Tektronix PS 503A User manual

OOilAAN7TED
TD D~L .LEIVCE

~S 503
®tJAL
~~

E~ SUPPL
Y
INSTRUCTION
MANUAL
Tektronix, Inc .
P .O . Box500
Beaverton, Oregon 97077

Serial Number
070-1834-01

First Printing SLPT 1974

Page
SECTION 1

OPERATING
INSTRUCTFONS

1-1
SECTION 2 , ;

SPECIFICATION AND PEFIFORMANCE CHECK

2-1
The
remaining portion of this Table,of Contents lists servicing
instructions that
expose personnel
to hazardous voltages : These instructions are for qualified
service personnel
only .

s
SECTION 3

ADJUSTMENT
SECTION 4

MAINTENANCE AND INTERFACING INFORMATION

4-1
SECTION 5

CIRCUIT DESCRIPTIpN ± .=

-

5-1
SECTION 6"

REPLACEABLE ELECTRICAL PARTS LIST

6-1
OPTIONS
'SECTION 7

DIAGRAM AND CIRCUIT BOARD
.ILI .USTRATION .

7-1
SECTION 8

REPLACEABLE MECHANICAL PARTS LIST AND
EXPLODED
VIEW

8-1
CHANGE INFORMATION
WARNING
TABLE
OF CONTENTS
PS 503A

Fig . 1-1 .
PS 503A Dual Power Supply plug-in module .

INTRODUCTION

diode as well as a dimming
of the VOLTS indicator
light if
the supply output voltage is
above approximately
10 V .
These functions are easily verified
by momentarily shor-
Description

ting the output
of the supply .
The
PS 503A is a dual
0 to 20 V do constant-voltage,
current-limited,
floating power supply .
It is designed to
operate in the high-power
compartment
of the TM 504 or
TM 506 Power Module
. In the high-powercompartment,
it
provides a floating dual
Oto 20 Vdc at 1 .0
A . Operating in a

installation and Removal
standard
compartment of a TM
500 Series Power
Module,
the PS 503A
supplies a floating
dual 0 to 20 V do at
400 mA .

c~~
The
supply is designed
for conveniently
powering
complementary and linear
integrated circuits such
as
operational
and differential
amplifiers as well as differen-
tial
comparators . A ground
referenced +5 V auxiliary
supply
(suitable for bipolar
logic, light-emitting diodes,
incandescent
displays and similar
applications) is also
included . With the
floating supply available for
powering
discrete
interface circuits
and level shifting, the
PS 503A
can be
used for many digital/analog
applications .
The
plus and minus outputs
from the dual floating
power supplies
are independently
variable or bo
variable-at a constant
ratio by a
common controi
Ea
, .~ .

,-- ; .-
/align `the PS503A
chassis with the upper and
lower
supply provides
dither a plus or'mir~us 0to 20
V do with

`guides of the selected
compartment . Push the module
in
respect
to the common terminal,
By connecting
across the

and press firmly to seat the
circuit board in the inter
plus and minus
terminals, the
PS503A can provide 0 to

connecting
jack .
40 V dc . Either terminal
may be grounded
or floated to
350 V (dc + peak ac) .
Each supply also features
con-
tinuously variable current
limiting from less than
50 mAto

To remove
the PS 503A, pull
on the release latch 400 mA
(standard
compartment) or 1 A (high
power
compartment)
at both 20 V
and 40 V output .

located in the
lower left corner, until the interconnecting
jack
disengages and the PS 503A will slide
out .
The
presence and variability of the output
voltage is
verified by the
VOLTS indicator light on the front panel .
The brightness
of this light varies with output voltage . A
panel-mounted light-emitting
diode (LED) indicates when

Controls
and Connectors
the PS 503A is operating in
a standard compartment of a
TM
500 Series Power Module and
the output current is

Refer
to
Fig . 1-3
. Even though the PS 503A
is fully
limited to a maximum
of
400
mA . Other panel-mounted,

calibrated and ready
to use, the functions and actions
of
light-emitting
diodes indicate when
either
the +
or
-

the controls and
connectors should be reviewed before
supply goes
into current-limiting . Hard limiting is in-

attempting to use it . Press the OUTPUT
button to apply
dicated by maximum brightness
of the light-emitting

power to the
PS
503A .
REV . CMAR 1977
CAUTION
Section 1-PS 503A
OPERATING
INSTRUCTIONS
Turn the
power module off before
inserting the plug-
in ; otherwise,
damage may occur to
the plug-in
circuitry . Because of
the high current drawn
by the
PS 503A, it is also
recommended that the
power
module be turned off
before removing the PS
503A .
Refer io Fig . 1-2 . . Check
to see that the plastic
barriers on
the interconnectingjack
of theselected
power module
compartment match the
cut-outs in
the PS 503A circuit board
edge connector .

