1 ° at 50 kc can be made with two properly cali­brated Type 2A63 modules.

Accessories

Information on accessories for use with this instrument 1s

included at the rear of the mechanical parts list.

portions of a waveform in the vertical channel toward the
top of the screen, and the more positive portions of a wave­form in the horizontal channel toward the right side of the
screen (see Fig. 2).

When it is desired to display the difference between two
signals, one signal is connected to each INPUT connector
and both AC-DC-GND switches ore placed in either the
AC or DC position. In this mode of operation, the two

signals are subtracted from each other algebraically, and
the difference is displayed as a single trace on the oscillo­scope screen. This is called the differential mode of opera­tion. It permits you to eliminate signals which are common
to both inputs and to observe a waveform which is peculiar
to one (see Fig. 3).

Use of the differential mode of operation is limited to

signals of about +5 volts maximum at the input to the first
amplifier stage of the module. For this reason, the common
mode signal at the INPUT connectors should be limited to
about ±5 volts when the VOLTS/DIV. switch is set at any

I

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Fig. 2. Left-Displayed waveform when positive-going sawtooth
signal is applied lo
waveform when positive-going sawtooth is applied lo

connector.

• Rejection ratios as high as 2000 lo 1 can be obtained through
the use of two Tektronix Type P6023 attenuator probes.

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+ INPUT connector. Right-Displayed

the

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-INPUT

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to + INPUT connector

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IV v

V IVV

/V~VI

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Displayed
waveform

Signal applied

to - INPUT connector

fig. 3. Rejection of common-mode signal by differential operation.
The signal applied lo the
tracted from

difference waveform is displayed

the signal applied lo the

-INPUT connector is algebraically sub-

+ INPUT connector and the

on the screen.

I"

IV V

1

Type 2A63

position from l mVOLTS through .2 VOLTS and to about
+50 volts when the VOLTS/DIV. switch is set at .5, 1, or
2 VOLTS. In the 5, 10, and 20 VOLTS positions of the
VOLTS/DIV. switch, the common-mode signal at the INPUT
connectors may be as high as +500 volts.

For best results, the signal or signals to be displayed
should always be applied through a shielded cable, with
the shield connected to the chassis of both the oscilloscope
and the signal source. All leads and cables should be kept
as short as practicable.

High impedance attenuator probes are available for use
with the Type 2A63 module. These probes reduce the re­sistive and capacitive loading effects of the module and, at

the same time, attenoate the signal to allow the display of
larger signals than would otherwise be possible. These
probes and other accessories are described in the Acces-

sories section of the oscilloscope manual.

Displaying a Signal

To display a signal with the Type 2A63 module, pro-

ceed as follows:

1. Connect the signal to one or both INPUT connectors as

described in the foregoing paragraphs.

2. Establish a common ground between the oscilloscope
and the signal source. This can be done by connecting the
ground clip on a Tektronix attenuator probe to signal
ground.

3. Adjust the time-base controls to obtain a stable dis­play.

4. Set the VOL TS/DIV. switch and the POSITION control
so that the signal is placed as desired on the graticule. In
general, if you are interested only in the ac component of
the signal, you should set the appropriate AC-DC-GND
switch to AC; if you are interested in the de level of the
signal, you should set the appropriate AC-DC-GND switch
to DC. An exception to this is in observing low-frequency
signals. When the AC-DC-GND switch is in the AC posi-

tion, and the AC STABILIZED switch is in the OFF position,
the lower bandpass limit (3-db point) of the module is about

1.5 cps. Therefore, when displaying signals with frequency
components of less than about 2 cps (0.2 cps when using a

OX attenuator probe), the best response will be obtained

1
with the AC-DC-GND switch in the DC position.

When looking at ac signals of very small amplitude (less
than about l
STABILIZED switch to eliminate de drift in the oscilloscope
trace. Placing this switch in the ON position introduces ac
coupling into the amplifier whenever the VOLTS/DIV. switch
is in one of its five most sensitive positions (1 mVOL TS
through 20 mVOLTS). This prevents small de drift conditions
in the Input Amplifier of the module from causing trace
shift on the screen. When the VOLTS/DIV. switch is at
1 mVOLTS and the AC STABILIZED switch is ON, the lower
bandpass limit (3-db point) of the module is about 10 cps.

Note that the small neon lamp to the left of the AC
STABILIZED switch lights when either AC-DC-GND switch
is in the DC position while the AC STABILIZED switch is ON.
This is to warn the operator that the amplifier is ac coupled
when the VOL TS/DIV. switch is in one of its five most
sensitive positions, even though the AC-DC-GND switch is
in the DC position. (The light can be ignored if the
VOLTS/DIV. switch is not in one of these positions.) If you
wish to measure de levels in one of the five most sensitive
positions of the VOL TS/DIV. switch, you must set the
STABILIZED switch to OFF.

Probe Compensation

If an attenuator probe is used, its input time constant must

be compensated to that of the module for best signal
response. It is advisable to check the compensation of the
probe each time it is used. To compensate a Tektronix
attenuator probe, proceed as follows:

1. Connect the probe to the INPUT connector with which
it will be used, and touch the probe tip to the CAL. OUT
connector.

2. Set the oscilloscope controls to display several cycles
of the Calibrator waveform, as shown in Fig. 4.

3. Adjust the variable capacitor in the body of the probe
to obtain a square leading corner on the positive half-cycle

O millivolts), you may wish to use the AC

AC

2

r

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----

~--

Under-compensated Properly compensated

~-

......

-

-

-

-

-

Fig. 4. Probe compensation waveforms.

r

-

----

i---

--

....

.........

.....

--

Over-compensated

-

..._

I!----

Type 2A63

if the probe is connected to the + INPUT connector, or on
the negative half-cycle if the probe is connected to the

-INPUT connector.

Gain and DC Balance Adjustment

Any time you move the Type 2A63 module from one
oscilloscope opening to another you must adjust the gain
to compensate for difference in crt deflection sensitivities.
This should also be done from time to time even if the

module has not been moved. In addition, the de balance
of the module should be checked and adjusted, as necesary,
from time to time, especially when you are making de volt­age measurements on small signals.

To properly set the gain of the Type 2A63 module, pro-

ceed as follows:

1. Set the + INPUT AC-DC-GND switch to DC and the

-INPUT AC-DC-GND switch to GND.

2. Set the VOLTS/DIV. switch to .2 VOLTS and the VARI-

ABLE control fully clockwise (to the CALIBRATED position).

3. Apply a 1-volt signal from the oscilloscope Calibrator

to the + INPUT connector.

4. Adjust the front-panel GAIN ADJ. for a deflection of

exactly five major divisions on the oscilloscope screen.

To properly adjust the de balance of the Type 63 module,

proceed as follows:

1. Set both AC-DC-GND switches to GND and the

VOLTS/DIV. switch to

1 mVOLTS.

2. Set the AC STABILIZED switch to ON and pos1t1on a
free-running trace (or spot) to the horizontal centerline of
the graticule.

3. Set the AC STABILIZED switch to OFF and adjust the
front-panel DC BAL. control to bring the trace or spot back
to the centerline of the graticule.

4. Repeat steps 2 and 3 until no further adjustment is

necessary.

If it is not possible to set the de balance with the DC
BAL. control, the COARSE DC BAL. needs resetting (see
Calibration instructions).

the VARIABLE control is set fully clockwise (to the CALI­BRATED position). The AC-DC-GND switch may be 1n
either the AC or DC position.

2. Multiply this distance by the setting of the VOLTS/DIV.
switch and the attenuation factor, if any, of the probe.
This is the potential difference between the two points
measured.

To measure the de level at a given point on a displayed

signal, proceed as follows:

1. Set both AC-DC-GND switches to GND and check the

de balance of the module. Make sure the VARIABLE con­trol is set fully clockwise (to the CALIBRATED position).

2. Position a free-running trace so that it lies along one
of the horizontal graticule lines. This line will be used as
a zero reference line. Do not adjust the POSITION control
on the Type 2A63 module after the reference line has been
established.

3. Set the appropriate AC-DC-GND switch to DC. If
the differential mode of operation is being used, set both
AC-DC-GND switches to DC. (If the position of the trace
or spot shifts by more than

1 minor graticule division, see

Troubleshooting, "DC Reference-Level Shift.")

4. Connect the probe, or probes, to the signal source and

adjust the VOLTS/DIV. switch for suitable vertical deflec­tion and the time-base controls to obtain a stable display.

5. Measure the vertical distance, in graticule divisions,

from the zero reference line established in step 2 to the
point on the waveform at which the de level is desired.
Make sure the VARIABLE control is set fully clockwise (to
the CALIBRATED position).

6. Multiply this distance by the setting of the VOLTS/DIV.
switch and the attenuation factor, if any, of the probe. This
is the de level of the point measured.

NOTE

When measuring very small de voltages, it is
wise to repeat the above procedure

possible error due to drift.

to eliminate

Phase-Shift Measurements

Voltage Measurements

NOTE

When making any measurements, make sure there
is a common ground between the oscilloscope
and the signal source.

To measure the potential difference between two points

on a displayed signal (such as peak-to-peak ac volts), pro-

ceed as follows:

1. Measure the vertical distance, in graticule divisions,

between the two points you wish to measure. Make sure

To measure the phase difference between two sine waves
of the same frequency, using two Type 2A63 modules
the X-Y mode of operation, proceed as follows:

1. Insert the two Type 2A63 modules into the oscillo­scope.* For accurate measurements, they must be properly
phase-shift compensated as described in the Calibration in­structions. (You can check the phase-shift compensation by
performing this procedure with in-phase sine waves applied
to both modules.)

2. Set both +INPUT AC-DC-GND switches to AC and

both -INPUT AC-DC-GND switches to GND.

• Type 565 Oscilloscope cannot be used in this application.

in

3

Type 2A63

3. Apply the two sine waves to the two +INPUT con­nectors. The display will be an ellipse. (Actually, the dis­play will appear as a diagonal straight line if the two sine
waves are in phase or exactly 180 ° out of phase, or it
will appear as a circle if the two sine waves are exactly
90° out of phase. Application of these instructions, however,
will still apply.)

4. Center the ellipse horizontally on the screen.

5. Measure the distances A and B on the display as
shown in Fig. 5. A/B is equal to the sine of the phase dif­ference between the two signals. (see Table 1, page 11 ).

X-Y phase measurements can also be made using a Type
2A63 module with a Type 2A60 or Type 3A75 in the same
oscilloscope. In this case, it will be necessary to insert an
adjustable phase-shifting network ahead of the Type 2A60
or Type 3A75, apply the same sine wave to both modules,
and adjust the phase-shifting network for zero phase differ­ence as displayed on the screen. The signal through either
module will then serve as a reference against which to
measure the phase of any signal of the same frequency
applied to the other module.
will have to change the setting of the phase-shifting net­work.) The proper method for setting the internal adjust-

ments of the Type 2A63 module for this type of operation

is described in the Calibration instructions.

(If you change frequency you

B

Fig. 5. X-Y method of calculating phase difference (0) between

two sine waves.

A

8

A

== sin 0

Circuit Description

The Type 2A63 Differential Amplifier consists basically of
two opposing input circuits, a two-stage Input Amplifier, and
a one-stage push-pull Output Amplifier. The Input Am­plifier is inherently an extremely high-gain amplifier, lim­ited to a maximum gain of about 1000 by negative feed­back. The Output Amplifier has a gain of about 20. Step
changes in sensitivity are accomplished by input attenua­tion and changes in the amount of negative feedback in
the Input Amplifier. Vernier changes in sensitivity are
accomplished by varying the amount of degeneration in
the cathode circuit of the Output Amplifier.

Input Circuits

The signals to be displayed are applied either "straight
through" or through a
circuit, or circuits, of the Input Amplifier. The attenuators
are both resistive and capacitive dividers which provide con­stant attenuation throughout the frequency range of the
amplifier. At low frequencies they act primarily as resistive
dividers; at the higher frequencies, they act primarily as
capacitive dividers.

In addition to providing the proper degree of attenuation,
the resistance and capacitance values of the attenuators are
chosen (or adjusted) to provide a constant input resistance
of one megohm and a constant input capacitance of 47
picofarads, regardless of which attenuator is in the circuit.

lOX or l00X attenuator to the grid

Input Amplifier

The first stage of the Input Amplifier amplifies the poten-

tial difference between the two grids of V424. When one

grid goes positive and the other goes negative, the output
of the stage is proportional to the sum of the amplitudes of
the two signals. When both grids go positive or both go

negative, the output is proportional to the difference

between the amplitudes of the two signals. In single-ended

operation, a signal is applied to one grid while the other

grid circuit is grounded; therefore, the output is proportional
to the amplitude of the signal applied. The output of
then, is a push-pull signal to the bases of the transistors,

Q454 and Q464, regardless of whether the module is being

operated single-endedly or differentially.

The high gain of the Input Amplifier is provided by posi­tive feedback from the collector of each transistor to the
base of the other. This feedback is developed across R459
and R460 in parallel with the base resistance of each of the
transistors. R460 provides the means of adjusting the
amount of positive feedback to set the gain of this stage.

At the same time, the transistors also develop signals
across R408 which are applied to the cathodes of V424
as negative feedback to limit the overall gain of the Input
Amplifier. The amount of negative feedback is least when

R408 is the smallest, hence the effect of R460 on the over­all gain of the amplifier is greatest when the VOLTS/DIV.
switch is set at 1 m VOL TS.

C426, C436, C456, C457, C458, C466, and C467 are

included to maintain constant feedback ratios throughout

V424,

4

®!

Type 2A63

the frequency range of the amplifier. This is necessary
because of the increased effects of the tube and transistor
capacitances at higher frequencies. C457 and C467 pro­vide the means of adjusting the feedback ratios at high
frequencies to be equal to those at low frequencies.

