Tektronix 310A User manual

IV IA IM L J A L
Tektronix, Inc.
S.W. Millikan
070-0893-00
Serial Number
TYPE
310M
OSCILLOSCOPE
Way • P. O. Box 00 • Beaverton, Oregon 9700 • Phone [phone] • Cables: Tektronix
669

WARRANTY
All Tektronix instruments are warranted
against defective materials and workman
ship for one year. Tektronix transformers,
manufactured in our plant, are warranted
for the life of the instrument.
Any questions with respect to the war
ranty mentioned above should be taken
up with your Tektronix Field Engineer.
Tektronix repair and replacement-part
service is geared directly to the field,
therefore all requests for repairs and re
placement parts should be directed to the
Tektronix Field Office or representative
in your area. This procedure will assure
you the fastest possible service. Please
include the instrument Type and Serial or
Model Number with all requests for parts
or service.
Specifications and price change privi
leges reserved.
Copyright c 1969 by Tektronix, Inc.,
Beaverton, Oregon. Printed in the United
States of America. All rights reserved.
Contents of this publication may not be
reproduced in any form without permis
sion of the copyright owner.

Type 310A

TYPE 310A OSCILLOSCOPE
SERIAL ^VERTICAL AMP]
------ v
VOLTS/DIV
HORIZONTAL
POSITION
VERTICAL
POSITION
SCALE ILIU M
INTENSITY
FOCUS
, ----- CALIBRATOR
m il M il 10 H««
E BASE
■TlME/DIV.
stability
RIG. IEVEI
M N CA llM A TID
iM I t
«XT
HO tlZ. M isr
ADJUST
TEKTRONIX. INC
LANO. O tfO O N U S-A
Fig. 1-1. The Type 31OA Oscilloscope.
Type 310A

SECTION 1
TYPE 310A SPECIFICATION
Type 310A
Change information, if any, affecting this section will be fo nd at the rear of the man al.
Introduction
The Tektronix Type 310A Oscilloscope is a portable
precision instr ment designed for eq ipment maintenance
or calibration at its point of se. A DC to fo r megahertz
vertical system provides calibrated deflection factors from
0.01 to 50 volts/division (0.01 to 0.05 volts/division AC
co pled only). The trigger circ its provide stable triggering
over the f ll vertical bandwidth. The horizontal deflection
system provides calibrated sweep rates from 0.2 second to
0.5 microsecond/division. A X5 magnifier allows each
sweep rate to be increased five times and provides a maxi
m m sweep rate of 0.1 microsecond/division in the .5 j SEC
position. X - Y meas rements can be made by applying the
vertical (Y) signal to the vertical INPUT connector and the
horizontal (X) signal to the EXT HORIZ INPUT binding
post on the rear panel (Horizontal Display switch set to
EXT HORIZ). The reg lated DC power s pplies maintain
constant o tp t over a wide variation of line voltages and
freq encies. Total power cons mption is abo t 175 watts.
This instr ment will meet the electrical characteristics
listed in Table 1-1 following complete calibration as given
in Section 5. The performance check proced re given in
Section 5 provides a convenient method of checking instr 
ment performance witho t making internal checks or
adj stments. The following electrical characteristics apply
over a calibration interval of 500 ho rs after a warm p time
of 20 min tes.
TABLE 1-1
ELECTRICAL
Vertical Deflection System
Characteristic Performance Characteristic Performance
Deflection Factor
Calibrated range
.01,.02 and .05
volts/division
(AC only)
3.5 megahertz or greater.
DC co pled 0.1 volt/division to 50 volts/
division in 9 steps. Steps in 1-2-5
seq ence.
Lower —3 dB point,
AC (capacitive) co 
pled
AC co pled 0.01 volt/division to 50 volts/
division in 12 steps. Steps in
1-2-5 seq ence.
Witho t probe Two hertz or less.
With probe 0.2 hertz or less.
Risetime
Acc racy Within 3% of indicated deflec
tion factor.
.1 to 50 volts/
division Approximately 90 nanoseconds.
Uncalibrated (vari
able) range Contin o sly variable between
steps. Extends maxim m ncali
brated deflection factor to at
.01, .02 and .05
volts/division
(AC only)
A pproxim a tely 100 nano
seconds.
least 125 volts/division. Inp t Co pling AC (capacitive) and DC (direct)
Bandwidth
Upper -3 dB point,
AC (capacitive) and
DC (direct) co pled
.1 to 50 volts/
co pled. Selected by front-panel
Inp t Co pling switch.
Fo r megahertz or greater.
Maxim m Inp t Voltage
Inp t RC Characteristics
Resistance
600 volts + peak AC.
One megohm.
division Capacitance 40 picofarads.
1-1

