ericssonz MAINTENANCE MANUAL AUDIO DISTRIBUTION MODULE ROA TABLE OF CONTENTS Page

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1 MAINTENANCE MANUAL AUDIO DISTRIBUTION MODULE ROA TABLE OF CONTENTS SPECIFICATIONS DESCRIPTION INTERFACE HARDWARE CIRCUIT ANALYSIS TEST AND TROUBLESHOOTING PARTS LIST IC DATA OUTLINE DIAGRAM SCHEMATIC DIAGRAM Page ericssonz Ericsson Inc. Private Radio Systems Mountain View Road Lynchburg, Virginia AE/LZB R1A (Outside USA, ) Printed in U.S.A.

2 Input Voltage Current drain Operating Temperature Indicator (1) Audio Channels Input Impedance Output Impedance Gain SPECIFICATIONS +12 Vdc ~11.2 milliamperes -30 C to +60 C DS1 (green) PWR 2 (Each with 6 outputs) ~10 k Ohms 600 Ohms Unity Inputs (2) IN_A (J1 A3, B3, C3) IN_B (J1 A5, B5, C5) Outputs (6/Input) OUTA1_T (JI A7) OUTB1_T (J1 A9) OUTA1_R (J1 C7) OUTB1_R (J1 C9) OUTA2_T (J1 A11) OUTB2_T (J1 A13) OUTA2_R (J1 C11) OUTB2_R (J1 C13) OUTA3_T (J1 A15) OUTB3_T (J1 A17) OUTA3_R (J1 C15) OUTB3_R (J1 C17 OUTA4_T (J1 A19) OUTB4_T (J1 A19) OUTA4_R (J1 C19) OUTB4_R (J1 C19) OUTA5_T (J1 A23) OUTB5_T (J1 A25) OUTA5_R (J1 C23) OUTB5_R (J1 C25) OUTA6_T (J1 A27) OUTB6_T (J1 A29) OUTA6_R ((J1 C27) OUTB6_T (J1 C29) NOTICE! Repairs to this equipment should be made only by an authorized service technician or facility designated by the supplier. Any repairs, alterations or substitution of recommended parts made by the user to this equipment not approved by the manufacturer could void the user s authority to operate the equipment in addition to the manufacturer s warranty. This manual is published by Ericsson Inc., without any warranty. Improvements changes to this manual necessitated by typographical errors, inaccuracies of current information, or improvements to programs /or equipment, may be made by Ericsson Inc., at any time without notice. Such changes will be incorporated into new editions of this manual. No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying recording, for any purpose, without the express written permission of Ericsson Inc. DESCRIPTION Audio Distribution Module ROA is part of a GPS Simulcast system (Figure 1). This module is used to buffer two independent audio channels provide six separate 600 ohm outputs for each channel. The input to the Audio Distribution Module is taken from the ALC module (Refer to Maintenance Manual AE/LZB ). Six outputs from the Audio Distribution Module feed up to a maximum of six (6) multiplexers in the same cabinet. Audio Distribution Modules plug into Audio Distribution Shelf ROA The green LED labeled PWR lights when power is applied. The Audio Distribution shelf mounts in the Control Point Audio Distribution/MUX Rack (Refer to the appropriate maintenance Manual for shelf information). INTERFACE Module pinouts are shown in the following table labeled Audio Distribution Module Pinouts. Inputs to the module are high impedance (approximately 10k ohms). This allows additional site cabinets to be added. Each output is a separate 600 ohm, transformer coupled, balanced line. HARDWARE Each audio channel consists of an input to a nominal unity gain non-inverting operational amplifier, followed by six unity gain operational amplifiers connected in parallel. The actual gain of the first stage is chosen to provide overall unity gain. Each amplifier drives an output. Other than the +5 Vdc on board regulated supply, no parts are shared between the two channels. CIRCUIT ANALYSIS The +12 Vdc input on connector J1 C31 connects through 0.5 amp. thermister fuse F1 to operational amplifiers U1-U4, Pin 4. This +12 Vdc also connects through resistor R19 to zener diode V1 where it is regulated to a +5 Vdc. The +5 Vdc is used to provide a reference voltage (VREF). Filtering for the +12 Vdc is provided by capacitors C15 C17. Filtering of the regulated +5 Vdc reference voltage is provided by capacitors C16 C18. The +5 Vdc connects through resistors R5 R6 to operational amplifier inputs at U4, Pins 3 5 respectively. The inputs to the Audio Distribution module on connector J1 A3, B3, C3 (1IN_A) J1 A5, B5, C5 (1IN_B) connect through coupling capacitors C1 C2 resistors R2 R4 to the inputs of operational amplifiers U4, Pin 3 U4, Pin 5 respectively. The output on U4, Pin 1 connects to the inputs of six (6) operational amplifiers U1, Pins 3, 5, 10, 12, U2, Pins 3 5. The output on U4, Pin 7 connects to the inputs of six (6) operational amplifiers U2, Pins U3, Pins 3, 5, Output of each of these amplifiers (U1-U3) connect through resistors R7-R18 coupling capacitors C3-C14 to the inputs on Pin 1 of coupling transformers T1-T6 respectively. These transformers provide six (6) 600 ohm T (Tip) R (Ring) outputs for each audio channel. A U D I O D I S T R I B U T I O N PWR Figure 1 - Front Panel Copyright September 1996, Ericsson Inc. 1

