Tektronix 50 User manual

The following pages contain the text, parts list, andschematics for the
Type 50 Plug-In Module.
This module is designedfor use with Tektronix
Type 560-Series Oscilloscopes.
Insert these pages into the binder you received with the Indicator
Unit manual so that you will have a complete instruction manual for
your oscilloscope.

Instruction Man ua
TYPE 50 AMP

Copyright @ 1961 by Tektronix, lnc.,
Beaverton, Oregon. Printed in the United
States of America. All rights reserved. Con-
tents of this publication may not be repro-
duced in any form without permissiqn of
the copyright owner.
Tektronix Inc. 070-264
P. 0. Box 500
@ Beaverton, Oregon @ Phone: MI 4-0161 @ Cables: Tektronix

Fig. 1. Type 50 Amplifier module.

*
TYPE 50
INTRODUCTION
The Tektronix Type 50 Amplifier, Fig. 1, is designed for
use with Tektronix Type 560-Series Oscilloscopes. It has a
nominal sensitivity of one millivolt per division -that is,
one millivolt of signal at the INPUT connector will produce
a deflection of one graticule division at the oscilloscope
screen. The sensitivity is adjustable, by means of a front-
panel screwdriver adjustment, between about 0.5 and 1.5
millivolts per division. The Type 50 has a bandpass of
15cps to 200 kc and an input resistance of one megohm.
The Type 50 Amplifier is intended primarily to be used
with the Type 51 Sweep module in the Type 560 or Type
AMPLIFIER
561 Oscilloscope for displaying signals produced by
magnetic-ink characters as they are scanned by a magnetic-
ink tester, such as the Kidder Whirly-Sig. A special manual
has been prepared containing instructions for the operation
of these oscilloscopes (with the Type 50 and Type 51
modules) specifically in this application. If you are using
your Type 50 module for this purpose and do not have
the special manual, contact your Tektronix Field Engineer.
This manual describes operating instructions for general
use of the Type 50 module. It also contains a detailed circuit
description of the module, and troubleshooting instructions.
A parts list and schematic diagram are contained at the
rear.
Operating Instructions
Throughout the instructions that follow, it is assumed,
unless otherwise stated, that the Type 50 module is inserted
in the Y-axis opening of a Type 560-Series Oscilloscope,
thereby providing vertical deflection of the trace. If the
module is inserted in the X-axis opening it will provide
horizontal deflection, and the instructions must be inter-
preted accordingly. It is further assumed throughout the
discussion that there is a time-base or sweep module in the
X-axis opening of the oscilloscope.
Signal Connections
The signal to be displayed is applied to the INPUT con-
nector on the front panel of the module. For best results,
the signal should be applied through a shielded cable, with
the shield connected to the chassis of both the oscilloscope
and the signal source. Leads should be kept as short as
possible.
High-impedance attenuator probes are available for
applying the signal to the module. These probes reduce
the resistive and capacitive loading effect of the module
and, at the same time, attenuate the signal to allow 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 50 module, proceed
as follows:
1. Apply the signal (preferably through a shielded cable
or an attenuator probe) to the INPUT connector.
2. Adjust the time-base or sweep controls to obtain a
stable display of the signal.
3. Set the POSITION control on the Type 50 module so
that the waveform
is placed as desired on the graticule.
CALIBRATIONAdjustment
The sensitivity of the Type 50 module is adjusted by
means of the front-panel CALIBRATION adjustment. The
setting of this adjustment should be checked and adjusted,
as necessary, whenever the module is moved from one
oscilloscope opening to the other, due to differences in
cathode-ray tube deflection plate sensitivities. It may also
need to be adjusted when you change the module in 'the
other channel because differences in average output volt-
ages between modules can affect the sensitivity of the crt.
The nominal sensitivity of the Type 50 module is 1 milli-
volt per division. To set the CALIBRATION adjustment for
this sensitivity, proceed as follows:
1. If you are using a Type 560 or Type 565 Oscilloscope,
apply 1 millivolt of Calibrator signal through a shielded
cable to the INPUT connector. If you are using a Type
561
Fig. 2. Five-millivolt Calibrator signal displayed with Type 50
CALIBRATION control set for 1 millivolt per division.