OperatingInstructions-PS 503A
Load and
Monitor Connections
POWER
MODULE
~~ rrier
Improper
connections between the power-supply
out-
put and the load (s)
or monitoring devices) are
a common
cause of errors
. Multiple loadsor monitoring
devices must
be
connected directly to the output
terminals with
separate pairs of leads as shown
in Fig . 1-4 . Avoid using
clip leads, since their
contact resistance can exceed the
output impedance of
the PS 503A and cause
significant
measurement
error .
Fig . 1-2 . Plug-in module
installation/removal .
Bottom
Groove
PLUG-IN
Groundedand Floating
Operation
OPERATINGCONSIDERATIONS
The PS 503A
is a + and -20 V "floating" supply
since
no internal
connections are made to either
the chassis or
Overheating

ground .
The supply can thus
be used as a positive or
The PS 503A is designed to
operate at ~n ambient

negative supply by
simply, connecting between the com-
fAmr "
Qrature from 0°G
to +5G"C . ~lowever,
when

mon and the negative
or positive uutpur terminal
.
operating
saveral power supplies in a
rpe~? ;
i-p!ug-in
pow~ . "

However, there
may bs : : :,desirable effects caused by
module, especially at low output voltages,
or when

grounding
the supply to the chassis while the load
is
operating close to other heat-producing
equipment, inter-

grounded
at some point removed
from the supply chassis .
nal temperature
may exceed safe limits and
actuate a

Forexample, if a remote load is
connected as shown in Fig,
thermal cutout
in the power module . Refer to
the power

1-5
.
ground currents containing
the power-line frequency
module instruction manual for
more complete informa-

could result and
create excessive noise and ripple in series
tion .

with the load . Thus,
floating operation is recommended to
ensure against
problems caused by undersirable
ground
currents .
ReverseCurrent
Loading
In some bias
supply and digital circuitry
applications
the load
might behave as a current source
for part of its
operating cycle . Since the
output circuit of a series-
regulated supply is
unidirectional, current will not pass in
the opposite direction except
through undesirable paths .
The internal reverse-current
diodes conduct only when
the PS 503A
terminal voltage reverses and therefore
will
not work
when the voltage is correctly
polarized . Connec-
REV . A MAR 1977

4p0 mA LIMIT Indicator
Light
emitting diode in-
dicates whenPS 503A is
installed in a 'standard
compartment
of a power
module,
limiting the
current output .
VOLTS
Controls
and
Indicators
Variable
coarse and tine
controls
provide con-
tinuously
variable + or-
voltage election
from the
respective 0-20
voli
supply
The presence
and
variability
of output
voltage is
verified 'by
voltage indicalor
lights
(OUTPUT
button
pressed) . Brightness
of
lights
varies with output
voltage :
REV .
B
MAR
1977
Floating Output
Terminals
Fig . 1-3 .

PS 503A controls and
connectors .
5-way binding post ter-
minals that provide either
a positive 0-20- volts
between
the binding post
on
the right (red) and
t :OMMON,
or a negative
t)-20 volts between the
binding past on the left
(green) and COMMON .
When the
PS503A is in-
stalled in he high
power
compartment of aTM
504
or TM 506 power module
that
has a high ; power
compartment, tt e current
available
at either the r or
- outputs is from less
than `
100 mA to at least
1 A : When the
PS 503A is
compartment, the
current

Output Terminals
available is from ess than
100 mA `to

at `least

5-way binding-posttermi-
400 mA . 0 to 4Q volt out-

nals

that

provide

a
put
s'obtained' between

ground-referenced +5 V,
the +
and - output ter-

1 A, fixed output .
urinals .
Operating
Instructions-PS 503A
VOLTS DUAL
TRACKING Control
When pulled
out, vanes
both the'-1-'and
- outputs
from 0 volts to he value
set on the + and - VOLTS
controls
.' The - ratio be-
tween
the+and-outputs
is maintained
throughout
the range
of the VOLTS
DUALTRACKING con-
trol .
OUTPUT Pushbutton
When
pressed, applies
power
to both 0-20V
binding
post terminals
and the +5V
binding post
terminal .
CURRENT LIMIT
Controls and Indicators
Continuously variable
controls that select the
and -output current limit .
Light-emitting diode in-
dicates' when hard
limiting occurs .
installed in a
standard _
1834-05

OperatingInstructions-PS 503A
NOTE
Supply is
connected for 20 to 40 V output .
Over-voltage
POWER
SUPPLY
AC
VOLT
+
METER
ting a shunt resistor (Rs) as shown
in Fig .1-6 provides an
external, reverse-current path to the power supply
sources or delivers current only .
The PS 503A is protected from over-voltageconditions
by an over-voltage protection circuit
that shuts down the
power
supply
when the voltage rises to about 26 V dc .
POWER I

I ACTIVE
SUPPLY

LOAD
Rs
NOTE
Supply is
connected
for
0 to 40 V output .
Fig,
t-4 . Monitor and load connections .

Fig .
1-4 . Reversr current shunt
(Rs)
with active load .
NOTE
The point at which the overvoltage protection blows
the fuse
may be changed forspeclfic applications by
changing the Zener diode .
OPERATION
The following steps demonstrate the use of the
PS503A controls and connectors .
1 . install the PS 503A into'(preferably) the high-power
compartment of the power module .
2 . Press the OUT button to apply power to the
PS503A .Observethatthe+and-VOLTSindicatoriights
come on (the lights will be very dim at low voltages) ._
Single
Supply Operation (t20 V Maximum)
1 . Set the + and - VOLTS controls for approximately
2 V .
2 . Turn the CURRENT
LIMIT
controls
fully ccw (to
NOTE

protect the
ammeter) . Connect an ammeter between the
supply is connected for o to ao v output .

common terminal and the + or - terminal and adjust the
appropriate CURRENT LIMIT control for the maximum

)
Fig . 1-5 . Ground loop
created by grounded remote lead .

desired current
output .
REV . A MAR 1977

3 . Removethe ammeter . Connect the
load between the

Stair-Step Operation
common
terminal and the+or-terminal .
Adjust the+or

The PS 503A can be operated
to provide a "stair-step"
,~

- VOLTS
control for the desired output .

output characteristic by choosing certain load limits
and
control settings . Forexample, Fig .1-7showsthestair-step
output
from the
PS 503A when a variable load (RL) is
connected between the +
and - output terminals . With
each supply set for maximum
voltage and current (40 V,
y

1 A) theoutput voltage remains constant
from open circuit
Combined
Supply Operation (40 V
Maximum)

~

until the
load reachesapproximately 40 S2 as illustrated by
1 .