C408 is effectively in the circuit when the AC STABILIZED
switch is ON and the VOLTS/DIV. switch is in one of its
five most sensitive positions (1 mVOLTS through 20 mVOLTS).
The purpose of C408 is to ac couple the two sides of the
first stage of the Input Amplifier. This prevents small de
drift conditions within V424 from causing excessive trace
shift at the higher sensitivity positions. The AC STABILIZED
switch also activates indicator lamp B407 when either AC­DC-GND switch is in the DC position. This is to warn the
operator that de coupling does not exist in the five most
sensitive positions of the VOLTS/DIV. switch unless the AC
STABILIZED switch is returned to the OFF position.

De balance of the Input Amplifier is accomplished by
means of the COARSE DC BAL. adjustment (an internal
adjustment) and the DC BAL. adjustment (a front-panel
adjustment). Proper adjustment of these two controls sets
the two ends of R408 at the same potential (under no-signal
conditions) so that there is no current flowing through it.
This prevents the de level of a no-signal trace from shifting
as the VOLTS/DIV. switch is moved from position to posi­tion.

In addition to changing the value of R408 and selecting
the input attenuators, the VOLTS/DIV. switch also changes
the value of C480 to compensate for changes in the effec­tive tube and transistor capacitance as the value of R408
is changed. This maintains equal phase shift through the
amplifier at all settings of the VOLTS/DIV. switch.

Output Amplifier

The gain of the Output Amplifier is adjusted by means of

the GAIN ADJ. adjustment, R497, and the VARIABLE con-

trol, R498, which vary the amount of degeneration in the
cathode circuit. The GAIN ADJ. is a front-panel screw-

driver adjustment which sets the overall gain of the ampli­fier to match the sensitivity of the crt deflection plates to
which its output is connected. The VARIABLE control pro­vides the means of reducing the sensitivity of the module

by a factor of about 2½ at any position of the VOLTS/DIV.
switch. When the VARIABLE control is set fully clockwise

(to the CALIBRATED position), R498 is set at zero resistance.

Adjustment of the POSITION control varies the return

voltage of each of the cathodes of the Output Amplifier

inversely to the other and, at the same time, produces a
small de voltage change of opposite polarity at the cor-

responding grid. The result is that the cathodes remain

essentially constant in voltage while the current through
the resistors, and therefore through the tubes, changes. The
change in current through each of the Output Amplifier
tubes changes the average de plate voltage of each tube

inversely to the other, and the position of the crt beam is
shifted correspondingly.

Trigger Pickoff Circuit

The Trigger Pickoff Cathode Follower, V503, applies a

sample of the signal at the plate of V484 through the inter-

connecting plug to the sweep triggering circuit, if used.
The time-base generator, then, may use this as an internal
triggering signal. The output of V503 has a peak-to-peak
amplitude of about 4 volts for each division of deflection
on the screen.

Troubleshooting

General maintenance and troubleshooting information is
contained in the Type 560-Series Oscilloscope manuals. In
the following discussion it is assumed that you have already
read that information and have definitely isolated
to the Type 2A63 module by the procedures described

there.

CAUTION

Do not operate the module with V424 removed;

it may ruin Q454 and/or Q464.

No Spot or Trace

If there is no spot or trace on the crt, the trouble is

probably a de imbalance between the two sides of the
amplifier.
strap between the collectors of Q454 and Q464. If the
spot or trace appears and can be positioned with the

POSITION control, the trouble is in the Input Amplifier.

If the spot or trace does not appear, the trouble is in the
Output Amplifier.

To isolate the imbalance, connect a shorting

®!

a trouble

If the trouble is found to be in the Input Amplifier,
change V424 and then the two transistors. If the trouble
still persists, set the VOLTS/DIV. switch to .2 VOLTS and

measure the voltage at the cathodes (pins 3 and 8) of
V424. Both cathodes should be at approximately the same
voltage and should be between 1 and 2 volts positive with
respect to ground. If they are not, the trouble is probably in
some component in that side of the amplifier. Check espe­cially the plate load resistor and the divider in the collector
circuit of the transistor.

If the trouble is found to be in the Output Amplifier,

replace V484 and V494. If the trouble still persists, check
the rest of the circuit by voltage and resistance measure-

ments.

Insufficient Deflection

If the proper deflection cannot be obtained through

adjustment of the GAIN ADJ. control (see Operating lnstruc-

5

Type 2A63

tions), check the supply voltages in the Indicator Unit. If
they are all correct, check the deflection at all positions of
the VOLTS/DIV. switch and with the signal applied to first
one INPUT connector and then to the other. If the deflec­tion is incorrect at only one or a few positions of the
VOLTS/DIV. switch, or only when the signal is applied to
one of the INPUT connectors but not to the other, comparing
the conditions under which the trouble occurs with the
schematic diagram will give an indication as to where the
trouble lies. Then it can be isolated by voltage and resist­ance checks.

If the deflection is incorrect at all positions of the
VOLTS/DIV. switch and with the signal applied to either
INPUT connector, replace V424, V484, V494, Q454, and
Q464, in that order. If this does not eliminate the trouble,
check those components which can affect the gain of the
amplifier but not the de balance, such as R450, R451, R452,
R453, R459, R460, C453, and the common cathode re­sistors.

Calibration

Calibration of the Type 2A63 is performed with the module
inserted in the left-hand opening of a Type 560-series
oscilloscope. For calibration of the coarse de balance,
one-millivolt gain, and internal de triggering level, you may
have either an amplifier module or a time-base module in
the other opening. For calibration of the input capacitance
and the attenuator frequency compensation, you should
have a time-base module in the X-axis opening.* Two
methods for phase-shift compensation are given; one with
another Type 2A63 module in the X-axis opening, one with

a Type 2A60 or Type 3A75 module in the X-axis opening.

In order to maintain the high degree of accuracy of the
instrument, we recommend that it be fully calibrated after
each 500 hours of operation. The one-millivolt gain should
be checked from time to time between calibration periods.
The phase-shift compensation is necessary only where two
amplifier modules are being used together to make X-Y
phase comparisons between two sine waves. Each of the
calibration adjustments should be checked as necessary
whenever a component has been changed.

Because of interaction among some of the adjustments,
it is recommended that you perform the calibration pro­cedures in the order presented. To obtain access to the
adjustments referred to in the procedures, the left-hand side

panel of the oscilloscope must be removed. The locations

of the internal adjustments are shown in Fig. 6.

DC Reference Level Shift

If, when the AC STABILIZED switch is OFF and the
VOLTS/DIV. switch is at 1 mVOLTS, the position of a no­signal trace shifts by more than 1 major graticule division
as either AC-DC-GND switch is moved from GND to DC,
V424 is probably gassy and should be replaced. (The trace
will shift less at the other positions of the VOLTS/DIV.
switch; at positions above 50 mVOLTS, the shift should be
less than one-half minor division.)

If this condition occurs and cannot be immediately cor­rected, or if the amount of shift cannot be tolerated due
to accuracy requirements, satisfactory measurement of de
levels can be accomplished by establishing the zero ref­erence line with the appropriate AC-DC-GND switch set
at DC and the signal probe connected to signal ground
(see Operating Instructions, "Voltage Measurements"). In
this case, you should establish the zero reference line each
time you move the VOLTS/DIV. switch.

l microsecond or less. (You may use the oscilloscope Cali­brator output if a square-wave generator is not available;

is has a risetime of about 2 microseconds, which will allow
accurate enough calibration for most normal use of the
module.)

3. 47-picofarad capacitance standardizer (Tektronix Type
CS 47 recommended), and an attenuator probe with adjust­able capacitance.

4. Signal generator, capable of producing a JO-millivolt

(peak-to-peak) sine wave at 350 kc. (This generator and the
one following are required only for phase-shift compensa-

tion of two Type 2A63 modules.)

5. Signal generator, capable of producing a 100-kc sine

wave of at least one volt amplitude (peak-to-peak) into
a 93-ohm load. (You may wish to select a different fre­quency for this generator; see the introductory remarks
under "Phase-Shift Compensation.")

6. l 00X zero-phase-shift attenuator (see the note regard­ing this attenuation following step 11 of the first method

of phase-shift compensation).

7. Adjustable phase-shifting network. (This will be required
only if you are going to phase-shift compensate a Type
2A63 module against a Type 2A60 or Type 3A75 module.)

Equipment Required

The following special equipment is used in a complete

calibration of the Type 2A63 module:

1. De voltmeter.

2. Square-wave generator, capable of producing a SO-

volt (peak-to-peak), 1-kc square wave with a risetime of

• In the Type 565 Oscilloscope there is no X-axis opening; the

time-base circuitry is part of the Indicator Unit itself.

6

Coarse DC Balance

The COARSE DC BAL. of the Type 2A63 module should
be adjusted any time you are not able to obtain de bal­ance with the front-panel DC BAL. The proper method

of setting the front-panel DC BAL. control is described in
the Operating Instructions.

DC BAL. adjustment, proceed as follows:

1. Set both AC-DC-GND switches to GND, the

VOLTS/DIV. switch to 1 mVOLTS, and the AC STABILIZED
switch to ON.

To properly set the COARSE

®I

Type 2A63

C48QF

C480B

INT. TRIG.

C467

C457

COARSE

DC BAL.

C406

C405C

C404C

C405B C415C

C404B

C416 C414C

C414B

Fig. 6. Type 2A63 module internal calibration adjustments.

2. Set the front-panel DC BAL. control to midrange

(approximately five turns from either extreme.)

3. Position a free-running trace (or spot) to the horizontal

centerline of the graticule with the POSITION control.

4. Set the AC STABILIZED switch to OFF. The trace or

spot will probably move, possibly clear off the screen.

5. Adiust the COARSE DC BAL. adiustment to bring the

trace or spot back to the horizontal centerline of the grati-

cule.

Subsequent adiustments of de balance can now be accom-

plished with the front-panel DC BAL. control.

Internal Trigger DC Level Adjustment

The INT. TRIG. DC LEVEL adiustment sets the output de

level of the Trigger Pickoff circuit.

adiustment, proceed as follows:

l. Set both AC-DC-GND switches to GND.

2. With the POSITION control, position the spot or trace

to the horizontal centerline of the graticule.

3. With the de voltmeter, measure the voltage at pin 11
of the plug-in connector to which the module is connected
and adiust the INT. TRIG. DC LEVEL adiustment for a read-

ing of zero volts.

To properly set this

1 mV GAIN Adjustment

The l mV GAIN adiustment sets the gain of the ampli­fier at the higher sensitivity settings of the VOL TS/DIV.
switch.
as follows:

-INPUT AC-DC-GND switch to GND, and the AC STA­BILIZED switch to OFF. Make sure the VARIABLE control is

set fully clockwise (to the CALIBRATED position).

1-volt Calibrator signal to the + INPUT connector.

exactly five maior graticule divisions.

10-millivolt Calibrator signal to the +INPUT connector.
(If you are using a Type 561 Oscilloscope, you may set
the VOLTS/DIV. switch to l mVOL TS and apply a 5-milli­volt Calibrator signal.)

exactly five maior graticule divisions.

to interaction between the GAIN ADJ. and the 1 mV GAIN
adiustments.

ing adiustment of the l mV GAIN adiustment (see Operat­ing Instructions).

To properly set the 1 mV GAIN adiustment, proceed

l. Set the +INPUT AC-DC-GND switch to DC, the

2. Set the VOLTS/DIV. switch to .2 VOLTS and apply a

3. Set the front-panel GAIN ADJ. for a deflection of

4. Set the VOLTS/DIV. switch to 2 mVOLTS and apply a

5. Set the l mV GAIN adiustment for a deflection of

6. It may be necessary to repeat steps 2 through 5 due

The de balance will probably need readiustment follow-

®I

7

Type 2A63

Input Capacitance Standardization and Attenu­ator Frequency Compensation

The input capacitance standardization and attenuator fre­quency compensation interact so both are performed in the
same procedure. The need for either or both of these
calibrations is normally indicated by distortion of fast­rising waveforms on one or more sensitivity ranges of the
module.

Standardization of the input capacitance of the module
requires the use of 47-picofarad capacitance standardizer.

If you do not have such a standardizer, you can make an
attenuator probe into one by performing these five steps
(if you do have a 47-picofarad standardizer, you may skip
these five steps and go immediately to the procedure fol-

lowing them):

l. Set the VOLTS/DIV. switch on the Type 2A63

module to .2 VOLTS, the VARIABLE control fully clock-

wise (to the CALIBRATED position), and the AC-DC-

GND switch to DC. Turn the instrument on.

2. Measure the input capacitance at the +INPUT con­nector. With a low-capacitance screwdriver, adjust
C416 for a reading of 47 picofarads on the capacitance
meter.

3. Disconnect the capacitance meter and connect the
attenuator probe to the +INPUT connector.

4. Touch the probe tip to the output of the square­wave generator or the oscilloscope Calibrator, and
adjust the oscilloscope controls to display several

cycles of the square-wave signal.

5. Adjust the variable capacitor in the body of the
probe to obtain the best square-wave response.

Your probe is now standardized to perform as a 47-pico­farad capacitance standardizer. You may use it as such
in the following procedure to set the input capacitances of
any Type 2A63 module to 47 picofarads. (Do not adjust
the probe further during the procedure.)

To set the input capacitances of a Type 2A63 module to

47 picofarads and to frequency compensate the input atten­uators, proceed as follows:

l. Set the +INPUT AC-DC-GND switch to DC, the

VOLTS/DIV. switch to .2 VOLTS, and the VARIABLE control
fully clockwise (to the CALIBRATED position).

2. Apply the output of the square-wave generator (or the
oscilloscope Calibrator) through the 47-picofarad capaci­tance standardizer (or the standardized probe) to the

+ INPUT connector.

3. Set the time-base controls so that several cycles of
the square wave are displayed on the screen. (In this step
and throughout the rest of the procedure adjust the ampli­tude of the square wave and the VARIABLE control on the

Type 2A63 module as necessary to maintain about 6 divi­sions of deflection on the screen, if possible.)

