Crown FM500 User Manual

Revision Control

Revision Print Date

Initial Release (K80713–9) June 1996 Revision 1 (101033–1) November 1996 Revision 2 (101033–2) August 1997 Revision 3 (900239–1) February 1998 Revision 4 (900239–1) October 1998 Revision 5 (901047-1) October 1999 Revision 6 (901047-2) May 2000 Revision 7 March 2002

Revision 8 February 2006

Important Notices

©2006, Crown Broadcast, a division of International Radio and Electronics, Inc. Portions of this document were originally copyrighted by Michael P. Axman in 1991. All rights reserved. No part of this publication may be reproduced, transmitted,

transcribed, stored in a retrieval system, or translated into any language in any form by any means without the written permission of Crown International, Inc.

Printed in U.S.A. Sony and RCA are trademarks of their respective companies. Crown attempts to provide information that is accurate, complete, and useful.

Should you find inadequacies in the text, please send your comments to the following address:

International Radio and Electronics

25166 Leer Drive, P.O . Box 2000

Elkhart, Indiana, 46515-2000 U .S.A.

ii

ContentsContents

Contents

ContentsContents

Section 1—Getting Acquainted ..................................... 1–1

1.1 Your Transmitter ...............................................................................................1–2

1.2 Applications and Options...................................................................................1–3

1.2.1 Stand-Alone ..................................................................................................1–4

1.2.2 Backup..........................................................................................................1–4

1.2.3 Booster .........................................................................................................1–4

1.2.4 Exciter...........................................................................................................1–4

1.2.5 T ranslator......................................................................................................1–5

1.2.6 Satellator ......................................................................................................1–6

1.3 T ransmitter/Exciter Specifications .....................................................................1–7

1.4 Receiver Specifications .....................................................................................1–9

1.5 Safety Considerations......................................................................................1–10

1.5.1 Dangers ......................................................................................................1–10

1.5.2 Warn ings ....................................................................................................1–10

1.5.3 Cautions......................................................................................................1–10

Section 2—Installation ............................................... 2–1

2.1 Operating Environment......................................................................................2–2

2.2 Remove PA Tray Spacers ..................................................................................2–2

2.3 Power Connections ...........................................................................................2–3

2.4 Frequency (Channel) Selection ..........................................................................2–5

2.4.1 Modulation Compensator..............................................................................2–6

2.4.2 RF T uning Adjustments.................................................................................2–7

2.5 Receiver Frequency Selection............................................................................2–7

2.6 RF Connections.................................................................................................2–9

2.7 Audio Input Connections .................................................................................2–10

2.8 SCA Input Connections ...................................................................................2–11

2.9 Composite Input Connection ........................................................................... 2–11

2.10 Audio Monitor Connections.............................................................................2–12

2.11 Pre-emphasis Selection...................................................................................2–12

2.12 Processor Bypass Option ................................................................................2–12

2.13 Program Input Fault Time-out .........................................................................2–13

2.14 Remote I/O Connector.....................................................................................2–13

iii

Section 3—Operation................................................. 3–1

3.1 Initial Power-up Procedures ..............................................................................3–2

3.2 Power Switches.................................................................................................3–4

3.2.1 DC Breaker....................................................................................................3–4

3.2.2 Power Switch................................................................................................3–4

3.2.3 Carrier Switch...............................................................................................3–4

3.3 Front Panel Bar-Dot Displays.............................................................................3–5

3.3.1 Audio Processor Input ..................................................................................3–5

3.3.2 Highband and Wideband Display ..................................................................3–5

3.3.3 Modulation Display .......................................................................................3–5

3.5 Processing Control............................................................................................3–6

3.6 Stereo-Mono Switch..........................................................................................3–6

3.4 Input Gain Switches ..........................................................................................3–6

3.7 RF Output Control .............................................................................................3–7

3.8 Digital Multimeter..............................................................................................3–7

3.9 Fault Indicators .................................................................................................3–8

Section 4—Principles of Operation................................. 4–1

4.1 Part Numbering.................................................................................................4–2

4.2 Audio Processor Circuit Board ..........................................................................4–3

4.3 Stereo Generator Circuit Board..........................................................................4–4

4.4 RF Exciter Circuit Board ....................................................................................4–6

4.5 Metering Circuit Board ......................................................................................4–8

4.6 Motherboard .....................................................................................................4–9

4.7 Display Circuit Board.......................................................................................4–10

4.8 Voltage Regulator Circuit Board ......................................................................4–11

4.9 Power Regulator Circuit Boards ......................................................................4–12

4.10 RF Driver.........................................................................................................4–12

