Tektronix 321 A User manual

]VTANIJAL Seriol Number 6r/ S-
Teklronix, lnc.
S.W. Millllon Woy O P. O. Box 500 a Beoverton, Oregon 97005 O phone 641-0'16l O Cobles, Tektronix
070-0891-00 1168
L
L
r NSTFrUrdrroN
TYPE 327A
oscil.LoscoPE
STY6OOO up
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WAR RANTY
All Tdktronix instruments are warranted
against defective materials and workmanship
for one year, Tektronix transformers, manu-
factured in our own plant, are warranted for
the life of the instrumslt.
Any questions with respect to the war'
ranty mentioned above should be taken up
with your Tektronix Field Engineer.
Tektronix repair and replaement-part
service is geared direetly to the fleld, there-
fore all requests for repain and replacement
parts should be directed to the Tektronix ,
Field Office or Representative in'your irea.
This procedure will assure you the fastest
, possible service. Please include the instrument
Type and Serial number with all requests for
parts or service.
Specifications and price change privileges
reserved.
Copyright @) 1968 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 wilhout permission of the
copyright owner.
!
.A
Type 321A
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CONTENTS
Type 321A Specification
Operating I nstructions
Circuit Description
Maintenance
Perf ormance Check/Cal ibration
Abbreviations and Symbols
Parts Ordering lnformation
Electrical Parts List
Mechanical Parts List lnformation
Mechanical Parts List
Diagrams
Mechanical Parts List lllustrations
Accessories
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7
Section 8
Abbreviations and symbols used in this manual are
based on or taken directly from IEEE Standard
260 "Standard Symbols for Units", MIL-STD-128
and other standards of the electronics industry.
Change information, if any, is located at the rear of
this manual.
EType 32tA
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TYP' 321A TRIGGERING
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Fi& l-1, The Type 32lA Oscilloscope.
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sEcrror t
TY PE 32IA SPEC' F'CAT'ON
lntroduction
The Tektronix Type 321A is a portable instrument of
solid-state design that combines small size and light weight
with the ability to make precise waveform measurements.
The instrument is mechanically constructed to withstand
the shock, vibration and other environmental extremes
associated with portability. A DC to six m@ahertz vertical
system provides calibrated deflection factors from 0.01 to
20 volts/division.
The trigger circuits provide stable triggering over the full
vertical bandwidth. The horizontal deflection system pro,
vides calibrated sweep rates from 0.5 second to 0.5
microsecond/division. A 5X magnifier allows each sweep
rate to be increased Ilve times (provides a maximum sweep
rate of 0.1 microsecond/division in the .5 gSEC position).
X-Y measurements can be made by applying the vertical
(Y) siqnal to the vertical INPUT connector and the horizon,
tal (X) signal to rhe EXT HORIZ INPUT jack (TtME/D|V
^ switch set to the External Horizontal position).
TABLE.t.1
ELECTRICAL
Characteristic Performance
Vertical Deflection System
Deflection Factor
Calibrated range
Without probe 0.01 volt/division to 20 volts/division
in 1 1 steps. Steps in 1-2 5 sequence.
The Type 3214 can be operated from any one of three
power sources; AC line, external DC or internal batteries
(optional). A power regulator circuit ensures that instru-
ment performance is not affected by variations in internal
battery charge level, applied DC voltage, or AC line voltage
or frequency. l\,4aximum total power consumption is 12
watts for external DC (11.5 to 20 volts DC source) or inter-
nal battery operation and 26 watts when operatd from an
AC line (with trickle charge to batteries). A built-in battery
charger allows rechargeable batteries to be charged from an
AC line voltage source.
This instrument will meet the electrical characteristcs
listed in Table 1-1 following complete calibration as given
in Section 5. The performance check procedure given in
Section 5 provldes a convenient method of checking instru-
ment performance without making internal checks or ad-
justments. The following electrical characteristics apply
over a calibration interval of 1000 hours and an ambient
temperature range of I 50 C to +55' C, except as otherwise
indicated. Warm,up time Jor given accuracy is 20 minutes.
Characteristic Performance
Bandwidth with
Four-Division
Reference (VARI-
ABLE VOLTS/
DIV control at
CALIB)
DC input cou-
pling
AC input cou-
pling
Without probe
wirh P6012
Probe 0.1 volt/division to 200 volts/division
in '1 'l steps. Steps in 1,2-5 sequence.
Within 3% of indlcated deflection
without probe)
Uncalibrated (vari Continuously variable between cali-
brated deflection factor settings.
Extends maxirnum deflection factor to
at least 50 volts/division
able) range
DC to at least six megahertz (-3 dB
points).
Two henz or less to six megahenz or
greater (-3 dB points).
O.2 herlz or less to six megahertz or
greater(3dBpoints).
58 nanoseconds or iess with positive
four'division step input.
Peak aberrations not to exced +2% or
-2o/o: total peak-to-peak aberrations
not to exceed 37o within 300 nano-
seconds atter leading edge of step.
with P6012
Probe
Step Response
Bisetime
Low'frequency
linearity Aberrations
1-1
Change information, if any. affecting this section will be found at the rear of the manual.
Accuracy (with or throughout calibrated range.
0.1 division or less compression or
expansion of a center-screen two-
division signal when positioned to the
top and bottom of the graticule area.
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Without probe
One megohm i2%
41 picofarads 16
pF.
Specif ication-Type 321 A
Characteristic
lnput Coupling
Modes
Maximum lnput
Voltage
DC and AC input
coupling
ELECTRICAL (Cont)
Performance
AC (capacitive) coupled, DC (direct)
coupl;d and internally grounded.
Selected by front-panel lnput Cou-
pling switch.
500 volts (DC + peak AC). Peak'to
peak AC less than 500 volts.
With P6012 Probe
10 megohms 13% AC
8.5 p icofarads 11.5
pF.
Constant within 2olo at all VOLTS/DlV
switch setting.
500 picoamperes or less resulting in
0.05 division or less trace shift at 0.01
VOLTS/DIV
One volt peak to peak minimum, DC
to one kilohertzi increasing to three
volts peak to peak at six megahertz.
