RTS PS-31 User manual

User Manual
MODEL PS-31
Power Supply
POWER
THERMAL
OVERLOAD
321
FAULT
AUDIBLE
ALERT
ON
CHANNEL STATUS
PROGRAM
LEVEL
CHANNEL
ASSIGN
1
2
3
TW INTERCOM SYSTEM
POWER SUPPLY
PS31
RTS SYSTEMS
9300-4437-00 Rev H 06/2005

PROPRIETARY NOTICE
The product information and design disclosed herein were
originated by and are the property of Telex Communications, Inc.
Telex reserves all patent, proprietary design, manufacturing,
reproduction, use and sales rights thereto, and to any article
disclosed therein, except to the extent rights are expressly granted to
others.
COPYRIGHT NOTICE
Copyright 2005 by Telex Communications, Inc. All rights reserved.
Reproduction, in whole or in part, without prior written permission
from Telex is prohibited.
WARRANTY NOTICE
See the enclosed warranty card for further details.
CUSTOMER SUPPORT
Technical questions should be directed to:
Customer Service Department
Telex Communications, Inc.
12000 Portland Avenue South
Burnsville, MN 55337 U.S.A.
Telephone: [phone]
Fax: [phone]
RETURN SHIPPING INSTRUCTIONS PROCEDURE
FOR RETURNS
If a repair is necessary, contact the dealer where this unit was
purchased. If repair through the dealer is not possible, obtain a
RETURN AUTHORIZATION from:
Customer Service Department
Telex Communications, Inc.
Telephone: [phone]
Fax: [phone]
DO NOT RETURN ANY EQUIPMENT DIRECTLY TO THE
FACTORY WITHOUT FIRST OBTAINING A RETURN
AUTHORIZATION.
Be prepared to provide the company name, address, phone number,
a person to contact regarding the repair, the type and quantity of
equipment, a description of the problem and the serial number(s).
SHIPPING TO THE MANUFACTURER
All shipments of product should be made via UPS Ground or best
available shipper, prepaid. Any shipment upgrades will be paid by
the customer. The equipment should be shipped in the original
packing carton. If the original carton is not available, use any
suitable container that is rigid and of adequate size. If a substitute
container is used, the equipment should be wrapped in paper and
surrounded with at least four inches of excelsior or similar shock-
absorbing material. All shipments must be sent to the following
address and must include a Return Authorization.
Factory Service Department
Telex Communications, Inc.
1930 West 1st Street
Blue Earth, MN 56013 U. S. A.
Attn.: Service
Upon completion of any repair, the equipment will be returned via
United Parcel Service or specified shipper, collect.

TABLE OF CONTENTS
CHAPTER 1
DESCRIPTION 1
1.1 Description ......................................................................................................................................1
1.1.1 General ..........................................................................................................................1
1.1.2 Features ..........................................................................................................................1
1.2 Installation ......................................................................................................................................3
1.2.1 Mechanical Installation .................................................................................................3
1.3 Electrical Installation ......................................................................................................................3
1.3.1 Connecting Intercom Stations .......................................................................................3
1.3.2 Using Two Ps31's To Expand Capacity .........................................................................4
1.3.3 Program Inputs ..............................................................................................................4
1.3.4 Ac Power .......................................................................................................................4
CHAPTER 2
OPERATION 7
2.1 Power-up Indications .......................................................................................................................7
2.2 Fault Indications ..............................................................................................................................7
2.3 Thermal Overload ...........................................................................................................................8
2.4 Impedance Select Switches .............................................................................................................8
2.5 Program Input ..................................................................................................................................8
CHAPTER 3
THEORY OF OPERATION 9
3.1 General ............................................................................................................................................9
3.2 Ac To Dc Conversion ......................................................................................................................9
3.3 Impedance Generator ....................................................................................................................10
3.4 Program Insertion Amplifier .........................................................................................................10
3.5 Display And Diagnostic Circuitry .................................................................................................11
3.5.1 Channel Status Indicators ............................................................................................11
3.5.2 Fault Indicator .............................................................................................................11
3.5.3 Thermal Overload ........................................................................................................11

2
CHAPTER 4
MAINTENANCE 13
4.1 Introduction ...................................................................................................................................13
4.2 General Maintenance ....................................................................................................................13
4.2.1 Safety Considerations ..................................................................................................13
4.2.2 Access ..........................................................................................................................14
4.2.3 Cleaning ......................................................................................................................14
4.2.4 Input Power Selection .................................................................................................14
4.2.5 Channel Dc Output Fuse Replacement .......................................................................15
4.3 Test Procedures .............................................................................................................................15
4.3.1 Test Equipment ............................................................................................................15
4.3.2 Initial Inspection ..........................................................................................................15
4.3.3 Power-up Test ..............................................................................................................15
4.3.4 Powered Channel Test .................................................................................................16
4.3.5 Functional Test Of All Outputs ...................................................................................17
4.4 Troubleshooting ............................................................................................................................19
CHAPTER 5
REPLACEMENT PARTS 21
5.1 Where To Obtain Parts ..................................................................................................................21
5.2 Mechanical Parts ...........................................................................................................................22
5.3 Electrical Parts .............................................................................................................................23
CHAPTER 6
DIAGRAMS and SPECIFICATIONS 29
Specifications ......................................................................................................................................31

1
1.1 DESCRIPTION
CHAPTER 1
DESCRIPTION
1.1 DESCRIPTION
1.1.1 GENERAL
The Model PS31 supplies 32 volts regulated DC power to each of three intercom channels. It has short circuit
and thermal overload protection, with automatic recovery when the fault is removed.
1.1.2 FEATURES
Program Input
There is a PROGRAM INPUT connector on the rear panel. A CHANNEL ASSIGN switch on the front panel
assigns the program to any of the three channels. A LEVEL control adjusts the program level to the intercom
channel.