Specification-Type 310A
Characteristic Performance
Triggering
Trigger So rce Internal, external, or line.
Selected by TRIGGER switch.
Trigger Co pling AC (capacitive) or DC (direct)
co pled. Selected by Trigger
Co pling-Mode switch.
Trigger Polarity Sweep can be triggered from
positive-going or negative-going
portion of trigger signal.
Selected by TRIGGER switch.
Trigger Mode Man al trigger adj stable for
desired level or a tomatic trig
gering at average level of trigger
ing waveform with free-r nning
sweep at 50 hertz repetition rate
in absence of adeq ate trigaer
signal. Selected by Trigger
Co pling-Mode switch.
Trigger Sensitivity
Internal (minim m for
stable triggering)
AC 0.25 division of deflection mini
m m, 30 hertz to one kilohertz;
increasing to two divisions at
fo r megahertz. Typical —3 dB
point, 16 hertz.
DC 0.25 division of deflection mini
m m, DC to one kilohertz;
increasing to two divisions at
fo r megahertz.
AUTO 0.25 division of deflection mini
m m, 60 hertz to one kilohertz;
increasing to two divisions at
two megahertz.
External (minim m
signal for stable
triggering)
AC 0.2 volt minim m, 30 hertz to
one kilohertz; increasing to two
volts at fo r megahertz. Typical
—3 dB point, 16 hertz.
DC 0.2 volt minim m, DC to one
kilohertz; increasing to two volts
at fo r megahertz.
AUTO 0.2 volt minim m, 60 hertz to
one kilohertz; increasing to two
volts at two megahertz.
External Trigger Inp t
Inp t Resistance Approximately one megohm.
Characteristic Performance
Time Base
Sweep Rate
Calibrated range 0.5 microsecond to 0.2 second/
division in 18 steps. Steps in
1 -2-5 seq ence. Each sweep rate
can be increased five times with
the X5 magnifier. Extends fast
est sweep rate to 0.1 micro-
second/division.
Unmagnified time
meas rement ac
c racy over center
eight divisions of
gratic le
Within 3% of indicated sweep
rate.
Magnified time meas
rement acc racy
over center eight
divisions of grati
c le (eq ivalent
magnified sweep
rates given)
0.2 microsecond to
40 millisecond/
division
Within 4% of eq ivalent magni
fied sweep rate.
0.1 microsecond/
division Within 5% of eq ivalent magni
fied sweep rate.
Uncalibrated (vari
able) range Contin o sly variable sweep rate
between steps. Extends slowest
ncalibrated sweep rate to at
least 0.5 second/division.
External Horizontal Operation
Deflection Factor 1.5 volt/division, or less, with
HO RIZ GAIN control f lly
clockwise.
X Bandwidth at Upper
—3 dB Point, DC
(direct) co pled
At least 500 kilohertz.
Inp t Resistance Approximately 100 kilohms.
Calibrator
Wave shape Sq are wave.
O tp t Voltage 0.5 to 100 volts peak to peak in
1 1 steps. Steps in 1-2-5 se
q ence.
Voltage Acc racy Within 3% of indicated o tp t
voltage.
Repetition Rate Approximately one kilohertz.
1-2

Specification—Type 310A
Characteristic Performance
Power S pply
Line Voltage Range
110 volts nominal
117 volts nominal
124 volts nominal
220 volts nominal
234 volts nominal
248 volts nominal
99 to 117 volts.
105 to 124 volts.
111 to 132 volts.
198 to 234 volts.
210 to 248 volts.
222 to 264 volts.
Line Freq ency 50 to 800 hertz (increase line
voltage abo t 4% for correct
reg lation at 800 hertz).
Power Cons mption Approximately 175 watts.
Cathode-Ray T be (CRT)
Gratic le
Type External with variable edge light
ing.
Area Eight divisions vertical by 10
divisions horizontal. Each divi-
sion eq als 0.25 inch.
Characteristic Performance
Beam Mod lation 20 volts peak to peak connected
to CRT CATHODE binding
posts provides trace mod lation
at normal intensity.
TABLE 1-2
PHYSICAL
Dimensions (meas red at
maxim m points)
Height 10 7/8 inches (27.6 centi
meters).
Width 6 15/16 inches (17.6 centi
meters).
Depth 17 11/16 inches (44.9 centi
meters).
Finish Anodized fro n t panel and
chassis. Bl e vinyl painted
cabinet.
STANDARD ACCESSORIES
Standard accessories s pplied with the Type 310A are
listed in the Mechanical Parts List at the rear of this man al.
For optional accessories available for se with this instr 
ment, see the Tektronix, Inc. catalog.
7-3

NOTES

SECTION 2
OPE ATING INST UCTIONS
Type 310A
Change information, if any, affecting this section will be found at the rear of the manual.
General
To effectively se the Type 310A, the operation and
capabilities of the instr ment m st be known. This section
describes the operation of the front-panel controls, gives
first-time and general operating information and lists some
basic applications.
Power Requirements
The Type 31OA can be operated from either a 117-volt
or a 234-volt nominal line-voltage so rce. Two a xiliary
windings in addition to the standard windings allow the
nominal primary voltage to be increased or descreased in
steps of seven volts from 117-volts nominal (to provide
110, 117 or 124 volt nominal operation) or 14 volt steps
from 234-volts nominal (to provide 220, 234 or 248-volt
nominal operation). As the nominal operating voltage is
changed, the reg lating range of the power s pply changes
also, to provide reg lated o tp t voltages with inp t line
voltages abo t 10% lower and 6% higher than the nominal
voltage. The reg lating range for each line voltage that this
instr ment can be wired for is as follows.
110-volts nominal
117-volts nominal
124-volts nominal
220-volts nominal
234-volts nominal
248-volts nominal
99 - 117 volts
105-124 volts
111 -132 volts
198 - 234 volts
210 -248 volts
222 - 264 volts
This instr ment will reg late over a line freq ency range
of 50 to 800 cycles. For correct reg lation at 800 cycles,
increase the minim m line voltage req irement abo t 4%.
Power cons mption is approximately 175 watts. To convert
to a different line voltage than the one for which the instr 
ment is wired, se the following proced re.
1. Disconnect the instr ment from the power so rce.
2. Connect the transformer for the desired line voltage
as shown in Fig. 2-1.
Mm-
99-117
volt*
193-234
volt*
^ ........................ — ^
l 87654321 J
N. __ A
^ 87654321 j
105-124
volts
117-Volt Nominal Connection*
□ c
111-132
volts
j t
k. 87654321 J 87654321 j
210-248
volts
230-Volt Nominal Connections
222-264
volts
2-1
Fig. 2-1. Power transformer primary connections.

Operating Instructions-Type 310A
2-2
Fifl. 2-2, Front- and rear-panel controls and connectors.