One volt peak to peak rninimum,30
hertz to one kilohertz; increasing to
three volts peak to peak at six mega'
hertz.
External Trigger ln 100 kilohms t2oolo paralleled by nine
put RC Character- picofarads t4 pF
istics
Sweep Bate
Calibrated range 0.5 microsecond to 0.5 second/
division in 19 steps. Steps in 1-2"5
sequence. Each sweep rate can be
increased five times with the 5X mag'
nifier. Extends fastest sweep rate to
0 1 microsecond/division.
Perlormance
0.2 division ol deflection minimum,
DC to one kilohertz; increasing to one
division at six megahertz.
0.2 division of deflection minimum at
one kilohert/, increasing to one divi.
sion at six megahertz.
Continuously variable between cali'
brated sweep rate settings- Extends
slowest uncalibrated s1,/eep rate to at
least 1.25 seconds/division.
Within 3% of indicated sweep rate over
center eight divisions of graticule.
Within 5% oI equivalent m4nified
sweep rate over center eight divisions
of graticule.
Characteristic
Trigger Sensitivity
lnternal
DC
AC
External
DC
Trigger Source lnternal or external. Selected by front
nel Triggering Source switch
Triqger Coupling AC (capacitive) coupled or DC (direct)
coupled. Selected by front panel Irig
gering Coupling switch.
lnput RC Character-
istics
Besistance
Capacitance
Time constant
lnput Current
(25" C 15' C)
Trigger Mode
!lweep can be triggered from positive-
oing or negative-going portion of trig-
er signal. Selected by front-panel
SLOPE switch
lvanual triggering adiustable for dq
sired level; automatic triggering at
average level of triggering waveform
with free'running sweep at 50 hertz
!125 hefiz rate in absence of adq
quate triqger signal; free-running at the
repetition rate of the sweep Genera-
tor. Selected by front-panel LEVEL
control.
Uncalibrated {vari-
able) range
Sweep Accuracy
Unmagnified time
meE6urement ac-
curacy. 5X MAG
switch pushed in
Magnif ied time
measurement ac'
curacy, SX l\,4AG
switch pulled out
1-2
Time Base
Triggering
Trigger Polarity
A_
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ELECTRICAL (Cont) Characteristic
Characteristic Performance Maximum power
consumption
External Horizontal Ampli{ier
Deflection Factor One voll/division with 5X magnifier Power switch set
To ON EXT AC.
DC, Charger
switch set to D
Cells
Deflection Accuracy Within '10%.
lnput RC Character- 100 kilohm l5olo paralleled by 25 pico- POWER switch
set to ON EXT
EXT AC.DC,
Charger switch
set to High
istics farads t5 pF
X Bandwidth with DC to at least one megahertz (-3 dB
Four-Division Ref'
erence
Calibrator POWEB sWitch
set to OFF
FULL CHG.
Charger switch
set to High
Waveshape Square wave.
Output Voltage
lnternal 0 millivolts !2%. lnternally connect-
to vertical amplifier in CAL 4 DIV
position of VOLTS/DlV switch
Specif ication-Type 321 A
Performance
26 watts
30 watts
DC Operation
Voltage range 1 1.5 to 35 volts.
lvlaximum current 600 milliamperes.
l\,4aximum power
consumption
1 '1.5 volts DC 6.9 watts
20 volts DC
35 volts DC i watts.
Battery Operation
Batteries 10 size D cells
Operating time pproximately eight hours with fully
charged n ickel-cadmium batteries
(Te k tronix Part No. 146-0010-0O)
within operating temperature range
given in Table 1-2.
Cathode-Fay Tube (CRT)
Graticule
Type External with variable edge lighting
hen operated from AC line
Area ix divisions vertical by 1O divisions
horizontal. Each division equals 0.25
inch.
Geometry 0.1 division or less
, CAL OUT iack +500 millivolts 13%
Repetition Rate Two kilohertz i20%
R isetime One microsecond or less.
Duty Cycle 45o/. to 55o/o.
Z-Axis lnput
Sensitivity Five volts peak,to-peak signal at one
kilohertz provides visible trace modu-
ation at normal intensity_
Coupling C (one megohm and 0.01 micro-
rad )
lnpul Resistance ne megohm !20%
Power Supply
/-\AC Operation
\ Line voltage range
1 15-volts nominal 103.5 to 126.5 votts
230 volts nominal 207 to 253 volts At least 120 markers in 10 divisions
5 to 800 herrz Horizontal Besolu-
tion
1-3
on.
points)
20 watts.
12 watts.
Line Frequency
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Specification-Type 321A
TABLE 1.2
ENVIRONMENTAL
Characteristic
Shock
Operating
Non'operating
Transportation
Performance
Two guillotine type shocks of 20 9,
one-half sine. ll millisecond duration
each direction along each major axis
for a total of l2shocks.
One guillotine-type shocks of 60 g.
one-half sine, 11 millisecond duration
each direction along each majol axis
for a total of 6 shocks.
Ouali{ies under National Safe Transit
Committee test procedure 1A.
Characteristic PerJormance
NOTE
This instrument will meet the electrical characteristics
given in this section over the following environmental
limits. Complete details on environmental test pro-
cedures, including failure criteria, etc., can be ob-
tained from Tektronix, lnc. Contact Your local Tek'
tronix Field Office or representative.
-15"c to +55' c
Non-operating
15' C to +4O" C. Operating time is
reduced at 15" C. Dimensions (meas
ured at maximum
points)
Height B 1/2 inches (21.6 centimeters)
width
Length
Weight
Without batteries Approximately 14 pounds (6.4
k ilograms).
With batteries Approximately 17 1/2 pounds (7.9
kilograms).
F in ish Anodized front panel with chrome
plated front and rear castings. Blue
vinyl painted cabinet.
STANDARD ACCESSORIES
Standard accessories supplied with the Type 32iA are
listed on the last pullout page at the rear of this manual.
For optional accessories available for use with this instru-
ment, see the Tektronix, lnc. catalog.