DESCRIPTION
2
Status Indicators
There is an audible alarm and a red FAULT indicator for current overload indication on any of the three channels.
An AUDIBLE ALERT switch on the front panel turns the alarm on or off, but the FAULT indicator will continue
to flash during current overload conditions. There is also a green status indicator for each channel. Each of these
indicators will remain lit during normal operation, but will turn off during a channel current overload condition.
Output current is automatically reduced during an overload, and normal operation is restored when the overload
is removed.
Input Power
The PS31 is available in two versions: one for 115 VAC operation and one for 230 VAC operation. A simple
internal modification changes the operating voltage for 100 VAC or 200 VAC. A POWER on/off switch is pro-
vided on the front panel.
Figure 1. PS-31 Front and Back View
TELEX COMMUNICATIONS, INC.
MADE IN USA
TW INTERCOM SYSTEM
POWER SUPPLY
MODEL PS 31
NOTE
INTERNALLY
FUSED
CONNECTOR
PIN-OUT CODE
CH1-2
PIN - 1 COM
PIN - 2 CH 1
PIN - 3 CH 2
CH1-3
PIN - 1 COM
PIN - 2 CH 1
PIN - 3 CH 3
CH2-3
PIN - 1 COM
PIN-2 CH2
PIN-3 CH3
CH1-2-3
PIN - 1
PIN-2 CH2
PIN-3 CH3
PIN - 4 COM
CH 1
OUTPUTS CONNECT TO
TW INTERCOM SYSTEM COMPONENTS
REFER TO OPERATION MANUAL
OUTPUTS
IMPEDANCE SELECT
CHANNEL
CH 1-2-3 CH 1-2-3 CH 1-2-3
PUSH
12 3
J107 J108 J109
J110
J111
AC POWER
J101 J102 J103 J104 J105 J106
CH 2-3CH 2-3CH 1-3CH 1-3CH 1-2CH 1-2
PROGRAM INPUT
Z = 10K BALANCED
PIN 1 - GROUNDED
PIN 2 - LO
PIN3-HI
400
DUAL
200
NORM
W
W
CAUTION
WARNING
- TO REDUCE THE RISK OF FIRE, REPLACE ONLY WITH SAME TYPE FUSE
- TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE
POWER
THERMAL
OVERLOAD
321
FAULT
AUDIBLE
ALERT
ON
CHANNEL STATUS
PROGRAM
LEVEL
CHANNEL
ASSIGN
1
2
3
TW INTERCOM SYSTEM
POWER SUPPLY
PS31
RTS SYSTEMS

3
1.2 Installation
Intercom Channel Connections
Intercom channels are connected to the rear panel of the PS31. A variety of connector pin-outs is provided to
accommodate individual system requirements.
Impedance Selection
The PS31 provides the required channel terminating impedance for each channel. A 200/400 ohm IMPEDANCE
SELECT switch for each channel is located on the rear panel. These switches are set to 200 ohms for normal
operation. The 400 ohm setting permits two PS31's to be coupled to double the DC capacity of the system.
1.2 Installation
1.2.1 MECHANICAL INSTALLATION
The Model PS31 can be rack mounted or used free standing. The rack mount is a standard 19-inches wide by 3.5-
inches high. Allow room for cable connections.
1.3 ELECTRICAL INSTALLATION
1.3.1 CONNECTING INTERCOM STATIONS
NOTE: When connecting intercom stations, do not exceed the power supply capacity, either for one channel
or for all three channels. Power supply capacity is graphically illustrated in Figure 1. If more capacity
is required, refer to “PS 31 Capacity” on page 5.
Connect intercom channels to the OUTPUTS connectors on the rear panel. Pin assignments are printed above the
connectors. These connectors provide three alternatives for intercom channel connection:
•Connectors J101 through J106 can be used to connect various combinations of two channels.
•Connectors J107 and J108 can be used to connect all three channels.
•Connector J109 can also be used to connect three channels, but unlike all the other connectors, no power
is supplied at this connector. This connector can be used to interconnect the audio channels when using
two PS31 power supplies.

DESCRIPTION
4
1.3.2 USING TWO PS31'S TO EXPAND CAPACITY
If there are more stations on one or more channels than the power supply capacity will allow, two PS31 power
supplies may be used to double capacity. For each channel that requires added capacity:
1. Use the J109 connectors on both power supplies to interconnect the audio and ground pins of the desired
channel (See “PS-31 Front and Back View” on page 2.).
2. Divide the stations that you wish to connect into two groups. Connect one group to the first power supply.
Connect the other group to the second power supply. For each group, do not exceed the capacity (either
total or per channel) of the power supply.
3. On both power supplies, set the IMPEDANCE SELECT switches for the channel to the
400<F128M>W<F255D> DUAL position. (Leave all impedance switches for channels that are not inter-
connected in the 200<F128M>W<F255D> NORM position.
1.3.3 PROGRAM INPUTS
A program source may be connected to the PROGRAM INPUT connector on the rear panel. Pin assignments are
printed above the connector (See “PS-31 Front and Back View” on page 2.).
To connect an unbalanced program source, connect pin 2 to to pin 1. Then connect program ground to pin 1 and
program HI to pin 3.
If two PS31's are interconnected, a separate program source may be connected to each.
1.3.4 AC POWER
Plug the AC power cord into the PS31 and into an AC mains outlet.
NOTE: The PS31 is factory-set for either 110-120-volt operation or 220-240-volt operation. The operating
voltage is indicated on the back of the unit. Operation at 100-110 volts or 200-220 volts requires an
internal modification. Refer to “MAINTENANCE” on page 13.

5
1.2 Installation
Figure 2. PS 31 Capacity

DESCRIPTION
6