Set the + and - VOLTS control
for approximately

the solid line in Fig . 1-7 .
At this crossover point, theoutput
j

2 V and turn the
CURRENT LIMIT controls fully
ccw
(to

voltage decreases with the load
and the output current is
protect the
ammeter) .

limited at 1 A . Therefore,
below approximately 40 S2, both
supplies act as current sources with
output voltage
variable with the load . Since both supplies are set for the
'

2 .
Connect an ammeter
between the + and - ter-

same output voltage,
each supply shares equally in the
urinals . First
adjust one CURRENT LIMIT
control for the

Power output

I Z R . If one supply
is set for a lower output
maximum desired current
output ; then adjust the other

voltage than the other, output power
is shared at the same
CURRENT LIMIT control
until the CURRENT LIMIT

ratio as the output voltage .
indicator just reaches maximum
brightness, i .e ., both
1

supplies at the
same CURRENT LIMIT
setting .
3 . Remove the ammeter .
Connect the load between the
+ and
- terminals and set the + and -
VOLTS controls so
that both settings
added togetherequal thedesired output
voltage . (See Dual-Tracking
Operation for varying the
output with the VOLTS DUAL
TRACKING control .)
Dual-Tracking Operation
When pulled
out, the VOLTS DUAL TRACKING
control
varies the output of
both supplies at a constant ratio from
zero to the value set on the +
and - VOLTS controls . For
example, if the + and -
VOLTS controls are set for
maximum
output (approximately 20
V), both outputs can
be varied
from zero to 20 V with the
VOLTS DUAL
TRACKING control (1
:1 ratio) . Likewise, if one supply is
set for 10 V and the other for
20
V,
each 1 V change in the
10 V output
will be matched by a2 V
change in the 20 V
output (2 :1 ratio)
.

ao
Note also that no matter where
the VOLTS DUAL

I

w
j
30
TRACKING control is set, the
outputs will return to the

~

1
voltage
selected by the + and - VOLTS
control when the

~

20
0
VOLTS DUAL
TRACKING control is pushed in .
Therefore,

>
rapid selection of two
preset outputs from each supply is

~

10
achieved by merely switching the
VOLTS DUAL

w
TRACKING
control in or out .
REV
. B MAR 1977
Now, by setting
supplyEzforacurrentlimitof0 .5 Aand
varying the load
over the same range, the supplies act as
constant-voltage sources until
the load reaches ap-
proximately 80 S2 . At that crossover point,
the supply set
for 0 .5 A
(Ez)
becomes a current source and
its output
OperatingInstructions-PS
503A
!
o
9
0
When the +and
- supplies are connected as described

I ~

Is
under Combined Supply
Operation, the VOLTS DUAL

CURRENT IN AMPERES
TRACKING control will
vary the output from zero to the
value
selected by the + and -
VOLTS controls added

Fig . 1-7 . Output characteristics with
various currents, voltages,
together .

and loads .

OperatingInstructions-PS
503A
voltage
decreases with the
load . At approximately
40
f2

Parallel-Connected
Supplies
and
20 V, supply
Ez
no longer
contributes to the power
output .
Subsequently, supply E,
supplies all the output

"""'
power and
operates as a constant-voltage
source with

CAUTION
output current
variable with the load . Then,
at ap-
proximately 20 f2, supply
E, crosses over and becomes
a

Parallel
operation is not recommended
unless a
current
source at its maximum
output of 1 A . Thus, by

forward biased
diode capable of handling
the re-
choosing
the appropriate load limits
and control settings,

quired current and voltage
is inserted between
each
any of the four
operating characteristics
is possible .

power supply and the
load . Failure to do this may
cause power supply damage .
A
second stair-step output can
be preselected and
switched
in or out with the VOLTS
DUAL TRACKING

The outputs of two or
more PS 503's can be
connected
control (see
Dual-Tracking Operation
for details on the

in parallel as shown in Fig . 1-9
to obtain an output current
function of the
VOLTS DUAL TRACKING
control) .

equal to the sum of theoutput
currents from each supply .
Each
supply must be adjusted
individually to obtain the
desired output current
.
Series-Connected
Supplies
The outputs of two
or more PS 503A's can
be con-
nected in series as shown
in Fig . 1-8 to obtain an output
voltage equal to the sum
of the output voltages from each
supply
. Each supply
must be adjusted individually to
obtain the
desired output voltage
(see Dual-Tracking
Operation for varying
the output of both supplies
with the
VOLTS DUAL TRACKING
control) .
One supply should
be set for the desired output
voltage
NOTE

and the other for a slightly
higher voltage . The supply
set
forthe desired voltage will then
become a constant voltage
The PS 503A has internal
diodes connected across

source, while the
supply with the
higher voltage output
the
output to protect the
series-connected supplies

becomes a
current source (due to
automatic crossover),
against reverse
polarity if the load is
shorted, or one

which results
in their output voltage
decreasing to that of
of the supplies is
not on .

the supply with the
lowest output voltage .
POWER I

I
POWER
SUPPLY

SUPPLY
LOAD
NOTE
Each supply is connected for 0 to 80 V output .
NOTE
The + and -
supplies are internally
connected in
series . Therefore, the
+ and - supplies cannot
be
externally connected
in parallel to obtain an
output
current equal to the
sum of the currents from
each
supply .
POWER

POWER
SUPPLY
I

I
SUPPLY
NOTE
Each supply is connected
for 0 to 2A output .
Fig . 1-8 . Supplies
series-connected .