Temperature
Without batteries
Operating
Operating
(charging)
Altitude
Operating
Humidity
Non-operating
Vibration
Ooeratinq and
non-operating
TABLE 1.3
PHYSICAL
O' C to +40' C.
Non-operating Test limit 50,000 feet
-40" c ro +60"c
Five cycles (120 hours) of N/il Std-
202C, N/lethod '1068. Omit fteeu ing
and vibration. Allow 24-hour post-test
drying period at +25' C 15" C and 2ook
to 80% relative humidity.
15 minutes along each of the three
maior axes at a total displacement of
0.025'inch peak to peak (4q at 55 c/s)
with frequency varied from 10-55'10
c/s in one minute cycles. Hold at 55
c/s for three minutes on each axis.
1-4
-55" c to +75o C.
5 3/4 inches (14.6 centimeters).
16 inches (40.6 centimeters). \_
With batteries
Operating (dis-
charge)
Non-operating
15,000 feet maximum
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General
To effectively use the Type 321A, rhe operation and
capabilities of the instrument must be known. This section
describes selection of the power source, operation of the
front- and rear panel controls and connectors, gives first
time and general operating information and lists some basic
applicatiOns tor this instrument.
OPERATING VOLTAGE
Power Requirement
The Type 32'lA can be operated ,rom either a 11s-volt
or a 230-volt nominal AC line voltage source, from a I l.b
to 35 volt external DC source or from internal batteries.
The following discussions provide the information neces
sary for operation in each mode as well as information on
rechargeable nickel-cadm ium batteries.
AC Operation
A tag on the bottom of the Type 32'lA indicates the
voltage lor which it was wired at the factory. When con
nected {or 115-volt nominal operation, this instrument
provides stable operation over a line voltage ranqe o, 103.5
to '126.5 volts. When connected for 230-volt nominal opera-
tion, stable operation is provided with line voltage varia,
tions between 2O7 and 253 volts. Stable operation is also
provided for line frequencies between 50 and 8OO hertz at
the line voltage for which the instrument is wired.
To convert this instrument to a different nominal line
voltage than the one for which it is wired, use the following
procedure-
2. Connect the transformer for the desired line voltage
as shown in Fig- 2-1.
3. Change the line{ord power plug to match the power-
source receptacle or use a suitable adapter.
1 4. Change lhe voltage tag to indicate the correct nomi-
nal operating voltage. The Tektronix Part No. for the volt-
age tags are:
i 1s'volt nominal, 50-800 hertz
9
5'
6
7
6
A. I I5-volts nominol
8.23o-vohs nohinol
Fi8.2-1. Powel tnnsformer primary connections for ll5- and
230-volt nominal operation.
This instrument is designed to be used with a three,wire
AC power system. lf the three- to two,wire adapter is used
to connect this instrument to a two-wire AC power system,
be sure to connect the ground lead of the adapter to earth
(ground). Failure to complete the ground system may allow
the chassis of this instrument to be elevated above ground
potential and pose a shock hazard.
The AC power cord is connected to the AC portion of
the power receptacle (s€e Fig. 2-2) tot AC operation. When-
ever the instrument is connected to an AC power source,
power is applied to the primary of the power transformer.
This provides power to the battery charger circuit and the
graticule lights in all posirions of the POWER switch except
ON INT BATT. Applications of power to thes€ circuits
allows the batteries to be charged when the instrument is
turned off. Also, the graticule lights are operative for AC
operation only to provide longer operating time from the
internal batteries-
SECT'ON 2
OPERAT'NG'NSTRUCT'ONS
Change information, if any. affecting this section will be found at the rear of tliis manual.
\
E
230-volt nominal. 50-800 hertz
334 0931,00
334-0938-00
2-1
1. Disconnect the instrument from the power source.
Type 321A
5
9
6
7
E
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Operating lnstructions-Type 321 A
Fig. 2-2. Power cord connections to the power receptacle on bot-
tom of irstrument for external AC and DC operation.
For AC of -"ration, t:re instrument is operative when the
POWER switch is set to ON EXT AC-DC. A trickle charge is
also available when using internal rechargeable batteries.
This instrument is inoperative in the OFF TRICKLE CHG
and oFF FULL CHG positions of the POWER switch. The
OFF TB ICKLE CHG position can be considered as the nor-
mal off position for AC operation. However, power is
applied lo the battery charger circuit in both OFF CHG
posilions to recharge internal batteries. For more informa-
tion on charging the batteries, see Battery Operation in this
section.
DC Operation
This instrument can be operatd from an external DC
source by connecting the DC power cord to the DC portion
of the power receptacle (see Fig. 2-2). The DC power cord
is supplied without an input connector. A suitable con-
nector may be added to malch the power source or the
pigtail leads can be used as supplied. Connect the white lead
{ground) and either the black or green lead as follows for
DC operation:
White lead Ground
Black lead +11.5 to +20 volts DC
Green lead +20 to +35 volts DC
WARNING
When this instrument is connected to a DC power
source, the chassis is {loating with respect to earth
(ground). Connect the instrument to earth with a
jumper lead from the front-panel GND post, Opera-
tion without this ground lead is not recommended
due to the potential shock hazard produced if the
chassis becomes elevated with respect to earth.
To turn the instrument on for OC operation, set the
POWER switch to the ON EXT AC-DC position. The insrru-
ment is off in either the OFF TR lC KLE CHG or OFF
FULL CHG position. The internal battery charger is inoper'
ative when connected lor DC operation. Therefore, the
internal batteries cannot be recharged from an external DC
source.
CAUTION
The power receptacle of this instrument is designed
so only one oi the external power cords supplied can
be connected at a time. To prevent damage to this
instrument, do not use power cords which allow both
external power sources to be connected to the instru-
ment at the same tim€.
Battery Operation
Battery Selection. The Type 321A can be operated from
10 size D battery cells. Table 2-1 lists some common size D
battery cells and the approximate continuous operating
time provided by each type. Other types oJ size D batteries
are available for use with this instrumenl. The operating
time provided depends upon the individual characteristics
oJ the batteries.