Operating Instructions-Type 310A
3. If converting from 117-volt to 234-volt nominal line
voltage or vice versa, change the line-cord power pl g to
match the power-so rce receptacle or se a s itable adap
ter.
4. If converting from 117-volt to 234-volt nominal line
voltage or vice versa, change the line f se as follows:
117-volts nominal 1.6 ampere, slow-blow
234-volts nominal 0.8 ampere, slow-blow
5. Change the voltage tag on the rear of the instr ment
to indicate the correct reg lating range. The new tag can be
obtained from yo r local Tektronix Field Office or repre
sentative. State the reg lating range desired.
This instr ment is designed to be sed with a three-wire
AC power system. If a three- to two-wire adapter is sed to
connect this instr ment to a two-wire AC power system, be
s re to connect the gro nd lead of the adapter to gro nd.
Fail re to complete the gro nd system may allow the
chassis to be elevated above gro nd potential and pose a
shock hazard.
Operating Temperature
The Type 310A is cooled by convection air flow thro gh
the holes in the cabinet. For this reason, it is important to
choose a location for the instr ment where the air flow is
not restricted or the temperat re of the cooling air is not
higher than the ambient temperat re. The clearance pro
vided by the feet at the bottom and rear sho ld be main
tained. Allow several inches clearance on the sides.
A thermal c to t provides thermal protection and dis
connects the power to the instr ment if the internal tem
perat re exceeds a safe operating level. If the thermal c t
o t opens freq ently, choose a different location for the
instr ment which provides better air circ lation, or pro
vides forced-air cooling. An accessory fan base is available
for se with the Type 310A. This fan base is partic larly
sef l when the Type 310A is placed in a permanent loca
tion. In addition to providing forced-air cooling, the fan
base elevates the front of the instr ment. This makes it
easier to view the display and adj st the front-panel con
trols. The fan base can be ordered thro gh yo r local Tek
tronix Field Office or representative.
Operating Position
R bber feet are provided both on the bottom and rear
of the Type 310A. In some locations, it may be easier to
view the display when the instr ment is set on the rear feet.
Flowever, the air flow thro gh the instr ment is restricted
in this position red cing the cooling effeciency. Therefore,
the instr ment may overheat.
CONTROLS AND CONNECTORS
General
A brief description of the f nction and operation of the
front- and rear-panel controls and connectors follows. Fig.
2-2 shows the front and rear panels of this instr ment.
More detailed information is given in this section nder
General Operating Information.
Cathode-Ray Tube (CRT)
FOCUS Provides adj stment for a well defined
display.
INTENSITY Controls brightness of display.
SCALE ILLUM D al p rpose control to determine
gratic le ill mination and to apply
power to the instr ment. In the f lly
co nterclockwise position, power is
off. As the control is rotated clockwise
o t of the detent, power is applied to
the instr ment and the gratic le lights
come on at maxim m intensity. Con
tin ed rotation of the control red ces
the gratic le ill mination.
Vertical
VOLTS/DIV Selects vertical deflection factor in
1-2-5 seq ence (Variable VOLTS/DIV
control m st be in CALIBRATED
position for indicated deflection).
Variable VOLTS/
DIV (not labeled-
red knob concen
tric with VOLTS/
DIV switch)
Provides contin o sly variable ncali
brated deflection factors between the
calibrated settings of the VOLTS/DIV
switch. UNCALIBRATED VERTICAL
light at lower right corner of front
panel indicates when the Variable
VOLTS/DIV control is not in the
CALIBRATED position.
INPUT Inp t connector for vertical deflection
signals.
Inp t Co pling Determines method of co pling inp t
(AC-DC) signal to vertical amplifier.
AC: DC component of inp t signal is
blocked. Low freq ency -3 dB
point is abo t two hertz.
DC: All freq ency components of the
inp t signal are passed to the ver
tical amplifier.
2-3

Operating Instructions-Type 310A
Trigger
TRIGGER
Trigger Co pling-
Mode (AUTO AC
DC)
TRIG LEVEL
STABILITY
PRESET ADJUST
Selects the so rce and slope of the
trigger signal which starts the sweep.
The sweep can be triggered from either
the positive-going or negative-going
portion of the trigger signal in each of
the following so rce positions;
+ EXT —: Trigger signal obtained
from an external signal applied to
the EXT TRIG INPUT binding
post.
+ IN T T rig g e r signal obtained from
vertical deflection system.
+ LINE —: Trigger signal obtained
from a sample of the line voltage
applied to this instr ment.
Determines the method of co pling
the trigger signal to the trigger circ it,
or the trigger mode.
AUTO; Sweep a tomatically triggered
at the average level of the applied
trigger signal when the trigger signal
repetition rate is above abo t 60
hertz. For lower repetition rates or
when an adeq ate trigger signal is
not applied, the sweep free r ns at
abo t a 50 hertz rate. TRIG
LEVEL control is inoperative.
AC: Rejects DC and atten ates signals
below abo t 30 hertz. Accepts sig
nals between abo t 30 hertz and
fo r megahertz. Triggering point
determined by TRIG LEVEL con
trol.
DC: Accepts all trigger signals from
DC to fo r megahertz or greater.
Triggering point determined by
TRIG LEVEL control.
Selects amplit de point on trigger sig
nal where sweep is triggered.
Sets the time-base generator for trig
gered or free-r nning operation. In the
f lly co nterclockwise PRESET posi
tion, the time-base is a tomatically set
for triggered operation.
EXT TRIG INPUT Inp t binding post for external trigger
signal.
Sweep
TIME/DIV Selects sweep rate of the time-base
generator (Variable TIME/DIV control
m st be in CALIBRATED position for
indicated sweep rate).
Variable TIME/
DIV (not labeled-
red knob concen
tric with TIME/
DIV switch)
Provides contin o sly variable ncali
brated sweep rates between the cali
brated settings selected by the TIME/
DIV switch. UNCALIBRATED TIME
BASE light at lower right corner of
front panel indicates when Variable
TIME/DIV control is not in CALI
BRATED position.
Horizontal Display Determines horizontal mode of opera-
(MAG-EXT HORIZ) tion.
XI MAG: Normal sweep at sweep rate
selected by the TIME/DIV switch.
X5 MAG: Magnified sweep at sweep
rate five times faster than setting of
TIME/DIV switch.
EXT HORIZ: Horizontal deflection
provided by an external signal con
nected to the rear-panel EXT
HORIZ INPUT binding post.
Other
VERTICAL Controls vertical position of the trace.
POSITION
HORIZONTAL Controls horizontal position of the
POSITION trace.
CALIBRATOR Selects the peak-to-peak amplit de of
the sq are wave available at the CAL
OUT binding post.
CAL OUT Calibrator o tp t binding post.
UNCALIBRATED TIME BASE: Light indicates that the
horizontal sweep rate is ncalibra
ted.
VERTICAL: Light indicates that the
vertical deflection factor is ncali
brated.
Screwdriver adj stment to provide cor
rect operation of the instr ment in the
PRESET position of the STABILITY
control.
Rear Panel
VERT GAIN ADJ Screwdriver adj stment to set the gain
of the vertical amplifier.
2-4