4.11 RF Amplifier ....................................................................................................4–13

4.12 Chassis ...........................................................................................................4–13

4.13 RF Output Filter & Reflectometer.....................................................................4–14

4.15 Receiver Circuit Board Option .........................................................................4–14

iv

Section 5—Adjustments and Tests ................................. 5–1

5.1 Audio Processor Adjustments ...........................................................................5–2

5.1.1 Pre-Emphasis Selection ................................................................................5–2

5.1.2 Pre-Emphasis Fine Adjustment .....................................................................5–2

5.2 Stereo Generator Adjustments ..........................................................................5–3

5.2.1 Separation ....................................................................................................5–3

5.2.2 Composite Output.........................................................................................5–3

5.2.3 19 kHz Level .................................................................................................5–3

5.2.4 19 kHz Phase................................................................................................5–3

5.3 Frequency Synthesizer Adjustments ..................................................................5–4

5.3.1 Frequency (Channel) Selection......................................................................5–4

5.3.2 Modulation Compensator..............................................................................5–4

5.3.3 Frequency Measurement and Adjustment .....................................................5–4

5.3.4 FSK Balance Control .....................................................................................5–4

5.4 Metering Board Adjustments.............................................................................5–5

5.4.1 Power Calibrate.............................................................................................5–5

5.4.2 Power Set .....................................................................................................5–5

5.4.3 SWR Calibrate...............................................................................................5–5

5.4.4 P A Current Limit ...........................................................................................5–5

5.5 Motherboard Adjustments.................................................................................5–6

5.6 Display Modulation Calibration..........................................................................5–6

5.7 Voltage Regulator Adjustments .........................................................................5–6

5.8 Bias Set (RF Power Amplifier)...........................................................................5–6

5.9 Performance Verification ...................................................................................5–7

5.9.1 Audio Proof-of-Performance Measurements .................................................5–7

5.9.2 De-emphasis Input Network..........................................................................5–7

5.10 Carrier Frequency..............................................................................................5–8

5.11 Output Power ....................................................................................................5–8

5.12 RF Bandwidth and RF Harmonics......................................................................5–8

5.13 Pilot Frequency .................................................................................................5–8

5.14 Audio Frequency Response ...............................................................................5–9

5.15 Audio Distortion ................................................................................................5–9

5.16 Modulation Percentage......................................................................................5–9

5.17 FM and AM Noise..............................................................................................5–9

5.18 Stereo Separation..............................................................................................5–9

5.19 Crosstalk ...........................................................................................................5–9

5.19.1 Main Channel Into Sub ..............................................................................5–10

5.19.2 Sub Channel Into Main ..............................................................................5–10

5.20 38 kHz Subcarrier Suppression.......................................................................5–10

5.21 Additional Checks............................................................................................5–10

v

Section 6—Reference Drawings .................................... 6–1

6.1 Views ................................................................................................................6–2

6.2 Board Layouts and Schematics .........................................................................6–4

Section 7—Service and Support.................................... 7 –1

7.1 Service ..............................................................................................................7–2

7.2 24–Hour Support ..............................................................................................7–2

7.3 Spare Parts .......................................................................................................7–2

Appendix................................................................ A–1

Glossary.................................................................G–1

Index................................................................Index–1

I

INFORMATION

Section 1—Getting Acquainted

This section provides a general description of the FM500 transmitter and introduces you to safety conventions used within this document. Review this material before installing or operating

the transmitter.

Getting Acquainted

1–1

I

1.1 Your Transmitter

The FM500 is a member of a family of FM stereo broadcast transmitters. Crown transmitters are known for their modularity, ease-of-use, and reliability.

The modularity is most apparent in the standard transmitter configuration which incorporates audio processing, stereo generation, and RF amplification without compromised signal quality. A single Crown transmitter can replace several pieces of equipment in a traditional system.

Ease-of-use is apparent in the user-friendly front panel interface and in the installation procedure. Simply select your operating frequency (using four rotary switches), add an audio source, attach an antenna, connect AC power, and you're ready to broadcast. Of course, the FM series of transmitters also feature more sophisticated inputs and monitoring connections if needed.