3 Audio Distribution Module Pinouts Terminal Function J1 A1, B1, C1 Ground J1 A2, B2, C2 J1 A3, B3, C3 IN_A (Input to audio channel A) J1 A4, B4, C4 GND_A (Ground) J1 A5, B5, C5 IN_B (Input to audio channel B) J1 A6, B6, C6 GND_B (Ground) J1 A7, C7 OUTA1_T Audio Distribution Module Pinouts - Cont. Terminal Function J1 A18, B18, C18 s J1 A19 OUTA4_T J1 B19 J1 C19 OUTA4_R J1 A20, B20, C20 s J1 A21 OUTB4_T J1 B21 TEST AND TROUBLESHOOTING Equipment Required: Extender Board Voltmeter Audio Generator Oscilloscope Procedure: 1. Place the Audio Distribution Module under test on an extender board plug it an appropriate slot in the Audio Distribution Shelf. 8. If the signal is not present connect the test lead of the oscilloscope to U1, Pin 1. If the signal is present replace resistor R7. 9. If the signal is not present connect the test lead of the oscilloscope to U1, Pin 3. If the signal is present replace U If the signal is not present connect the test lead to U4, Pin 3. If the signal is present replace U If the signal is not present check resistor R2 capacitor C Connect the audio generator to J1 C5 (IN_B). J1 B7 J1 C7 J1 A8, B8, C8 J1 A9 J1 B9 J1 C9 J1 A10, B10, C10 J1 A11 J1 B11 J1 C11 J1 A12, B12, C12 J1 A13 J1 B13 J1 C13 J1 A14, B14, C14 J1 A15 J1 B15 J1 C15 J1 A16, B16, C16 J1 A17 OUTA1_R s OUTB1_T OUTB1_R s OUTA2_T OUTA2_R s OUTB2_R OUTB2_R s OUTA3_T OUTA3_R s OUTB3_T J1 C21 J1 A22, B22, C22 J1 A23 J1 B23 J1 C23 J1 A24, B24, C24 J1 A25 J1 B25 J1 C25 J1 A26 B26 C26 J1 A27 J1 B27 J1 C27 J1 A28, B28, C28 J1 A29 J1 B29 J1 C29 J1 A30, B30, C30 J1 A31, B31 OUTB4_R s OUTA5_T OUTA5-R s OUTB5-T OUTB5_R s OUTA6_T OUTA6_R s OUTB6_T OUTB6_R s s 2. Check to see if the PWR LED on the front panel of the module is on. If not, with the voltmeter check for +12 Vdc on J1 C31. Ground is on J1 C4. If +12 Vdc is present check thermistor fuse F1. If fuse is open check filter capacitors C15 -C With the voltmeter check for regulated +5 Vdc at the junction between resistors R5 R6. It the +5 Vdc is not present or not correct check zener diode V1. Also check resistor R19 filter capacitors C16 C Set the audio generator for 200 mv at 1000Hz. Connect the audio generator to J1 C3 (IN_A). 5. Connect the oscilloscope across the outputs of transformer T1 (J1 A7 (OUTA1_T) J1 C7 (OUTA1_R) ). Since the circuit is unity gain, the output signal should be 200 mv at 1000Hz. If this signal is present this circuit is performing as it should. If a signal is found on any output of channel A, U4 for that channel is functioning as intended. Continue through the outputs of transformers T2-T6, etc. until the signal is lost. 6. If the signal is not present, i.e. OUTA1, connect the shield side of the oscilloscope to J1 C4. Connect the test lead to the negative side of capacitor C3. If the signal is present replace transformer T1. 7. If the signal is not present connect the test lead of the oscilloscope to the positive side of C3. If the signal is present replace C Connect the oscilloscope across the outputs of transformer T7 (J1 A9 (OUTB1_T) J1 C9 (OUTB1_R) ). Since the circuit is unity gain, the output signal should be 200 mv at 1000Hz. If this signal is present this circuit is performing as it should. If a signal is found on any output of channel B, U4 for that channel is functioning as intended. Continue through the outputs of transformers T8-T12, etc. until the signal is lost. 14. If the signal is not present (i.e. OUTB1) connect the shield side of the oscilloscope to J1 C4. Connect the test lead to the negative side of capacitor C9. If the signal is present replace transformer T If the signal is not present connect the test lead of the oscilloscope to the positive side of C9. If the signal is present replace C If the signal is not present connect the test lead of the oscilloscope to U2, Pin 8. If the signal is present replace resistor R If the signal is not present connect the test lead of the oscilloscope to U2, Pin 10. If the signal is present replace U If the signal is not present connect the test lead to U4, Pin 5. If the signal is present replace U If the signal is not present check resistor R4 capacitor C2. J1 B17 J1 C Vdc J1 C17 OUTB3_R J1 A32, B32, C32 Ground 2