Operating Instructions—Type 310A
ASTIG Screwdriver adj stment sed in con
j nction with the FOCUS control to
obtain a well-defined display.
CRT CATHODE Inp t binding post for intensity mod 
lating signals.
GND Gro nd terminal to establish a com
mon gro nd between this instr ment
and the so rce of the intensity mod 
lating signal.
Sweep controls
TIME/DIV
Variable
Horizontal Display
500 [tSEC
CALIBRATED
XI MAG
Other controls
VERTICAL POSITION Midrange
HORIZONTAL POSITION Midrange
Rear Panel controls
HORIZGAIN Clockwise
MAG CENTER
HORIZ GAIN
EXT HORIZ
INPUT
GND
Screwdriver adj stment to set the DC
level of the horizontal amplifier so de
flection at the center of the display
does not move when the horizontal
Display switch is set to X5 MAG.
Control to set the gain of the horizon
tal amplifier for external horizontal
operation.
Inp t binding post for external hori
zontal deflection signals.
Gro nd terminal to establish a com
mon gro nd between this instr ment
and the so rce of the external horizon
tal deflection signal.
2. Connect the Type 310A to a power so rce that meets
the voltage and freq ency req irements of the instr ment.
3. T rn the SCALE ILLUM control clockwise from the
PWR OFF detent to t rn on the instr ment. Allow several
min tes warm p so the instr ment reaches a normal opera
ting temperat re before proceeding.
CRT Controls
4. Advance the INTENSITY control ntil the trace is at
the desired viewing level (abo t midrange).
5. Connect the CAL OUT binding post to the vertical
INPUT connector with the 18-inch BNC-to-banana pl g
patch cord (s pplied accessory). For instr ments between
SN 10,000 and 20,474 se an 18-inch banana-pl g patch
cord.
SWEEP CAL Screwdriver adj stment to set the gain
of the horizontal amplifier for correct
normal sweep timing.
FIRST-TIME OPERATION
General
The following steps demonstrate the se of the controls
and connectors of the Type 310A. It is recommended that
this proced re be followed completely for first time famil
iarization with this instr ment.
6. Adj st the FOCUS control for a sharp, well-defined
display over the entire trace length. If foc sed display can
not be obtained, see Astigmatism Adj stment in this sec
tion.
7. Rotate the SCALE ILLUM control thro gho t its
range and notice that the gratic le lines are ill minated as
the control is t rned co nterclockwise (most obvio s with
tinted filter installed). Set the control so the gratic le lines
are ill minated as desired.
Setup Information
1. Set the front-panel controls as follows:
CRT controls
FOCUS
INTENSITY
SCALE ILLUM
Midrange
Co nterclockwise
PWR OFF
Vertical controls
VOLTS/DIV
Variable
Inp t Co pling
.1
CALIBRATED
DC
Trigger controls
TRIGGER +INT
Trigger Co pling-Mode AUTO
TRIG LEVEL Midrange
STABILITY PRESET
Vertical Controls
8. Center the display abo t the center horizontal line
with the VERTICAL POSITION control. The display is a
sq are wave, five divisions in amplit de with abo t five
cycles displayed. If the display is not five divisions in ampli
t de, see Vertical Gain Adj stment in this section.
9. Temporarily disconnect the inp t signal and position
the trace to the center horizontal line with the VERTICAL
POSITION control.
10. Reconnect the inp t signal to the vertical INPUT
connector. Notice that the baseline of the sq are wave is
near the center horizontal line.
11. Set the Inp t Co pling switch to AC. Notice that
the waveform is centered abo t the center horizontal line
(gro nd reference).
2-

