Tektronix TM 506 User manual

CHANGE
INFORMATION
TABLE
OF
CONTENTS
TM 506
Page
SECTION 0 INSTALLATION
INSTALLATION
PROCEDURE 0-1
RACKMOUNTING
0-3
SECTION 1 OPERATING
INSTRUCTIONS
INTRODUCTION
1-1
POWERING UP
1-1
BUILDING
A SYSTEM
1-2
SPECIFICATIONS
1-3
SECTION 2
SYSTEM MAINTENANCE
GENERAL
2-1
TROUBLESHOOTING
AIDS
2-2
TROUBLESHOOTING TECHNIQUES
2-2
PARTS ORDERING AND REPLACING
2-4
SECTION 3
OPTIONS
OPTION 2
SECTION 4 ELECTRICAL PARTS LIST AND
SCHEMATICS
ELECTRICAL REPLACEABLE PARTS LIST
4-1
POWER
MODULE INTERFACE PIN ASSIGNMENTS
DETAILED BLOCK DIAGRAM
PARTSLOCATION GRID
POWER SUPPLY DIAGRAM
PARTS LOCATION
GRID
SECTION 5 MECHANICAL REPLACEABLE PARTS
LIST

Section
0-TM 506
INSTALLATION
PROCEDURE
Before you start . . .
1 . Check the rear panel markings . If the factory settings are compatible with
the available line voltage and frequency, insert
the desired plug-ins . Use the bail to raise the front of the instrument .
2 .
If a
change
is
needed, follow these steps :
a . Line Selector Block(s)
Remove the four hold-down screws on the top of the dust cover cabinet and lift the
cabinet off . This gives easy access
to the Line Selector blocks located on the main circuit board .
Brown
120 V
4#Ita"C
. . . go to
Operating Instructions . . .
In service
selector block
The instrument can be damaged by using the 120 V Line Selector block with a 200 V nominal line voltage
.
Red
220 V

b . Line Range Taps
c . Rear
Panel
5 . Plug the cord into the power source .
6 .
Insert the desired plug-ins .
REV . A, APR . 1975
Universal Transformer
3 .
Replace the cabinet .
4 . If necessary, change the line cord power plug
to match the power source receptacle or use an adapter .
TM 506
7 . Use the bail to raise the front of the
instrument .

. . .90

t0

Operating

Instructions ...
0- 2
Line Regulating Ranges
Selector
Block
Position 120 Volts Nominal 220-Volts Nominal
L 90 VAC to 110 VAC 180 VAC to 220 VAC
M 99 VAC to 121 VAC 198 VAC to 242 VAC
H 108 VAC to 132 VAC 216 VAC to 264 VAC
Line Fuse
Data
4A slow-blow
f
2A
slow-blow

Installation
Procedure-TM 506
The rackmount version of
the TM 506 Power Module is
designed
for operation in a standard 19-inch wide
rack
that has Universal, EIA, RETMA, or
Western Electric hole
spacing . When properly
mounted, this instrument will
meet all electrical and
environmental specifications given
in Section
1 .
Mounting Method
This instrument
will fit most 19-inch wide racks
whose
front and rear holes conform to Universal hole
spacing ;
some drilling may be required on racks
having EIA,
RETMA, or Western Electric hole
spacing . The slide-out
tracks easily mount to the cabinet
rack front and rear
vertical
mounting rails if the inside distance between
the
front

and

rear

rails

is

within

10 9/16 inches

to
24 3/8 inches .

If

the

inside

distance

exceeds
24 .3/8 inches, some
means of support is required for the
rear ends of the
slide-out tracks . (For example, make
extensions
for the rear mounting brackets .)
RackDimensions
Height . At least 5 1/4 inches of
vertical space is re-
quired to mount this
instrument in a rack : If other
instruments are
operated in the rack, an
additional
1/4 inch is required, both above and below
the TM 506, to
allow space for proper circulation of cooling
air .
Width
. A standard 19 inch wide rack may be used .
The
dimension of opening between the
front rails mustbe at
least 17 5/8 inches for a cabinet in which
the front lip of
the stationary section is
mounted behind an untapped
front rail as shown
in Fig . 0-2A . If the front rails aretapped,
and the
stationary section is mounted in front of the
front
rails as shown in Fig . 0-2B, the dimension
between the
front rails should be at least 17 3/4 inches .
These dimen-
sions allow room on each
side of the instrument for the
slide-out
tracks to operate so the instrument can move
freely in and out of the rack .
Depth . For proper circulation of
cooling air, allow at
least two inches clearance behind the
rear of the instru-
ment andany enclosue on
the rack .
Installing the
Slide-Out Tracks
The
slide-out tracks for the instrument consists
of two
assemblies, one for the left side of the instrument
andone
for the right side . Each assembly
consists of three
sections . A stationary
section attaches to the front and
rear rails of
the rack ; the frame section installed at
the
factory
attaches to the instrument and the
intermediate
section fits between the other two
sections to allow the
instrument to fully extend
out of the rack .
0- 3
RACKMOUNTING
Hardware . The small hardware
components included
with the slide-out track
assemblies are used to mount
the
tracks to most standard
19-inch vertical rack rails
having
this compatibility .
NOTE
1 .