TABLE 2.1
Common Size D Battery C€lls for Use in the Type 321A
Battery type Advantages and
disadvantages
Standard flash
light cells
Alkaline cells
(such as Ever'
ready E95, Bur-
gess AL 2 or lvlal'
lory lvlN-'1300)
Rechargeable
nickel-cadmium
cells (Tektronix
Part No
146-0010.00).
Most practical
and convenient
frattery type
where battery op
eration is to be
used frequently.
Same as above ex-
cept this battery
type provides ex-
tended operating
time.
Provides econom-
ical battery op-
eration if bat-
teries are used in
frequently; cost
becomes exces
sive when battery
operation is used
repeatedly.
Battery lnstallation and Operation. lnstallation of the
batteries is illustrated in Fig. 2-3. First remove the battery
cover as shown in Fig. 2-3A. Then, following the instruc-
tions given in Fig. 2 38, install the battery cells. Be sure to
observe the battery polarity as printed inside the battery
E
AC
)
20 ro 35 volts
r t.5 20 vo
DC {blo.k)
0C op.r6tion
{whlt }
Continuous
operating
time (approximate)
About 0.5 hour
About 2.5 hours
About eight
hours (may vary
w ith manufac
turer or age of
cells).
2-2
L
7a
n
n
oc
o
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Operating lnstructions-Type 321 A
Loo.o6 lhsmb s<raw to unlo(k
.ov.r, fh.n pull (over lorword 1o
I
t
II
l. temovG bonlry tpo.e.. 2. ln.rall fiva ..ll! i..oci sid.
o, tho bott.ry holdcr. Be suro
to ob3 rue .€ll poloriiy.
IU
3. lnr.rt bottc.y !p.r..r. 4. lnrtell botEry Gov.r.
IE
TBE
Gts I
B
Tt
aa
aI
tI
GtEilI N
5fr
l{f;r mt
@
Iry
m
Fi8. 2-3. (A) Removing the battery cover from thc instrument. (B) installing the battenes.
2-3
,?
{0t
TT (
t
4?r
.-^r
'L)
li
II
Lzz
ti
aoa
o') a,,
!
G
i.l
l'
)
E
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Operating I nstructions-Type 321 A
compartment and on the battery cover. lf non-rechargeable
cells are used. be sure the Charger switch is set to the Dry
Cells position. More complete information is given under
Batlery Charging.
Rechargeable cells obtained from Tektronix, lnc. (Tek-
tronix Part No- 1460010O0) have solder tabs on each end.
These cells can be soldered together to reduce inter cell
contact resistance for improved battery operation.
This instrument can be operated on the internal batteries
over an ambient temperature range of -15'C to +40'C.
However, the maximum operating time and useful battery
life when using rechargeable batteries is provided between
+15" C and +25' C. For operation from the internal bat,
teries, set the POWER switch to the ON INT BATT posi-
tion. This instrument is off in either the OFF TRICKLE
CHG or OFF FULL CHG position. When the instrument is
connectd to an AC lin+voltage source, rechargeable bat-
teries can be charged with the correct setting of the Charger
switch (see Battery Charging). ln the ON INT BATT posi-
tion of the POWEB switch, the battery charqer circuit is
disconnected The LOW BATTERIES light provides an
indication that the batteries have been discharged to near
the minimum level necessary for correct power supply
regulation. Further discharge of the batteries beyond this
lwel not only provides inaccurate measurements but it may
also damage rechargeable batteries.
Battery Charging. When rechargeable battery cells are
used in this instrument, the batteries can be recharged with
the correct setting of the Charger switch. The Charger
switch is located behind the left side panel {see Fig. 24).
When the Charger switch is set to High or Low and the
instrument is connected to an AC line-voltage source, a
trickle charge is connected to the internal batteries in the
ON EXT AC-DC and OFF TRICKLE CHG positions of the
POWEB switch. This trickle charge maintains a full charge
on the batteries without over'charging them. ln the OFF
FULL CHG position of the POWEB $r'itch, the Charger
switch determines the charge rate of the internal batteries.
Iable 2-2 lists the charge rate in each position of the
POWE R and Charger switches at various line voltages within
the regulating range. The rechargeable batteries supplied by
Tektronix, lnc. can be charged in the High position of the
Charger switch at all line voltages. However, batteries ob
tained from other sources should be charged in the Low
position of the Charger switch unless the manufacturer's
specifications state that it will withstand the High position
charge rate. lf necessary, an autotransformer can be used to
lower the line voltage and reduce the charge rate (necessary
only for batteries obtained from sources other than Tek-
tronix, lnc.).
Fig. 24. Location of Chargei switch (left side),
T ABLE 2.2
Charging Current
AC
line
voltage
applied ONE OFF
Approximate charging current (milli-
amp_eres) in each position of the PO- \,
WER switch OFF
FUL ON INT
BATT
109 or
218 volts
115 or
230 volts
121 or
242 volts
103.5 or
2Oi vol
or
253 volts
AC_DC TR ICKLE
CHG CHG
410
Battery
charger
circuil
disconnected
A charqe period of 14 to l6 hours should be sufficient
to charge the battery cells to their full potential. Although
the batteries may not be damaged immediately by longer
charge periods, repeated overcharging will shorten the use-
iul life of the batteries. lf it is desired to maintain a full
charge on the batteries, use the OFF TRICKLE CHG posi,
tion of the POWEB switch. A trickle charge is also applied
to the batteries when operating from an external AC power
source.
The batteries in this instrument can be charged over an
ambient temperature range of 0'C to +40'C. However,
Charger
switch
positions
Low 31 20 160
High 22 34
Low 24 34 180
Hiqh 31 320
27
H igh 4130 360
Low 31 41 220
H igh 44 380
Low 33 44 23A
Hish 48
2-4
WARN ING
When this instrument is operated from internal bat-
teries, the chassis is floating with respect to earth
(ground). Connect the instrument to earth with a
jumper lead from the front-panel GND post. Opera-
tion without this ground lead is not recommended
due to the potential shock hazard produced if the
chassis becomes elevated with respe€t to earth.
ltl o
.l
o@
290
Low 200
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maximum operaling time and useful battery life is provided
when the batteries are charged and discharged at about
+25'C.
