Tektronix 321 A User manual

INSTRUCTIC>N
MANUAL
TYPE
321A
OSCILLOSCOPE
T ek tronix, Inc.
S. W. Millikan Way • P. 0 . Bo x 500 • B eaver t on , Or e gon 97005 • Phone [phone] e Cab l es : Tektronix
070 - 425
564

AU Tektto. i*lt!iflijilllllib
GQGinst defective . •• ._,.
ship for one year.
·.
Any que stions with respect to the wor-
raaty mentioned above should be token up
with your Tektronix Field Engineer.
Tektronix repoir
and replacement-port
semce is geared directly to the field, there -
fore all requests for repairs and reploce-
JIIent ports. should be directed to the Te k-
tfonix Field Offic:e oc Representa
ti ve in your
area . Th is procedure will assure you the
fclstett po ssible servic6. Please inctude th_e
iftsttument Type and Serial number with all
....,ests for ports or service.
• Specifications and pr ice change priv-
""-' reserved.
.,. :Copyright © 1964 by Tektroni ~, Inc .,
. ~erton, Oregc)n. Printed in the United
.,. '$ililes of America. All rights reserved.
Oottents of th is publication may n ot be re-
.. ~uced in o n~ form without permission
he copyright owner.

Type 321A

Type 321A
SECTION I
CHARACTERISTICS
lntrodudion
The Tektronix Type 321A is a high-performance, dc -to-6
me, transistorized oscilloscope. Its light weight, small size
and ability to operate from o variety of powe r sources make
it a versatile field and laboratory instrument. The oscillo-
scope con operate from its internally-contai ned rechargeable
battery pock, on external de source or from o 115/230-vo lt
50-800 cycle ac line. Regulated power supplies in the instru-
ment, accur
ate calibration, and precise linearity assure exa ct
time
and amplitude measurements despite normal voltage-
source and powe r- supply-lo ad changes that occur under
odual operating conditions.
Operating temperature range derived from tests in dicates
optimum performance
and reliability on its self- conta i ned
batteries from o· to + 40° c ot altitudes up to 15,000 feet.
Temperature
range without batteries when opera ting from on
external source is - 15 • C to +55 • C. Non-operating tem-
perature range is -55" C to +7 5" C without batteries
and -40• C to + 60" C with batteries at alt itu des to
50 , 000 feet.
For the operator's convenience, a front-panel battery lighl
in dicates when the internal batteries o re low. If external de
or ac operation is being used instead of the batteries, the
light turns on if the external volt ag e source drops too low
for
proper power supply regulation.
A 4-position
power switch on the front panel permits
convenient selection
of charging rote and /or power source.
Vertical Deflection System
Bandpass-De to at least 6 me (3-db down) using de cou-
pl in g; using oc coupling, low-frequency 3-db down po in l
is 2cps typical from a 1-kc reference.
Sensitivity-0.01
v/div to 20 v/div in 11 calibrated steps;
occurocy is within 3"/o of front- pane l markings. Con-
tinuously variable from 0. 01 v/div to abou t 50 v/div
uncolibroted.
Input lmpedanc
e-35 pf nominal paralleled by 1 megohm
(:.t 1 "/o), 8.2 pf nominal paralleled by 10 megohms
(±2%1 when using the P6006 lO X Probe.
Maximum Allowable Input Voltage
Roting-600 volts com-
bined
de and peak oc ; 600 volts (not 1200 volt s) peak-to-
peak oc .
Triggering
Type-Automatic, or amplitude-level selecti on using pre -
set stability.
Modo-Ac -c oupled or De-coupled.
Slope-P lus, from rising slope of triggering waveform, or
minus from negative slope of triggering waveform.
Source-Internal from vertical signal, or external from
triggering signal.
Signal Requirements-Internal: 0.2 majo r division vertical
deflection at 1kc increasing to 1 major division at 6 me.
External: 1 volt peok-to-peak at l kc increasing to 3 volts
peak -to-peak at 6 me. Nominal input impedance: 5 pf
paralle l ed by 100 kilohms (± 20%).
Sweep
Type-Miller Integrator.
Sweep Rotes-0 .5JLsec/div to O.S sei:/div in 19 c alibrated
steps. Accurate 5X sweep magnifier extends calibrat ed
range to 0.1 p.sec/div. Calibrated sweep-rote accuracy
is :
t: 3"/o. Sweep time adjustable between steps and to
~ 1.5 sec/div uncolibrated.
External Ho rizontal Input
Bandpas s- De to at least 1 me (3-db down).
Deflection Foetor-! vfdv + 10"/o with 5X magnifier an .
Input lmpedanc&-30 pf typical paralleled by 100 kilohms
1±
5% ).
Amplitude Calibrator
Square Wove-Frequency about 2 kc.
Amplitud e-500 mv peak - to -pe ak . Also 40 mv peok-to·
peak internally coupled in CAL4 DIV position of VOLTS/
DIV switch. Peak-to- peok amplitude accu racy is ± 3% .
Cathode-Ray Tube
Typ e-Speci al Tektronix-manufactured 13211. 3" flat-face,
post-deflection
acce le rator . l ow healer power .
Accelerating
Potcntiol-4 kv.
Z-Axis Modulation-External terminal permits
RC coupling
to crt grid.
Unb lonking -Defle ction unblanking.
Phosphor-Type
P31 normally furnished; PI, P2 , P7, and
Pl l phosphors optional. Other phosphors furnished on
special
order .
Graticule
Illumination-Variable edge lighting when operating from
ac line.
Display Area -Marked In 6-vertical and 10-horizontol 1
/4"
divisions.
Power Requirements
Source-Operates from I0 size D flashlight cells, or 10
size D rechargeable cells (approximately 3 hours using
2.5
ampere -hour cells; approximately 5 hours using 4
1-1