Front and rear rail holes
mustbe large enough to
allow inserting a 10-32
screw through
the rail
mounting hole
if the rails are untapped
(see Fig . 0-
1A) .
2 .
Or, front and rear rail holes
must be tapped to
accept a 10-32 screw if
Fig . 0-18mounting method is
used . Ncte in Fig . 0-18
right illustration that a No .
10
washer (not supplied)
may be added to
provide
increased
bearing surface for the slide-out
track
stationary
section front flange .
Because of the above
compatibility, there will be some
small parts left over .
The stationary and
intermediate
sections for both
sides of the rack are
shipped as a
matched
set and should not be
separated . The matched
sets of
both sides including hardware
are marked 351-
0195-00
on the package . To
identify the assemblies,
note
that the automatic
latch and intermediate section
stop is
located near
the top of the matched set
.
Mounting
Procedure . Use the
following procedure to
mount both sides . See Fig .
0-1 for installation details .
1 . To mount
the instrument directly
above or below
another
instrument in a cabinet
rack, select the ap-
propriate holes in the front
rack rails for the stationary
sections, using Fig . 0-2 as a
guide .
2 .

Mount the stationary slide-out
track sections to the
front
rack rails using either of
these methods :
(a)

If the front flanges of
the stationary sections
are to
be mounted
behind the front rails (rails
are counter-
sunk
or not tapped), mount
the stationary sections as
shown in Fig . 0-2A, right
illustration .
(b)

If the front flanges of the
stationary sections are to
be
mounted in front of the
front rails (rails are tapped
for 10-32 screws) mount
the stationary sections as
shown in Fig .
0-1B, right illustration . To
provide
increased bearing surface
for
the screw head to
securely fasten the front
flange to the rails, a flat
washer
(not supplied)
may be addedunder the screw
head .

Deep Rack Configuration
Slideout Track
Stationary
Section
Deep Rack Configuration
10-32
BHS
Screw
(2)
Slideout Track
Stationary
Section
Rear Mounting
Bracket
(B)
Top view of
iew of cabinet
rack . Front and rear rails are not
Shallow Rack
Configuration
- 10-32
BHS
Screw
(2)
Slideout Track Stationary
Section
cabinet rack .
Front and rear rails are tapped
f
Bar _-
Nut
tapped
.
Slideout Track
Stationary Section
or No . 10-32 screws .
10-32
pHs Screw
(2)
10-32
Screw
pHs
(2)
10-32
FHS
Screw
(2)
Untapped
Front Rail
Left Front
corner of
Cabinet Rack
No . 10 Washer
(not supplied,
see text)
Fig . 0-1 . Mounting the left stationary section (with its matched
intermediate section, not shown in illustrations A and B) to
the
rack rails
.
However,
if this mounting method is used, the front
panel will not fit flush against the front rail because of
the stationary section andwasher thickness .
If
aflush
fit is preferred, method 1(a) should be
used .
3 . Mount the stationary slide-out sections to
the rear
rack rails using either of these methods
.
(a)

If the rear rack rail holes are not tapped to
accept
10-32 machine screws,
mount the left stationary sec-
tion with hardware
provided as shown in the left or
center illustration of Fig . 0-1A . Note that the rear
mounting bracket can be installed either
way so the
slide-out tracks will fit a deep or
shallow cabinet rack .
Installation Procedure-TM 506
Use Fig . 0-1A
as a guide for mounting the right
stationary
section . Make sure that the stationary
sec-
tions are horizontally aligned so they
are level and
parallel with each other
.
(b)

If the rear rack rail holes
are tapped to accept 10-32
machine
screws, mount the left stationary section
with
hardware provided as shown in the left or center
illustration of Fig . 0-1B . Note that the rear
mounting
bracket can be installed either way so
the slide-out
tracks will fit a deep or
shallow cabinet track . Use Fig . 0-
1 B as a guide
for mounting the right stationary section .
Make sure the stationary sections are horizontally
aligned so they are level and parallel with each
other .
0-4
Shallow
Rack Configuration
10-32
10-32
BHS
BHS
Screw Screw
(2) (2) Slideout Track
;Slideout Track Stationary Section
Stationary Section