During normal usage or storage, the individual battery
cells in this instrument attain slightly different charge
characteristics. To provide the best overall operation and
-..\maximum operating life, the charge on the battery cells
'should be equali.,ed periodically. This can be done without
damage to the battery cells by charging the batteries at the
full,charge rate tot 24 hours. This should be done after
ever occurs first.
Operating I nstructions-Type 321A
o, boric acid in water. A 2% solution of boric acid can be
obtained by dissolving 1 1/4 teaspoons o{ boric acid powder
in one cup of water. After the residue has been cleaned
from the batteries and the battery companment, dry the
wetted area thoroughly with a soft cloth.
ll the total potential across the battery terminals (see
Fig- 2-38) does not reach 13-14 volts even after the recom-
mendd charge time. one or more of the battery cells is
probably de{ective. To locate the defective cell, first be sure
the batteries have been charged for the recommended
charge period. Then, while operating the instrument on the
internal batteries, measure the potential across each individ-
ual cell. Use a meter which has a long, thin probe tip to
reach the contacts between the batteries. lf an individual
battery cell measures below about 1.15 volts, it is probably
defective; above this voltage, the battery cell is probably
operating correctly. lf the total potential across the battery
terminals is 13-14 volts after the recommended charge
period, but the LOW BATTERIES lighl comes on too soon
when operating on internal batteries, the charge retaining
capacity of one or more of the battery cells has probably
decreased below rhe acceptable limits. (NOTE: Batteries
may not be reaching full charge due to a defective charger
circuit.) This can be checked in a manner similar to that
described above. First be sure that the batteries have been
charged for the recommended charge period. Then, operate
the instrument on the internal batleries until the LOW
BATTEBIES light comes on. Now measure the potential
across each cell. lf an individual cell measures below about
1.15 volts, it is probably defective; above this voltage, it is
probably acceptable. lf the voltage of all the cells is above
1.2 volts and the charger circuit is operating correctly. the
LOW BATTERIES circuit may be at fault.
When replacing battery cells in this instrument, charge
the entire set of batteries at the recommended charge rate
and charge period before operating the instrument from the
internal batteries. This equalizes the charqe on all the bat-
tery cells and protects the new cells from polarity reversal
damage. The batteries should be replaced only with cells
which have the same charge rate and charge capacity as
those in the instrument (see Battery Charging for more
information).
Battery Storage. The battery cells used in this instru,
ment may be stored in a charged or partially charged condi,
tion. For best shelf-life when storing individual cells, fully
recharge the battery cells at three to six month intervals.
Although replacement cells obtained from Tektronix, lnc.
are fully charged before shipment, recharge the complete
set of batteries before operating the instrument.
Charge retention characteristics of nickel-cadmium cells
vary with the storage temperature. They may be stored at
any temperature between -4O' C and +60'C without
damage, either in the instrument or as individual cells. How
ever, the self-discharge rate increases with ambient tempera-
ture and humidity. For example, cells stored at +20'C will
lose about 50% of their stored charge in thre€ monlhs but
Nickel-Cadmium Battery I nformation
General, The nickel-cadmium battery cells available
from Tektronix, lnc. for use with this instrument have been
selected as a result of extensive evaluation. Each battery
cell has received an ampere hour test, has met or exceeded
the minimum ampere-hour storage requirement and has
been rigidly inspected. The battery cells used in this instru,
ment should provide a useful operating life extending over
several hundred charge-discharge cycles.
Precautions To extend the useful operating life of the
nickel-cadmium battery cells used in this instrument, ob-
serve the following precaulions.
l. Do not exceed the recommended charge rate and
/.,\ period (see Battery ChargingJ.
2. Be sure the battery charger is operated correctly as
described previously in this section.
3. Be sure to observe the cell polarity when inserting the
batteries (see Fig. 2-38).
4. Excessive discharge of the batteries after the LOW
BATTEBIES light comes on may cause one or more of the
cells to reverse polarity. Although the cells are protected
against immediale damage, repeated polarity reversal will
shonen the useful life of the batteries.
E2-5
5. Observe the temperature limits given in this manual
for battery charging, operation and storage-
Maintsnance, When the battery cells are overcharged or
when discharged to the point of polarity reversal, gas is
formed within the nickel cadmium cells. This gas produces
pressure within the cells. The nickel cadmium cells supplied
by Tektronix, lnc. (Tektronix Part No. '146-0010,00)
incorporate a vent so this internal pressure does not damage
^ the battery. However, as the internal pressure is relieved, a
\small amount of the electrolyte may be expelled with the
gas. Although the cell will probably not be damaged, this
loss oI electrolyte may result in shorter overall battery li{e.
The batteries and battery compartment should be inspected
occasionally for any electrolyte residue on the batteries
themselves or in the battery compartment. Any residue
which is found should be cleaned away with a 2% solution
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Operating lnnructions-Type 321 A
when stored at +50' C, they will be almost completely
seli-discharged in only one month. High humidity also
increases the rate of self-discharge. lf this instrument must
be stored at either high anrbient temperature or high
humidity for an extended period of time, it is recom-
mended that the batteries be continuously trickle charged
using the OFF TRICKLE CHG position of the POWER
switch (charge batteries completely at full-charge rate be-
fore extended trickle charge).
Low-Batteries Light
The LOW BATTERIES light indicates when the unregu
lated voltage connected to the Power supply series Begula-
tor stage is too low for continued measurement accuracy.
This is particularly useful when using rechargeable batteries
as these battery cells may be damaged by excess discharge.
Therelore, the instrument should not be operated from the
internal batteries after the LOW BATTEBIES liqht comes
on since it no1 only may provide inaccurate measurements
but it may also shorten the useful life of the rechargeable
battery cells. For external operation, the LOW BAT-
TE R IES light comes on when the external voltage source is
too low for correct operation.
OPERATING TEMPERATURE
General
The Type 3214 depends upon radiant cooling Jrom the
side and rear panels to maintain a safe operating tempera-
ture. Adequate clearance on all sides must be provided to
allow heat to be dissipated away from the instrument. The
clearance provided by the feet at the bottom should be
maintained. Provide at least two inches of clearance at the
sides. top and rear (more if possible).