4. Adjust C416 for the most nearly square leading corner
on the positive half-cycle of the displayed waveform.

5. Set the VOL TS/DIV. switch to .5 VOLTS and adjust
C415B and C415C for the most nearly square leading
corner on the positive half-cycle.

6. Set the VOLTS/DIV. switch to 5 VOLTS and adjust
C414B and C414C for the most nearly square leading
corner on the positive half-cycle.

7. Set the +INPUT AC-DC-GND switch to GND, the

-INPUT AC-DC-GND switch to DC, and the VOLTS/DIV.
switch to .2 VOL TS.

8. Apply the square wave through the 47-picofarad
capacitance standardizer (or the standardized probe) to the

-INPUT connector.

9. Adjust the C406 for the most nearly square leading

corner on the negative half-cycle of the displayed waveform.

10. Set the VOLTS/DIV. switch to .5 VOLTS and adjust
C405B and C405C for the most nearly square leading corner
on the negative half-cycle.

11. Set the VOL TS/DIV. switch to 5 VOLTS and adjust
C404B and C404C for the most nearly square leading
corner on the negative half-cycle.

12. Disconnect the square-wave generator and the capaci­tance standardizer.

Phase-Shift Compensation

NOTE

If you do not intend to use your Type 2A63 module

for X-Y phase shift comparisons, leave all phase
shift compensation adjustments (C457, C467,
C480, C480D, and C480F) as they are. Readjust
these compensating adjustments only if the specific
2A63 to be matched is at hand.

The purpose of phase-shift compensation is to allow you

to make accurate phase comparisons by the X-Y mode of

operation - that is, with amplifier modules in both open­ings of a Type 560-Series oscilloscope.* The adjustments
compensate for differences in the amount of phase shift
a sine wave will undergo at the various sensitivity ranges

as it passes through a Type 2A63 module.

X-Y phase comparisons can be made using either two

Type 2A63 modules or one Type 2A63 module and one

Type 2A60 or Type 3A75 module. The method of com-

pensation differs with the modules used. Therefore, two

methods are presented here. You should use the first method
if you are planning to use two Type 2A63 modules; you
should use the second if you are planning to use a Type
2A63 and a Type 2A60 or Type 3A75.

The frequency of the signal used in steps 8 through 20

of the first method (100 kc) has been selected to provide 1
or less of phase difference between the two modules at
all frequencies up to 50 kc and at all sensitivity ranges.

However, any frequency between about 30 kc and 500 kc

may be used, if desired, to give more exact compensation

at a specific frequency, with some sacrifice in compensation

at other frequencies. (See item 5 under "Equipment Re-

quired".) The second method provides compensation at

only a specific selected frequency.

• Type 565 cannot be used in this application.

°

8

®

Type 2A63

The Type 2A63 module, or modules, must be properly

calibrated in accordance with the foregoing procedures be-

fore either method of phase-shift compensation is under-

taken. Likewise, the Type 2A60 or Type 3A75 module must
be properly calibrated according to the procedures in its
instruction manual.

First Method-SI N3480-up I for two Type 2A63 mod-

ules). To mutually phase-shift compensate two type 2A63

modules, proceed as follows:

1. Insert one of the modules in the left-hand opening of
the oscilloscope. Set its +INPUT AC-DC-GND switch to AC
and its -INPUT AC-DC-GND switch to GND. (You do not

need a module in the right-hand opening at this point.)

2. Set the GAIN ADJ. adjustments according to the pro-

cedure given in the Operating Instructions.

3. Set the VOLTS/DIV switch to 20 mVOLTS and apply a
350-kc sine wave of about 200 millivolts amplitude (peak­to-peak) to the +INPUT connector. (It is important that you
know the amplitude of this signal very accurately; the fre­quency is also rather critical. Use auxiliary measuring equip-

ment if necessary.)

4. Set C467 so that the length of the displayed vertical
line on the screen is 0.707 times the amplitude of the applied
signal divided by 20 millivolt per division. (For a 200 milli­volt signal the line should be 7.1 major graticule divisions
long.)

5. Disconnect the 350-kc signal, move this module to the
right-hand oscilloscope opening, and insert the other Type
2A63 module in the left-hand opening.

6. Set both GAIN ADJ adjustments according to the pro­cedure given in the Operating Instructions.

7. Set both VOLTS/DIV switches to 20 mVOLTS, both +
INPUT AC-DC-GND switches to AC, both -INPUT AC-DC­GND switches to GND, and both AC STABILIZED switches
to ON.

8. Apply a 100-kc sine wave to the +INPUT connectors
of both modules. (This signal is used throughout the remain­der of this procedure; see the discussion regarding its fre­quency in the introduction to the procedure.)

9. Adjust the output amplitude of the signal generator
to produce about 8 divisions of deflection vertically and
horizontally.

10. Adjust C467 of the left-hand module to close the
ellipse on the screen.

11. Set both VOLTS/DIV switches to 1 mVOLT and adjust

the output of the signal generator to obtain 8 divisions of

deflection vertically and horizontally.

12. Adjust C456 of the left-hand module to close the

ellipse on the screen.

13. Attenuate the signal at the +INPUT connector of the
right-hand module by a factor of 100.

NOTE

The attenuator, or attenuators, called for in this
step must not introduce any phase shift or delay

into the signal at the INPUT connector. We recom-

mend that you use 93-ohm 10-to- 1 "T" attenuators

(Tek part no. 011-062) connected as shown in

Fig. 7. It should be noted that these attenuators

will terminate the output of the signal generator

in

93 ohms, which will probably be beyond its

specified output loading. Check to see if the gen-

erator will put out adequate signal ( approximately

1 volt peak-to-peak) under these conditions.

14. Set the VOLTS/DIV switch on the left-hand module to
50 mVOLTS, and adjust the signal amplitude to produce
approximately 8 divisions of vertical deflection. Adjust C480F
to close the ellipse on the screen.

15. Set the VOLTS/DIV switch on the left-hand module to
.1 VOLTS, and increase the signal amplitude to produce
approximately 8 divisions of vertical deflection. Adjust
C480D to close the ellipse on the screen.

16. Set the VOLTS/DIV switch on the left-hand module to
.2 VOLTS, and increase the signal amplitude to produce
approximately 10 divisions of horizontal deflection. Adjust
C480B to close the ellipse on the screen.

17. On the left-hand module, set the +INPUT AC-DC-·
GND switch to GND and the -INPUT AC-DC-GND switch

AC.

to

18. On the left-hand module, disconnect the signal from
the +INPUT connector and apply it to the -INPUT con­nector. Adjust C457 to close the ellipse on the screen.
Remove the signal leads and attenuators.

19. Interchange the positions of the two modules, and
reset the GAIN ADJ adjustments.

20. Set both +INPUT AC-DC-GND switches to AC and
both -INPUT AC-DC-GND switches to GND. Set the
VOLTS/DIV switch on the right-hand module to 20 mVOLTS.

21. Apply the 100-kc signal directly to the + INPUT con­nector of the left-hand module, and through the
attenuation to the + INPUT connector of the right-hand
module.

22. Repeat steps 9 through 18. (This time you will be

adjusting the other module.)

First Method S/N 101-3479 (for two Type 2A63

modules). To mutually phase-shift compensate two type

2A63 modules, proceed as follows:

1. Insert one of the modules in the left-hand opening of

the oscilloscope. Set its +INPUT AC-DC-GND switch to
AC and its -INPUT AC-DC-GND switch to GND. (You
do not need a module in the right-hand opening at this

point.

2. Set the GAIN ADJ. adjustments according to the pro-

cedure given in the Operating Instructions.

3. Set the VOLTS/DIV. switch to 1 mVOLTS and apply

a 350-kc sine wave of about 10 millivolts amplitude (peak­to-peak) to the +INPUUT connector. (It is important that
you know the amplitude of this signal very accurately; the
frequency is also rather critical. Use auxiliary measuring
equipment if necessary.)

4. Set C467 so that the length of the displayed vertical

line on the screen is 0.707 times the amplitude of the applied

lOOX

®I

9

Type 2A63

signal divided by 1 millivolt per division. (For a 10-millivolt
signal the line should be 7.1 major graticule divisions long.)

5. Disconnect the 350-kc signal, move this module to the
right-hand oscilloscope opening, and insert the other Type
2A63 module in the left-hand opening.

6. Set both GAIN ADJ. adjustments acording to the

procedure given in the Operating Instructions.

7. Set both VOLTS/DIV. switches to 1 mVOLTS, both
+INPUT AC-DC-GND switches to AC, both -INPUT AC­DC-GND switches to GND, and both AC STABILIZED
switches to ON.

8. Apply a 100-kc sine wave to the +INPUT connectors

of both modules. (This signal is used throughout the

remainder of this procedure; see the discussion regarding
its frequency in the introduction to the procedure.)

9. Adjust the output amplitude of the signal generator to
produce about 8 divisions of deflection vertically and
horizontally.

10. Adjust C467 of the left-hand module to close the

ellipse on the screen.

11. Attenuate the signal at the + INPUT connector of the

right-hand module by a factor of 100.

NOTE

The attenuator, or attenuators, called for in this

step must not inroduce any phase shift or delay

the signal at the INPUT connector. We recom-

into
mend

that you use 93-ohm 10-to- 1 "T" atten-

uators (Tek

shown in Fig.

attenuators will
generaor in 93 ohms, which will probably be
beyond is specified

part no. 011-062) connected as

7. It should be noted that these
terminate the output of the signal

output loading. Check to see

if the generator will put out adequate signal

( approximately

conditions.

1 volt peak-to-peak) under these

12. Set the VOLTS/DIV. switch on the left-hand module
to 50 mVOLTS, and adjust the signal amplitude to produce
approximately 8 divisions of vertical deflection. Adjust
C480F to close the ellipse on the screen.

13. Set the VOLTS/DIV. switch on the left-hand module
to .1 VOLTS, and increase the signal amplitude to produce
approximately 8 divisions of vertical deflection. Adjust

C480D to close the ellipse on the screen.

14. Set the VOL TS/DIV. switch on the left-hand module
to .2 VOLTS, and increase the signal amplitude to produce
approximately 10 divisions of horizontal deflection. Adjust

C480B to close the ellipse on the screen.

15. On the left-hand module, set the +INPUT AC-DC-

GND switch to GND and the -INPUT AC-DC-GND switch
to AC.

16. On the left-hand module, disconnect the signal from
the + INPUT connector and apply it to the -INPUT con­nector. Adjust C457 to close the ellipse on the screen.
Remove the signal leads and attenuators.

17. Interchange the positions of the two modules, and

reset the GAIN ADJ. adjustments.

18. Set both +INPUT AC-DC-GND switches to AC and

both -INPUT AC-DC-GND switches to GND. Set the

VOLTS/DIV. switch on the right-hand module to 1 mVOLTS.

19. Apply the 100-kc signal directly to the + INPUT con­nector of the left-hand module, and through the 1

OOX attenu-

ation to the +INPUT connector of the right-hand module.

20. Repeat steps 12 through 16. (This time you will be

adjusting the other module.)

Second Method-SN 101-up ( for a Type 2A63 and

a Type 2A60 or Type 3A75 module). To phase-shift com-

pensate a Type 2A63 module against a Type 2A60 or Type
3A75 module, proceed as follows:

1. Perform steps 1 through 4 of the First Method (pre-

ceding).

2. Disconnect the 350-kc signal and insert the Type 2A60
or Type 3A75 module in the right-hand oscilloscope open­ing. Connect the adjustable phase-shifting network to the

INPUT connector of the module in the right-hand opening.

3. On the Type 2A63 module, set the AC CTABILIZED
switch to ON, the +AC-DC-GND switch to AC, and the

-AC-DC-GND switch to GND. On the other module, set

the AC-DC-GND switch to AC.

4. Apply a sine wave of the frequency to be measured
to the +INPUT connector of the Type 2A63 module and
through the phase-shifting network to the INPUT connector

of the other module.

5. Set the VOLTS/DIV. switches of the two modules to
the lowest settings (farthest clockwise) you expect to use

during the measurements.

6. Adjust the phase-shifting network to close the ellipse

on the screen.

7. Set the Type 2A63 VOLTS/DIV. switch to the other
settings you expect to use and adiust C480B, C480D, and
C480F (in the Type 2A63 module) as appropriate to close
the ellipse at each setting. (At the 50 mVOLTS, .5 VOLTS, or
5 VOLTS position, adiust C480F; at the .,1 1, or 10 VOLTS

position, adjust C480D; at the .2, 2, or 20 VOLTS position

adjust C480B.)

10

®

TABU: 1

NATURAL S!NE FUNCTIONS

Type 2A63

ANGLE SIN ANGLE SIN

(in degrees)

0

1

2
3 .0523 33
4
5
6
7

8

9
10 .1736
11 .1908 41
12 .2079 42
13

.0000
.0175
.0349

.0698
.0872
.1045
.1219 37
.1392
.1564

.2250 43 .6820

lin degrees)

30
31
32

34
35
36

38
39
40

ANGLE

lin degrees)

.5000
.5150

.5299 62
.5446 63
.5592
.5736 65
.5878
.6018 67
.6157
.6293
.6428 70
.6561 71
.6691 72

60
61

64

66

68
69

73

SIN

.8660
.8746
.8829
.8910
.8988
.9063

.9135
.9205
.9272
.9336
.9397
.9455
.9511
.9563

14 .2419 44
15
16 .2756 46 .7193
17 .2924 47
18 .3090 48
19 .3256 49
20
21

22 .3746

23 .3907
24 .4067 54
25 .4226
26 .4384 56
27 .4540
28 .4695 58
29 .4848 59

.2588 45

.3420 50
.3584

51
52
53

55

57

.6947 74
.7071

.7314 77
.7431
.7547 79
.7660 80

.7771

.7880

.7986 83
.8090 84
.8192
.8290 86
.8387

.8480 88
.8572

75
76

78

81
82

85

87

89

.9613
.9659
.9703
.9744
.9781
.9816
.9848
.9877
.9903
.9925
.9945
.9962
.9976
.9986
.9994
.9998

90

1.0000

11

TECHNIQUES

DIODES HELP WITH GROUND-LOOP PROBLEMS

When working with low level signals, the ground wire

of our power cords can introduce error signals. To
eliminate this problem, mount parallel back-to­back diodes

pin and the chassis of your Variac test set. The

diodes act as an open circuit to millivolt level sig­nals below their forward-bias point, and at the same
time will handle enough current to blow the Variac

fuse in case of a short. The circuit is shown at right

in fig.