Operating Instructions-Type 310A
12. T rn the Variable VOLTS/DIV control thro gho t
its range. Notice that the UNCALIBRATED VERTICAL
light in the lower right corner of the front panel comes on
when the Variable VOLTS/DIV control is moved from the
CALIBRATED position (f lly clockwise). The deflection
sho ld be red ced to abo t two divisions in the f lly co n
terclockwise position. Ret rn the Variable VOLTS/DIV
control to the CALIBRATED position.
Triggering Controls
13. Rotate the TRIG LEVEL and STABILITY controls
thro gho t their range. Notice that neither control has any
effect on the display in the AUTO position of the Trigger
Co pling-Mode switch. Set the TRIG LEVEL control co n
terclockwise and the STABILITY control to PRESET.
14. Temporarily disconnect the inp t signal. Notice that
a reference trace is presented. Reconnect the inp t signal.
15. Set the Trigger Co pling-Mode switch to AC. Slowly
rotate the TRIG LEVEL control clockwise ntil a display
appears. Notice that the display starts near the bottom of
the sq are wave. Contin e rotating the TRIG LEVEL con
trol clockwise and notice that less of the leading edge of the
sq are wave is shown as the TRIG LEVEL control is t rned
toward + (it may be diffic lt to observe this effect d e to
the fast rise of the calibrator waveform).
16. Set the TRIG LEVEL and STABILITY controls
f lly clockwise. Notice that the display drifts across the dis
play area, indicating that the time-base generator is free
r nning.
17. Slowly rotate the STABILITY control co nterclock
wise ntil the display disappears. Now rotate the TRIG
LEVEL control co nterclockwise ntil a stable display
appears. This setting of the TRIG LEVEL and STABILITY
control provides a stable display of this signal, b t may
need readj stment if the signal changes amplit de or repeti
tion rate.
18. Set the STABILITY control to the PRESET posi
tion. The display sho ld again be stable (if not, readj st the
TRIG LEVEL control for a stable display). This position of
the STABILITY control a tomatically provides the correct
STABILITY setting, and can be sed for most applications.
Now, when the inp t signal changes amplit de or repetition
rate, only the TRIG LEVEL control needs readj stment.
19. Set the TRIGGER switch to —INT. The trace starts
on the negative-going part of the sq are wave. Ret rn the
TRIGGER switch to+IN T; the display starts with the
positive-going part of the sq are wave.
20. Set the Trigger Co pling-Mode switch to DC. T rn
the VERTICAL POSITION control clockwise ntil the dis
play becomes nstable or disappears completely (only part
of sq are wave may be visible). Ret rn the Trigger
Co pling-Mode switch to AC; the display is again stable.
Since changing vertical position of the trace changes the DC
level of the internal trigger signal, this demonstration shows
how DC level changes affect DC trigger co pling. Ret rn
the display to the center of the display area.
21. Connect the 10X probe (s pplied accessory) to the
vertical INPUT connector. Connect the probe tip to a line-
voltage so rce. Set the TRIGGER switch to - LINE and
set the VOLTS/DIV switch for a display abo t fo r di
visions in amplit de. If necessary, adj st the TRIG LEVEL
control for a stable display. Notice that the display starts
on the negative-going part of the sine wave. Set the TRIG
GER switch to + LINE; the display starts with the positive
going part of the sine wave. Disconnect the probe.
22. Connect the CAL OUT binding post to the vertical
INPUT connector with the 18-inch BNC-to-banana pl g
patch cord (s pplied accessory) and to the EXT TRIG IN
PUT binding post with an 18-inch banana-pl g patch cord
(for instr ments between SN 10,000 and 20,474 se two
banana-pl g patch cords). Set the TRIGGER switch to
+EXT and the VOLTS/DIV switch to .1. Operation of the
Trigger Co pling-Mode, TRIG LEVEL and STABILITY
controls are the same as described in steps 12 thro gh 20.
23. Disconnect the patch cord from between the CAL
OUT and EXT TRIG INPUT binding posts. Set the TRIG
GER switch to +INT.
Normal and Magnified Sweep
24. Set the TIME/DIV switch to 1 MSEC and note the
CRT display. Then set the TIME/DIV switch to 5 MSEC
and set the Horizontal Display switch to X5 MAG. The
display sho ld be similar to that obtained with the
TIME/DIV switch set to 1 MSEC and the Horizontal Dis
play switch set to XI MAG.
25. T rn the HORIZONTAL POSITION control
thro gho t its range and note that the sweep is magnified
in both directions from the center vertical line. Any 10-
division portion of the magnified sweep can be positioned
onto the viewing area with the HORIZONTAL POSITION
control. Ret rn the TIME/DIV switch to 500 p,SEC, the
Horizontal Display switch to XI MAG and ret rn the start
of the trace to the left edge of the gratic le with the HORI
ZONTAL POSITION control.
26. T rn the Variable TIME/DIV control thro gho t its
range. Notice that the UNCALIBRATED TIME BASE light
in the lower right corner of the front panel comes on when
the Variable TIME/DIV control is moved from the CALI
BRATED position (f lly clockwise). The sweep rate is re
d ced as the Variable TIME/DIV control is t rned co nter
clockwise as indicated by more cycles displayed on the
CRT. Ret rn the Variable TIME/DIV control to the CALI
BRATED position.
External Horizontal
27. Connect the CAL OUT jack to the EXT HORIZ
INPUT binding post on the rear panel with two 18-inch
2-6

