Tektronix TM 504 User manual

Hektronix-
COMMITTEO TO E)CCELLENCE
POWER MODULE
TM 504
INSTRUCTION MANUAL

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97005
070-1716-00 First Printing JUNE 1974

WARRANTY
All TEKTRONIX instruments are warranted against
defective materials and workmanship for one year.
Any questions with respect to the warranty should
be taken up with your TEKTRONIX Field Engineer or
representative.
All requests for repairs and replacement parts
should be directed to the TEKTRONIX Field Office
or representative in your area. This will assure you
the fastest possible service. Please include the
instrument Type Number or Part Number and Serial
Number with all requests for parts or service.
Specifications and price change privileges reserved.
Copyright ®1974 by Tektronix, Inc., Beaverton,
Oregon. Printed in the United States of America. All
rights reserved. Contents of this publication may not
be reproduced in any form without permission of
Tektronix, Inc.
U.S.A. and foreign TEKTRONIX products covered
by U.S. and foreign patents and/or patents pending.
TEKTRONIX is aregistered trademark of Tektronix,
Inc.

TM 504
TABLE OF CONTENTS
Page
INSTALLATION PROCEDURE 1
OPERATING INSTRUCTIONS 4
POWERING UP 4
BUILDING ASYSTEM 6
SPECIFICATIONS 7
SYSTEM MAINTENANCE 8
GENERAL 8
TROUBLESHOOTING AIDS 9
TROUBLESHOOTING TECHNIQUES 9
PARTS ORDERING AND REPLACING 11
SERVICE INFORMATION 15
OPTIONS 16
INTERFACE PIN ASSIGNMENTS
DETAILED BLOCK DIAGRAM
PARTS LOCATION GRID
ELECTRICAL PARTS LIST 17
SCHEMATIC
MECHANICAL PARTS LIST
EXPLODED VIEW DRAWING
CHANGE INFORMATION
®i

TM 504
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.
...go to Operating Instructions...
2. If achange 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.
Stored
selector block
Stored
selector block
In-service
selector block
In-service
selector block
Brown
\g
The instrument can be
damaged by using the
120 VLine Selector block
with a220 Vnominal line
voltage.
1REV. B, MAR. 1975

TM 504
b. Line Range Taps Universal Transformer
Line
Selector
Block
Position
Regulal
120 Volts Nominal
:ing Ranges
220-Volts Nominal
L90 VAC to 110 VAC 180 VAC to 220 VAC
M99 VAC to 121 VAC 198 VAC to 242 VAC
H108 VAC to 132 VAC 216 VAC to 264 VAC
Line Fuse
Data 3A slow‘blow 1.6A slow-blow
c. Rear Panel
3. Replace the cabinet.
4. If necessary, change the line cord power plug to match the power source receptacle or use an adapter.
5. Plug the cord into the power source.
6. Insert the desired plug-ins.
7. Use the bail to raise the front of the instrument. ...go to Operating Instructions...
2

TM 504
OPERATING
INSTRUCTIONS
INTRODUCTION
Description
The TEKTRONIX TM-504 Power Module is amain-
frame for the TM 500 Series of Modular Instrumentation. It
accepts up to four independently functional plug-in
modules to form acompact versatile and low cost instru-
mentation system. The TM 504 is abasic power source and
provides 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 compart-
ments.
Power Source
This instrument is designed to operate from apower
source with its neutral at or near earth (ground) potential
with aseparate safety-earth conductor. It is not intended
for operation from two phases of amulti-phase system, or
across the legs of asingle phase, three-wire system.
Power Usage
With four plug-in modules installed, the TM 504 can
require up to 220 Wof power at the upper limits of the
high line voltage ranges. Actual power consumption de-
pends on the particular module combination and operating
mode selected at any one time.
NOTE
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 504 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
504 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
asafe level.
Since the TM 504 can be stored in temperatures between
—40°C and +75°C, allow the instruments's chassis to return
to within the operating limits before applying power.
POWERING UP
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.
Turn the Power Module off before inserting the plug-
in; otherwise, damage may occur to the plug-in
circuitry.
Module Installation
1.Check the location of the white plastic barriers on the
TM 504 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-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 located in the lower left
corner of each module.)
REV. B, MAR. 1975 4

Operating Instructions—TM 504
3. Pull the PULL ON POWER button on the right side
of the TM 504. Some plug-in modules have independent
power switches, usually labeled OUTPUT, controlling ap-
plication of mainframe power to the module. Push this
button to activate the plug-in module.
Loading Considerations
With four plug-in modules installed, the TM 504 can
require up to 220 Wof power from the line at high-line
voltage range settings. Actual power consumed, of course,
depends on the particular module combination selected at
any one time.
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 three
left hand compartments and full load in high power com-
partments, (2) as much power as possible dissipated in ex-
ternal loads, and (3) operating In an ambient temperature
of about +25°C.
The TM 504 provides each plug-in module with access to
apair of heat-sinked, chassis-mounted transistors, one NPN
and one PNP. These Series-Pass transistors allow the plug-in
modules to operate in power ranges not possible if the
power had to be dissipated within the modules.