Installation Procedure-TM
506
r
1895
Drill and tap
10-32 in each
front
rail, if the
instrument front-panel
is going
to be secured to
the
rack
. Securing screws
are not
provided .
0- 5
This hole must be
drilled (and
tapped 10-32, if
desired) in each
front and rear rail of
EIA, RETMA
or Western
Electric racks .
25/8"
for securing
front-panel
screw
Panel
of
instrument
above
Fig . 0-2 . Dimensional
diagram .
18
.87
19 .47
W/OPT
5
.25
20 .69
21 .28
W/OPT
5 1/4"
opening for
installing the
TM 506 (5 3/4" if
adjacent
instru-
ments are to be op-
erated) .
19 .13
RACK RAIL TYPES
19125 *0062
~` CABINET OPENING

UNIVERSAL
ALTERNATE

FOR 81" PANEL
7 TYPE
TYPE

GRILLING
DRILLING
_
S

0123,-0187
OIB7 TNIGB

175675

TNIGN
MOUNTING

MOUNTING
P" ll

GLEAR

PEN IN G

RAIL
0625
0
0500
0
0625
I
s
a
oo
o
o
S8
a__
.
1
I
TEKTRONix6
TM 506
- _
17 AA

TM 506 Installation and Adjustment
follows :
To insert the instrument
into the rack, proceed as
1 .

Pull the slide-out track intermediate
sections out to
the fully extended position .
2 . Insert the instrument chassis
sections into the
intermediate
sections .
3 . Press the stop
latches on the chassis sections and
push the instrument
toward the rack until the
latches snap
into
their holes .
4 . Again press the stop
latches and push the
instru-
ment into
the rack .
To secure the instrument
front-panel to the rack, the
rack must either have
universal hole spacing, or a hole
mustbe
drilled and tapped for a 10-32 screw, see
Fig . 0-2 .
Using the hardware (not furnished) indicated
in Fig . 0-2,
secure the TM 506 to the front
rails of the rack .
Slide-Out TrackMaintenance
Installation Procedure-TM
506
To adjust the slide-out
tracks forsmooth sliding action,
loosen thescrews
used to join the stationary sections to
the rails of
the rack . Center the instrument,
allowing the
slide-out tracks to seek the proper
width, then tighten the
screws .
The slide-out tracks require no
lubrication . The special
dark gray finish on
the sliding parts is a permanent
lubrication
.

Description
The TEKTRONIX
TM 506 Power Module is a
mainframe
for the
TM 500 Series of Modular
Instrumentation . It
accepts up to six independently
functional plug-in
modules to form a versatile and
compact instrumentation
system . The TM 506 provides
the basic power source
and
an interconnecting
scheme for the other members
of the
TM 500
Series family . Factory options allow
customer
modification using signal access
at the plug-in
module/power module
interface to provide rear panel
inputs and outputs,
and interconnections
between com-
partments .
Power
Source
The instrument is designed to
operate from a power
source with its neutral at or
near earth (ground) potential
with a separate
safety-earth conductor . It is not intended
for operation
from two phases of a
multi-phase system, or
across the legs of a single phase,
three-wire system .
Power
Usage
With six plug-in modules installed,
theTM 506 requires
up to 320 watts at the upper
limits
of
the high line voltage
Plug-in Modules
It is not necessary
that all the plug-in compartments
be
utilized
in order to operate the Power Module
. The only
modules needed are those
necessary to accomplish the
task .
REV . A, APR . 1975
Turn the
Power Module off before
inserting theplug-
in ; otherwise, damage may
occur to the plug-in
circuitry .
INTRODUCTION
POWER UP
ranges . Actual
power consumption depends
on the par-
ticular
module combination and
operating modes
selected .
NOTE
Section
1-TM 506
OPERATING
INSTRUCTIONS
The
compartment closest to the PULL ON
POWER
switch is high power . Some of the TM
500 Series
plug-in modules require
high power to operate at
their maximum
capabilities .
Operating Temperatures
The TM 506 can be
operated in an ambient air
temperature of 0°C to
50°C . Thermal cutout devices
protect the
system by disconnecting the power to
the
TM 506
Power Module when internal
temperatures rise
above a safe operating level .
These devices automatically
return power to the unit
when the internal temperatures
return to a safe
level .
Since the TM 506 can be
stored in temperatures
between -40* C and
+75 0 C, allowthe instruments chassis
to return to
within the operating limits before
applying
power .
Module
Installation
1 . Check the location of the white
plastic barriers on
the TM 506 interconnecting jack to
ensure that their
locations match the slots
in the edge of the plug-in
module's circuit
board .
2 . Align the plug-in-module
chassis with the upper and
lower guides of the selected
compartment . Push
the
module in and press
firmly to seat the circuit board
in the
interconnecting
jack . (Remove the plug-in
module by
pulling on the white release latch
in the lower left corner of
each module .)