Reliability is a Crown tradition. The first Crown transmitters were designed for rigors of worldwide and potentially portable use. The modular design, quality components, engineering approach, and high production standards ensure stable performance.

Remote control and metering of the transmitter is made possible through a builtin I/O port. For more direct monitoring, the front panel includes a digital multimeter display and status indicators. Automatic control circuitry provides protection for high VSWR as well as high current, voltage, and temperature conditions.

Audio Input

High

-12

-18 Low

Modulation

10

2

High Band

Expand

Compress

2

-6

Wide Band

+6 dB

20

+12 dB

ProcessingInput Gain

®

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Carrier

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Illustration 1–1 FM500 Stereo Broadcast Transmitter

1–2

FM500 User's Manual

1.2 Applications and Options

Crown transmitters are designed for versatility in applications. They have been used as stand-alone and backup transmitters and in booster, translator, and satellator applications. The following discussion describes these applications further.

Model numbers describe the configuration of the product (which has to do with its intended purpose) and the RF output power which you can expect.

The number portion of each name represents the maximum RF output power. The FM500, for example, can generate up to 500 watts of RF output power.

Suffix letters describe the configuration. The FM500T, for example, designates a "transmitter" configuration. Since this is standard, it is what is described in the manual except where specified. In this configuration, the product includes the following modules (functions):

❑ audio processor ❑ stereo generator ❑ RF exciter ❑ metering ❑ low-pass filter

Stereo Generator

Audio Processor

Audio Input

10

High

-6

-12

-18 Low

2

Wide Band

+6 dB

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 1–2 Standard (Transmitter) Configuration

RF Exciter

Low-pass Filter

Metering

Getting Acquainted

1–3

I

1.2.1 Stand-Alone

In the standard configuration, the FM500 is an ideal stand-alone transmitter. When you add an audio source (monaural, L/R stereo, or composite signal), an antenna, and AC power, the transmitter becomes a complete FM stereo broadcast station, capable of serving a community.

As stand-alone transmitters, Crown units often replace multiple pieces of equipment in a traditional setup (exciter, audio processor, RF amplifier).

1.2.2 Backup

In the standard configuration, Crown transmitters are also used in backup applications. Should your primary transmitter become disabled, you can continue to broadcast while repairs take place. In addition, the FM transmitters can replace disabled portions of your existing system including the exciter, audio processor, or amplifier. Transfer switches on each side of the existing and backup transmitters make the change-over possible with minimal downtime.

1.2.3 Booster

Also in the standard configuration, Crown transmitters have been used as booster transmitters. Booster applications typically involve certain geographic factors which prevent your system from broadcasting to the full coverage area allowable. For example, a mountain range might block your signal to a portion of your coverage area. Careful placement of a Crown transmitter, operating on the same frequency as your primary transmitter, can help you reach full coverage.

1.2.4 Exciter

In addition to the standard configuration, the FM500 is available in optional configurations to meet a variety of needs.

An "E" suffix, as in the FM500E, for example, represents an exciter-only configuration. In this configuration, the audio processor and stereo generator are not included. The exciter configurations are the least expensive way to get Crownquality components into your transmission system.

You might consider the Crown exciter when other portions of your system are performing satisfactorily and you want to maximize your investment in present equipment.

1–4

FM500 User's Manual

1.2.5 Translator

A receiver configuration (FM500R, for example) takes an exciter configuration and adds receiver circuitry as well. This added feature makes the FM500 ideal for translator service in terrestrial-fed networks. These networks represent a popular and effective way to increase your broadcasting coverage. Translators, acting as repeater emitters, are necessary links in this chain of events.

Traditionally, network engineers have relied on multiple steps and multiple pieces of equipment to accomplish the task. Others have integrated the translator function (receiver and exciter) to feed an amplifier. Crown, on the other hand, starts with an integrated transmitter and adds a solid-state Receiver Module to form the ideal translator.

Receiver Module

RF IN

Low-pass Filter

RF Out

(option)

Stereo Generator

RF Exciter

Metering

Audio Input

10

High

-6

-12

-18 Low

Expand

Compress

2

20

Wide Band

+12 dB

+6 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 1–3 Crown's Integrated Translator

This option enables RF in and RF out on any of Crown’s FM series of transmitters. In addition, the module supplies a composite output to the RF exciter portion of the transmitter. From here, the signal is brought to full power by the built-in power amplifier for retransmission. The Receiver Module has been specifically designed to handle SCA channel output up to 100 kHz for audio and high-speed data.