Operating Instructions-Type 310A
banana-pl g patch cords. Red ce the INTENSITY control
setting to protect the CRT phosphor.
28. Set the VOLTS/DIV switch to 1, the Horizontal
Display switch to EXT HORIZ and the CALIBRATOR
switch to 5. Advance the INTENSITY control setting ntil
a display is visible (two dots displayed diagonally). The
display sho ld be five divisions vertically and abo t fo r
divisions horizontally.
29. T rn the HORIZ GAIN control on the rear panel
thro gho t its range and notice that the display decreases
horizontally as this control is rotated co nterclockwise.
This control can be sed to provide calibrated external hori
zontal deflection. Disconnect the patch cords and set the
Horizontal Display switch to XI MAG.
Z-Axis Input
30. If an external signal is available (20 volts peak-to-
peak minim m), the f nction of the CRT CATHODE inp t
on the rear panel can be demonstrated. Remove the gro nd
strap from between the CRT CATHODE and GND binding
posts and connect the external signal to both the vertical
INPUT connector and the CRT CATHODE binding post.
Set the TIME/DIV switch to display abo t five cycles of
the waveform and, if necessary, adj st the INTENSITY
control to show blanking. The positive peaks of the wave-
form sho ld be blanked and the negative peaks intensified.
31. Disconnect all eq ipment and replace the gro nd
strap between the CRT CATHODE and GND binding posts.
This completes the basic operating proced re for the
Type 310A. Instr ment operations not explained here, or
operations which need f rther explanation are disc ssed
nder General Operating Information.
TEST SETUP CHART
General
Fig. 2-3 shows the front and rear panels of the Type
310A. This chart can be reprod ced and sed as a test-set p
record for special meas rements, applications or pro
ced res, or it may be sed as a training aid for familiariza
tion with this instr ment.
GENERAL OPERATING INFORMATION
Intensity Control
The setting of the INTENSITY control may affect the
correct foc s of the display. Slight readj stment of the
FOCUS control may be necessary when the intensity level
is changed. To protect the CRT phosphor, do not t rn the
INTENSITY control higher than necessary to provide a
satisfactory display. The light filters red ce the observed
light o tp t from the CRT. When sing these filters, avoid
advancing the INTENSITY control to a setting that may
b rn the phosphor. When the highest intensity display is
desired, remove the filter and se the clear gratic le only.
Apparent trace intensity can also be improved in s ch cases
by red cing the ambient light or sing a viewing hood.
Also, be caref l that the INTENSITY control is not set too
high when changing the TIME/DIV switch from a fast to a
slow sweep rate, or when switching to the external horizon
tal mode of operation.
Astigmatism Adjustment
NOTE
To check for proper setting of the ASTIG adjust
ment, slowly turn the FOCUS control through the
optimum setting. If the ASTIG adjustment is correct
ly set, the vertical and horizontal portions of the dis
play will come into sharpest focus at the same setting
of the FOCUS control. This setting of the ASTIG
adjustment should be correct for any display. How
ever, it may be necessary to reset the FOCUS control
slightly when the INTENSITY control is changed.
If a well-defined display cannot be obtained with the
FOCUS control, adj st the ASTIG adj stment on the rear
panel as follows:
1. Connect the CAL OUT binding post to the vertical
INPUT connector and set the VOLTS/DIV switch to pre
sent a two-division display.
2. Set the TIME/DIV switch to 200 pSEC.
3. With the FOCUS and ASTIG adj stments set to mid
range, adj st the INTENSITY control so the rising portion
of the display can be seen.
4. Set the ASTIG adj stment so the horizontal and ver
tical portions of the display are eq ally foc sed, b t not
necessarily well foc sed.
5. Set the FOCUS control so the vertical portion of the
trace is as thin as possible.
6. Repeat steps 4 and 5 for best overall foc s. Make
final check at normal intensity.
Graticule
The gratic le of the Type 310A is scribed on the clear
plastic faceplate protector. The gratic le is marked with
eight vertical and 10 horizontal divisions. Each division is
1/4-inch sq are. In addition, each major division is marked
off in five minor divisions at the center vertical and hori
zontal lines. The vertical gain and horizontal timing are
calibrated to the gratic le so acc rate meas rements can be
made from the CRT. The ill mination of the gratic le lines
can be varied with the SCALE ILLUM control. Fig. 2-4
shows the gratic le of the Type 310A and defines the vari
o s meas rement lines. The terminology defined here is
sed in all disc ssions involving gratic le meas rements.
When making waveform meas rements sing the grati
c le, be caref l that errors are not introd ced into the
2-7

rsj
60
®
TYPE 310A TEST SETUP CHART
Fig. 2-3.
Operating Instructions-Type 310A

Operating Instructions-Type 310A
Sec
vert
lii
ond Cei
ical ver
ie li
'ter Te
icol veri
' • li
ith
teal
ie
Center
line IIH
Fig. 2-4. Definition of measurement lines on Type 310A graticule.
meas rement d e to parallax. Fig. 2-5 ill strates how paral
lax affects a meas rement. To minimize meas rement
errors d e to parallax be s re that the gratic le is installed
so the scribed side is toward the CRT face. Also, when
making the meas rement, attempt to position yo r eye on
a viewing plane perpendic lar to the CRT face. The grati
c le, tinted filter or similar clear plastic protector sho ld be
sed at all times to prevent permanent damage to the CRT
face.
Light Filter
The tinted light filter provided with the Type 31OA
minimizes light reflection from the face of the CRT to
improve contrast when viewing the display nder high am
bient light conditions. To install the filter, remove the fo r
bezel n ts on the gratic le cover and remove the cover.
Place the filter on the mo nting st ds and replace the grati
c le cover and bezel n ts. The filter can be sed with or
witho t the gratic le.
Vertical Gain Check
To check the vertical gain, set the VOLTS/DIV switch to
.1 and the CALIBRATOR switch to .5. Connect the CAL
OUT binding post to the vertical INPUT connector with the
18-inch BNC-to-banana pl g patch cord (s pplied acces
sory). (For instr ments between SN 10,000 and 20,474 se
an 18-inch banana-pl g patch cord.) The vertical deflection
sho ld be exactly five divisions. If not, adj st the rear panel
VERT GAIN adj stment for exactly five divisions of deflec
tion NOTE
For the most accurate vertical gain adjustment and
best measurement accuracy, use the vertical gain ad
justment procedure given in the Calibration section.
The best meas rement acc racy when sing a probe is
provided if the VERT GAIN adj stment is made with the
probe installed. This compensates for any inacc racies of
the probe. Also, to provide the best meas rement acc racy,
calibrate the vertical gain of the Type 310A at the tempera
t re at which the meas rement is to be made.
Fig. 2- . Effect of parallax on measurement accuracy.
Signal Connections
In general, probes offer the most convenient means of
connecting a signal to the vertical INPUT connector of the
Type 310A. Tektronix probes are shielded to prevent pick
p of electrostatic interference. A 10X atten ator probe
offers a high inp t impedance and allows the circ it nder
test to perform very close to normal operating conditions.
However, a 10X probe also atten ates the inp t signal 10
times. A IX probe can be sed for signal connection, al
tho gh it does not provide as high an inp t impedance and
may res lt in a lower overall bandwidth. Specialized probes
are also available from Tektronix, Inc. for high-voltage
meas rement, c rrent meas rement, etc. See the Tektronix,
Inc. catalog for characteristics and compatibility of probes
for se with this system.
In applications req iring maxim m overall bandwidth,
se coaxial cables terminated in their characteristic impe
dances at the Type 310A vertical INPUT connector. High-
level, low-freq ency signals can be connected directly to
the Type 310A vertical INPUT connector sing the BNC-
to-BNC patch cord or BNC-to-banana pl g patch cord
(s pplied accessory). This co pling method works best for
signals below abo t one kilohertz and deflection factors
above one volt/division. When this co pling method is
sed, establish a common gro nd between the Type 310A
and the eq ipment nder tost. Attempt to position the
leads away from any so rce of interference to avoid errors
in the display. If interference is excessive with nshielded
leads, se a coaxial cable or a probe.
Loading Effect of the Type 310A
As nearly as possible, sim late act al operating condi
tions in the eq ipment nder test. Otherwise, the eq ip-
2-9