Operating Instructions-TM 506
Loading
Considerations
With six plug-in modules installed, the TM 506
can
require up to 320 watts from the line at high-line
voltage
range settings . Actual power consumed, of
course,
depends on the particular module
combination selected at
anyone time .
3 .
Pull the PULL ON POWER button on the right side of
the TM 506 . Some plug-in modules have independent
power switches, usually labeled OUTPUT,
controlling
application of mainframe power to
the module . Push this
button to activate the
plug-in module .
Family Compatibility
Mechanically, the plug-in
modules are very similar to
other Tektronix
product families . However, they are not
electrically compatible . Therefore, the TM 506 interface
has barriers on the mating connectors between pins 6
and
7 to ensure that incompatible modules
cannot be inserted .
See Fig . 1-1 . A
compatible module will have a matching
slot
between pins 6 and 7 of its main circuit board edge
connector . This slot and barrier combination is
the
primary keying assignment .
TM 500-compatible plug-in modules are
also identified
by the white color of the
release latch .
Customizing the Interface
The modularity of
this instrumentation system provides
for
many different functions to be performed by
the plug-
in modules . Specific functions are
grouped into families or
classes, of which there
may be several plug-in module
members . For instance, some
classes are Power Supplies,
Signal Sources,
Measurement, and so forth . Each modular
member of a functional family will have a second
slot
peculiar to its family assignment
located in its edge
connector . The
TM 506 user can "program" one or more
compartments to accept
only members of that family by
installing a second barrier in the interface
connector to
match the module's slot location
. An entireTM 506can be
"programmed" in this
manner to set up instruction
systems for specific
work functions . For extra barriers,
order
Tektronix Part No . 214-1593-02 .
Jumper wires can be used to further specilize
the
interface . Compartments can
be made to "talk" to each
other by
connecting jumpers on the back side of
the
BUILDING A
SYSTEM
This power capability can best be utilized by
carefully
planning the functional
combinations of plug-ins, their
external loads, and
the resulting power distributions .
Optimum
conditions can be (1) equal loads in all five
left
hand compartments and full load
in the high power
compartment, (2) as much of
the consumed power as
possible
dissipated in external loads, and (3) operating in
an
ambient tempterature of about 25°C .
The TM 506
provides each plug-in module with access
to
a pair of heat-sinked, chassis-mounted, series-pass
transistors, one NPN and one PNP . These transistors
allow the plug-in modules to operate in
power ranges not
possible if the power were to be
dissipated within the
modules .
interface board,
using pins 14 through 28 (A-side and B-
side both) of the interconnecting jacks . Seethe
following
description of Option 2 . Refer to each plug-in
module's
Manual for the I/O
assignments of each pin at the rear
interface . Once having made
interconnections of a
specialized nature,
it is recommended that barriers be
installed on the interconnecting jacks to ensure module
compatibility with the customized wiring .
Rear Panel
The rear subpanel has a connector mounting plate for
BNC and multi-pin connector mountings . Customer or
factory-installed connectors and wiring (see
following
description of Option
2) could provide external access to
the interface for external I/O control . This feature makes
the TM 500 Series Modular Instrumentation System
very
flexible in bench-top or
rackmounted systems .
Option 2 . This factory-installed option
adds 25-mil
square-pin connectors to the rear of
the interconnecting
jacks at all pin locations
froms pins 14Aand B through
pins 28A
and B . This will keep the interface
flexible by
making it easy and fast to change customized wiring
using
preparedwireswith square-pin receptacles
and long-nose
pliers or tweezers . It also
protects the circuit board from
damage by repeated
soldering and unsoldering of jumper
wires . This option
also adds six BNC connectors andone
50-pin
connector to the rear panel . These connectors are
not pre-wired . Instead, prepared jumpers,
coaxial cables,
and interconnection jack
barriers are included in a kit .
This gives a system designer as much
flexibility as
possible .