Fig . 1-9 . Supplies
parallel-connected .
REV . B MAR 1977

SPECIFICATION AND
PERFORMANCE CHECK
Performance Conditions
The electrical characteristics
are valid only if the
PS 503A has been calibrated at an ambient temperature
between +20° C and +30° C and is operating at an ambient
temperature between 0°C and +50°C unless otherwise
noted .
Voltage Outputs
Variable Current
Limiting
Minimum Resolution
ELECTRICAL
CHARACTERISTICS
Characteristics

Performance Requirements

Supplemental Information
SPECIFICATION
Table 2-1
Plus and Minus 20 V Floating Supplies
Less than 100 mA to at least 1 A
when installed in a high-power
compartment .
Less than 100 mA to at least 400 mA
when installed in a low power
compartment .
50 mV
Section 2-PS 503A
Items listed in the Pertormance Requirements
column
are verified by completing the Performance Check in this
manual . Items listed in the Supplemental Information
column
are
not verified in this manual ; they are either
explanatory notes or pertormance
characteristics for
which no limits are specified .
0V (1100 mV) to at least
20
V
do
(20 .1, - .1, + .4 V dc) with re-
spect to common terminal, or 0 V
to at
least
40
V
do across the
plus and
minus terminals .
Outputs either ind

bndently
variable or both variable at
a constant ratio of a common
control (Dual Tracking) .
Maximum limit ; 1 .5 A
Maximum limit ; 600 mA

Specification and Performance Check-PS 503A
Load Regulation

Within 3 mV with a 1 A load change .

I Within 1 mV
with a 400 mA load
change .
Line Regulation

Within 5 mV for a t10% line
voltage change .
Ripple and Noise

3 mV peak-to-peak or less with a

1 mV peak-to-peak
or less with
(2 Hz
to
2 MHz instrument

1 A load .

a 400 mA load (noise and
not in current limiting .)

ripple increase unpredictably
when
current is being limited) .
Temperature Coefficent

~

~
0 .025%/°C or less .
Stability

0 .1% +5 mV (or
less) of drift in 8
hours . Line voltage, load
and
tem-
perature held constant .
Supply Isolation from

I
350 V (dc + peak ac) .
Ground
Dual Tracking Mode

If the two supplies are set indepen-
Offset
Error

dently to any given voltage ratio, and
if both supplies are then monitored
and varied a given amount (by using
the VOLTS DUAL TRACKING control),
the two supplies will maintain the
same voltage ratio as initially set
within 50 mV ; until oric supply roaches
either
Qv or 20
V .
f
Output
Load Regulation
Line Regulation
Ripple and Noise
(2 Hz to 2 MHz)
LongTerm
Stability
Overload Protection
2-2
Table 2-1 (cont)
Characteristics

~

Performance Requirements

~

Supplemental
Information
Transient Recover

~20 ps for a constant voltage
to
recover within 20 mV for a
nominal output voltage after a
400 mA change
in output current .
+5 V Ground ReferenceSupply
4 .75Vdcto5 .25Vdcwitha5ohm
load .
Within 100 mV with a 1 . A load change .
Within 50 mV for a ±10% line volt-
age change .
5 mV peak-to-peak or less
with a 1 A
load
.
Measured at a temperature be-
tween
+20°
C
and +30° C .
Measured at a temperature be-
tween +20° C and +30° C .
0 .5% or less of drift .
Fixed
(automatic) current limiting
and over-temperature shutdown .
REV . A, AUG . 1977

Temperature
Operating
Storage
Altitude
Operating
Storage
Vibration
Operating and
Non-Operating
Shock
Operating and
Non-Operating
Width
Length
Characteristics
Net Weight (Instrument only)
Characteristic
Overall Dimensions
(measured at maximum points)
Height
Perf
o rmance Requirements

I

Suppl emental Information
0° C to +50° C .
-40° C to +75° C .
To 15,000 feet .
To 50,000 feet .
Table
2-2
ENVIRONMENTAL
With
the instruments complete and oper-
ating, vibration frequency swept from
10 to 50 to 10 Hz at 1 minuteper sweep .
Vibrate 15 minutes in each of the three
major axes at 0 .015" total displace-
ment . Hold 3 minutes at any major re-
sonance,
or if none, at 50
Hz . Total
time, 54 minutes .
30 g's, 1/2 sine, 11 ms duration, 2
shocks in
each direction
along
3
major
axes, for a total of 12 shocks .
Table 2-3
PHYSICAL
Specification and Performance
Check-PS 503A
5 .0 inches
12 .7 cm
2 .6 inches
6 .6 cm
11 .75 inches
29 .7 cm
1 Ib
13 oz
821 grams
Information