(152-088) between the third wire ground

1.

FEN 10-11-63

AC Input

to Variac

TEK 2A63 IRB

1-25-64

~

)>

z

~

m

z

)>

z

()

m

St. Louis 11, Mo.

Inter-City Mf,;i. Co., Inc.

CONTENTS-MAINTENANCE

MODIFICATIONS

Modification Suw.mary

Modification instructions
Modification kits
Strip layout

MAINTENANCE NOTES

Q454 and Q464 sockets must be rewired to accommodate new transistors,

9-29-61

Quick-fix for "AC stabilized" neon, 8-10-62

Use 157-066 6DJ8's for easier balancing, 3-8-63

Characteristics vs specifications, 7-18-63
2A63 phasing, 3-26-64

Excessive DC shift reduced by transistor change, 3-12-65
Troubleshooting section of manual (located in ENG section)

PARTS

Parts replacement kits
Parts list

CALIBRATION

Manual calibration procedure (located in ENG section)

SCHEMATICS

TEK 2A63 RB 2-12-68

MODIFICATI N SUMMARY

@' 10-1-65

@ 1965, Tektronix, Inc.

All Rights Reserved.

63/2A63 MODIFICATION SUMMARY

Page 1

,---------

'

Type 63

SEMICONDUCTOR INFORMATION
STANDARDIZED

Effective

Prod s/n not given

INFORMATION ONLY

DESCRIPTION:
The following changes are to be made, as applicable:

1. All semiconductor type numbers are deleted from the chassis, leaving only the circuit

designation.

2, Circuit designations of silicon diodes change from "V" to 110.

11

3. Circuit designations of transistors change from "V" to nQ."

VOL TS/DIV SWITCH PHASE
SHIFT COMPENSATION

See SQB

NETWORK CHANGED

Effective Prod s/n 301

DESCRIPTION:
To eliminate selection of C480A and C480B, and to allow C480B to adjust near midrange,

C480P was added in parallel with C480A and C480B. C480P is a selected part located on
the VOLTS/DIV switch.

M3535

M3543

Parts Removed:

Parts Added:

C480P
Parts Required for Field Installation:
See 'Parts Added. '

INSTALLATION INSTRUCTIONS:
Install C480P, a selected capacitor, in parallel with C480A-B,

midrange.

Selected

to allow C480B to adjust near

4-28-66

63/2A63 MODIFICATION SUMMARY

Page 3

Type 63 (cont)

INTERCONNECTING PLUG PIN 24
GROUNDED TO ELIMINATE INTENSITY
MODULATION IN THE 561 AND RM561

Effective Prod s/n 357 Usable in field instruments s/n 101-356

w/exceptions: s/n 113, 125, 271, 289, 349-53, 355.

DESCRIPTION:
To eliminate high voltage intensity modulation in the 561 and RM561, pin 24 on the inter-

connecting socket was grounded. This will bypass R854 (2.2M) in the 561 and RM561 CRT
Cathode circuit when this plug-in is used in the left-hand housing.

With a 3B1 or 3B3 in the 561A or RM561A, lack of ground at this point will cause excessively
dim start of delayed sweep at faster rates.

See SQB M3682

Parts Removed:

INSTALLATION INSTRUCTIONS:
Ground pin 24 on the interconnecting socket.

Parts Added:

Page 4

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 63 (con'd)

SECOND STAGE AMPLIFIER
PROTECTIVE DIODES ADDED

See SQB

Effective Prod s/n 360 Usable in field instruments s/n 101-359

DESCRIPTION:
To provide protection for the amplifier transistors during warm-up, a pair of diodes were

added between the transistor collectors and a voltage divider to the +300v supply.

Parts Removed:

R453

10k l/2w 5%

301-0103-00

Parts Added:

R453
R454

D454,D464

6.8k 1/2w 5%

3.3k l/2w 5%

Tl2G

301-0682-00
301-0332-00
152-0008-00

Parts Required for Field Installation:

I

P arts Added.

See

1

INSTALLATION INSTRUCTIONS: (See schematic on following page.)
a) Remove the following wires and components:

1) Bare wire that connects CSE-3 and CSE-4.

2) Bare wire that connects the center terminal of R460

to CSE-5.

3) Bare wire that connects CSE-6 to ground.

4) C453, an 0.1 µf capacitor, connected between CSD-6 and CSE-6.

5) R453, a 10k l/2w resistor, connected between CSD-6 and CSE-6,

6) Bare wire that connects CSE-5 and CSE-10.

M3545-l

b) Relocate R468, an 820k 1/2 w resistor, from CSE-4 to CSE-3.
c) Relocate two white-orange wires from CSE-4 to CSE-3.
d) Install a bare wire from CSE-4 to CSE-10.
e) Install a bare wire from the center terminal of R460

to CSE-4.

f) Relocate the following wires and components:

1) White-brown wire from CSE-5 to CSE-4.

2) Bare wire from CSE-5 to CSE-4.

3) R434, a 75k l/2w resistor, from CSE-5 to CSE-4.

4) Bare wire from CSE-6 to CSE-5.

g) Install the following wires and components:

1) Bare wire from CSE-5 to ground lug.

2) R454, a 3.3 k 1/2 w resistor, from CSE-6

to ground.

3) D454, a Tl2G diode, from CSE-6 to CSD-3
(banded end to CSD-3).

4) D464, a Tl2G diode, from CSE-6 to CSD-9
(banded end to CSD -9) .

5) R453, a6.8k resistor, fromCSD-6toCSE-6.

6) C453, an 0.1 µF capacitor, from CSD-6

to

CSE-5.

cs~ cs o C£'E.

Continued.

4-28-66

63/2A63 MODIFICATION SUMMARY

Page 5

Type 63 (cont)

M3545-l

(cont)

+ 12.S '-I

R.452..

\OK.

R.4SS

c&.S~

R.4S<c:.

~OK_

-=-

0454-

i 1'2.Gi

1

-=-

R.5"46"

3.3lc::..

C4S7

C4G:.7

C463

0-1

C 45'=,

2... '2.

R 458.

52.0

'R.4Co~

8201<.

Q4S4

Q,457

12..SK

I<..

C 4"-8

12 ,-c..r

R4(olo

sqo "'-

l'Z.. '5 "-

l C4"'=>

Page 6

63/2A63 MODIFICATION SUMMARY

4-28 -66

Type 63 ( cont)

INPUT AIVIPLIFIER PHASE SHIFT
VS. TEIVIPERATUREIIVIPROVED

Effective Prod SN 360

See SQB

Usable in field instruments SN 101-359

DESCRIPTION:
To reduce change in phase shift with change in temperature, the two-conductor cable from

the AC Stability switch to C408 was replaced with two miniature coaxes and a 12 pF capacitor
was added to the collector circuit of Q464.

Parts Removed: Parts Added:

C468 12pF

281-0505-00
Parts Required for Field Installation:
See 'Parts Added.'

INSTALLATION INSTRUCTIONS:
a) Install C468, a 12 pF S00V capacitor, from CSE -3 to the ground lug on the chassis,

NOTE: For instruments below SN 360, step 'a' involves CSE-4, unless M3545- l

has been installed.
b) Remove the coax cable connected from the VOL TS /DIV switch to the AC Stabilized switch.
c) Install one 9-3/4in. piece of coax cable from WS-llF of the VOLTS/DIV switch to the

bottom 'off' terminal of the AC Stabilized switch.

M3545-2

d) Install one 9-3/4in. piece of coax cable from W6-13R of the VOLTS/DIV switch to the

bottom center terminal of the AC Stabilized switch.

e) Connect the ground shield of both cables to the plus input jack ground lug. Dress the

new cables the same as the old cable.

f) Install the 3/16in. cable clamp below the cable clamp used for mounting C408. It will

be necessary to install a larger mounting screw (6/32 x 1/2). Dress the new clamp

180° from the existing clamp holding C408.

NOTE: The following method is used to identify the

VOLTS/DIV switch terminals:

The wafers are numbered from front to rear.

( TYPICAL SWITCH CONFIGURATION)

The contact positions are numbered 1 through 12

relative to the index key as shown

in drawing.

The contacts have an 'F' or 'R' suffix which denotes
that they are on the front or rear of the wafer.

Example: W2-7R (denoted by * on drawing) is

contact #7 on the rear of wafer #2.

The sample drawing shows a switch with 12
contacts. The VOL TS /DIV switch has 22
contact positions and they are numbered in

the same way.

4-28-66

63/2A63 MODIFICATION SUMMARY Page 7

Type 63 ( cont)

INPUT AMPLIFIER TRANSISTORS

REPLACED

Effective Prod SN 410

See SQB
Usable in field instruments SN 101-409

DESCRIPTION:
The OCJ 70 /2N 1516 transistors were replaced with 2Nl 7 49 type transistors. The new tran -

sistors have a higher output capacitance which makes it easier to attain the proper phase
shift compensation. 2Nl 749 's however, had excessive DC shift and thermal sensitivity, and
were replaced in both production and in kit 050-0057-01 with silicon types in 1965.

Parts Removed:
Q454, Q464 OCl 70/2Nl516

151-0015-00 Q454,Q464 2Nl749

Parts Added:

151-0081-00

Parts Required for Field Installation:
Parts Replacement Kit 050-0057-01 (with 2N2191 transistors)

INSTALLATION INSTRUCTIONS:
Refer to kit instructions.

PHASE SHIFT COMPENSATION

CAPACITOR RANGE CHANGED

See SQB

M3797

M5791

Effective Prod SN 1000

Usable in field instruments SN 101-999

DESCRIPTION:
To allow C457 to adjust near the middle of its range, decrease the value of a fixed capacitor

which is connected in parallel with C457.

Parts Removed:

C458

68pF

281-0549-00 C458

Parts Added:

47pF

281-0519-00

Parts Required for Field Installation:

See 'Parts Added. '
INSTALLATION INSTRUCTIONS:

Replace C458 with a 47 pF capacitor.

Page 8

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 63 ( cont)
AC STABILIZED INDICATOR NEON

CIRCUIT MODIFIED

Effective Prod SN 1240 Usable in field instruments SN 101-1239
DESCRIPTION:

To insure proper functioning of the AC stabilized indicator neon, reduce the value of series
resistor to 100k. Also see M7843.

Parts Removed:
R407 180k l/4W

Parts Required for Field Installation:
See 'Parts Added. '

INSTALLATION INSTRUCTIONS:
Replace R407 with a 100k resistor.

INPUT AMPLIFIER OSCILLATIONS
ELIMINATED

Effective Prod SN 1300

316-0184-00 R407

SQB

See

Parts Added:

100k 1/4W 316-0104-00

SQB

See

Usable in field instruments SN 101-1299

M6185

M6591-J

DESCRIPTION:
To reduce the possibility of the input tubes oscillating, the parasitic suppressing resistors

in the grid circuit are changed
each input connector lead.

Parts Removed: Parts Added:

R421, R431 470Q l/2W 10% 302-0471-00 R421, R431 47

Parts Required for Field Installation:

See 'Parts Added.'

INSTALLATION INSTRUCTIONS:

a) Replace R421, a 470n resistor, connected to pin 7 of V424 with a 47n resistor.
b) Replace R431, a 470 n resistor, connected to pin 2 of V424 with a 47
c) Install two ferramic suppressor beads on the wires that connect the input connector

to the AC-DC switches.

to 47 n, and two ferramic suppressor beads are added to

Q 1/2W 10% 302-0470-00

L400,L401)_ ferramic suppr. 276-0507-00
L410,L411)

n resistor.

4-28-66

63/2A63 MODIFICATION SUMMARY

Page 9

Type 63 ( cont)

AC STABILIZED INDICATOR
CIRCUIT CHANGED

Effective Prod SN 1300

See SQB
Usable in field instruments SN 101-1299

DESCRIPTION:

To eliminate trace pulses caused by random ionization of the AC Stabilized Indicator neon,
the neon is shorted out when the AC Stabilized switch is in the 'off' position.

Parts Removed: Parts Added:

R410

100k l/4W

3] 6-0104-00
Parts Required for Field Installation:
See 'Parts Added.'

INSTALLATION INSTRUCTIONS:
a) Locate the black-brown-black-brown wire that connects to the indicator neon. Cut this

wire off about 1 -1 /2 in. from the neon holder

b) Install R410 from the contact on the AC Stabilizer switch contact with the white-red wire,

and to the right hand contact.

c) Connect both black-brown-black-brown wires to the right hand contact on the AC Stabilizer

switch.

M6591-2

FRONT PANEL CHANGED

INFORMATION ONLY

Effective Prod SN 1320

DESCRIPTION:

Change type designation on front panels from "63

11

to 112A63.

11

Add a mod slot to the front
panel in addition to the existing SN slot. A blank mod tag will be used in the mod slot
except for instruments which require mod information. Type designation change and addition

of mod slot will necessitate changing the front panel part numbers.
Change color of front panel knobs, bushings, and switches (buttons) from black to their

equivalent in charcoal gray.
Parts Removed:

Knob, black
SW400 switch

Front panel

366-0058-00
260-0251-00
333-0622-00

Parts Added:
Knob, charcoal

SW400 switch

Front panel

Tag, mod insert

366-0144-00
260-0450-00
333-0725-00
334-0029-00

M6052

Page 10

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 2A63

PHASE SHIFT COMPENSATION
CAPACITOR RANGE INCREASED

Effective

Prod SN 1880 Usable in field instruments SN 101-1879

See SQB

DESCRIPTION:
To assure that C480D has a sufficient range

of adiustment, add C480H in parallel with C480C

and C480D.