Operating Instructions-Type 310A
ment nder test may not prod ce a normal signal. The 10X
atten ator probes mentioned previo sly offer the least cir
c it loading. See the probe instr ction man al for loading
characteristics of the individ al probes.
When the signal is co pled directly to the vertical INPUT
connector of the Type 31OA, the inp t impedance is abo t
one megohm paralleled by abo t 40 picofarads. When the
signal is co pled to the vertical INPUT connector thro gh a
coaxial cable, the effective inp t capacitance is increased.
The act al inp t capacitance depends pon the type and
length of cable sed and the freq ency of the signal.
Ground Considerations
Reliable signal meas rements cannot be made nless this
oscilloscope and the nit nder test are connected together
by a common reference (gro nd) lead in addition to the
signal lead or probe. Altho gh the three-wire AC power
cord provides a common connection when sed with eq ip
ment with similar power cords, the gro nd loop prod ced
may make meas rements impossible. The gro nd straps
s pplied with the probes provide an adeq ate gro nd. The
shield of a coaxial cable provides a common gro nd when
connected between two coaxial connectors (or with s it
able adapters to provide a common gro nd). When sing
nshielded signal leads, a common gro nd lead sho ld be
connected from the Type 310A chassis to the chassis of the
eq ipment nder test.
Input Coupling
The Inp t Co pling switch (AC DC) allows a choice of
the inp t co pling method. The type of display desired and
the applied signal will determine the co pling sed.
The DC co pling position can be sed for most applica
tions. This position allows meas rement of the DC compo
nent of a signal. It m st also be sed to display signals
below abo t 20 hertz (two hertz with a 10X probe) as they
will be atten ated in the AC position.
In the AC co pling position, the DC component of the
signal is blocked by a capacitor in the inp t circ it. The
low-freq ency response in the AC position is abo t two
hertz (—3 dB point). Therefore, some low-freq ency atten
ation can be expected near this freq ency limit. Atten a
tion in the form of tilt will also appear in sq are waves
which have low-freq ency components. The AC co pling
position provides the best display of signals with a DC com
ponent that is m ch larger than the AC component.
Deflection Factor
The amo nt of vertical deflection prod ced by a signal is
determined by the signal amplit de, the atten ation factor
of the probe (if sed), the setting of the VOLTS/DIV
switch and the setting of the Variable VOLTS/DIV control.
The calibrated deflection factors indicated by the VOLTS/
DIV switch apply only when the Variable VOLTS/DIV con
trol is set to the CALIBRATED position.
The Variable VOLTS/DIV control provides variable ( n
calibrated) vertical deflection factors between the cali
brated settings of the VOLTS/DIV switch. The Variable
VOLTS/DIV control extends the maxim m vertical deflec
tion factor of the Type 31 OA to at least 125 volts/division
in the 50 position.
Trigger Source
I NT. For most applications, the sweep can be triggered
internally. IntheIN T position of the TRIGGER switch, the
trigger signal is obtained from the vertical deflection sys
tem. The sweep is triggered from the same waveform that is
displayed on the CRT.
EXT. An external signal connected to the EXT TRIG
INPUT binding post can be sed to trigger the sweep in the
EXT position of the TRIGGER switch. The external signal
m st be time-related to the displayed signal to prod ce a
stable display. An external trigger signal can be sed to
provide a trigger display when the internal signal is too low
in amplit de for correct triggering, or contains signal com
ponents on which it is not desired to trigger. It is also sef l
when signal tracing in amplifiers, phase-shift networks,
wave-shaping circ its, etc. The signal from a single point in
the circ it nder test can be connected to the EXT TRIG
INPUT binding post. Then the sweep is triggered by the
same signal at all times. This allows amplit de, time rela
tionship or wave shape changes of signals at vario s points
in the circ it to be examined witho t resetting the trigger
controls.
LINE. The LINE position of the TRIGGER switch con
nects a sample of the power- line freq ency to the trigger
circ it. Line triggering is sef l when the inp t signal is
time-related to the power-line freq ency. It is also sef l
for providing a stable display of a line-freq ency compo
nent in a complex waveform.
Trigger Coupling
AC. In the AC position of the Trigger Co pling-Mode
switch, the DC component of the trigger signal is blocked.
Signals with low-freq ency components below abo t 30
hertz are atten ated. In general, AC co pling can be sed
for most applications. However, if the sweep is to be trig
gered at a low repetition rate or a DC level, se the DC
position of the Trigger Co pling-Mode switch.
The triggering point in the AC position depends pon
the average voltage level of the trigger signal. If the trigger
signals occ r in a random fashion, the average voltage level
will vary, ca sing the triggering point to vary also. This shift
of the triggering point may be eno gh to make it impossible
to maintain a stable display. In s ch cases, se DC trigger
co pling.
DC. DC trigger co pling can be sed to provide stable
triggering with low-freq ency signals wnich sho ld be atten
ated in the AC position, or with low-repetition rate sig
nals. It can also be sed to trigger the sweep when thp
2-10