4 PARTS LIST AND IC DATA AE/LZB VF (AUDIO) DISTRIBUTION MODULE ROA SYMBOL PART NO. DESCRIPTION U1 - U4 QUAD OPERATIONAL AMPLIFIER RYT /2C (3303) CAPACITORS C1 C2 C3 thru C14 C15 C16 C17 C18 RJE /22 RJE /47 RJE /1 RJC /1 Tantalum: 2.2 µf, ±20%, 20 WVDC. Tantalum: 4.7 µf, ±10%, 25 WVDC. Tantalum: 10 µf, ±10%, 25 WVDC. Ceramic: 0.01µF, ±10%, 50 WVDC. DS1 RKZ /3 LED: Green, 12 Vdc. F1 REZ /1 0.5A 15V PTC/Thermistor DIODE FUSE OUT 1 In- 1 In+ +12 Vdc 2 In+ 2 In OUT 4 In- 4 In+ GROUND 3 In+ 3 IN- 2 OUT OUT CONNECTOR J1 RPV /03 96-Pin VME, Right Angle RESISTORS R1 REP /2 Chip: 20k Ohms ±1%, 1/8 Watt. R2 REP /1 Chip: 10k Ohms ±1%, 1/8 Watt. R3 REP /2 Chip: 20k Ohms ±1%, 1/8 Watt. R4 REP /1 Chip: 10k Ohms ±1%, 1/8 Watt. R5 R6 R7 thru R18 REP /27 REP /51 Chip: 270k Ohms ±1%, 1/8 Watt. Chip: 510 Ohms ±1%, 1/8 Watt. R19 REP /1 Chip: 10k Ohms ±1%, 1/8 Watt. R20 REP /1 Chip: 1k Ohms ±1%, 1/8 Watt. R21 R22 REP /1 Chip: 10k Ohms ±1%, 1/8 Watt TRANSFORMERS T1 thru T12 REG 13557/1 600 Ohms, 1:1 U1 thru U4 RYT /2C - -INTEGRATED CIRCUIT- - Quad low-power Operational Amplifier DIODE V1 RKZ /8 Zener: 4.7 Vdc. *COMPONENTS ADDED, DELETED OR CHANGED BY PRODUCTION CHANGES 3

5 OUTLINEDIAGRAM (ROA , Rev B) 4

6 SCHEMATIC DIAGRAM AE/LZB (1911 ROA Sheet 1, Rev.B) 5

7 SCHEMATIC DIAGRAM (1911 ROA Sheet 2, Rev. B) 6

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