Type 50
Fig. 3. Probe-compensation waveforms.
Oscilloscope, apply 5 millivolts of Cali
brator signal through
a shielded cable to the INPUT connector.
2. Adjust the time-base or sweep controls to obtain a
stable display of several cycles of the Calibrator waveform.
3. Set the CALIBRATION adjustment so that the vertical
portions of the displayed waveform are exactly 1 graticule
division high if you are using the Type 560 or Type 565
Oscilloscope, or 5 divisions high if you are using the Type
561 Oscilloscope. See Fig. 2. (The slope in the top and
bottom of the waveform is due to ac coupling within the
amplifier.)
Probe Compensation
If the attenuator probe is used, its capacitance must be
compensated to that of the module to which it
is connected
for best signal response. To compensate a Tektronix 10X
attenuator probe, proceed as follows:
If desired, you may use a higher-frequency square wave
for compensating the probe. In this case, display several
cycles on the screen, and adjust the variable capacitor in
the body of the probe for the best square-wave response.
Above a frequency of approximately 1 kc, the slope of the
top and bottom of the waveform is not noticeable.
Voltage Measurement
NOTE
When making voltage measurements with the
Type
50 module, make sure there is a common
ground between the oscilloscope and the signal
source.
If you are using a probe, you can estab-
lish this common ground by attaching the ground
clip of the probe to signal ground.
To measure the potential difference between two points
on a signal, such as peak-to-peak ac volts, proceed as
1. Connect the probe to the INPUT connector of the follows:
module.
2. If you are using a Type 560 or Type 565 Oscilloscope,
apply 10 millivolts of Calibrator signal through the probe to
the INPUT connector. If you are using a Type 561 Oscillo-
scope, apply 20 millivolts of Calibrator signal through the
probe to the INPUT connector.
3. Adjust the controls on the time-base or sweep module
to produce a stable display of several cycles of the Cali-
brator waveform.
1. Measure the vertical distance, in graticule divisions,
between the two points whose potential you wish to meas-
ure.
2. Multiply the measurement obtained in step
1 by the
sensitivity of the module (nominally 1 millivolt per division
if you have set the CALIBRATION adjustment as previously
described) and the attenuation factor, if any, of the signal
probe. This is the potential difference between the two
points measured.
4. Adjust the variable capacitor in the body of the probe Since the Type 50 is an ac-coupled amplifier, it cannot
for the correct signal response, as shown in Fig. 3, center. be used to measure dc voltages.
Circuit Description
The Type 50 Amplifier consists basically of a two-stage The Input Amplifier consists of a cathode-coupled para-
lnput Amplifier and a one-stage push-pull Output Amplifier. phase amplifier stage, V424, and a push-pull transistorized
Overall signal gain through the amplifier is about 20,000; stage. The signal to be displayed is applied through the
1000 in the lnput Amplifier and 20 in the Output Amplifier. INPUT connector to the grid of V424A. V424 converts the

Type 50
single-ended input to a push-pull output which is then
amplified by the second stage. Positive feedback from the
collector of each transistor to the base of the other pro-
vides very high gain in this stage. Negative feedback from
the collector circuit of each transistor to the cathodes of
V424 controls the gain and prevents the circuit from oscillat-
ing.
The gain of the Output Amplifier is controlled by the CALI-
BRATION adjustment, R497, which varies the cathode
degeneration.
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 dc 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 cathode resistors, and therefore through the tubes,
changes. The change in current through each of the Output
Amplifier tubes changes the average plate voltage of each
tube inversely to the other, and the position of the crt
beam is shifted accordingly.
A sample of the signal at the plate of V484
is obtained
at the junction of R487 and R488. This sample is applied
through C488 and the interconnecting plug to the time-base
circuitry as a triggering signal. The signal at the junction
of R487 and R488 has a peak-to-peak amplitude of about
3.5 volts for each division of deflection produced 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 read
that information and have definitely isolated a trouble to the
Type 50 module by the procedures described there.
First, remove the left-hand side panel of the oscilloscope
and check to see if there is heater glow in all tubes in the
module. Replace any in which there is no heater glow.
If there is still no heater glow in any tube, trace out its
heater circuit to find the trouble.
If there is heater glow in all tubes, remove the module
and inspect it closely for damaged or burned components,
loose wires, etc., which could cause trouble. If the visual
inspection does not reveal the source of the trouble, reinsert
the module in the oscilloscope and change all the tubes
and transistors. If this does not eliminate the trouble, it
will be necessary to isolate it by voltage and resistance
checks.
Insert the module in the right-hand opening of the oscillo-
scope and remove the right-hand side panel to gain access
to the wiring and components. You do not need to have
a module in the left-hand opening. If, for some reason, you
do not wish to exchange positions of modules for trouble-
shooting work, use a plug-in extension, Tektronix part no.
013-034, which allows the module to be operated while
extended partially out of the front of the oscilloscope.
Typical voltages to be encountered throughout the unit
are shown on the schematic diagram at the rear of this
manual. Resistance measurements in a circuit will usually
be point-to-point checks, for which the proper values can
be approximated from the schematic diagram. Resistance
measurements from the base to the collector or emitter of
each of the transistors should be in the vicinity of 500
to 700 ohms when the negative ohmmeter lead is connected
to the base, and in the vicinity of 50
k to 80 k when the posi-
tive ohmmeter lead
is connected to the base. Use the
XlOOO range of the ohmmeter when checking transistors;
otherwise, you might damage them.
When the trouble has been isolated, replace the faulty
component.

NOTES
Type 50

RTS LIST

HOW TO ORDER PARTS
Replacement parts are available through your local Tek-
tronix Field Office.
Improvements in Tektronix instruments are incorporated as
soon as available. Therefore, when ordering a replacement
part it is important to supply the part number including any
suffix, instrument type, serial number, plus a modification
number where applicable.
If the part you have ordered'has been improved or re-
placed, your local Field Office will contact you if there
is a
change in part number.