CONTROLS AND CONNECTORS
General
A brief description of the function and operation of the
ironl- and rear-panel controls and connectors follows. Fig.
2-6 shows the front and rear panels of this instrument.
More detailed information is given in this section under
General Operating lnrormation.
Fi& 2-5. hBeument positi,oned on bail stsnd,
CRT Controls
FOCUS Provides adjustment tor optimum
display definition.
AST IGI\,4AT ISI\,4
Vertical
VE BTICA L
POSITION
lnput Coupling
(AC DC GND)
Controls vertical p3sition of trace
Selects method of coupling input
signal to vertical deilection system.
AC: DC component oJ input signal
is blocked. Low-frequency -3 dB
point is about i.6 hertz.
DC: Provides equal coupling for all
signals from DC to six megahertz or
qreater.
a
!a
c
ao
{t
2"6
VOLTSiDIV
A thermal cutout in the instrument provides thermal
protection and disconnects the power to the instrument if
the internal temperature exceeds a safe operating level.
Power is automatically restored when the temperature
returns to a safe lwel. The Type 32'lA can be operated
where the ambient air temperature is between -15'C and
+55'C (+40'C maximum with batteries). After storage at
temperatures beyond the operating limits, allow the chassis
temperature to come within the operating limits before
power is applied.
OPERATING POSITION
General
A bail-type stand is mounted on the bottom of this
instrument. This stand permits the Type 321A to be tilted
up lor more convenient viewing (see Fig.2-5).
INTENSITY
SCALE ILLUI!1
Used in conjunction with the r-
FOCUS control to obtain a well'
defined display.
Controls brightness ot the display. \/,, -
Controls graticule illumination
(only when operating from an AC
line voltage source).
GND: lnput circuit is grounded
(does not ground applied signal).
Selects vertical deflection factor in
1 2'5 sequence (VABIABLE con-
trol must be in CAL position for
indicated deflection factor). Fully
clockwise position of $ruitch selects
internal cal ibrator siqnal.
A
lo
!{{a
(
\
I
v"
o- )
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Operating lnstructions-Type 321 A
T
t
I
:
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E
I
rl
at
t,
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T
I
II
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o
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2-7
o
'ld
I
Fig. 2{. Front- and rerr-panel controls and connectorc.
E
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Operating lnstructions-Type 321 A
VABIABLE
INPUT
DC BAL
Calibrator
CAL OUT
Triggering
STABILITY
IN PUT
Provides continuously variable un-
calibrated deflection factors b+
tween the calibrated sellings ol the
VOLTS/DlV switch.
lnput connector for vertical deflec-
tion signal.
Screwdriver adjustment to balance
the Vertical Amplifier so there is no
vertical shift of lhe trace as the
VABIABLE control is rotated
{with no signal applied ).
Terminal for establishing a common
ground between the equipment
under test and the Type 321A.
Output jack providing 500-millivolt
sq uare wave signal for compen
sating a probe.
Screwdriver adjustment to provide
correct operation of the trigger cir-
cuit (see Calibration Procedure lor
adjustment procedure).
lnput jack for external trigger sig'
nal.
Selects source of trigger signal
INT: Trigger signal obtained from
vertical deflection system.
EXT: Trigger signal obtained from
an external signal applied to the
Triggering lN PUT jack.
D etermines method of coupling
trigger signal to trigger circuit.
AC: Beiects DC and attenuates sig'
nals below about 600 hertz in INT
position of the Source switch or be
low about 30 hertz in EXT posi
tion. Accepts all signals above lower
frequency limit to six megahertz or
greater.
DC: Accepts all trigger signals from
DC to six megahertz or greater.
Selects slope of trigger signal which
starts the sweep.
+: Sweep can be triggered from
positive-going portion of trigger sig
nal.
Source
(INT EXT)
LEV E L
Time Base
HOBIZONTAL
POSITION
TIIVE/DIV
VABIABLE
5X IMAG
EXT HOR IZ INPUT
Power
Power on Light
(not labeled)
-: Sweep can be triggered from
negative-going portion of trigger sig
nal.
Selects amplitude point on trigger
signal at which sweep is triggered.
When turned fully counterclock-
wise to the AUTO position, the
sweep is automatically triggered. ln \
the FBEE RLlN position, fully \z
clockwise, the sweep free runs.
Controls horizontal position of
trace.
Selects sweep rate of the sweep cir
cuir (VARIABLE control must be
in CALIB position for indicated
sweep rate). ln the External Hori-
zontal position {note arrow from
EXT HORIZ INPUT jack), hori-
zontal deflection is provided by a
signal connected to the EXT
HOBIZ IN PUT jack.
Control concentric with TlN,4 E/D lV
switch which provides continuously
variable sweep rates between the
calibrated settings oJ the Tll\4El-
DIV switch. Sweep rate is cali
brated when control is set fully
clockwise to CA LIB position.
Switch actuated with VAR IABLE
TIME/DlV knob. When pulled out,
sweep rate is increased five times
the setting of the Tl[,4ElDlv switch
by horizontally expanding the
center two divisions of the display.
lnput iack for external horizontal
signal when Tll\,4ElDlV switch is set
for external horizontal operation
(arrow connects EXT HORIZ IN'
PUT jack to External Horizontal
position of TIME/DlV switch).
lndicates that POWER switch is in
one of the ON positions and power
is available.
Light which indicates that the input
voltage to the Regulator circuit is
too low ,or correct power supply
regulation. Operable with all three
modes of power; external AC, ex
ternal DC and internal batteries.
Coupling
(AC DC)
S LOPE
2-a
LOW BATTE R IES
GND
E
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Operating I nstructions-Type 321 A
POWE RFour-position switch which deter
mines the operating power source
and the battery charging voltage.
ON EXT AC-DC: lnstrument op,
erable from an external AC or DC
power sou rce. External power
source determined by connections
to the power receptacle.