The part of the mod dealing with C456-C466 has been superseded

by M7920 and M9106-l.

For installation details of C456, refer to M7920, and for C466 details, refer to M9106-

Parts Removed:

C456, C466 2.

2 pF ±0. 5 pF

281 -0500-00 *C480H

Parts Added:

C456, C466

l0pF 500V

2.2pF ±0.25pF
Parts Required for Field Installation:
See 'Parts Added' with asterisk.

INSTALLATION INSTRUCTIONS:
Install C480H, a

10 pF capacitor, in parallel with C480D, located on the VOLTS/DIV switch.

M6844-l

l.

281-0504-00
281-0604-00

INPUT AMPLIFIER CHANGED
TO A CHECKED TUBE

Effective Prod SN 1880

See SQB
Usable in field instruments SN 101-1879

DESCRIPTION:
To save test time, V 424, the input amplifier, was changed to a checked tube.

Parts Removed:
V424

6DJ8

154-0187-00 V424

Parts Added:

6DJ8

Parts Required for Field Installation:
See 'Parts Added.'

INSTALLATION INSTRUCTIONS:
Replace V 424 with a checked tube.

M6844-2

157-0066-00

4-28-66

63/2A63 MODIFICATION SUMMARY

Page 11

Type 2A63 (cont)

UHF CONNECTORS REPLACED
WITH BNC CONNECTORS

Effective Prod s/n 1880

DESCRIPTION:
The UHF connectors are replaced with BNC connectors to match the military and manu-

facturing trend toward the BNC type. The BNC type has a constant 50

lower input capacitance. It also required less front panel space.

Parts Removed:
Connector, UHF female (2) 131-081

Adapter, probe BNC to UHF (2) 103-015

PLUG-IN SPACER RODS CHANGED

Effective Prod SN 2720

DESCRIPTION:
To facilitate assembly by providing better method tightening plug-in rods, an ll/32in.

hexagonal section is added 3/8 in. from one end of the rod. No part number change.

INFORMATION ONLY

n impedance and a

Parts Added:
Connector, BNC female ( 2)

INFORMATION ONLY

131-126

M6860

M7457

PHASE SHIFT COMPENSATION

NETWORK IMPROVED

Effective Prod SN 3480
DESCRIPTION:

To permit phasing of unit without excessive selection of Q454 and Q464.
Parts Removed:

C456
Parts Required for Field Installation:

See 'Parts Added. '
INSTALLATION INSTRUCTIONS:

a) Remove C456, a 2.2pF capacitor, connected

between CSC-9 and CSD-10.

b) Remove a bare wire that connects CSD-8

and CSD-9.

c) Relocate two white-gray wires from CSD-9

to CSD-8.

d) Relocate R457, a 12.5k resistor, and C459,

a 24 pF capacitor, from CSD-9 to CSD-8.

e) Install a bare wire from CSC-9 to CSD-9.

2.2pF

281-0604-00 C456 0. 7-3pF

See SQB
Usable in field instruments SN 101-3479

Parts Added:

CSA.

I.

CSB

• I

•II II

281-0027-00

csc

F I

-

CSD ·

= I

II

M7920

f

R.

0

/II

-r

f) Install C456, an 0. 7-3pF variable capacitor,

between CSD -9 and CSD-10.

Page 12

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 2A63 (con'd)

NEON BULBS REPLACED TO
STABILIZE FIRING POTENTIAL
AFTER PROLONGED DARKNESS

See SQB

M7843

Effective Prod SN 3860

Usable in field instruments SN 101 -3859

DESCRIPTION:

NE2 neons may not fire after they have been subjected to prolonged darkness, because of

increased firing potential. They are replaced with NE23 neons, which contain a small
deposit of radioactive material to aid in the ionization process. Also see M6185, SN 101-1239.

Parts Removed: Parts Added:
B407

NE2 150-0002-00

B407 NE23

150-0027-00

Parts Required for Field Installation:

See 'Parts Added.'

INSTALLATION INSTRUCTIONS:
Replace NE2 neon, B407 located in the AC STABILIZED neon holder, with an NE23 neon.

DIFFERENTIAL AMPLIFIER CAPACITOR

REP LACED TO INCREASE RELIABILITY

See SQB

M7928

Effective Prod SN 3860

Usable in field instruments SN 101-3859

DESCRIPTION:
Accumulated breakdown failures in all types of instruments prompted a "blanket" replace-

ment of ceramic disc capacitor 283-0012-00 with a higher rated capacitor.

Parts Removed:

C426,C436, )_ 0 l f l00
C453 ) .

µ v

283-0012-00

Parts Added:
C426,C436, )_ 0.l µf

C453 )

200

v

283-0057-00

Parts Required for Field Installation:
See 'Parts Added.

1

INSTALLATION INSTRUCTIONS:
a) Replace C426 connected

to the COARSE DC BAL potentiometer, R426, with an 0.1 µf

200 v capacitor.

b) Replace C436 connected to the DC BAL potentiometer, R436, with an 0.1 µf 200 v

capacitor.

c) Replace C453, located between ceramic strip notches above Q454 socket, with an 0.1 µf

200 v capacitor.

4-28-66

63/2A63 MODIFICATION SUMMARY

Page 13

Type 2A63 (con 'd)

TRANSISTOR SOCKETS CHANGED

Effective Prod s/n 4860

DESCRIPTION:
Provides a better and more economical way to mount transistor sockets, by replacing sockets

with new snap-in type.

Parts Removed:
Socket, 4-pin transistor (2)

AMPLIFIER FEEDBACK CHANGED
TO REDUCE SECOND
HARMONIC DISTORTION

Effective Prod SN 4945

w/exceptions: SN 4234,4258,4297,4329,4375,4430,4469,4517,4522,4528,

4577,4580,4669,4692,4720,4736,4776,4806,4810,4844
4861-83,4885-97,4899-4904,4906-7,4910-43

DESCRIPTION:

Second harmonic distortion shows up as a figure 8 when adjusting the X-Y phasing. This
was corrected by changing the value of C466 and adding C455 which is a selected part.

136-095

INFORMATION ONLY

Parts Added:
Socket, 3-pin transistor (2)

Ring, transistor socket (2)

See SQB

Usable in field instruments SN 101-4944

136-181
354-234

M8208

M9106-l

NOTE: If M9106- l is installed in an instrument below s/n 3480, install M7920 first.

Parts Removed: Parts Added:

C466 2.2pF 500V 281 -0604-00 C466, C455

Parts Required for Field Installation:

See 'Parts Added. '

INSTALLATION INSTRUCTIONS:
a) Replace C466 located between CSC-3 and CSD-2

with a 1 . 5 pF 500 V capacitor.

b) Add C455, a

CSD-9 and CSD-10.

1. 5 pF 500 v capacitor, between

1. 5 pF 500 V

ces c

281-0529-00

cs t)

Page 14

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 2A63 (con1d)

AMPLIFIER HF FEEDBACK ADDED

TO SUPP RESS OSCILLATIONS

Effective Prod SN 4945

See SQB

Usable in field instruments SN 101-4944

w /exceptions: See M9106-l

DESCRIPTION:

Prevents high frequency amplifier oscillations by adding C461 and R461 in series between

the bases of transistors Q454 and Q464 respectively.

NOTE: If M9106-2 is installed in an instrument below s/n 3480, install M7920 first.

Parts Removed:

Parts Added:

C461
R461

27pf 500v

6800 1/4w 5%

281-0512-00

315-0681-00

e.so

Parts Required for Field Installation:

1

See

P arts Added.

1

INSTALLATION INSTRUCTIONS:
Add a 27 pf 500v capacitor and a 680

n 1/ 4w 5%

resistor, connected in series between CSD-4

and CSD- 7. See drawing.

M9106-2

DC SHIFT AND THERMAL GAIN

CHANGES MINIMIZED BY CHANGE

See SQB

TO SILICON TRANSISTORS

Effective Prod SN 4945

Usable in field instruments SN 101 -4944

w /exceptions: See M9106- l.

DESCRIPTION:
Reduces DC shift from 3-5%

to <1% for up to 20 cm step; also minimizes gain changes with

temperature variation by changing Q454 and Q464 to silicon transistors.

Parts Removed:

Q454,Q464 2Nl749 151-0081-00

Parts Added:
Q454,Q464 2N2191

Parts Required for Field Installation:
See 'Parts Added.'

INSTALLATION INSTRUCTIONS:

Replace Q454 and Q464 with 2N2191 transistors.

4-28-66

63/2A63 MODIFICATION SUMMARY

M9106-3

151-0100-00

Page 15

Type 2A63 (con'd)

INPUT AND TRIGGER AMPLIFIER
TRANSISTORS CHANGED BECAUSE
OF AVAILABILITY

Effective Prod s/n 4945

DESCRIPTION:
The Input and Trigger Amplifier 2N2191 transistors were changed to type MM999 because of

availability problems.

The 2N291 transistors are now available in quantity for replacement purposes. In symmetrical
circuits, it is important that both transistors be of the same type.

INFORMATION ONLY M9296

Parts Removed:
Q454,Q464 2N2191

Parts Added:

151-100 Q454,Q464 MM999

151-133

Page 16

63/2A63 MODIFICATION SUMMARY

7-29-65

Type 2A63 (cont)

DIFFERENTIAL AMPLIFIER CATHODE
RESISTORS CHANGED TO CORRECT PLUS
TO MINUS INPUT GAIN DIFFERENCE

Effective Prod s/n 6200

See SQB

Usable in field instruments s/n 101-6199

M9428-l

FRONT PANEL SYMPTOM: The amplifier gain changes from 1/4

to 3/4 mm with a 4 cm

display between the plus and minus inputs. The amount varied with the setting of
coarse DC Bal adj R426 and DC Bal adj R436.

PROBLEM: The gain change, along with tolerance problems in the attenuator resistors

(see M9428-2), could accumulate to exceed specs.

PRODUCTION CHANGE: The coarse DC Bal potentiometer was changed from 250n to 200n,

the same value as the DC Bal pot, and the tolerance of the DC Bal shunt resistors,

R427 and R437, was changed from 10% to 5%,

A part of this mod is superseded by Mll354.

Parts Removed:

R426
R427, R437
SW404

Potentiometer, comp 250n ±20%

Resistor, comp

1000 1/2W ±10%

Switch, wired "Volts/Div"

311 -0367 -00
302-0101-00

Parts Added:

* R426

R427, R437
SW404

Potentiometer, comp 200n

Resistor, comp lO0n l/2W 5%

Switch, Wired, "Volts/Div"

311-0178-00
301-0101-00

INST ALLA TI ON INSTRUCTIONS:
Parts Required: See 'Parts Added' with asterisks and parts listed below

C426, C436

R427, R437

Capacitor, 0. 005

Resistor, 4 70

µF 500V

n l /2 W 5%

283-0001-00
301 -04 71 -00

Installation Procedure:

a) Remove the parallel combination of R427, a l00n 1/2 W resistor, and C426, a 0. 1

100 V discap, connected between the outside terminals of R426, the chassis mounted
Coarse DC Balance pot.

b) Remove the parallel combination of R437, a IOOn 1/2 W resistor, and C436, a 0. 1

100 V discap connected between the outside terminals of R436, DC Balance pot. DC

Bal pot is mounted on the front panel.

c) Replace R426, the Coarse DC Balance pot, located on the Amplifier chassis, with a

200n pot.

d) Install the parallel combination of R427, a 470 n 1/2 W 5% and C426, a 0. 005

µF

S00V discap across the outside terminals of R426 Coarse DC Bal.

c) Install the parallel combination of R437, a 470 n 1/2

0. 005

µF 500 V discap, across the outside terminals of R436 DC Bal.

W 5% resistor, and C436, a

µF

µF

2-13-67

63/2A63 MODIFICATION SUMMARY

Page

17

Type 2A63 (cont)

VOL TS/DIV SW RESISTORS CHANGED
TO REDUCE ATTENUATOR ERROR

Effective Prod s /n 6200

See SQB
Usable in field instruments s/n 101-6199

FRONT PANEL SYMPTOM: None.

PROBLEM: The 1% attenuator resistors could allow too much error between attenuator

positions.

PRODUCTION CHANGE: The values of R409, R408C and R408N were changed and R408A,

R408C and R408N were changed to precision metal film resistors with l /2% tolerance.

Parts Removed:

R408A
R408C
R408N
R409

SW404

Resistor, 10k l/2W 1%
Resistor, 3. 33 k 1/2 W 1%
Resistor, SO. 9 n 1/2 W 1%
Resistor, 21.Sk l/2W 1%

Switch, Volts/Div

309-0100-00
309-0283-00
309-0216-00
309-0290-00
262-0374-00

Parts Added:

R408A

R408C
R408N
R409
SW404

Resistor, 10 k 1/2 W 1/2%
Resistor, 3. 32 k 1/2 W 1/2%
Resistor, SO.Sn l/2W 1/2%
Resistor, 21. 8 k 1/2 W 1/2%

Switch, Volts/Div

323-0289-01
323-0243-01
323-1068-01
323-1321-01
262-0374-01

M9428-2

INSTALLATION INSTRUCTIONS:

Parts Required:

See 'Parts Added'.

( TYPICAL SWITCH CONFIGURATION)

Installation Procedure:

NOTE: The following method is used to

identify the Volts/Div Switch terminals:

The wafers are numbered from the front to

the rear.

The contact positions are numbered l through

12 relative to the index key as shown in the

drawing.