PARTS LlST
Type 50
Values are fixed unless marked Variable.
Capacitors
Tolerance 220% unless otherwise indicated. Telctronix
Part Number
Ckt. No.
SIN Range Description
EMT
EMT
Cer.
Cer.
EMT
C453 .1 ,uf Cer.
C456 2.2
,u,u~ Cer.
C457 101-21
9 18 PP~ Cer.
C457 220-up 12
UP^ Cer.
C460 47
PP~ Cer.
C466 2..2
,u,u~ Cer.
C467 101-21
9 18 PP~ Cer.
C467 220-up 12
PP~ Cer.
C487 2.7
UP^ Cer.
C488 .O1 ,uf Cer.
Resistors
Resistorsare fixed, composition, &lo% unless otherwise indicated.
R400 16Q 5w
R402 101-160X 1 k l/2 W
R408 51 Q
'/2 W
R404 1.2 k 2w
R416 1 meg
l/2 W
Prec.
Prec.
Prec.
Prec.
Prec.
Prec.
Prec. 1
%
POSITION
0:
PARTS LIST - TYPE 50

Resistors (confinved)
Transistors
Electron Tubes
Diodes
X220-up T12-G Germanium Diode
X220-up TI2-G Germanium Diode
Tektronix
Part Number
5% 305-123
WW CALIBRATION 311-141
311-222
302-391
302-221
PARTS LIST - TYPE 50

Mechanics Parts List
Type 50
BUSHING, ALUM. 3/8-32 x 9/16 x .412
CABLE, HARNESS
CHASSIS
CLAMP, CABLE
3/," Plastic
CONNECTOR, CHASSIS MT.
1 contact, female
CONNECTOR, CHASSIS MT.
24 contact, male
FASTENER, PAWL, RIGHT w/stop
GROMMET, RUBBER 3/8
GROMMET, RUBBER
GROMMET, POLYPROPOLENE
x .202 x 3/32
GUIDE, PLUG-IN, 5/8 x I3/l6 w/~/~~ track
KNOB, SMALL BLACK
KNOB, ALUM.
LOCKWASHER, STEEL INT.
#4
LOCKWASHER, STEEL INT. #6
LOCKWASHER, STEEL INT. l/4
LOCKWASHER, STEEL INT. POT,
3/8 x 1/,
LOCKWASHER, STEEL INT., 3/8 x '
LOCKWASHER, STEEL, INT. '/,
LUG, SOLDER SE4
LUG, SOLDER SE6 w/2 wire holes
LUG, SOLDER POT, PLAIN,
3/8
LUG, GROUND .025 x l5A6
NUT, HEX 4-40 x 3/1 6
NUT, HEX 6-32 x '/4
NUT, HEX 3/8-32 x Y2
NUT, HEX BUSHING, 3/8-32 x x 1 Yl6
NUT, HEX '/4-28~~/~
PANEL, FRONT
PLATE, REAR
PLATE, FRONT
POST, BINDING
ROD, FRAME
SCREW
4-40~ '/4 BHS
SCREW
4-40 x 3/8 BHS
SCREW
4-40 x 3/8 RHS
SCREW
4-40 x 5/16 PAN HS w/lockwasher
SCREW 6-32 x l/4 BHS
Tektronix
Part Number
358-010
179-490
441-349
343-008
131-081
131-149
214-052
348-004
348-005
348-031
351-037
366-044
366-109
210-004
210-006
210-011
210-012
210-013
210-046
210-201
210-202
210-207
210-241
210-406
210-407
210-413
210-429
210-455
333-634
387-581
387-583
129-053
384-566
PART LIST- TYPE 50

Mechanical Parts List (continued] Tektronix
Part Number
SCREW 6-32
x 3/8 BHS
SCREW 6-32
x 5/16 FHS 100°, CSK, Phillips
SCREW 8-32x FHS 100°, Phillips
SCREW 8-32
x 1/2 RHS Phillips
SCREW, THREAD CUTTING 4-40
x '/4 PHs, Phillips
SCREW, THREAD CUTTING 5-32
x 3/16 PHs, Phillips
SCREW 2-32
x 5/16 RHS Phillips
SOCKET STM7
SOCKET,
9 PIN SHIELDED BASE
SOCKET, 4 PIN TRANSISTOR
SPACER, NYLON
3/16 (For Ceramic Strip)
STRIP, CERAMIC
7/16 x 3 notches, clip mounted
STRIP, CERAMIC
x6 x 5 notches, clip mounted
STRIP, CERAMIC
x6 x 11 notches, clip mounted
TAG, SERIAL NO. INSERT
TUBING, PLASTIC INSUL., #20 BLACK (Skein)
WASHER, STEEL 6L x
3/8 x .032
WASHER, STEEL .390 x
9/16 x .020
PART LIST- TYPE 50

V494 V484
OUTPUT
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TYPE 50 PLUG-IN
C402, R40'1 J
I
REMOVED S/N 161