Operating Instructions—TM 504
BUILDING ASYSTEM
Family Compatibility
Mechanically, the plug-in modules are very similar to
other Tektronix product families. However, they are not
electrically compatible. Therefore, the TM 504 interface
has barriers on the mating connectors between pins 6and 7
to ensure that incompatible modules cannot be inserted.
See Figure 1. Acompatible module will have amatching
slot between pins 6and 7of 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 afunctional family will have asecond
slot peculiar to its family assignment located in its edge
connector. The TM 504 user can ''program'' one or more
compartments to accept only members of that family by
installing asecond barrier in the interface connector to
match the module's slot location. An entire TM 504 can be
"programmed" in this manner to set up instruction systems
for specific work functions. For extra barriers, order
Tektronix Part Number 214-1593-02.
Jumper wires can be used to further specialize the
interface. Compartments can be made to "talk" to each
other by connecting jumpers on the back side of the
interface board, using pins 14 through 28, A-side and B-side
both, of the interconnecting jacks. See the 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 aspe-
cialized nature, it is recommended that barriers be installed
on the interconnecting jacks to ensure module com-
patibility with the customized wiring.
MEASUREMENT
|:|4^^21A
POWER SUPPLY
FAMILY KEY
HIGH POWER
COMPARTMENT
TM 500
FAMILY KEY
SIGNAL SOURCE
FAMILY KEY
Fig. 1. Keying assignments for family functions. One of many possible sequence combination.

Operating Instructions—TM 504
Rear Panel
The rear subpanel is punched for BNC and multi-pin
connector mountings. Customer- or factory-installed con-
nectors 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 from pins 14A and Bthrough pins
28A and B. This will keep the interface flexible by making
it easy and fast to change customized wiring using prepared
wires with 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 add three BNC connectors and one 50-pin
connector to the rear panel. These connectors are not
pre-wired, in order to give asystem designer as much
flexibility as possible. Instead, prepared jumpers, coaxial
cables, and interconnection jack barriers are included in a
kit.
SPECIFICATIONS
Power Requirements
Line Voltage Ranges. Universal Transformer: 100, 110,
120, 200, 220, 240 VAC, all within 10%. Range changing
for transformer accomplished with quick-change line-
selector block.
Line Frequency Ranges. Universal Transformer: 48 Hz to
440 Hz.
Power Consumption. Maximum primary power approxi-
mately 220 Wat high line. Actual power consumption
depends on plug-in selection and operating modes.
Supplies (Unregulated)
+33.5 VDC and -33.5 VDC, 1.4 Amaximum, shared by
all compartments.
Low Power (Left and Two Center Supplies). Two
25 VAC windings 500 mA each, supplied to each
compartment, independently.
17.5 VAC and +11.5V, 3.6 Amaximum, shared In
any combination between these two supplies and
shared among all three compartments.
High Power (Compartment Nearest Switch). Two
25 VAC windings, 1Asupplied only to high power
compartment.
17.5 VAC and +11.5, 4Amaximum, shared In any
combination between these two supplies.
NOTE
Current and voltage ratings are for main frame
maintenance only, in practice, not all available power
may be used at once. More detailed information is
supplied with kit 040’0652-02 (TM 500 plug-in).
Temperature Range
Operating: 0°C to +50°C. Nonoperating: —40°C to
+75°C.
Altitude Range
Operating: To 15,000 feet. Nonoperating: To 50,000
feet.
Other
Dimensions with Feet and Bail: H9.5 In., W12 in., L
20 in.
Weight without plug-ins: Approximately 18.5 lbs.
7REV C,OCT 1978