Specification
and Performance
Check-PS 503A
Introduction
This procedurechecks
the electrical characteristics
of
the
PS 503A that appear in
the Specification portion of this
section .
Limits and tolerances given
in the Supplemental
Information
column are provided
for user and service
information only, and
should not be interpreted
as re-
quirements for this
Performance Check .
The electrical
characteristics are
valid only if the
instrument has been
calibrated atan ambient
temperature
between +20° C and +30°
C, and is operated at an
ambient
temperature
between 0°C and
+50°C unless otherwise
noted .
Special test devices are
used where
necessary to
Limits
and tolerances given
in this Performance
Check

facilitate the procedure .
Most of these are available
from
are for the instrument
under
test and do not include test

Tektronix,
Inc . and can be ordered
through your
local
equipment
error . Limits and tolerances
in this procedure

Tektronix Field
Office or representative
.
Performance
Description

Requirements

Application
Oscilloscope

Bandwidth,
do to 2 MHz ;

Used throughout
pro-
minimum deflection
factor,

cedure to provide
1 mV/div ; sweep rate,

display .
10 ms/div to 1 ~s/div .
Digital
voltmeter

~

Range,
zero to 1000 volts ;

~

VoItagP
measurements .
acc! .!racy,
within 0 .1% .
Power
Module
Autotransformer
with ac volt-
meter
Coaxial
cable
Patch cord
(2 required)
PERFORMANCE
CHECK
Table 2-4
LIST
OF TEST Ef~UIPMENT REQUIREMENTS
Four compartments or more,

All tests .
with one
high-power
compartment
.
Test Equipment
Required
Capable of supplying an

Regulation and
output voltage
from 90

ripple
checks .
t o 132
volts, ac ; 120 W
of power at the upper
limits .
Impedance, 50 f2 ; length,

I

Provides signal inter-
42 inches
; connectors, bnc .

connection .
Banana-plug-jack
to banana-
plug-jack ; length,
18 inches .
are instrument
performance requirements
only if stated as
such in the Specification
portion of this section
.
The following test equipment,
orequivalent, is required
to perform the performance check
and adjustment
procedure . Test equipment characteristics
listed are the
minimum
required to verify the performance
of the
equipment under test .
Substitute equipment must
meet or
exceed the stated requirements
. All test equipment
is
assumed to be operating within
tolerance .
Provides signal inter-
connection .
Example
Tektronix 5110,
5B10N
Oscilloscope
System .
Tektronix
DM 501
Digital Multimeter
.'
Tektronix TM 504
or TM 506
.
General
Radio
W10MTR3W
Variac
Autotransformer .
Tektronix Part
No .
012-0057-01 .
Tektronix Part No .
012-0031-00 (black),
012-0039-00
( red ) .

)

Table 2-4
(cont)
Performance
Description I

Requirements I

Application I

Example
Adapter

I

Bnc female
to dual-banana

I

Provides
signal inter-

I

Tektronix Part No .
plugs .

connection .

103-0090-00 .
Load resistor

20 f2, 20W, 5%,

Load tests .

Tektronix Part
No .
(two 10
n,
10 W in series) .

I

I

308-0246-00 .
Load resistor

5 f2, 5 W, 5% .

Load tests .
Resistor

4 .99 kf2,
1/2 W, 1%

Dual tracking
detector
(2
required)

or better .

test .
1 X passive
probe
'Requires TM 500-Series Power
Module .
Compatible with
5A-series

Provides signal inter
amplifiers used in

connection .
osci I loscope .
Specification and
Performance Check-PS
503A
Tektronix Part
No .
308-0179-00 .
Tektronix
Part No .
323-0260-00 .
Tektronix P6028
Probe .
Preliminary
Procedure

6 . Adjust the
autotransformer to the
nominal line
1 . Ensure that all
test equipmentand the PS 503A

voltage and check that the two
VOLTS indicator lights
on
under test are suitably
adapted to the line voltage to be

the PS 503A are on .
applied
. Refer to the installation
section of the power
module
manual
.
7 . Set the vertical
deflection factor for 1
mV/div and
sweep rate for 5
ms/div on the test oscilloscope .
Use ac
coupliny ioi fhe vertical
amplifier unit during this
2 . . .Be . certain
that the POWER switch
on the ptw!er

~ procedure :
module is off and that
the OUTPUT pushbutton on the
PS 503A
is in the out position .
8 .

Connect all test
equipment to a suitable line
voltage
source .
3 . Install the
PS 503A in the far right (high power)
compartment of the power
module .
9 .
Turn
on all test equipment and allow
at least twenty
minutes for the equipment
to warm-up and
stabilize .
4 . Connect
the power module
to the autotransformer
and connect the
autotransformer to the
line voltage
source . Set the autotransformer
voltageoutput control for

NOTE
zero volt
output .
During warm-up time,
attach banana pins to
the
leads of the 20 f2 and 5 f2
load resistors so that they
5 . Set all
front-panel controls on the
PS 503A fully

can be inserted in the
holes of the dual-banana
counterclockwise
(ccw) . Apply power to the
power

adapter . This allows the
load resistors to be con-
module and press in the
OUTPUT pushbutton on the

nected as close as possible to
the output terminals
PS
503A
.
Push the PS 503A
VOLTS DUALTRACKING

on the
PS 503A so contact resistance
is kept to a
control in .

minimum .
2-5

Specification and
Performance Check-PS
503A
Performance
Check Procedure

b . Disconnect the red patch cord from
the digital
voltmeter high input
terminal and set the digital
voltmeter
1 . Check 0-20 Volt
Output Voltage

to the 2000 mA do range . Reconnect
the red patch cord
to
the digital
voltmeter high input terminal .
a .