OFF TR lC KLE CHG: lnstrument
inoperable. Trickle charge is applied
to internal batteries when connec-
ted to an external AC power source.
OFF FULL CHG: lnstrument in,
operable. lnternal batteries can be
charged when the Charger switch is
set to Low or High and the instru-
ment ls connected to an external
AC power source.
ON INT BATT: lnstrument oper-
able from internal batteries
Rear Panel
CRT GRID lnput jacks for intensiry modula,
tion of the CRT display.
FIRST.TIME OPERATION
General
The followinq steps demonstrate the use of the controls
and connectors of the Type 321A. lt is recommended that
this procedure be followed completely for general familiari,
zation with this instrument.
Setup lnformatron
1. Set the front-panel controls as follows
OFF TBICKLE CHG
3. Set the POWER switch to ON EXT AC-DC. A ow
about five minutes warmup so the instrument reaches a
normal operating temperature before proceeding.
CRT Controls
4. Advance the INTENSITY control until the dlsplay
is at the desired viewing level (near midrange).
5. Adjust the FOCUS and ASTIG[/lATlSM control for
a sharp, well'defined display over the entire trace length.
Vertical Controls
7. Turn the VERTICAL POSITION control to center
the display. The display is a square wave, about lour divi,
sions in amplitude with about four cycles displayed on the
screen.
8. Turn the VABIABLE VOLTS/D|V control through-
out its range. The deflection should be reduced so
1.6 divisions or less in the fully counterclockwise position.
Return the VAR IABLE control to CALIB.
L Set the VOLTS/DlV switch to .02 and position rhe
display to the center horizontal line with the VEBTICAL
POSITION control. This provides a ground reference at the
center horizontal line.
10. Rotate the VARIABLE VOLTS/DlV controt
throughout its range, lf the vertical position of the trace
changes, see DC Balance in this section for the balancing
procedure. Return the VARIABLE control to CALIB.
Triggering
Source
Coupling
SLOPE
LEVEL
Time Bases
HORIZONTAL POSITION
TII\4ElDIV
VARIABLE
5X MAG
INT
AC
+
FHEE BUN
N4 idrange
.2 MILLISEC
CA LIB
Pushed in
Power
POWEB
CRT Controls
FOCUS
ASTIGI\,4ATISNiI
INTENSITY
SCALE ILLUIV
Vertical Amplif ier
VERTICAL POSITION
lnput Coupling
VOLTS/DIV
VAB IABLE
Midrange
lvl idrange
Counterclockwise
Counterclockwise
Midrange
GND
CAL 4 DIV
CAL IB
E2-9
2. Connect the Type 32lA to an external AC power
source that meets the voltage and lrequency requirements
oI this instrument. lf external DC or the internal batteries
must be used for this procedure, see Operat;ng Voltage in
this section for more information.
6. Flotate the SCALE ILLUM conrrol throughout its
range and notice that the graticule lines are illuminated as
the control is turned clockwise (most obvious with mesh or
tinted light filter installed). Set control so graticule lines are
illuminated as desired.
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11. Connect the 10X probe (supplied accessory) to the
venical INPUT connector. Position the probe tip so it is in
contact with the cAL ouT jack for steps 12 through 19.
12. Set the lnput Coupling switch to DC. Notice that
the baseline of the waveform remains at the center horizon-
tal line (ground reference).
13. Set the lnput Coupling switch to AC. Notice that
the waveform is centered about the center horizontal line
(ground reference).
Triggering Controls
.14. Turn the LEVEL control clockwise to the FREE
RUN position. The display appears as two lines 2.5 divi'
sions apart (free running).
15. Rotate the LEVEL control counterclockwise until a
stable display appears. This indicates that the sweep is trig-
gered. Continue rotating the LEVEL control counterclock-
wise and notice that more of the leading edge oJ the display
is shown as the LEVEL control is turned toward - (due to
the fast rise of the calibrator waveform, it may be difficult
to observe this effect). Turn the LEVEL control fully
counterclockwise to the AUTO position. The trace is again
stable.
16. Set the SLOPE switch to . The trace starts on the
negative part of the square wave. Return the switch to +;
the trace starts with the positive part of the square wave.
17. Set the Coupling switch to DC and turn the LEVEL
control clockwise until the display is lriggered on the posi
tive part of the square wave. Now turn the VERTICAL
POSITION control clockwise until the display becomes un'
stable or disappears completely. Return the Coupling
switch 10 AC; the display is again stable. Since changing
vertica! position of the trace changes the DC level of the
internal trigger signal, this demonstration shows how DC
level changes aifect DC trigger coupling. Return the display
to the center of the screen.
,l8. Connect the CAL OUT connector to the Triggering
INPUT jack with a dual banana'plug patch cord and recon-
nect the 10X probe tip to the CAL OUT jack. Set the
Triggering Source switch to EXT. LEVEL, SLOPE and
Coupling operation is the same as described in steps 14
through l7
19. Disconnect the 10X probe and the patch cord from
between the CAL OUT and Triggering INPUT jacks. Set the
VOLTS/DIV switch to CAL 4 DIV and the Triggering
Source switch to lNT.
Normal and Magnif ied Sweep
20. Note the CRT display- Then, set the Tll\,4ElDlV
switch to 1 MILLISEC and pull the 5X MAG switch. The
display should be similar to that obtained with the TIME/
DIV switch set to .2 MILLISEC and the 5X MAG switch
pushed in.
22. Turn the VABIABLE TIME/DlV control through-
out its range. The sweep rate is reduced as the VABIABLE
control is turned counterclockwise as indicated by more
cycles displayed on the CRT. Return the VARIABLE con-
trol to cALlB.
External Horizontal
23. Connect the CAL OUT jack to the EXT HORIZ
INPUT jack with a banana plug patch cord. Reduce the
INTENSITY control setting to protecr the CRT phosphor.
24. Set the TIME/DlV switch to the External Horizon-
tal position (position with arrow to EXT HOBIZ INPUT
jack) and pull the 5X N/AG switch. lncrease the INTEN-
SITY control setting until a display is visible (two dots
displayed diagonally). The display should be lour divisions
vertically and about 0.5 divisions horizontally.