TM 504
SYSTEM
MAINTENANCE
GENERAL
Introduction
This section of the manual is meant to support the entire
TM 500 Series family of modules with ageneral coverage of
the most commonly-needed service information pertinent
to preventive maintenance, troubleshooting, ordering parts,
and replacing components and sub-assemblies.
Cabinet Removal
WARNING
Dangerous potentials exist at several points through-
out the system. When the system must be operated
with the cabinet removed, do not touch exposed
connections or components. Some transistors have
voltages present on their cases. Disconnect power
before cleaning the system or replacing parts.
Four screws on the top secure the cabinet to the TM 504
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 calibration.
Re-install the cabinet to protect the interior from dust and
to remove personnel shock hazards.
Exterior. Loose dust may be removed with asoft cloth
or adry brush. Water and amild detergent may be used;
however, abrasive cleaners should not be used.
Interior. Cleaning the interior of aunit should precede
calibration since the cleaning processes could alter the set-
tings of calibration adjustments. Use low-velocity com-
pressed air to blow off accumulated dust. Hardened dirt can
be removed with asoft, dry brush, cotton-tipped swab, or a
cloth dampened In asolution of water and mild detergent.
Preventive Maintenance
Preventive maintenance steps performed on aregular
basis will enhance the reliability of the instrumentation sys-
tems. However, periodic checks of the semiconductors in
the absence of amalfunction are not recommended as pre-
ventive maintenance measures. See the semiconductor
checking Information under Troubleshooting Techniques,
which follows. Aconvenient time to perform preventive
maintenance is just before Instrument calibration.
Cleaning
Avoid using chemical cleaning agents which might
damage plastic parts. Avoid chemicals containing
benzene, toluene, zylene, acetone, or similar solvents.
Calibration
To Insure accurate signal generation and measurement,
the performance of individual units composing the system
should be checked periodically. Refer to the Instruction
Manual for each unit for complete calibration and verifi-
cation procedures.
®8

System Maintenance—TM 504
TROUBLESHOOTING AIDS
Introduction
The following is provided to augment information
contained elsewhere in this and other TM 500 Series family
manuals when troubleshooting becomes necessary.
Circuit Descriptions
Each manual has asection devoted to explaining circuit
operating theory. Used conjointly with the schematics, this
can be apowerful 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.
Usually the first page of the service section defines the
circuit symbols and reference designators used in that
particular instrument. Major circuits are usually identifiable
by aseries of component numbers. Important waveforms
and voltages may be shown within the diagrams or on
adjoining aprons. Those portions of the circuits located on
circuit boards are enclosed with ablue or grey tint outline.
Cam Switch Charts
Cam switches shown on the diagrams are coded on
comprehensive charts to locate the cam number of the
switch contract in the complete switch assembly, counting
from the front, or knob end, toward the rear of the switch.
The charts also indicate with asolid dot when each contact
is closed.
Circuit Board Illustrations
Line illustrations showing component locations keyed
with agrid scheme for each circuit board are usually placed
on the back of afoldout page and sequenced as close as
possible to an associated schematic. The GRID LOG
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 stand-
ards. Components not color-coded usually have information
printed on the body. The wiring coding follows the same
EIA standards
.
Power Cord Conductor Identification
Conductor Color Alternate Color
Ungrounded (Line) Brown Black
Grounded (Neutral) Blue White
Grounding (Earthing) Green-Yellow Green-Yellow
Testing Equipment
Generally, awide-band oscilloscope, aprobe, 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.
TROUBLESHOOTING TECHNIQUES
Introduction
This troubleshooting procedure is arranged in an order
which checks the simple trouble possibilities before pro-
ceeding to extensive troubleshooting.
Control Settings
Incorrect control settings can indicate atrouble that does
not exist. If there is any question about the correct
function or operating 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
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 be checked for
proper operation quickly by substituting other like units
9REV. CJAN 1977