Check that ali controls
on the PS503A front panel
are fully
ccw and that the 400 mA MAX
indicator light is off
(this light should
remain off as long as the
PS
503A
is
installed in the high-power
compartment of the power
module) . Also check that
both CURRENT LIMIT indicator
lights are
off . (For instruments
SN 8022064-below, these
lights may be on ; if
so, adjust the appropriate CURRENT
LIMIT control cw just
enough to turn them off) .
b .

Set the digital
voltmeter to the 2 volts do range . Use
patch cords to connect the
+20 V floating output ter-
minals
of the PS 503A to the digital
voltmeter input
terminals
; connect the red patch cord from the 0-20V
red
binding post
to the digital voltmeter high input terminal,
and the black patch cord
from the COMMON (black)
binding post to the digital
voltmeter low input terminal .
d . Set the digital
voltmeter to the 200 volts do range
and set the PS 503A +
VOLTS controls fully cw .
e .
Check-for a meter reading of
at
least
+20 .1 volts,
but less than +20
.4,volts .
f . Adjust the
PS 503A + VOLTS
controls fully ccw and
move the red patch
cord from the 0-20V
red binding post
to the 0-20V
green binding post on the
PS 503A .
g
. Repeat parts 1c
through 1e, using the PS 503A
-
VOLTS controls to check the
-20 V supply .
h . Set the PS 503A -
VOLTS controls fully ccw and
move the red
patch cord back
to the 0-20V red binding
post on the PS 503A . Check to be certain
that ali PS 503A
front-panel
controls are fully ccw .
2-6
c . Check-for a current reading
of less than
100 mA
for the +20 V supply . The
PS 503A + CURRENT
LIMIT
light should be on .
d . Move the red
patch cord from the PS
503A 0-20V
red binding post to the
PS 503A 0-20V green
binding
post .
e . Check-for acurrent reading
of
less than 100 mA
for the -20 V supply . The
PS 503A - CURRENT LIMIT
light should be on .
f . Rotate the PS 503A-
CURRENT LIMITcontrolfully
c w .
c .
Check that the PS 503A +
VOLTS controls are fully
ccw and check
for a meter reading of .0000, within
f100 mV .

g .
Check-for a current reading
of more than
1000 mA, but
less than 1500 mA for the
-20 V supply .

,
h . Reconnect the red patch
cord to the PS 503A
0-20V
red binding post and rotate the
PS 503A + CURRENT
LIMIT control fully cw .
i . Check-for a current
reading of more than 1000
mA,
but less than 1500 mA for the +20 V
supply .
j .

Set all controls on the
PS 503A front panel fully
ccw
and retain the digital voltmeter
connections to the
PS 503A
.
3 . Check Load Regulation
a . Disconnect the red patch cord from the
digital
voltmeter input terminal and set the digital voltmeter
to
the
20 volts
do
range .
Reconnect the red patch cord to the
digital voltmeter high
input terminal ; the meter reading
2 . Check Variable
Current Limiting .

should indicate approximately
zero volts . Both CURRENT
LIMIT lights
on
the PS 503A
front panel should be off and
a . Adjust the PS 503A +
VOLTS controls for +5 .0 V

remain off during the load regulation
check .
output . Move the red patch cord
to the PS503A 0-20V
green binding
post and adjust the
PS 503A - VOLTS
controls for -5 .0 V
output . Move the red patch
cord back

b . Rotate the CURRENT LIMIT control on the PS
503A
to the PS 503A 0-20V red binding post
.

fully cw .

I
Specification and Performance Check-PS
503A
c . Adjust the PS 503A +
VOLTS fine and coarse

b . Adjust the autotransformer
10% below and 10%
controlsforameterreading between +19
.900
and+19
.980

above the nominal line voltage setting .
volts . Note and
record the exact open-circuit voltage
reading before applying the
adapter (with load resistor
I

attached) in part d of this step .

c . Check-that the
voltage reading displayed on the
digital voltmeter does not change
more than t5 mV (5
counts) for each 10% line voltage change .
Readjust the
d . Insert
the leads of the 20 f2, 5% resistor into the

autotransformer
to the nominal line voltage .
holes of a dual-banana
plug adapter and connect the
adapter to the patch
cord jacks, which remain connected
to the PS 503A 0-20V red and the
COMMON binding post

d . Remove the adapter (with load
resistor) from the
terminals
. Observe correct polarity for the
adapter (GND

patch cord jacks .
Move the red patch cord to the
0-20V
to COMMON) .

red binding post terminal .
Reconnect the adapter (with
load resistor) to the patch cord
jacks . Observe correct
polarity for the adapter (GND to COMMON)
.
e . CHECK-that
the meter reading does not change
more than 3 mV (three
counts of the most right-hand
digit)
.

e . Note the exact
voltage reading displayed on the
digital voltmeter with
the adapter and load resistor still
attached to the 0-20V red
and COMMON binding post
NOTE

terminals (+19 .900 to +19 .980 volts)
.
If the reading on the digital voltmeter
changes by
more than
3 mV, another20 f2, load resistorhaving
a

f . Adjust the autotransformer 10% below
and 10%
resistance value
closer to 20 f2 should be used, or

above the nominal
line voltage setting .
the voltage output from
the PS 503A can be reduced
to +19 .000 (step 3c) .
g . Check-that the voltage reading displayed
on the
digital
voltmeter does not change more than t5 mV
(5
f . Remove the
adapter (with load resistor) from the

counts) for each 10% line
voltage change . Readjust the
PS 503A patch cord jacks .
Move the red patch cord to the

autotransformer to the nominal line
voltage .
0-20V green binding post
terminal .
g . Adjust the
PS 503A - VOLTS fine and
coarse