Power Requirements

17 .5 VAC and ±11 .5 V, 4 A maximum, shared
in any
combination
between these two supplies .
Line Voltage Ranges . Universal Transformer
:
110, 110,
120, 200, 220,
240 VAC all within 10% . Range change for
transformer accomplished with quick change line-
selector blocks .
Line Frequency Ranges . Universal Transformer : 48 Hz
to 60 Hz (fan limitation only) .
Power Consumption . Maximum primary power is ap-
proximately 320 W at high line . Actual power
consump-
tion depends on plug-in
selection and operating modes .
Supplies (Unregulated)
LowerPower (Left and Four Center Supplies) . Two
25 VAC windings, 500 mA each, supplied to each
compartment, independently .
17 .5 VAC and±11 .5 V, 6 .5 A maximum, shared in any
combination between these two supplies and
shared
among all five compartments .
REV
. A, APR . 1975
SPECIFICATIONS
+33
.5
VDC and -33 .5 VDC, 2 .1 A maximum, shared in
all
compartments .
Temperature Range
Operating : 0°C to +50°C .
Nonoperating : --40°C to 175°C .
Altitude Range
Operating :
To 15,000
feet .
Nonoperating : To 50,000 feet .
Other
Operating Instructions-TM 506
Dimensions with Feet and Bail : Width : 17 .25 inches,
Length : 19 .75 inches, Height : 9 .5 inches .
High Power (Compartment Nearest Switch) . Two
25 VAC winding, 1 A, supplied only to high power
compartment .

Weight without Plug-ins : Approximately 31 lbs .
P fj",'o

<_Y
i :
f~
M!1
. . .Y KFY
HIC,fi IPO'W"Ft
t :('tIA AJ
"
7POEN ;
Fig . 1-1 . Keying assignments for family functions . One of many possible sequence combinations .

Introduction
This
section of the manual is meant to
support the
entire TM 500 Series family of
modules with a general
coverage of the most
commonly-needed service informa-
tion
pertinent to preventive
maintenance,
troubleshooting, ordering parts, and replacing
com-
ponents and sub-assemblies .
Cabinet Removal
Dangerous
potentials exist at several points
throughout the system . When the
system must be
operated with the
cabinet removed, do not touch
exposed
connections or components . Some
tran-
sistors have voltage present on
their cases .
Disconnect power before
cleaning the system or
replacing
parts .
Six screws on
thetop secure the cabinet to the
TM 506
frame . Remove them and lift the cabinet
straight up . Do
not operate the system
with the cabinet removed any
longer than necessary for
troubleshooting and calibra-
tion . Re-install the cabinet
to protect the interiorfrom dust
and to
remove personnel shock hazards .
Cleaning
WARNING
Avoid
using chemical cleaning agents whichmight
damage
plastic parts . Avoid chemicals containing
benzene, toluene,
xylene, acetone, or similar
solvents .
GENERAL
Exterior .
Loose dust may be removed with a soft cloth
or a dry brush . Water and a mild detergent may be used .
However, abrasive cleaners should not be used .
Interior . Cleaning the
interior
of
a unit should precede
calibration since the
cleaning processes could alter the
settings of
calibration adjustments . Use low-velocity
compressed air to blow off accumulated
dust . Hardened
dirt can be removed with asoft
brush, cotton-tipped swab,
or a cloth
dampened in a solution of water and mild
detergent .
Preventive
Maintenance
Preventive
maintenance steps performed on
a regular
basis
will enhance the reliability of
the instrumentation
systems . However, periodic
checks of the semiconductors
in the absence of a malfunction are not
recommended as
preventive
maintenance measures . See the semiconduc-
tor
checking information under Troubleshooting
Techni-
ques which follow . A
convenient time to perform preven-
tive
maintenance is just before instrument calibration .
Calibration
Section 2-TM 506
SYSTEM
MAINTENANCE
To ensure
accurate signal generation and measure-
ment, the performance of individual units comprising
the
system should be checked periodically
. Refer to the
Instruction Manual for each
unit for complete calibration
and verification procedures .