The contacts have an "F" or "R" suffix which

denotes that they are on the front or the rear

of the wafer.

8F

Example: W2-7R (denoted by* on
the drawing is contact #7 on the rear
of wafer 2.

Replace the following resistors, located between contacts on the Volts /Div Switch as
shown below.

R408A
R408C
R408N
R409

WS-l0R and W6-10R with a lOk 1/2% resistor.
WS-llR and W6-11R with a 3.32k 1/2% resistor.
WS- SF and W6- SR with a SO.Sn 1/2% resistor.
WS-14F and W6-14R with a 21.Sk 1/2% resistor.

7R*

4R

5F

Page 18

63/2A63 MODIFICATION SUMMARY

4-28-66

Type 2A63 ( cont)

INPUT COUPLING CAPACITORS

CHANGED TO REDUCE MICROPHONICS

Effective Prod SN 6880

See SQB

Usable in field instruments SN 101-6879

FRONT PANEL SYMPTOM: Microphonics

PROBLEM: C400 and C410 were causing microphonics. The condition was more apparent

after the 500V input check was performed.

PRODUCTION CHANGE: C400 and C410 were replaced with better quality, Tek-made

capacitors. The value and voltage rating remains 0. 1

µF 600V.

Parts Removed:

C400, C410 Cap, 0. 1

µF 600V PTM

285-0587-00

Parts Added:

C400, C410 Cap, 0.1

µF 600V, Tek

285-0672-00

INSTALLATION INSTRUCTIONS:

Parts Required:

See 'Parts Added. '

Installation Procedure:

Ml0473

a) Replace C400, an 0.1

µF 600V capacitor located on -Input AC-DC-GND switch, with

the new type capacitor.

b) Replace C410, an 0.1

µF 600V capacitor located between +Input AC-DC-GND switch

and a contact on the VOL TS/DIV switch, with the new type capacitor.

NEON INDICATING LAMP
AND lIOLDER REPLACED

INFORMATION ONLY

WITH IMPROVED TYPE

Effective Prod SN 7010

FRONT PANEL SYMPTOM: None.

PROBLEM:

PRODUCTION CHANGE: The indicating neon holder was replaced with a type which has

increased wide -angle visibility and is neater in appearance. The new holder, being
slightly shorter, requires a type NE-2V neon bulb and a shorter mounting screw.

Parts Removed:

Parts Added:

B407

B407

Bulb, neon, NE-23
Holder, neon, single
Screw, 4-40

x 1 FI-IS

Bulb, neon, NE-2V
Holder, neon, single
Filter, lens, neon indicator

Screw, 4 -40

x 7 /8 FHS

150-0027-00
352-0008-00

211-0031-00

150-0030-00
352-0067-00
378-0541-00

211 -0109-00

M8002

2-13-67

63/2A63 MODIFICATION SUMMARY

Page 19

Type 2A63 (cont)

INPUT AMPLIFIER DC BALANCE RANGE
INCREASED TO EASE SELECTION OF
INPUT TUBES

Effective Prod SN 7660

See SQB

Usable in field instruments SN 6200-7659

** Usable 101-6199 if M9428- l is installed.

FRONT PANEL SYMPTOM: DC BAL range insufficient and evidence of grid current in

input amplifier.

PROBLEM: Inadequate range of Input Amplifier (V 424) DC BAL control because of grid

current caused by low plate voltage, in turn, caused a high reject rate of tubes used

in V424. Yield of selected tubes was less than lOfo, and many tubes were out of

specs when installed in plug-ins.

PRODUCTION CHANGE: Range of DC BAL pot was increased by changing the shunt

resistors, R427 and R437, from 100
changing C426 andC436 from 0.1 µ,F capacitors to 0.005 µ,F capacitors. With the
increased range of DC BAL, the test specification of the selected 6DJ8's were made

less stringent.

Parts Removed:
V424

C426, C436

R427, R437

Tube, 6DJ8 selected

Capacitor, cer 0. 1 µ,F 200 V
Resistor, comp 100

n to 4 70 n. The resistor change necessitated

157-0066-00

283-0057-00

n 1/2 W 5%

301-0101-00

Mll354

**

Parts Added:
V424

C426, C436

R427, R437

INSTALLATION INSTRUCTIONS:
Parts Required: See 'Parts Added'.

Installation Procedvre:
a) Replace the parallel combination of R427 - C426, a 100

capacitor mounted on the DC BAL pot, with a 470

b) In a similar manner, replace R437 - C437, also mounted on the DC BAL pot.

NOTE: R427 - R437 may be a 5% or a 10% resistor.

Tube, 6DJ8 selected

Capacitor, cer
Resistor, comp 4 70

O. 005 µ,F discap 500 V

157-0120-00

283-0001-00

n 1 /2 W 5%

S1 resistor and a 0. 1 µ,F

301-0471-00

n resistor and a 0. 005 µ,F capacitor.

JT:fb

Page 20

63/2A63 MODIFICATION SUMMARY

2-13-67

INPUT AMPLIFIER lmV GAIN

ADJUST POT CHANGED TO

See SQB

IMPROVE GAIN STABILITY

Effective Prod SN 9504

Usable in field instruments SN 101-9503

modified out of sequence:

8746 9150

8748 9195
8772 9208
8784 9238-9
8817 9243
9018 9262
9021 9264
9052 9269
9103 9276

9279
9290
9295
9342
9370
9378
9384
9409-10

9412

9418
9423
9437
9441-3
9458-9
9464
9467-8
9473
9476

9479
9482-4
9488

9490
9492
9494
9496
9499
9501

FRONT PANEL SYMPTOM: 1 mV gain is not sufficiently stable.

PROBLEM: R460, the 1 mV GAIN ADJ, usually ends up adjusted to some value below 1 k.

This places the wiper near the end of the resistance element. This setting becomes
unstable when influenced by time, vibration, and temperature.

Ml2919

PRODUCTION CHANGE: The 1 mV GAIN ADJ, R460, was changed in value from 20k to

5 k. This allows the adjustment to be set nearer its center of rotation.

Parts Removed:

R460 Potentiometer, comp 20 k ±20% 311-0364-00

Parts Added:

R460 Potentiometer, comp 5 k ±20% 311-0117-00

INSTALLATION INSTRUCTIONS:

See MI - 12919

11-2-67

63/2A63 MODIFICATION SUMMARY

Page 21

INPUT AMPLIFIER RESISTORS CHANGED
TO METAL FILM TYPE FOR IMPROVED

INFORMATION ONLY Ml2911

TEMPERATURE ST ABILITY

Effective Prod SN 9870
FRONT PANEL SYMPTOM: Gain varies and drift occurs with changes in temperature.

PROBLEM: The carbon film resistors used as R457 and R467 have a high temperature

coefficient.

PRODUCTION CHANGE: The resistors used as R457 and R467 were changed to metal

film types.

Parts Removed:

R457, R467

Parts Added:

R457, R467

BE:fb

Resistor, prec, 12.Sk 1/2W 1%

Resistor, prec, MF, 12.Sk l/2W 1/2%

309-0228-00

323-0721-01

Page 22

63/2A63 MODIFICATION SUMMARY

12-1-67

MI - 12919

Type 2A63 Differential Amplifier

®

Serial numbers 101-9503

1 mV GAIN POT CHANGED TO IMPROVE GAIN STABILITY

Most of the time the lm V Gain Adjust potentiometer R460 ends up being adjusted to

some value below
element. This can become an unstable setting later when influenced by time, vibration,
and temperature.

1 k which results in the wiper being near the end of the resistance

With R460 reduced in value from 20 k to

5 k, the adjustment ends up nearer its center

of rotation.

PAR TS REQUIRED

Quantity

1 ea

Tektronix Part Number

311-0117-00

Description

Potentiometer, comp

5 k ±20%

INSTALLATION

Replace the lm V Gain Adjust potentiometer R460 with a 5 k ±20% potentiometer.

BE:fb

11-3-67

PARALLEL REAR CONNECTORS

For the following Tektronix Plug-in Units:
2A61 SN 100- up

63SN 101-1319

2A63 SN 1320- up

67 SN 101-5000

2B67 SN 5001 - up

3Al SN 101 - up

This modification provides two coaxial lines to a
corresponding number of BNC connectors on the rear
panel of the instrument, paralleling the front panel
input connectors or binding posts. The plug-in/
indicator interface is fitted with a pair of mating
holders for miniature coaxial connectors, which per­mit withdrawal of plug-in with out unsoldering cables.

To complete the modification, you must install one
of the following Modification Kits in an RM561,

RM561A, or RM564 indicator: 040-0410-00 pro-

vides two coaxial lines for either right or left
plug-in compartment (but not both); 040-0411-00
provides four coaxial lines for either right or left
plug-in compartment.

Additional kits are available to install one or four
coaxial lines (depending upon plug-in type) in 2-

and 3-series plug-ins.* The connector holders are
the same whether they hold one, two, or four connec­tors, so the plug-ins having various numbers of
connectors are interchangeable. However, to insure
electrical continuity from front to rear panel, the
plug-in and indicator coaxial lines must 'match'.

* 040-0406-00 provides one coaxial line in Types 60,

2A60, 75, 3A75, 67, 2B67, 3B1, 3B3, and 3B4.
040-0408 -00 provides four coaxial lines in Types

3A3 and 3A74.

See LIMITATIONS on page 2 .

3A6 SN 100- up

72SN 101-1419

3A72 SN 1420- up

3B1 SN 101 - up
3B3 SN 100- up
3B4 SN 100- up

DESCRIPTION

®

Publication:
Instructions for 040-0407 -00

March 1967
Supersedes:

July 1966

@ 1966, Tektronix, Inc.

All Rights Reserved.

040-0407-00

Page 1 of 19

LlMITATIONS:

l. Compatibility

Modified plug-ins will not fit in the following indicators: Types 560, 561, 561A, 564, 567,
and RM567. In the Types 567 and RM567 the digital readout connector blocks insertion.
In the others the solid back wall of the plug-in compartment prevents sufficient insertion
of the plug-in to 'mate' the 24-pin connectors on the plug-in and indicator.

Modified plug-ins may be used in the Types RM561, RM561A, RM564, 565, RM565 and

129, although no kits are available to equip the 565, RM565 o,· 129 with rear input connec­tors. Also, there could be noise problems with one of the more sensitive plug-in units
having an open input connector facing into an indicator power supply.

2. Changes in Electrical Characteristics
The system is basically incompatible with conventional XlO or Xl00 high-impedance probes.

This is because the input capacitance of the plug-in is raised to approximately 100 pF, plus
the capacitance of the circuitry attached to the rear connector.

Optimum transient response for 10 MHz instruments may be preserved by terminating at

the front panel connector for signals applied
some degradation of transient response in 10 MHz instruments for signals applied to the

front panel input or terminated at the rear panel. For lower bandwidth instruments, the

only noticeable effect will be that of the increased cable capacitance on signals from
sources greater than 50

n.

to the rear panel connector. There will be

## CONNECTOR EXTRACTION

The Cannon DM series miniature connectors may be removed from their Delrin* holders by
using a special tool available from Cannon Electric Company. Order connector extractor

CET-C6B.
To use the extractor, plunge the tubing down over the connector as far as it will go, then push

the connector out with the inner shaft of the tool.

PARTS LIST

Quantity

(1 ea)

2 ea

l ea

2 ea

lea
l ea

3 ea
4 ea
2 ea
2 ea
2 ea
2 ea

lea
2 ea
2 ea

lea
2 ea
2 ea

l ea

Part Number

131 -0409 -00

35 2 -009 4 -00
(l 62-0531-00)
(l 75-0068-00)
(175-0068-00)

006-0531-00

210-0457-00
210-0802-00
211-0507-00
211-0512-00
316-0151-00
334-1070-00
343-0002-00
343-0088-00
348-0003-00
361-0007-00
385 -0113 -00
385 -0138 -01

Assembly, connector, consisting of:

Connector, coax, Cannon DM53743-5001

Holder, coax connector, Delrin *
Tubing, plastic, #12 3/4in.
Cable, coax, RG-174/U 21 in.
Cable, coax, RG-174/U 2lin.

Tie, cable, nylon, blue
Nut, Keps, 6-32 x 5/16
Washer, steel, flat, 6S
Screw, 6-32 x 5/16 PHS, Phillips
Screw, 6-32 x 1/2 FHS 100°, Phillips
Resistor, comp, 150Q l/4W 10%
Plate, information, 1/4 x l
Clamp, cable, plastic, 3/16in.
Clamp, cable, size C
Grommet, rubber, 5/16in.
Spacer, nylon molded, 0. 063
Rod, nylon, 5/16 x 1-1/8, tap 6-32 w/2 #27 holes
Rod, Delrin, 5/16 x 1-9/16, tap 6-32 w/4 #31 holes

Description

black (heat-shrinkable)
gray-orange-orange
gray-yellow-yellow

*Du Pont Registered Trademark.

Page 2 of 19

040-0407-00

INSTRUCTIONS
A. TO INSTALL CONNECTOR ASSEMBLY (ALL PLUG-INS): RefertoFig.

( ) 1. Mount the connector assembly (from kit) using the existing holes on the rear plate of

the plug-in. Use the 6-32 x 1/2 flat head screws and Keps nuts from the kit. Make

sure the coax cables are in positions J-1 and J-2 as shown.
NOTE: On some instruments, one mounting hole must be drilled through

the chassis lip, in line with the hole in the rear plate.

l.

u~e iN PLACE 01=

MOUNTING- NUT 11::::

PRe'!teNT IN YOUR
INST~UMENT

Fig. 1

040-0407-00

Page 3 of 19

INSTRUCTIONS (cont)

[~ .0

1-11

1-,__,(

Page 4 of 19

040 ... 0407-00

INSTRUCTIONS (cont)
B. TO MODIFY TYPE 2A61:

Refer to Fig. 2.