Choraderistics - Typ e 321A
ampere-hour cells), or 11.5 to 35 volts de (aircraft, auto ,
boot, etc.),
or 103.5 to 126.5 volts or 207 to 253 volts,
rms, 50 to 800 cycles, single-phose oc.
Power Consumption-Approximately 700 mo from internal
batteries
or eldernol de source; 20 watts nominal at
115 -v olt ac line.
Temperalure Prot ection- Thermal cutout switch interrupts
power
if amb ient temperature exceeds 13 1" F (55" C).
Built- in battery charger is standard equipment.
Environmental Capabilities
Vibration (operating)-0.025" peak-to-peale, 10 to 55 to
10 cps in 1 minute sweeps (4. G's) for 15 minutes on
each axis.. Three-minute vibration at resonance or
55cps on each axis.
Shock (operot ing}-20 G's, lj
2 sine, 11-msec duration.
1-2
Two shocks each direction along each of the three
ma jor a xis: bollom, lop, left side, right side, front
and rear.
To t al of 12 shocks.
Shock lnon-operaling)-60 G's, 1f
2 sine,
11 -msec duro-
lion.
One shock each direction al ong e ach of the three
major axis; total of 6 shocks.
Hum idity (non-o perating)-Mee ts Mi i- Std-2028, method
106A (ex cept freezing and vibrat ion) through 5 cycles
(120 ho urs).
Transit (non- ope roting}-Meets Notional Sofe Transit lest
when factory packaged . Vibration for one hour at
slightly greater than one G. Eight een-inch drop in any
orientation.
Mechanical Spe(ificotions
Construct ion-A luminum alloy chassis and cabinet.
Finish -Anodized panel, blue vinyl-finish cabine t.
Dimensions-Slf," high, 53//' wide, 16" deep overall.
ACCESSORIES
Information on accessories fo r use with this instrument is
included at the r ear of the mechanical ports list.