5 . Check
Ripple
and Noise
controls for a meter reading
between -19 .900 and -19 .980
volts
. Note and record the exact
open-circuit voltage

a . Disconnect the patch
cords from the PS 503A
reading before applying the adapter (with
load resistor

0-20V red and COMMON binding post
terminals and
attached)
in part h of this step .

reconnect the dual-banana adapter (with load resistor)
directly to the 0-20V red and COMMON binding post
terminals ; observe correct polarity of the adapter (,~aND to
COMMON) :

<
,~,~~ . . . .
h . Insert the leads
of the 20 f2, 5% resistor into the
holesofadual-banana adapter
and connect theadapterto

b . Connect the output of the adapter to the
vertical
the patch cord
jacks, which remain
connected to the

input of the oscilloscope, using a 42-inch bnc
cable . Set
PS 503A 0-20V
green and the COMMON binding
post
terminals . Observe
correct polarity for the adapter (GND

the oscilloscope vertical deflection factor for 1 mV/div
to COMMON) .
(calibrated) .
i .
Check-that the meter reading does not
change

c . Slowly adjust the autotransformer output
voltage
more than 3 mV
(three counts of the most right-hand

10% below and then 10% above the nominal line voltage .
digit) .
d . Check-the signal display on the
oscilloscope for
less than 3 mV peak-to-peak (within
three vertical
divisions) at all points of the specified voltage limits .
a . Note the exact
voltage reading displayed on the
digital voltmeter with the
adapter and load resistor still
attached to the PS 503A 0-20V
green and COMMON

e . Readjust the autotransformer to the nominal
line
binding
post terminals (-19 .900 to -19
.980 volts) .

voltage .
4 . Check Line Regulation

Specification and Performance Check-PS 503A
f . Connect
the adapter (with load resistor attached) to
the PS 503A 0-20V green and COMMON binding post
terminals ; observe correct polarity of the adapter (GND to
COMMON) .
g . Repeat
steps 5c through 5e to check the
ripple and

7 .
Check +5 Volt Output Voltage
noise of the PS 503A -20 V supply .

a . Connect the digital voltmeter~between the +5V@1 A
ground referenced red binding
post and the ground white
h
.
Readjust the autotransformer to the nominal line

binding post .
voltage and disconnect all connections from the PS 503A
.
6 . Check Dual Tracking Mode Offset Error
a . Pull out the PS 503A VOLTS DUAL TRACKING
control and set it fully ccw to ensure minimum output
voltage while connecting the resistors
.
b
.
Connect the two 4 .99 kS2, 1% resistors in series
between the
PS 503A 0-20V green and 0-20V red binding
post terminals . Do not connect the junction
of
the two
resistors to the COMMON terminal or the chassis .
c .
Connect the black patch cord from the digital
voltmeter low terminal
to
the
PS 503A COMMON binding
post, and thered patch
cord from the digital
voltmeter high
terminal to the PS 503A 0-20V red binding post .
j . Set
the PS503A VOLTS DUAL TRACKING control
fully ccw and push the control knob in . Disconnect both
patch cords and the two resistors from the
binding
post
terminals .
b .
Push in the OUTPUT button and check that the two
VOLTS indicator lights are on .
c . Check-for
a meter reading of +4 .75 to +5 .25 volts .
d . Connect a 5 i2, resistor between the +5V@1A
ground referenced red binding post
and the ground
(white) binding post
.
e . Check-that the meter reading does not change by
more than 100 mV
.
8 . Check +5 Volt Output Voltage Regulation
a . Adjust the
autotransformer output voltage from the
low limit to the high limit as indicated in Table 2-5 .
d . Set the PS 503A VOLTS DUAL TRACKING control
fully cw and adjust the PS 503A + VOLTS controls for a

b . Check-that
the digital voltmeter reading does not
meter reading of +18 V, t0 .1 volt .

changemore
than 50 mV for a plus 10% or minus 10% line
voltage change .
e . Connect the red patch
cord to
the 0-20V green
binding post and adjust the PS 503A-VOLTS controls far

c . Disconnect the digital voltmeter .
a
meter
reading of -18 V ; f0 .1 volt .
d . Connect the probe of the test oscilloscope between
f . Disconnect the red patch cord from the0-20V green

the+5V binding post and the ground (white) binding post .
binding post and connect it to the junction of the two
4 .99 kf2, 1%
resistors . Check that the digital
voltmeter
indicates a do voltage
less than
1 V .

e . Adjust the autotransformer
output
voltage
from the
low limit to the high
limit
as
indicated in Table 2-5 .
g .