( ) 1. Dress the coax cables (from connector assembly) through the grommet at the rear of

the chassis, along the wiring cable, and through the grommet in the INPUT SELECTOR

switch shield.

( ) Fasten the coax cables to the wiring cable with blue cable ties from the kit.
( ) 2. Solder the center conductor of the gray-yellow-yellow coax to the same switch

contact as the white-yellow wire (from pin 'A' of INPUT connector).

( ) Solder the coax shield to a ground point on the switch.
( ) 3. Solder the center conductor of the gray-orange-orange coax to the same switch

contact as the white-orange wire (from pin 'B' of INPUT connector).

( ) Solder the coax shield to a ground point on the switch.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 2A61.

( ) Remove the tape backing from the information plate (from kit) and attach the plate to the

front panel just beneath the words "Type 2A61 DIFFERENTIAL . "

( ) Fasten the insert page in your Instruction Manual.

040-0407-00

Page 5 of 19

INSTRUCTIONS

b.O

......

p:,,

Page 6 of 19

040-0407 -00

INSTRUCTIONS (cont)

C. TO MODIFY TYPE 63 or 2A63:

Refer to Fig. 3.

( ) 1. Drill two 5/32 in. holes and mount the 2-hole nylon posts (rods) from the kit at

convenient locations near each end of the chassis. Use the 6-32 x 5/16 PHS screws

from the kit.

( ) 2. Dress the coax cables (from connector assembly) through the nylon posts. Pass the

gray-orange-orange wire through the grommet in the chassis.

( ) 3. Solder the center conductor of the gray-yellow-yellow coax to the +INPUT connector.
( ) Solder the coax shield to the ground lug.

( ) 4. Solder the center conductor of the gray-orange-orange coax to the -INPUT connector.
( ) Solder the coax shield to the ground lug.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 63 OR 2A63.

( ) Remove the tape backing from the information plate (from kit) and attach the plate to the

front panel just beneath the words "DIFFERENTIAL AMPLIFIER".

( ) Fasten the insert page in your Instruction Manual.

040-0407-00

Page 7 of 19

INSTRUCTIONS (cont)

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040-0407 -00

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WI-

INSTRUCTIONS (cont)

D. TO MODIFY THE TYPE 67 or 2B67:

Refer to Fig. 4.

( ) 1. Install the 5/16 in. grommet (from kit) in the cutout in the TIME/DIV switch bracket.

( ) 2. Drill two 1/8 in. holes in the chassis, one just above V24 and the other midway

between V 45 and Vl 35.

( ) 3. Dress the gray-yellow-yellow coax (from connector assembly) through the grommet

installed in step D-1.

( ) 4. Solder the center cmductor of the gray-yellow-yellow coax to the EXT INPUT binding

post and the shield to the ground post.
() 5. Drill out the 'bottom' hole in the support post, near V24, to 1/8in.
( ) 6. Dress the gray-orange-orange coax (from connector assembly) through the post hole

drilled out in step D-5.

( ) 7. Solder the center conductor of the gray-orange-orange coax to the EXT TRIG binding

post and the shield to the ground post.

( ) 8. Secure the coax cables to the chassis by pressing snap-in cable clamps (from kit)

into the holes drilled in step D-2.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 67 OR 2B67.

( ) Fasten the insert page in your Instruction Manual.

040--0407-00

Page 9 of 19

INSTRUCTIONS (cont)

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Page 10 of 19

040-0407 .. oo

INSTRUCTIONS (cont)

E. TO MODIFY TYPES 3Al AND 3A6:

Refer to Figs. 5, 6, and 7.

( ) 1. Temporarily remove the extension shaft which couples the CALIB potentiometer to

the front panel.

( ) 2. Remove the shield between the two VOL TS /DIV switches.

3. Type 3Al SN 101-5049
( ) Drill two 5 /32 in. holes in the shield as indicated in Fig. 6.
( ) Mount a nylon molded spacer (from kit) in the front-most hole in the shield.

4. Type 3Al SN 5050-up and Type 3A6
( ) Drill three 5 /32 in. holes in the shield as indicated in Fig. 5.
( ) Mount nylon molded spacers (from kit) in the two front-most holes in the shield.

5. All Instruments
( ) Mount a 3 /16 in. cable clamp (from kit) in the rear-most of the holes drilled in step

A-3 or A-4 (see Fig. 5). Use a 6-32 x 5/16 PHS screw, flat washer and Keps nut
from the kit.

( ) 6. Replace the shield and the extension shaft (removed in step E -1).

7. Type 3Al
( ) Drill a 5 /32 in. hole in the chassis as indicated in Fig. 7.

( ) Mount a 3/16in. cable clamp (from kit) in this hole, using a 6-32 x 5/16 PHS screw,

flat washer and Keps nut from the kit.

8 .. Type 3A6

( ) Mount a 3/16in. cable clamp (from kit) under one delay line cover mounting screw,

as s.hown in Fig. 5. Use a new 6-32 x 5/16 PHS screw and a flat washer from the

.,__--~•-----

kit.

<?j...~

Fig. 6 3Al Fig. 7 3Al

040-0407-00

Page 11 of 19

INSTRUCTIONS (cont)

0

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Page 12 of 19

crr.J°.=,~.r..:r..:::-~1""L,-:r:..1T..

040 ... 0407-00

1

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I I I I J i I I I

INSTRUCTIONS (cont)

9. All Instruments
( ) Dress the coax cables (from connector assembly) through the cable clamps installed

in steps E-5, E-7, or E-8.

( ) 10. Dress the gray-yellow-yellow coax through the nylon molded spacer in the shield,

solder a 150

the other end of the resistor to the Ch 1 Input connector. Keep resistor leads short.

( ) Solder the coax shield to the grounded lug on the AC-DC-GND switch (or to the

connector ground lug,
NOTE: Dress the coax and resistor as far away from the VOL TS/DIV switch

( ) 11. Dress the gray-orange-orange coax through the nylon molded spacer (if present),

solder a 150

other end of the resistor to the Ch 2 Input connector.

( ) Solder the coax shield to the grounded lug on the AC-DC-GND switch (or to the

connector ground lug, if present).

THIS COMPLETES THE INSTALLATION FOR THE TYPE 3Al OR 3A6.

n 1/4W resistor (from kit) to the coax center conductor, and solder

if present).

variable capacitors as possible.

n l/4W resistor (from kit) to the center conductor, and solder the

( ) Remove the tape backing from the information plate (from kit) and attach the plate in the

upper right corner of the front panel. ·

( ) Fasten the insert page in your Instruction Manual.

F. TO MODIFY TYPE 72 or 3A72:

Refer to Fig. 8.

( ) 1. Temporarily unsolder the white-brown and white-orange wires passing through the

grommet near V593.
( ) 2. Remove the grommet and enlarge the hole to 5/16in.
( ) 3. Install a 5 /16 in. grommet (from kit) in the above hole.
( ) 4. Redress the white-brown and white-orange wires (unsoldered in step F-1) through the

grommet and resolder to their original locations.
( ) 5. Dress the coax cables (from connector assembly) through the 5/16in. grommet.
( ) 6. Dress the gray-yellow-yellow coax beneath the wiring cable which runs 'vertically'

up the chassis, then along the 'top' edge of the chassis to the front.

( ) Solder the coax center conductor to the Ch 1 Input connector, and the coax shield to

the ground lug.

040-0407-00

Page 13 of 19

INSTRUCTIONS ( cont)

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Page 14 of 19

040-0407-00

INSTRUCTIONS (cont)

F. TO MODIFY TYPE 72 or 3A72 (cont):

( ) 7. Dress the gray-orange-orange coax beneath the wiring cable along the 'bottom' edge

of the chassis toward the front.

( ) Solder the coax center conductor to the Ch 2 Input connector, and the coax shield to

the ground lug.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 72 OR 3A72.

( ) Remove the tape backing from the information plate (from kit) and attach the plate in the

upper right corner of the front panel.

( ) Fasten the insert page in your Instruction Manual.

G. TO MODIFY TYPE 3B1:

Refer to Fig. 9.

( ) 1. Unsolder, from the TIME/DV switch, the coax cable which passes through the support

post near Q23.

() 2. Replace the support post with a 4-hole post (rod) from the kit.
( ) 3. Dress the coax cable (unsoldered in step G-1) through the 'bottom' hole in the new

post and resolder to the TIME/DIV switch.
( ) 4. Drill a 5/32 in. hole at the rear of the chassis, as shown in Fig. 9.

CAUTION: Look out for the wiring cable on the other side of the chassis.

( ) 5. In the above hole, mount a 2-hole support post (rod) from the kit. Use a 6-32 x

5 /16 PHS screw from the kit.
( ) 6. Dress the gray-yellow-yellow coax cable (from connector assembly) through the

'top' holes in both the 2-hole and the 4-hole posts.

( ) Solder the coax center conductor to the Delayed SOURCE switch (lug connected to

EXT TRIG binding post). Solder the coax shield to the middle grounded lug of the

switch.

( ) 7. Dress the gray-orange-orange coax cable (from connector assembly) through the

'bottom' hole in the 2-hole post and the second hole from the 'top' in the 4-hole post.

( ) Solder the coax center conductor to the Normal SOURCE switch (lug connected to

EXT TRIG binding post). Solder the shield to the ground lug of the switch.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 3B1.

( ) Fasten the insert page in your Instruction Manual.

040-0407-00

Page 15 of 19

INSTRUCTIONS (cont)

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040-0407 -00

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INSTRUCTIONS (cont)

H. TO MODIFY TYPE 3B3

Refer to Fig. 10.

( ) 1. Unsolder, from the TIME/DIV switch, the coax cable which passes through the

support post near Q23.

( ) 2. Replace the support post with a 4-hole post (rod) from the kit.

( ) 3. Dress the coax cable (unsoldered in step H

post and resolder to the TIME/DIV switch.

() 4. Drill a 5/32in. hole at the rear of the chassis, as shown in Fig.10.

CAUTION: Look out for the wiring cable on the other side of the chassis.

( ) 5. In the above hole, mount a 2-hole support post (rod) from the kit. Use a 6-32 x

5/16 PHS screw from the kit.

( ) 6. Dress the gray-yellow-yellow coax cable (from connector assembly) through the

'top' holes in both the 2-hole and the 4-hole posts.

( ) Solder the coax center conductor to the Delayed EXT TRIG binding post and the

shield to the grounded SOURCE switch terminal.

( ) 7. Dress the gray-orange-orange coax cable (from connector assembly) through the

'bottom' hole in the 2 -hole post and the second hole from the 'top' in the 4 -hole post.

( ) Solder the coax center conductor to the Normal EXT TRIG binding post and the

shield to the ground post.

THIS COMPLETES THE INSTALLATION FOR THE TYPE 3B3.

( ) Fasten the tnsert page in your Instruction Manual.

-1) through the 'bottom' hole in the new

040-0407-00

Page 17 of 19

INSTRUCTIONS (cont)

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Page 18 of 19

040-0407 -00

INSTRUCTIONS (cont)

J. TO MODIFY TYPE 3B4:

Refer to Fig. 11.

( ) l. Drill a 5/32 in. hole in the chassis, slightly above and to the rear of V24.

CAUTION: Look out for the wiring cable on the other side of the chassis.

( ) 2. Drill a 5/32 in. hole in the chassis between Vl61 and Vl 73.

( ) 3. In each of the holes drilled above, mount a 2-hole support post (rod) from the kit.

Use 6-32 x 5/16 PHS screws from the kit.

( ) 4. Dress the gray-yellow-yellow coax cable (from connector assembly) through the

'top' holes in the support posts.

( ) Solder the coax center conductor to the EXT HORIZ IN connector and the shield to

the ground lug.

( ) 5, Dress the gray-orange-orange coax cable (from connector assembly) through the

'bottom' holes in the support posts.

( ) Solder the coax center conductor to the EXT TRIG IN connector and the shield to

the ground lug.

THIS COMPLETES THE INSTALLATION PO R THE TYPE 3B4.

( ) Fasten the insert page in your Instruction Manual.

DW:ls

040-0407-00 Page 19 of 19

PARALLEL REAR CONNECTORS

Types 2A61, 63, 2A63, 67, 2B67, 3Al, 3A6, 72, 3A72, 3B1, 3B3, 3B4 -- All serial numbers

Installed in Type ___ SN ___ Date __ _

GENERAL INFORMATION

This modification provides two coaxial lines to a corresponding number of BNC connectors on
the rear panel of the instrument, paralleling the front panel input connectors or binding posts.

The plug-in/indicator interface is fitted with a pair of mating holders for miniature coaxial

connectors, which permit withdrawal of plug-in without unsoldering cables.
To complete the modification, you must install one of the following Modification Kits in an

RM561, RM561A, or RM564 indicator: 040-0410-00 provides two coaxial lines for either right

or left plug-in compartment (but not both); 040-0411-00 provides four coaxial lines for either

right or left plug-in compartment.

Additional kits are available to install one or four coaxial lines (depending upon plug-in type)
in 2- and 3-series plug-ins. The connector holders are the same whether they hold one, two,
or four connectors, so the plug-ins having various numbers of connectors are interchangeable.
However, to insure electrical continuity from front to rear panel, the plug-in and indicator
coaxial lines must 'match'.