SECTION 2
PRELIMINARY INSTRUCTIONS
Power Requirements
The regulated power supplies in the Type 321 A w ill operote
form 115-v or
23 0-v rms oc line, from on external de so urce
(11.5 to 35 volts),
or from o ''battery pock '' consisting of
either 10 size D flashlight cells or 10 size D recharge ab le
cells.
Fuse Data
Use only the recommended f uses in the Type 321A Oscil-
loscope. The upper fu se , F 621 ( se e Fig. 2-1 ), is a 1.5-amp
3AG Fast-Blo; th e lower fuse , F601 , is a . 25 -omp 3AG Fast -
Bio.
Neither fuse needs to be changed if the oscilloscope
is converted from one line voltage to the other
(115 v and
230v).
fig . 2- 1. location of fu ns and Charger twitch lleft-sl de v ie w) .
Ac Operation
Unless togged otherwise, your instrument is connected ot
the factory lor operation ot 103 .5 to 126 .5 volts, 50 to 800
cycles oc ( 11 5 volts nominal). How ev er, provisions ore mode
for easy conversion to operate at 207 to
253 volts, 50 to
800 cycles (230 volts nominal). The power transformer T601
is provided with split input windings which ore normally
connected in parallel for 115-volt operation, but which can
be connected in series for 230 -vo lt operation.
The primary windings ore marked l, 2, 3, and 4. Terminols
1 and 3 ore connected to one winding and terminals 2 and 4
ore connected to the second winding. The oc inp ut leads ore
connected to terminals 1 and 4 for both 115-volt one 230-
®
volt operation, so these connections do not hove to be
chang ed when converting from one line voltage to the other.
When wired for 115-volt operation, te
rm inals 1 and 2 are
joined by o bare bus wire, ond termina ls 3 and 4 ore simi-
larly joined, as shown in Fig. 2-2 1o). To convert to 230-
volt operation, remove the bore bus wires between these
termina ls and substitute a single connecting wire between
terminals 2 and 3,
as shown in Fig. 2-2(b).
To turn on the Type 321A when the power cord is con-
nected to the oscilloscope power connect or and to t he oc
voltage so urce, se t the POWER switch to EXT ON. To turn
off the oscilloscope, set the POWER switch .to TR IC KLE . The
TRICKLE position con be regarded as the normal " off " posi-
tion for t he instrument.
To 115 -v AC
(al
To 230-v AC
F lg . 2-2 . ( al Transform er connection for operation from 1 03 .5-
126 .5 vo lt oc line ; lb) tonneclions fo r operation from 207-253
volt ac line .
As lo ng as the oc power cord is connected to the oc line,
power is being applied to the power transformer T 60 1, ac-
rectifier c ir cuit, and groticule light s for oil positions of the
POWER switch. Appli cation of power to these circuit is re-
quired to provide battery-charger operation for th e internal
batteries; t
he groticule lights provide visual indication that
these circuits ore ··on". Power to the battery charger itself is
controlled by o Charger switch (see Fig. 2·1). If the switch
2-1

Preliminary Instruction s- Type 321 A
1s set to LOW or HIGH, the ac rectifier is connected to the
battery charger circuit which, in turn, provides charging cur-
rent to the internal rechargeable batteries.
NOTE
If dry cells ore used inst ead of rechargeable bat-
teries, then the Charger switch must be set to DR Y
CELLS to disconnect the charger circuit. For further
information about battery operation, r efer to the
topics tilled "Battery Operation" and "Ba tt ery
Charger" appearing in this sect io n of the manual.
If the Type 321 A is being operated exclusively from the
oc line and the internal batteries ore removed, the Charger
switch can remain in the DRY CELLS position to disconnect
the charger ci rcuit. If you prefer to completely turn off
oil power to t he Type 321 A, set the POWER sw itch to
TRICKlE and either disconnect the power cord from the
ac li
ne or turn off the power at o wall switch (or equiv-
alent).
Batt ery Operation
Operation from the internal battery source can be accom-
plished by using :
1. Ten size D flashlight cells (approximately 1
/1-hour con-
tinuous operation, more with intermittent operation), or
2. Ten si ze D Alkaline cells such as Eveready E95 , Bu rgess
Al-2, or Mallory MN-1300 (about 21
/2 hours
co ntinuous
operation), or
3. Ten size D ni ckel -cadmium rechargeable cells (up to
about 5 hours continuous operation, depending on the
type
used).
The nickel-cadmium cells ore the most practical type where
considerable battery operation
is planned.
To install the cells, ftrst open the battery cover as ill us -
trated in Fig. 2-3. Next, install the batteries by following
the procedure gi
ven in Fig . 2-4.
CA U TIO N
Be su re to observe cell po lari ty i ndi cated on the
battery cover.
To turn on the Type 321A when operating from the internal
batteries,
set the POWERswitch to BATT ON. To turn off the
oscilloscope, set the POWER switch to one of the OFF posi-
tions-FULL or TRICKLE. These OFF positi ons disconnect
t
he batteries from the oscilloscope load (1 0-volt regulated
supply)
so there is no battery drain. To charge the recharge-
able batteries, refer to the next topic titled "Battery Charger".
Fig. 2·3 • .Removing lhe ba ii••Y cover from the Typ• 321 A Oscllloltope .
2-2