Set the digital voltmeter to the 2-volts do range and
adjust either the + VOLTS or - VOLTS controls on the

f . Check-the test oscilloscope display for not more
PS 503A to obtain a meter reading of 0V do (f100 mV) .

than 5 mV peak-to-peak
ripple and noise .
h .
Adjust the PS 503A VOLTS DUAL TRACKING

g . Return the
autotransformer
to
the nominal tine
control slowly from cw
to ccw
.

voltage
setting .
i . Check-that
the meter reading remains within

h . Disconnect the test oscilloscope probe from the
±25 mV of zero volts .

binding posts
.
2-8

i . Press and
release the PS 503A
OUTPUT button to
turn
off the power
to the PS 503A .
POWER MODULE
UNIVERSAL TRANSFORMER
Line
Selector
Block
Position
L
M
H
Line Fuse
Data
Table 2-5
Regulating
Ranges
110-Volts
Nominal

~ 220-Volts
Nominal
90 VAC
to 110 VAC
99 VAC
to
121
VAC ~ 198 VAC to 242 VAC
108 VAC to 132
VAC ~ 216 VAC to 264 VAC
1
.6
A
slow-blow
9 . Check
Variable Current Limiting
180 VAC to 220
VAC
0
.8
A
slow-blow
a . Turn the power
off to the TM 500 Series Power
Module and remove the
PS 503A from the high-power
compartment and install the
PS 503A in the low-power
compartment .
b .
Turn on the power to the power
module and press
the
PS 503A OUTPUT button
in . Set all front panel
controls fully
ccw and allow approximately
three minutes
for the equipment
to stabilize .
c . Check-that the
400 mA MAX indicator light is on .
d . Adjust
the PS 503A + VOLTS and
- VOLTS coarse
controls to the 4V
position (leave the fine
controls fully
ccw) .
Specification and
Performance Check-PS
503A
f . Set the PS 503A + and -
CURRENT LIMIT controls
fully cw .
g . Check-that the
digital voltmeter indicates a
current reading of more
than 400mA, but less than
600 mA . The + CURRENT
LIMIT light should beon .
h . Move the red patch cordfrom the 0-20V
red binding
post to
the 0-20V green
binding post .
i . Check-that the digital voltmeter
display indicates a
current reading of more than 400 mA, but
less than
600 mA . The -
CURRENT LIMIT light should be
on
.
j . Set the PS 503A - CURRENT LIMIT
control fully
ccw .
k . Check-that the
digitalvoltmeterindicatesacurrent
reading of less than 100 mA . The
-CURRENT LIMIT light
should remain on .
I . Move the red
patch cord from the 0-20V
green
binding post to the 0-20V red binding post
and set the
PS 503A + CURRENT LIMIT control
fully ccw .
m .
Check-that the digital voltmeter
indicates a
current reading of less than
100 mA . The + CURRENT
LIMIT light should be on .
n . Turn off all power
to the power module . Push and
release the PS 503A OUTPUT button and
set all other
front-panel controls fuljyccw .. . .
e .

Setthe
digital voltmetertothe
2000 mA position and
connect the black patch
cord from the digital voltmeter
low
terminal to the PS
503A COMMON binding post and
the red
patch cord from the digital
voltmeterhigh terminal

o . This completes the Performance
Check Procedure
to the PS
503A 0-20V red binding post
.

for the PS 503A .

Introduction
d .
Install all TM 500-series equipment,
including the
This
adjustment procedure is to be used to restore the

PS 503A into the power module .
PS 503A to original
performance specifications . Adjust-
ment need not be
performed unless the instrument fails to
meet the requirements listed in the
Specification section,

e . Connect all test equipment to a suitable line voltage
or the Performance Check cannot be completed satisfac-

source .
tori ly .
Services Available
Tektronix, Inc . provides complete instrument repair
and adjustment at local Field Service Centers and at the
FactoryService Center . Contact your local Tektronix Field
Office or representative for further information .
Test Equipment Required
The test equipment listed in Table 2-4 or equivalent, is
required for adjustment of the PS 503A . Specifications
given for the test equipment are the minimum necessary
for accurate adjustment and measurement . All test equip-
ment is assumed to be correctly calibrated and operating
within specification .
If other test equipment is substituted, control settings
or calibration setup may need to be altered to meet the
requirements of the equipment used .
Preparation
a

Remove the left-hand and right-hand side covers of
the PS 503A to gain access to the component side of the
circuit boards
.
Pull the
rear end of the side
coveroutward
from the side of the instrument (the cover snaps into
place) .
b . Install the
PS 503A into the far right (high power)

I

'
power module compartment,
or
if
appropriate, connect

~®
the PS 503A to the power module
by means of the flexible
plug m
extender If a flexible extender is used current
-

f

JIJ :
Section 3-PS
503A
ADJUSTMENT
f . Turn on all test equipment and allow at least twenty
minutes for the equipment to warm-up and stabilize .
g . Set the autotransformer to the nominal line
voltage
setting .
Initial Control Settings
Set the following controls during warm-up time :
PS 503A Duai Power Supply
- VOLTS (coarse and fine)

fully
ccw
+ VOLTS (coarse and fine)

fully cww
CURRENT LIMIT
Plus supply

fully ccw
Minus supply

fully ccw
VOLTS DUAL TRACKING

pushed in and
fully
ccw
limiting switch
S95 must . be engaged in the maximum

~

~ CJpf"
current (HI) position .
See Fig . 3-1 for switch location .
r~
o-

aea

"" ~~
.  .
B
R45
+20V Adj
c . Set the
power module for the line voltage to be

~

~

-20v Adj
applied (see power
module manual) and connect it to the
1

autotransformer, then connect the
autotransformer to the
line voltage
source . Be sure that the power switch is off .

Fig . 3-1 . Location of +20 V and -20 V
adjustment .
R 145