System Maintenance—TM 504
known to be operating properly. If the trouble persists after
substitution, then the power module is probably at fault.
Moving aproperly operating plug-in from compartment to
compartment will help determine if one or more compart-
ments has aproblem.
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 boards, damaged components, etc.
Instrument Calibration
Check the calibration of the suspected plug-in module or
the affected circuit if the trouble Is obviously in acertain
circuit. The trouble may only be aresult of misadjustment
or may be corrected by re-calibration. Complete calibration
instructions are given in the manual for each instrument in
the system.
Circuit Isolation
Note the symptom. It often identifies the circuit In
which the trouble is located. When trouble symptoms
appear in more than one circuit, check the affected circuits
by making waveform and voltage measurements.
Incorrect operating of all circuits often means trouble in
the power supplies. Using amultimeter, check first for
correct voltages of the individual regulated supplies ac-
cording to the plug-in module schematics and calibration
procedures. Then check the unregulated supplies of the
power modules. Defective components elsewhere in the
instruments can appear as power supply problems. In these
instances, suspected circuits should be disconnected from
apparently bad power supplies one at atime to narrow the
search.
Voltages and Waveforms
Often defective components can be located by using
waveform and 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 conditions
similar to those used to take these readings, refer to the
first diagram in the service sections.
Component Checking
If acomponent 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 one end from the circuit board.
Transistors and IC's. Turn the power switch off before
removing or replacing any semiconductor.
Agood check of transistor operation is actual perform-
ance under operating conditions. Atransistor can most
effectively be checked by substituting anew component for
it (or one which has been checked previously). However, be
sure that circuit conditions are not such that areplacement
transistor might also be damaged. If substitute transistors
are not available, use adynamic tester. Static-type testers
are not recommended, since they do not check operation
under simulated operating conditions. Asuction-type de-
soldering tool must be used to remove soldered-in tran-
sistors; see component replacement procedure for details.
Integrated circuits can be checked with avoltmeter, test
oscilloscope, or by direct substitution. Agood under-
standing of the circuit description is essential to trouble-
shooting 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 appro-
priate manual. Use care when checking voltages and
waveforms around the IC's so that adjacent leads are not
shorted together. Aconvenient means of clipping atest
probe to the 14- and 16-pln in-line IC's is with an Integrated
circuit test clip. This device also doubles as an extraction
tool.
Diodes. Do not use an ohmmeter that has ahigh internal
current. High currents may damage the diode.
Adiode 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 3V, 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.
Resistors do not normally need to be replaced unless the
measured value varies widely from the specified value.
Capacitors. Aleaky or shorted capacitor can be detected
by checking resistance with an ohmmeter on the highest
scale. Use an ohmmeter which will not exceed the 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.

System Maintenance—TM 504
PARTS ORDERING AND
REPLACING
Ordering
Standard Parts. All electrical and mechanical replacement
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
Lists for value, tolerance, rating, and description. When
selecting replacement parts, it is important 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
adifferent component will not adversely affect the Instru-
ment performance.
Special Parts. Some parts are manufactured or selected
by Tektronix, Inc., to satisfy particular requirements, or are
manufactured for Tektronix, Inc., to 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 repre-
sentive.
Ordering Procedure. When ordering replacement parts
from Tektronix, Inc., please include the following mini-
mum information:
1.Instrument Type (PS 501 ,SG 502, DC 501 ,etc.)
2. Instrument Serial Number (For example, B010251)
3. Adescription 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.
Alisting of Tektronix Field Offices, Service Centers, and
Representatives can be found in the Tektronix Product
Catalog and Supplements.
Replacing
The exploded view drawings associated with the Mechan-
ical Parts List, located to the rear of most manuals, may be
especially helpful when disassembling or reassembling in-
dividual components or sub-assemblies.
Circuit Boards. If acircuit board is damaged beyond
repair, the entire assembly, including all soldered-on com-
ponents, can be replaced.
To remove or replace aboard, proceed as follows:
1. Disconnect all leads connected to the board (both
soldered lead connections and solderless pin connections).
2. Remove all screws holding the board to the chassis 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.
Transistors and IC's. Transistors and IC's should not be
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 cali-
bration of the instruments. When atransistor is replaced,
check the operation of the part of the instrument that may
be affected.
11 REV. B, MAR. 1975

System Maintenance—TM 504
Replacement semiconductors should be of the original
type or adirect replacement. Figure 2shows the lead
configuration of the semiconductors used in this instrument
system. When removing soldered-in transistors, use a
suction-type de-soldering 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 1C. Try to avoid having one end of the
1C disengage from the socket before the other end.
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 which
clamp the transistor to the chassis. Remove the defective
transistor. When replacing the transistor, use amica washer
on the metal tab to Increase heat transfer from the
transistor to the chassis.
fl
C1E
BCCCBE
Plastic-Cased Transistors
ft
c'lL
EE
Metal-Cased Transistors
SS
V/? aa)
FET's
See manufacturer's
specification sheets
Power Transistors
SCR
Case
Ground
(Output) jjPin 1
I•(Input)
/
Pin 1
(Input) Pin 2
(Output)
Pin 3
(Ground)
Regulator IC's
Heat dissipator
(may be applied
to some metal-
cased transistors)
Integrated Circuits
Fig. 2. Semiconductor device lead configurations found in the TM 500 family.
REV. B, SEPT. 1975 12