Preliminary Instructions- Type 321 A
Fig. 2-4 . Proced11re for ln stolllng the bo »eries .
Battery Charger
As mentioned previously, the battery charger is connected
to the internal batteries as long as the oc power cord is
connected to
an ac power source and the Charger switch
(see Fig. 2-1) is set to HIGH or LOW. No charging occurs if
the Charger switch is set to DRY CELLS .
Table
2-1 summarizes the charging currents that con be
obtained by using various line voltages in combination with
various settings
of the POWER and Charger switches. Th e
table shows the Type 321A wired for 115-volt nominal line
operation. If the oscillosco pe is wired for 230-vo lt nominal
line
operation, the charging currents will still be the some
but the ac li ne voltages will be twice the amount shown in
the table.
Use Table 2-1
as on aid in determining the proper posi·
lion for the POWER and Charger switches for the particular
brand or type of rechargeable batteries being used in the
Type 321A. After setting the switches to th eir proper posi-
tion, the line voltage con then be set to the charging rote
recommended by the manufacturer of the cells. An auto-
transformer having a rating of at least I ampere and
equ i pped with on rms-reoding oc voltmeter con be used to
set the line voltage.
When using rechargeable batteries, sixteen hours of
charg ing at the full rated charging current recommended
by the manufacturers should be adequate to fully charge
the batteries. Excess charging may damage the batter ies.
One method for determining charge conditions of the bat -
teries is to set the POWER switch to BAIT ON and then
measure the voltage across the battery terminals ( sec Fig.
2-
4) . A read ing higher than 13 volts in dicates that the
ba tteries are fully charged. A reading lower than 13 volts
indic
ates that more cha rging time is required.
As mentioned previously, if dry cells ore installed in the
battery holder and the Type 321A is being operated from
the
ac line, the Charger switch must be set to the DRY CELLS
position. This position disconnects the charging circuit from
the batteries.
TABLE 2-1
Charging Currents
PO WER • Charger Aproximote Charging
Swit ch Switch Current in Ma
Position Po sitio!:'... ]_0~.5 - " ... ) - ~(~~ ;~ (~ .- ~ ·.·. ;:, 12 ~ ~ 1 126.5 v
- Low ······ · 2o · ·········· 2:.~ ··r-· v 31 · 33
EXT ON - - .. ······----·-··-- -- ·
-- -- · ·- ·- · - [6~ r----· ;f. - ;: ' --1§ --·- ~~ L - ---·--- !~ ····-
TRICKLE - - ·· -········- -
HIGH 34 37 1 41 4A 48
~~~ -~ ~~~ --- ·.·.·.· .. -~ J - ~ ~- -: r ;~ -=- ~~ - -- - ·---·- ~~ ~
"The BATl ON po•llion is not Inclu ded in the tab le becouae the
T ype 321 A should not be operored from the oc tine ond lho
bollories or the some limo. R eosona Bollory drain oxc::eod• chorg ·
lng role .
2-3

Prelim inary Instructions- Typ e 321A
De Operation
Operation from on external de source is ocompli1hed by
connecting the special pigtail-type de power cord in the
proper manner.
Fo r 11.5 - to 20-volt operation, t he block
1+1 and white 1-) leads ore connected to the voltage
source ; for 20- to 35 -volr operation, the green 1+1 and wh ite
1-·) lea ds or e connected to 1hc voltage source. When the
connect
io ns to the external de voltage source arc properly
mode, the external de source
is floating with res pect to the
Type
321A chassis. Up to 600 volts difference is permissi-
ble, if necessary.
To turn on the Type 321 A, set the POWER swi t ch to E XT
ON . To turn off the oscilloscope, set th e POWER switch to
one of t he OFF pos itio ns - TRICKLE or FULL.
When operating from the external de source, the ac line
cord
shou ld be disconnected. Tha t is, only one of th e exter-
nal
sources sh ould be used rather than bo th at the some time.
2-4
NO TE
Th e internal battery cha r ge r circuit is d is connected
during external de operation . Ther efo re, ext ernal
batteri es ( if used as the de sourcel cannot be
ch arged by connecting the line cord to the oc line.
Also, on external de source
cannot be used to
ch ar ge the internal batter i es since the POWER
switch does not electrically connect the twa
sources t ogether.
LOW BATTERIES Ught
The LOW BATT ERI ES light tu rns on when the following
conditions exist:
1. Tho POWER switch is set to BA TI ON and the internal
batteries drop to
11.5 v ( :!.:. 0.2 v) or lower.
2. T he POWER swi t ch is set to EXT ON and the external
source voltage is low enough to ca use the Type 321A un-
regulated voltage to drop to about 11.5 v or lower.