Operating ln$truction$-Type 310A
trigger signal reaches a DC voltage level selected by the
setting of the TRIG LEVEL control. When sing the inter
nal trigger so rce, the setting of the VERTICAL POSITION
control affects the DC triggering point.
Trigger Slope
The TRIGGER switch selects the triggering slope as well
as the so rce. Each so rce selected by the TRIGGER
switch provides both + and — slope selection. When the
TRIGGER switch is in a + (positive-going) position, the
trigger circ its respond to the positive-going portion of the
triggering waveform; in a — (negative-going) position, the
trigger circ its respond to the negative-going portion of the
triggering waveform (see Fig. 2-6). Since this instr ment
does not have an internal delay line, the display may not
start-on the selected slope, partic larly when the displayed
waveform has a high repetition rate. When several cycles of
a signal appear in the display, the triggering slope is often
nimportant. However, if only a certain portion of a cycle
is to be displayed, correct setting of the TRIGGER switch
is important to provide a display of the desired portion of
the inp t signal.
Stability Control
The STABILITY control determines whether the time-
base generator is free-r nning, triggerable, or not trigger-
able when the Trigger Co pling-Mode switch is set to AC or
DC. When the STABILITY control is set f lly clockwise,
the time-base generator is free-r nning at a repetition rate
determined by the setting of the TIME/DIV switch. As the
STABILITY control is t rned co nterclockwise, the free-
r nning condition ends when the control is near midrange
(TRIG LEVEL control set f lly clockwise). At this setting
of the STABILITY control, a triggered display can be ob
tained with the TRIG LEVEL control (adeq ate trigger sig
nal applied). In the f lly co nterclockwise position (not in
PRESET detent), the time-base generator is inoperable and
cannot be triggered. The PRESET position a tomatically
sets the time-base generator for triggerable operation with
most trigger signals. In this position, only the TRIG LEVEL
control needs to be adj sted to obtain a stable display. The
STABILITY control is inoperable in the AUTO position of
the Trigger Co pling-Mode switch.
Trigger Preset Adjustment
The PRESET ADJUST is normally adj sted d ring in
str ment calibration (see Calibration section) and sho ld
not need readj stment d ring normal se. However, the
following proced re can be sed to set the PRESET AD
JUST if the Type 31OA cannot be triggered correctly. Be
fore readj sting the PRESET ADJUST, be s re the trig
gering controls are correctly set and the applied trigger
signal is within the req ired limits.
1. Set the TIME/DIV switch to 1 MSEC.
2. Set the Trigger Co pling-Mode switch to AUTO.
3. T rn the PRESET ADJUST f lly co nterclockwise.
®
4. Slowly t rn the PRESET ADJUST clockwise ntil
the trace first appears. Note the position of the PRESET
ADJUST.
5. Contin e to slowly t rn the PRESET ADJUST clock
wise ntil the trace brightens. Again note the position of
the PRESET ADJUST.
6. Set the PRESET ADJUST halfway between the point
where the trace first appeared in part 4 and where the trace
brightened in part 5.
Trigger Level
The TRIG LEVEL control determines the voltage level
on the triggering waveform at which the sweep is triggered
(Trigger Co pling-Mode switch set to AC or DC). When the
TRIG LEVEL control is set in the + region, the trigger
circ it responds at a more positive point on the trigger
signal. In the — region, the trigger circ it responds at a
more negative point on the trigger signal. Fig. 2-6 ill strates
this effect with different settings of the TRIGGER switch.
The TRIG LEVEL control is inoperative in the AUTO posi
tion of the Trigger Co pling- Mode switch.
To set the TRIG LEVEL control, first select the trigger
so rce, slope and co pling. Then set the STABILITY con
trol to the PRESET position. Now, rotate the TRIG
LEVEL control f lly co nterclockwise and slowly t rn it
back clockwise ntil a stable display appears. F rther rota
tion in the clockwise direction ca ses the sweep to trigger
at a more positive point on the triggering waveform. If a
stable display cannot be obtained in this manner with the
STABILITY control set to the PRESET position, se the
following proced re; (be s re an adeq ate trigger signal is
available):
1. Set the TRIG LEVEL control f lly clockwise.
2. Set the STABILITY control f lly clockwise and then
rotate it co nterclockwise ntil the free-r nning display
j st disapppears.
3. Rotate the TRIG LEVEL control co nterclockwise
ntil a stable display is obtained.
Trigger Mode
The Trigger Co pling-Mode switch (concentric with the
TRIGGER switch) selects the operating mode of the trig
gering circ its. When this switch is in the AC or DC posi
tions, the trigger circ its operate in the normal triggering
mode. The TRIG LEVEL and STABILITY controls m st
be adj sted to obtain a stable display. When a trigger signal
is not present, there is no display. Use the normal triggering
mode to display signals with repetition rates below abo t
60 hertz, or when it is desired to select the triggering point
on the displayed waveform. This mode provides an indica
tion of an adeq ate trigger signal as well as the correctness
of trigger control settings, since there is no display witho t
correct triggering. For information on selecting the trigger
2-11

Operating Instructions-Type 310A
Waveforms obtained with the TRIG LEVEL
control set in the + region.
STABILITY
Waveforms obtained with the TRIG LEVEL
control set in the — region.
2-12 ®
Fig. 2-6. Effect of the TRIG LEVEL control and triggering slope selection on the CRT display.