System Maintenance-TM
506
Introduction
The following is provided to augment information
contained elsewhere in this and other
TM 500 series
family manuals
when troubleshooting becomes
necessary .
Circuit Description
Eachmanual
has a section devoted to explaining circuit
operating theory . Used conjointly with the schematics,
this can be a powerful analytic tool .
Diagrams
Block diagrams and detailed circuit
schematics are
located on foldout pages
in the service section of most of
the TM 500 Series family manuals . The schematic
diagrams show the component values and assigned
circuit reference numbers of each part necessary to the
circuit design . Usuallythe first page of the service
section
defines the circuit symbols and
reference designators
used
in that
particular
instrument . Major circuits are
usually identifiable by a series of component numbers .
Important waveformsand voltages may be shown within
the diagrams or on adjoining aprons . Those portions of
the circuits located on circuit boards are
enclosed with a
blue tint outline .
Cam Switch Charts
Cam switches shown on
the diagrams are coded on
comprehensive charts to locate the cam number of the
switch contact in the complete switch assembly, counting
from the front, or knob end, toward the rear of the switch .
The charts also indicate with a solid dot
when each
contact is closed .
Introduction
This troubleshooting procedure is arranged in an order
which checks the simple trouble possibilities before
proceeding to extensive troubleshooting
.
Control Settings
Incorrect control settings can indicate a trouble that
does not exist . If there is any question about
the correct
2-2
TROUBLESHOOTING AIDS
Circuit Board Illustrations
TROUBLESHOOTING
TECHNIQUES
Line illustrations
showing component locations keyed
with a grid scheme for each circuit board are usually
placed on the back of a foldout page and sequenced as
close as possible to an associated schematic .
The GRID
LOC columns,
located near the Parts Location Grid, keys
each component to easy location on the board .
Component and Wiring Color Codes
Colored stripes or dots on electrical
components
signify electrical values, tolerances, etc ., according to
EIA
standards . Components
not color-coded usually have
information printed on the body . The wiring coding
follows the same EIA standards with the exception of the
ac power cord of the Power Modules . It is coded
like this
:
Power
Cord Conductor Identification
Testing Equipment
Generally, a wide-band oscilloscope, a probe, and a
multimeter are all that is needed to perform basic
waveform and voltage checks for diagnostic purposes .
The calibration procedures in the manual for each
plug-in
module list
specific test
equipment and the features
necessary to adequately check out that particular module .
function or operation of any control, see the Operating
Instructions
section of the manual for the instrument
involved
.
System and
Associated Equipment
Before
proceeding with troubleshooting the TM 500
Series system, check that the instruments in the system
are operating correctly . Check for proper
interconnection
REV . A, AUG . 1976
Conductor
Color
Alternate Color
Ungrounded (Line)
Brown Black
Grounded (Neutral)
Blue White
Grounding
(Earthing) Green-Yellow Green-Yellow

between the power module and the plug-in
modules .
Check the line voltage at
the power source . Check that the
signal is properly
connected and that the interconnecting
cables
and signal source are not defective .
The associated plug-in modules can bechecked for
proper operation quickly by substituting
other like units
known
to
be operating properly . If the trouble persists
after substitution, then the power module is probably
at
fault . Moving a properly operating plug-in
fromcompart-
ment to compartment
will help determine if one or more
compartments
have a problem .
Visual Check
Inspect the portion of
the system in which the trouble is
suspected
. Many troubles can be located by visual clues
such as unsoldered connections, broken wires, damaged
circuit board, damaged components, etc .
Instrument
Calibration
Check the calibration of the suspected plug-in module
or the affected circuit if the trouble is obviously
in a certain
circuit . The trouble may onlybe a result of
misadjustment
or may be
corrected by re-calibration . Complete calibra-
tion instructions are given in the manual for each instru-
ment in the system .
Circuit Isolation
Note the trouble
symptoms . These often identify the
circuit in which the trouble is located . When trouble
symptoms appear in more than one circuit, check the
affected circuits by makingwaveformand
voltage
measurements .
Incorrect operation of all circuits often means trouble
in the power supplies . Using a multimeter, check
first for
correct voltages of
the individual regulated supplies
according
to the plug-in module schematics and calibra-
tion procedures . Then check the unregulated supplies of
the powermodules . Defective components elsewhere in
the instruments can appear as power supply problems .
In
these instances, suspected circuits should be dis-
connected from apparently
bad power supplies one at a
time to
narrow the search .
Voltages and Waveforms
Often defective components can be located by using
waveformand voltage indications when
they appear on
the schematic or in the calibration procedures .
Such
waveforms and
voltage labels are typical indications and
will vary between instruments . To obtain operating con-
ditions similar to those used to
take these readings, refer
to
the first diagram in the service sections .
REV . A, AUG . 1976
Component Checking
System Maintenance-TM
506
If a component cannot be disconnected from its circuit,
then the effects of the associated circuitry must be
considered when evaluating the measurement
.
Except
for
soldered-in transistors and integrated
circuits,
most
com-
ponents can be
lifted
at
oneend from the circuit board .
Transistors and IC's
. Turn the power switch off before
removing or replacing
any semiconductor .
A good check of transistor operation is actual
perfor-
mance under operating conditions .
A transistor can most
effectively be checked by substituting a newcomponent
for it (or one which has been
checked previously) .
However, besure
that circuit conditions are not such that a
replacement transistor might also be damaged . If sub-
stitute transistors are not available, use a dynamic
tester .
Static-type testers are not recommended,
since they do
not check operation
undersimulated operating conditons .
A
suction-type desoldering tool must be used to remove
soldered-in
transistors ; see component replacement
procedure for details .
Integrated circuits can be checked
with a voltmeter,
test oscilloscope, or
by direct substitution . A good
understanding of the
circuit description is essential to
troubleshooting
circuits using IC's . Operating waveforms,
logic levels, and other operating information
for the IC's
are given in the
circuit description information of the
appropriate manual . Use care when checking voltages
and waveformsaround the IC's so that adjacent leads
are
not shorted together . A convenient means of
clipping a
test probe to the 14- and 16-pin
in-line IC's is with an
integrated circuit test clip
. Thisdevice also doubles as an
extraction tool
.
Diodes . Do not use an
ohmmeter that has a high
internal
current . High currents may damage the diode .
A diode may be checked for an open or
shorted
condition by measuring
the
resistance
between terminals .
With an ohmmeter
scale having an internal source of
between
800 mV and 3 V, the resistance should be very
high in one direction and very low when the leads
are
reversed .
Resistors . Check the resistors
with an ohmmeter .
Resistor tolerances
are given in the Electrical Parts List in
every manual . Resistors do not normally need to be
replaced unless the measured value varies
widely from the
specified value .
2- 3