System Maintenance—TM 504
Interconnecting Pins. To replace apin which is mounted
on acircuit board, first disconnect any pin connectors.
Then, unsolder the damaged pin and pull it out of the
board with apair of pliers. Be careful not to damage the
wiring on the board with too much heat. Ream out the hole
In the circuit board with a0.031 -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. If the old pin was bent at
an angle to mate with aconnector, bend the new pin to
match the associated pins.
NOTE
Apin 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 the switch.
For assistance, contact your local Tektronix Field Office or
representative.
NOTE
Acam-type switch repair kit including necessary
tools, instructions, and replacement contacts is avail-
able from Tektronix, Inc. Order Tektronix Part No.
040-0541-00.
The cam-type switches consist of rotating cam drums
which are turned 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 disassembled for inspection, cleaning,
repair, or replacement as follows:
3. Remove the screws (from the opposite side of the
circuit board) which hold 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 are not
repairable and should be replaced as aunit if defective. Use
asuction-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.
Light-Emitting Diodes. LED's used as indicators are
mounted on the sub-panels with plastic sleeve sockets
similar to the incadenscent bulb mountings or they are
soldered directly to asub-assembly and so mounted that
they protrude through holes in the panel. In these cases, the
sub-assembly must be exposed and the anode and cathode
lead orientations carefully noted before unsoldering the
defective LED. See Figure 3for LED lead identifying
information.
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 aswitch 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.
Power Transformer. Replace the transformer only with a
Tektronix direct replacement transformer. Refer to the
exploded view drawing at the rear of the Power Module
manuals for disassembly of the rear panel to expose the
power transformer. Refer to the schematic diagrams color-
coding information for correct wiring. After replacement
check out the power supply voltages before installing a
plug-in module.
®
13

System Maintenance—TM 504
Fuse Replacement. Table 1gives the rating and function of the fuses used in this power supply.
TABLE 1
Circuit Number Rating Function
F2 120 VAC- 3A Slow
220 VAC -1.6A Slow
Line Voltage Input
F50 11.5 VAC- 5A Slow High Power Hole
F35 11.5 VAC-5A Slow Low Power Holes
F20, R22 +33.5 VAC -1.6A Slow Low Power Holes
+33.5 VAC -1.6A Slow Low Power Holes
Repackaging for Shipment
If the Tektronix instrument is to be shipped to aTektronix
Service Center for service or repair, attach atag showing:
owner (with address) and the name of an individual at your
firm that can be contacted, complete instrument serial
number and adescription of the service required.
Save and re-use the package In which your instrument was
shipped. If the original packaging is unfit for use or not
available, repackage the instrument as follows:
1.
Obtain acarton of corrugated cardboard having inside
dimensions of no less than six inches more than the
instrument dimensions; this will allow for cushioning.
Refer to the following table for carton test strength
requirements.
2. Surround the instrument with polyethylene sheeting to
protect the finish of the instrument.
3. Cushion the instrument on all sides by tightly packing
dunnage or urethane foam between carton and instru-
ment, allowing three inches on all sides.
4. Seal carton with shipping tape or industrial stapler.
SHIPPING CARTON TEST STRENGTH
Gross Weight (lb) Carton Test Strength (lb)
0-10 200
10-30 275
30-120 375
120-140 500
140-160 600
REV. B, JAN. 1977 14

TM 504
SERVICE
INFORMATION
SYMBOLS AND REFERENCE DESIGNATORS
Electrical components shown on the diagrams are in the following units unless noted otherwise:
Capacitors =Values one or greater are in picofarads (pF).
Values less than one are in microfarads (juF).
Resistors =Ohms (^2)
Symbols used on the diagrams are based on ANSI Y32.2 —1970.
Logic symbology is based on Ml L-STD-806B in terms of positive logic. Logic symbols depict the logic function performed
and may differ from the manufacturer's data.
The following special symbols are used on the diagrams:
External Screwdriver adjustment.
External control or connector.
Clockwise control rotation in direction of arrow.
Refer to diagram number indicated in diamond.
Refer to waveform number indicated in hexagon.
Connection soldered to circuit board.
Connection made to circuit board with interconnecting pin.
Blue tint encloses components located on circuit board.
P/0 circuit board
15
SERVICE
INFORMATION

Option Information—TM 504
OPTION INFORMATION
Your instrument may be equipped with one or more options. This section describes those options,
or directs the reader to where the option is documented.
Option 1—Not applicable
Option 2Wire Kit Described in this section 3Pages
16
OPTIONS