25. Disconnect the jumper lead from between the CAL
oUT and EXT HORIZ INPUT jacks. Ser rhe TtME/Dlv
switch to .2 l\llLLISEC and push in the 5X [,4AG switch.
Z-Axis lnput
26. lf an external signal is available (10 volts peak to
peak minimum) the function of the CRT GRID input (rear
panel) can be demonstrated. Remove the ground bar from
between the tvvo jacks on the rear panel and connect the
external signal to both the vertical INPUT connector and
the CBT GR lD jacks (connect the signal to the red jack and
the generator ground to the black jack). Set the TlN,4ElDlV
switch to display aboul five cycles on the waveform (if
necessary adlust the INTENSITY control to show blank-
ing). The positive peaks of the waveform should be intensi
fied and the negative peaks blanked, indicating intensity
modulation.
This completes the basic operating procedure for the
Type 321A. lnstrument operations not explained here, or
operations which need further explanation are discussed
under General Operating lnformation.
E
2-10
Operating lnstructions-Type 321A'
2'1. Turn the HORIZONTAL POSITION control so the
display starts at about the center of the graticule. Now turn
the HORIZONTAL POSITION control slowly in the oppo
site direction. Notice that for about 60'oI rotation the
trace moves slowly to the left and the control turns easily.
Then, the drag on the control increases slightly and the
trace beqins 10 move much faster to the left. This control
provides a combination of coarse and fine adiustment in a
single control. To use the control effeclively, turn it slightlyl
past the desired point of adjustment (course adjust). Then \;
rev€rse the direction of rotation and use the fine adjust-
ment to establish the precise position. Set the TIME/DIV
switch to .2 l\,llLLlSEC, push the 5X MAG switch in and
return the start of the trace to the left edge of the graticule.
27. Disconnect the signal from the CRT GRID jack and
replace the ground bar.
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TYPE 32IA TEST SETUP CHART
B. Porlial rGor ponet
Operating I nsructions-Type 321 A
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ot
V ERTI CA TItME !rr ^rL,
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IT IGGEN IN G
2-11
FiA.2-1.
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Operating Instrustions-Type 321 A
TEST SETUP CHART
General
Fig. 2-7 shows the front and rear Danels of the Type
321A. This chart can be reproduced and used as a test-setup
record for special measurements, applications or proc+
dures, or it may be used as a training aid for familiarization
with this instrument.
GENERAL OPERATING INFORMATION
lntensity Control
The setting of the INTENSITY control may affect the
correct focus of the display. Slight readjustment of the
FOCUS and ASTIGMATISM controls may be necesary
when the intensity level is changed. To protect the CRT
phosphor, do not turn the INTENSITY control higher than
necessary to provide a satisfactory display. The light filters
reduce the observed light output from the CRT. When using
these filters, avoid advancing the INTENSITY control to a
setting that may burn the phosphor. When the highest
intensity display is desired, remove the filters and use the
clear graticule only. Apparent trace intensity can also be
improved in such cases by reducing the ambient light or
using a viewing hood. Also be careful that the INTENSITY
control is not set too high when changing the TIIVE/DIV
switch from a tast to a slow sweep rate, or when switching
to the external horizontal mode oJ operation.
The Type 321A CBT uses dellection plate blanking to
deflect the CRT beam off the viewing area during retrace
time and when the sweep is not operating. With this type
of blanking system. the CRT cathode is emitting electrons
at the same rate whether a display is produced or not. The
cathode current is determined ehtirely by the setting of the
INTENSITY control. For this reason, the CHT may fail pre
maturely even though a display has not been presented if
the INTENSITY control is left at a high setting for extend
ed periods of time. Therefore to oblain maximum CRT life
always set the INTENSITY control fully counterclockwise
except when viewing the CBT.
Focus and Astigmatism Adjustment
The following procedure provides a convenient method
oJ establishing optimum setting of the FOCUS and ASTIG-
MATISM controls.
1. Set the VOLTS/DlV switch to CAL 4 DlV.
+
+
++-l-+++.]-+ ++ .l,+ 1-#
+
+
+
Center
cent.'
line
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 focus. Make
final check at normal intensity.
Graticule
The graticule of the Type 321A is scribed on the clear-
plastic faceplate protector. The graticule is marked with six
vertical and 10 horizontal l/4'inch divisions. ln addition,
each maior division is divided into five maior divisions at
the center vertical and horizontal lines. The vertical gain
and horizontal timing are calibrated to the graticule so
accurate measurements can be made from the CBT. Fig. 2€
shows the grat;cule of the Type 321A and defines the
various measurement lines. The terminology defined here is
used in all discussions involving graticule measurements.
Fig. 23. Delinition of measurement lines on Type 321A Sraticule,
When making waveform measurements using the grati-
cule, be careful that errors are not introduced into the
measurement due to parallax. Fig.2-9 illustrates how paral-
lax affects a measurement. To minimize measurement
errors due to parallax, be sure that the gratlcule is installed
so the scribed side is toward the CBT face. Also, when
making the measurement, attempt to position your eye on
a viewing plane which is perpendicular to the CRT face-
The graticule, tinted filter or similar clear-plastic protector
should be used at all times to prevent perrnanent damage to
the CBT face.
Light Filter
The mesh filter provided with the Type 321A provides
shielding against radiated EMI (electro magnetic interfer
ence) from the face of the CRT. lt also serves as a light
filter to make the trace more visible under high ambient
liqht conditions. To remove or install the filter, take out
the Phillips-head screw at the bottom of the graticule
cover and remove the cover. Place the mesh filter so the
2. Set the Tll\,4EiDlV switch to .2 NIILLISEC and the
LEVEL control to AUTO.
3. With the FOCUS and ASTIG[/ATISM controls set to
midrange, adjust the INTENSITY control so the rising por
tion of the display can iust be seen.
4. Set the AST lG lvlATlst\il control so the vertical and
horizontal portions of the display are equally focused, but
not necessarily wel I focused.
2-12
t
+
:t
+
ffi
S.cond
linc
T.nth
line
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