System
Maintenance-TM 506
Capacitors . A
leaky or shorted capacitor can be
detected by checking
resistance with an ohmmeter on the
highest scale . Use an
ohmmeter that will not exceed the
Ordering
Standard Parts . All electrical and mechanical replace-
ment
parts can be obtained through the local
Tektronix
Field Office or representative . However,
many of the
standard electronic components
can be obtained locally
in less time than is
required to order them from Tektronix,
Inc
.
Before purchasing or ordering replacement
parts,
check the Parts List for value,
tolerance, rating, and
description . When selecting replacement
parts, it is impor-
tant to remember that the
physical size and shape of the
component may
affect its performance in an
instrument .
All replacement
parts should be direct replacements
unless it is
known that a different component
will not
adversely affect the instrument
performance .
Special Parts . Some
parts are manufactured or selected
by Tektronix,
Inc
.
t
o
satisfy particular requirements,orare
manufactured for Tektronix, Inc . t o our
specifications .
Most of the mechanical parts used
in this system have
been manufactured by
Tektronix, Inc . Order all special
parts directly from the
local Tektronix Field Office or
representative .
Ordering Procedure . When ordering
replacement parts
from Tektronix, Inc ., please include the
following
minimum information :
1 . Instrument Type (PS
501, SG 502, DC 501, etc .)
2 .

Instrument Serial
Number (For example, B010251)
3 . A description of the part
(if electrical, include the
circuit number)
4 . Tektronix part number
Please do not return any
instruments or parts before
receiving directions from
Tektronix, Inc .
PARTS
ORDERING AND
REPLACING
voltage
rating of the capacitor . The resistance reading
should be high after initial charge of
the capacitor . An
open capacitor can best be
detected with acapacity meter,
or by checking
whether it passes ac signals .
A listing of Tektronix
Field
Offices,
Service Centers,
and Representatives can be
found in the Tektronix
ProductCatalog
and Supplements .
Replacing
The exploded view drawings associated
with the
Mechanical Parts List,
located to the rear of most manuals,
may
be especially helpful when disassembling or
reassembling individual components or
sub-assemblies .
Circuit Boards . If a circuit board is damaged beyond
repair, either the entire assembly including
all soldered-on
components, or the board only, can be replaced .
To remove or replace a board,
proceed as follows :
1 . Disconnect all leads connected to the board (both
soldered lead connections and solderless
pin connec-
tions) .
2 . Remove
all screws holding the board to thechassis
or other mounting surface . Some boards
may be held fast
by plastic mounting
clips around the board edges . For
these, push
the mounting clips away from the circuit board
edges to free the board . Also, remove any
knobs, etc ., that
would prevent the board
from being lifted out of the
instrument .
3 .