The following chart shows the proper connector on the indicator rear panel for each front panel
input, whether the plug-in is used in the left (vertical) or right (horizontal) compartment:

Using Left Using Right

Instrument Front Panel Input Compartment Compartment

2A61 A INPUT

B INPUT

63/2A63

67/2B67

3Al Ch 1 Input

3A6 Ch 1 Input

72/3A72

3B1

3B3

+ INPUT

- INPUT

EXT INPUT
EXT TRIG

Ch 2 Input

Ch 2 Input
Ch 1 Input

Ch 2 Input

Delayed EXT TRIG
Normal EXT TRIG

Delayed EXT TRIG
Normal EXT TRIG

J -1
J-2

J-1
J-2

J-1
J-2

J-1
J-2

J-1
J-2

J -1
J-2

J -1
J-2

J-1
J-2

J-5
J-6

J-5
J-6

J-5
J-6

J-5
J-6

J-5
J-6

J-5
J-6

J-5
J-6

J-5
J-6

3B4 EXT HORIZ IN

EXT TRIG IN

J -1
J-2

040-0407-00

J-5
J-6

Page 1 of 2

LIMITATIONS:

I . Compatibility

Modified plug-ins will not fit in the following indicators: Types 560, 561, 561A, 564, 567
and RM567. In the Types 567 and RM567 the digital readout connector blocks insertion.
In the others the solid back wall of the plug-in compartment prevents sufficient insertion
of the plug-in to 'mate' the 24-pin connectors on the plug-in and indicator.

Modified plug-ins may be used in the Types RM561, RM561A, RM564, 565, RM565 and

129, although no kits are available to equip the 565, RM565, or 129 with rear input
connectors. Also, there could be noise problems with one of the more sensitive plug-in
units having an open input connector facing into an indicator power supply.

2. Changes in Electrical Characteristics
The system is basically incompatible with conventional XIO or XlO0 high-impedance probes.

This is because the input capacirnnce of the plug-in is raised to approxirra tely 100 pF, plus

the capacitance of the circuitry attached to the rear connector.

Optimum transient response for 10MHz instruments may be preserved by terminating
the front panel connector for signals applied to the rear panel connector. There will be

some degradation of transient response in 10 MHz instruments for signals applied
front panel input or terminateJ at the rear panel. For lower bandwidth instruments, the
only noticeable effect will be that of the increased cable capacitance on signals from
sources greater than 50

## CONNECTOR EXTRACTION

The Cannon OM series miniature connectors may be removed from their Delrin holders by

using a special tool available from Cannon Electric Company. Order connector extractor
CET-C6B.

To use the extractor, plunge the tubing down over the connector as far as it will go, then push

the connector out with the inner shaft of the tool.

ELECTRICAL PARTS LIST

The following parts list applies only to the Type 3Al or 3A6.
Ckt. No.

Rl02-S (Ch
R202-S (Ch 2)

Part Number

1)

316-0151-00
316-0151-00

n.

150S1
150S1

Description

RESISTORS

l/4W
1/4W

comp
comp

10%

10%

to the

at

MECHANICAL PARTS LIST

343-0088-00
343-0002-00
131-0409-00
348-0003-00

352-0094-00

210-0457-00

334-1070-00
385-0138-01

385-0113-00
211-0507-00
211-0512-00
361-0007-00
210-0802-00

Page 2 of 2

040-0407-00

Clamp, cable, size C
Clamp, cable, plastic, 3/16
Connector, coax, Cannon DM53743-5001
Grommet, rubber, 5/16
I folder, coax connector, Delrin
Nut, Keps, 6-32 x 5/16
Plate, information, 1 / 4 x
Rod, Delrin, 5/16 x 1-9/16, tap 6-32 w/4 #31 holes
Rod, nylon, 5/16xl-l/8, tap6-32w/2#27holes
Screw, 6-32 x 5/16 PHS, Phillips
Screw, 6-32 x 1/2 FHS 100°, Phillips
Spacer, nylon molded, 0. 063
Washer, steel, flat, 6S

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MAINTENANCE NOTES

Q454 AND Q464 SOCKETS MUST BE REWIRED TO ACCOMMODATE NEW TRANSISTORS

Q454 and Q464 in the Type 63 were originally Hol­land-made OC170/2Nl516's. The American-made
equivalents of these transistors are not identical

Collector

and will not allow proper phasing between the two
channels.

Base

Mod 3797 (starting approx. SN 350) changes the
OC170's to Philco 2Nl749's (151-081). Wiring to
the sockets for Q454 and Q464 must be changed
slightly to accommodate the new transistors.
Remove the ground from the out-of-line pin and
connect

QUICK-FIX FOR "AC STABILIZED" NEON

In some Type 63 Plug-ins, the "AC Stabilized" neon
bulb sometimes goes out by itself after being turned
on (insufficient sustaining voltage). The problem

it as shown in the diagram at righto

BEFORE

is easily cured by changing R407 from 180 k to 100 k

1/2 w 10%. The change will be made a production

mod (M-6185-63).

FEN 9-29-61

Collector

Base

Strapped

Together

AFTER

FEN 8-10-62

USE 157-066 6DJ8'S FOR EASIER

BALANCING

As mentioned in the 1-12-62 FEN, the selected
6DJ8's for the 503 front end, 157-066, are suitable
for use in the input stage of the 2A63 (similar cir­cuit) to hold down drift, and make balancing easier.

FEN 3-8-63

Production mod M6844-2A63 makes the 157-066

standard in the 2A63, replacing the raw (but selec­ted) 6DJ8' s previously specified.

TEK 2A63 IRE 9-25-64

1

CHARACTERISTICS VS SPECIFICATIONS

GS 7-18-63

There are differences of test specs vs typical oper­ating conditions.

Subjects are included or omitted according to what
is most practical, rather than having a complete

point-by-point description.

TEST SPEC dated January 1961 is used in this com-

parison,

SOLUTION

It is doubtful that all 2A63 units will make this

1.

spec, because they are only QC'd in one
561-A, at one CRT SENSITIVITY.

With some CRT sensitivities along with nor-

5.

mal tolerances a 2.5:1 range may notbepos­sible.

To allow for cycling drift it may be wise to

6.

hold about 3/4 division to meet spec at QC.
Try to obtain at least 1 cm 6CB6 balance, then

with transistor selection obtain a 3/4cm

overall balance before cycling.

There are mixed feelings in Test about this.

7.

They have a little trouble with this balance
spec. Some felt that transistor selection

helped most, others thought tubes. It may be

50-50.

There are two places to watch, other than

8.

usual, for undesireable micro.

One input cap can lay against the gain adj
shaft, and the other cap may be bent down
against the chassis. By physically touching,
both of these would be excited by a fan or
other vibration from a nearby object.

In general they do not count micro as much of
a problem, considering it is a high gain am­plifier.

9. Typically one or two minor divisions.

13. If more than 100:1 rejection is wanted, con­siderable 157 -066 tube selection will be nec­essary. You will find a wide waveform varia­tion from tube to tube when looking at result­ant A-B differential signal, especially when

viewing high levels of common mode signal.

It is possible something may be done regard­ing the 157-066 tube specified for this socket.

In one group of nine tubes tried, only two were
well within rejection specs, which is not a

realistic yield. In another batch of tubes, nine

out of sixteen held A-B rejection capabilities
to 2 volts input, common mode.

It would be helpful, for those of you who have

a few 2A63 plug-ins in your area, if you could
send in some feedback on 157-066 yield and

what you want in the way of performance .
we had more information from the field we
could tell what needs to be done.

.If

2A63 PHASING

There has always been a sort of a problem when
operating two .2A63 in X-Y mode. This arises
from the fact that it is difficult to properly adj the
CRT deflection plate capacity, and that the high
freq response is dictated to a great extent by the
transistors (2Nl749) being used. This transistor

situation was brought to light when Philco (prime

source) said they may stop this transistor produc­tion. We found other brands not as acceptable as
Philco. Basically this is why Mod 7920 was run.

Replace C456, a 2.2 pf ceramic type capacitor,
with a . 7 -3 pf variable tubular type capacitor, 281-

027. This necessitates minor layout change.

PROCEDURE:

Remove C456 (2.2 pf) CSC9 to CSDl0. Remove wire

strap CSD8 to CSD9. Relocate (2) 9-8 wire leads

from CSD9 to CSD8. Relocate R457 (12.5k), and

C459 (24pf) from CSD9 to CSD8.

Add wire strap CSC9-CSD9. Add C456 (.7-3pf)

GS 3-26-64

CSD9-CSD10, outside of strip, and dress so that
adjustment can be made from bottom of instrument.

The following is a discussion of the phase shifting
capability put together by Bruce Hollister of Field

Technical Support.

The 0. 7 -3 pf variable cap is adjusted for zero phase

shift at 1 mv /div with 100 kc in. And that adjustment

holds for frequencies below lO0kc. However, above

l00kc some phase shift does occur.

On one pair of 2A63's, withC456adjustedat lO0kc,
phase shifted 0. 5° at 200 kc and 1 ° at 300 kc. That
looks almost too good to be typical and greater
shift at higher frequencies might be expected.

The variable cap has a total range of about 11 ° at

l00kc.

justed that would result in a range of ±5.5°. So

there is probably plenty of room for adjustment if

a customer wants to make phase measurements at

frequencies between 100 kc and 300 kc.

If it falls near midrange when properly ad-

2

9-25-64

TEK 2A63 IRB

Maintenance notes - continued

EXCESSIVE DC SHIFT REDUCED BY TRANSISTOR CHANGE

DC shift in the 2A63, which was originally spec'd at
2-1/2% with the OC-170 transistors used in early

production, became worse with the change to

2N 17 49' s and the addition of protective circuitry to

All instruments in process were reworked in De­cember 1964. Effective sn was 4945 with about 100
instruments reworked out of sequence between sn
4234 and 4943.

reduce catastrophic failures., The limit \Vas even-

tually deleted. Primary cause of the problem is
thermal shifts in the transistors for small changes
in collector dissipation, aggravated where the Gain
Adj and Variable V /Cm pots are at low settings.

For proper X- Y phasing and bandwidth control, Mod
9106 also reduces the value of C466 from 2.2
l.5pf, adds C455 (l.5pf nominal) across C456, and
adds a series RC network (27pf, 680n)betweenthe

bases of the two transistors. In instruments below
The 2N 17 49' s available after Philco quit making
them showed increased thermal sensitivity, to­gether with oscillation and phasing problems, and
the transistor type was finally elirn.inated from the

sn 3480 modified in the field, these changes plus the
change of C456 to a 0. 7 -3 pf variable (Mod 79 20)
will probably be necessary to restore optimum high

frequency performance.
2A63 by production Mod 9106, replacing both
2Nl749's with 2N2191 (151-0100-00) transistors,
Because of the very short supply of 2N219l's,cur­rent production is shifting to the Motorola MM999
(151-0133-00), which is more expensive but offers
better reliability and the same or better DC shift

Five 2A63's checked for DC shift after Mod 9106 all
showed less than 2 mm ( 1 %) shift for 20 cm step at

1 mv / cm. The 2-1 /2% level will probably not be ex-

ceeded in modified instruments except when the out-

put stage gain is at minimum.
improvement. The mod was designed to use either
type.

Geoff Gass 3-12-65

to

TEK 2A63 IRB 6-16-65

3

file

050-057

Type 63

•

•

REPLACEMENT PARTS INFORMATION

INPUT AMPLIFIER TRANSISTORS

INTRODUCTION:

Transistor TEK 151-081 (2Nl749)
Tektronix Type 63 Plug-in Units

The new transistors have a high

transistors presently availab

amplifier phase shift compe
The minor circuit

ment transistors.

date

changes.

you to use the replace-

January 15, 1962

1516) used in

as

TEK

OC170/2Nl516

To ensure optimum replacing both Q454 and

Q464 with

PARTS
Quant

2

INSTRUCTION

Refer to drawing on .Page 2 and complete the following steps:

() 1. Remove bare strap between Q464, pin 2 and Q454, pin 2 and grounded

notch of adjacent cera mic strip.

() 2. Solder a piece of bare strap (removed in Step 1) between pins 2

and

5 of Q454 and Q464 sockets, as shown in drawing.

() 3. Replace old transistors with new ones fro m kit.

"Philco"

Tek Number

151-081

* * *

January 15, 1962

050 -057

Page 1 of 2

INSTRUCTIONS: (continued)

() · 4. THIS COMPLETES THE INSTALLATION, Recheck your work.

For future reference, correct your Instructions Manual Parts List

and Schematic as required.

Refer to the Calibration Procedure in your Instruction Manual and

recalibrate your instrument as required.

COLLECTOR

BASE.

AFTER

OF Q,454 AND Q.464- SK15

* * *

Sl'Rt>-P'PE.0

iOGtTHE~

_J'

January 15, 1962

050-057

Page 2 of 2

INPUT AMPLIFIER TRANSISTORS

For the Following Tektronix Plug-ins:
Type 63 serial numbers 101-1319
Type 2A63 serial numbers 1320-4944*

DESCRIPTION

Transistor type MM999 (151-0133-00) replaces the
OC170/2Nl516 (151-0015-00) transistors used in
instrument serial numbers 101 through 409 and the
2Nl749 (151-0081-00) transistors used in instru­ment serial numbers 410 through 4944.

The OC170/2Nl516 transistors were replaced be­cause their lower output capacity made it difficult
to attain proper phase-shift compensation. To
make this replacement, it is necessary to rewire
the transistor sockets ,

The 2N 17 49 transistors were replaced because they
are no longer available from the manufacturer.

To insure proper phase-shift compensation in instru­ment serial numbers 101 through 3479, Phase-Shift
Compensating capacitor, C456, must be changed
from a 2.2pf fixed capacitor to an 0.7-3pf variable
capacitor.

To insure optimum performance, it is necessary to
replace both Q454 and Q464 at the same time. The
new transistors, with the associated changes, offer
the following improvements:

1. Reduce second harmonic content, visible when

making phasing adjustment.

2. Prevent oscillation of the Input Amplifier
3, Reduces gain change with temperature and

eases the selec tion of transistors.

NO TE:
above those listed, or if this kit has been installed,
disregard the instructions as P /N 151-0133-00,
MM999, is a direct replacement.

* A few instruments within this range were factory
modified.

If the serial number of your instrument is

Publication:

Instructions for 050-0057-01

May 1965

Supersedes:

050-0057-00

@ 1965, Tektronix, Inc.

All Rights Reserved.

050-0057-01

Page 1 of 3