Lift the circuit board out of the
unit . Do not force or
bend the board .
4 . To replace the board,
reverse the order of removal .
Use care when replacing
pin connectors . If forced into
place incorrectly
positioned, the pin connectors may be
damaged .
REV . B, AUGA 976

Transistors and IC's . Transistors and IC'sshould notbe
replaced unless they are
actually defective . If removed
from their sockets during routine
maintenance, return
them to their original
sockets . Unnecessary replacement
or switching of
semiconductor devices may affect
the
calibration of the instruments .
When a transistor is
replaced, check the operation of
the part of the instrument
that may be affected .
Replacement
semiconductors should be of
the original
type or a
direct replacement . Figure 2-1 shows
the lead
configurations of the semiconductors used
in this instru-
REV
.
B,
AUG . 1976
System Maintenance-TM
506
ment system . When
removing soldered-in transistors, use
a suction-type
desoldering tool to remove the solder from
the holes in the circuit board .
An extracting tool
should be used to remove the 14-and
16-pin
integrated circuits to prevent damage to the pins .
This tool is available from Tektronix, Inc . Order
Tektronix
Part No . 003-0619-00 . If an extracting tool
is not available,
use care to avoid damaging the
pins . Pull slowly and
evenly on both ends of
the
IC .
Try to avoid having oneend
of the IC
disengage from the socket before the other end .
B
C C
Metal-Cased Transistors
Dual FET's
Power Transistors
See manufacturers
specifications
C B E
Plastic-Cased Transistors
SCR
/

..

` Pin 3
Pin 1

(Ground)
(Input)

Pin 2
(output)
f
Pin 2

1 1\
(output)

1 Pi n 1
I I
(Input)
Regulator IC's
Heat dissipator
(may be applied
to some metal-
cased transistors)
Integrated Circuits
Fig . 2-1 . Semiconductor device lead configurations
found in the TM 500 family .
2-5

System
Maintenance-TM 506
To
replace one of the power transistors
mounted on the
Power Module chassis adjacent
to the interface circuit
board,
first unsolder the leads . Then, loosen the nuts
whichclamp the transistor to the chassis
. Remove the
defective transistor
.
When
replacing the transistor, use a
mica
washeron the metal tab to increase heat
transfer
from the transistor to the chassis .
Interconnecting Pins . To
replace a pin that is mounted
on a circuit board,
first disconnect any pin connectors .
Then, unsolder
the damaged pin and pull it out of the
board
with a pair
of
pliers . Be careful not to damage the
wiring on the board with too much heat . Ream
outthe hole
in the circuit board with a 0 .031-inch
drill . Remove the
ferrule from the new
interconnecting pin and press the
new pin into the hole
in the circuit board . Position the pin
in
the same manner as the old pin and solder it
in . If the old
pin was bent at an angle to mate
with a connector, bend
the new pin to match the associated
pins .
2- 6
NOTE
A pin replacement kit including necessary
tools,
instructions, and replacement
pins is available from
Tektronix,
Inc
.
Order Tektronix Part No . 040-0542-
00 .
Cam
Switches . Repair of cam-type switches should be
undertaken
only
by
experienced maintenance personnel .
Switch alignment and spring tension of the contacts must
be carefully maintained for proper operation of theswitch
.
For assistance, contact your local Tektronix
Field Office
or representative .
NOTE
A cam-type
switch repair kit including necessary
tools, instructions, and
replacement contacts is
available from Tektronix, Inc . Order Tektronix Part
No . 040-0541-00 .
The cam-type switches consist of
rotating cam drums
which areturned by
front-panel knobs, and sets of spring-
leaf contacts mounted on adjacent circuit boards .
The
contacts are actuated by lobes on the cams .
These
switches can be dissembled
for inspection, cleaning,
repair, or
replacement as follows :
1
.
Remove the
screws which hold the metal cover on
the switch, and lift the cover off the switch . The switch is
now open for inspection or cleaning .
2 . To completely remove a switch from the circuit
board, first remove any knobs or shaft extensions . Loosen
the coupling at the potentiometer at the rear of
the switch,
and pull the long shaft
out
of
the switch assembly .
3 . Remove the screws (from the opposite side of the
circuit board) that holds the cam drum to the board
.
4 . To remove
the cam drum from the front support
block,
remove the retaining ring from the shaft on the front
of
the switch and slide the cam drum out of the
support
block . Be careful not to lose the small
detent roller .
5 . To replace defective
switch contacts, follow the
instructions given in the switch repair kit .
6 . To re-install the switch
assembly, reverse the above
procedure .
Pushbutton Switches . The pushbutton switches arenot
repairable
and should be replaced as a unit if defective .
Use a suction-type de-soldering tool to remove
solder
from the circuit board when
removing these switches .
Incandescent
Bulbs . Most of these light bulbs are
mounted on the sub-panel using plastic sleeve stand-offs .
Unsolder the lead wires and pull the bulb out of
the sleeve
from the rear of the sub-panel
.
REV . B,
AUG . 1976