FSK ID programming is built-in to ensure compliance with FCC regulations regarding the on-air identification of translators. Simply specify the call sign of the repeater station when ordering. Should you need to change the location of the translator, replacement FSK chips are available. The Receiver Module option should be ordered at the time of initial transmitter purchase. However, an option kit is available for field converting existing Crown units.

Getting Acquainted

1–5

I

1.2.6 Satellator

Another option is available for all configurations—an FSK Identifier (FSK IDer). This added feature enables the FM500 to transmit its call sign or operating frequency in Morse Code. This option is intended for use in satellite-fed networks. Transmitters equipped in this fashion are often known as "satellators."

Connect the transmitter to your satellite receiver and the pre-programmed FSK IDer does the rest—shifting the frequency to comply with FCC requirements and in a manner that is unnoticeable to the listener. The FSK IDer module should be ordered at the time you order your transmitter but is available separately (factory programmed for your installation).

Add the FSK IDer option to the exciter configuration for the most economical satellator (a composite input signal is required).

FSK IDer (option)

Low-pass Filter

Stereo Generator

RF Exciter

Audio

Audio Input

High

-6

-12

-18 Low

Processor

2

High Band

Expand

Compress

2

Wide Band

+12 dB

+6 dB

ProcessingInput Gain

10

20

®

Metering

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Modulation

Over 100 90 80 70 60 50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Illustration 1–4 Transmitter with FSK IDer Option

RF Out

Carrier

Power

1–6

FM500 User's Manual

1.3 Transmitter/Exciter Specifications

Frequency Range 87 MHz–108 MHz (65 MHz–73 MHz

optionally available)

RF Power Output 100–550 watts (VSWR 1.5:1 or better) RF Output Impedance 50 Ω

Frequency Stability Meets FCC specifications from

0-50 degrees C

Audio Input Impedance 50 kΩ bridging, balanced, or 600 Ω Audio Input Level Selectable for –10 dBm to +10 dBm for

75 kHz deviation at 400 Hz

Pre-emphasis Selectable for 25, 50, or 75 µsec; or Flat Audio Response Conforms to 75 µsec pre-emphasis curve

as follows

Complete transmitter ±0.30 dB (50 Hz–10 kHz)

±1.0 dB (10 kHz–15 kHz)

Exciter only ±0.25 dB (50 Hz–15 kHz)

Distortion (THD + Noise)

Complete transmitter Less than 0.7% (at 15 kHz) Exciter only Less than 0.3% (50 Hz–15 kHz)

Stereo Separation

Complete transmitter Better than –40 dB (50 Hz–15 kHz) Exciter only Better than –40 dB (50 Hz–15 kHz)

Crosstalk Main into sub, better than –40 dB

Sub into main, better than –40 dB

Stereo Pilot 19 kHz ±2 Hz, 9% modulation Subcarrier Suppresion 50 dB below ±75 kHz deviation FM S/N Ratio (FM noise)

Complete transmitter Better than –60 dB Exciter only Better than –70 dB

Getting Acquainted

1–7

I

AM S/N Ratio Asynchronous and synchronous noise

better than NAB recommendations

RF Bandwidth ±120 kHz, better than –35 dB

±240 kHz, better than –45 dB

RF Spurious Products Better than –70 dB Operating Environment Temperature (0–50o C)

Humidity (0–80% at 20o C) Maximum Altitude (3,000 meters;

9843 feet)

AC Power 100, 120, 220, or 240 volts (+10%/–15%);

50/60 Hz

Regulatory Type notified for FCC parts 73 and 74;

Meets FCC, DOC, and CCIR requirements

Dimensions 17.8 x 41.9 x 44.5 cm

(7.0 x 16.5 x 17.5 inches)

Weight 29.5 kg (65 lbs);

31.8 kg (70 lbs) shipping weight

1–8

FM500 User's Manual

1.4 Receiver Specifications

Monaural Sensitivity (demodulated, de-emphasized)

3.5 µV for signal-to-noise > 50 dB

12.6 µV for signal-to-noise > 60 dB

Stereo Sensitivity (19–kHz pilot frequency added)

2.8 µV for signal-to-noise > 40 dB 8 µV for signal-to-noise > 50 dB 31 µV for signal-to-noise > 60 dB

Connector Standard type N, 50 Ω Shipping Weight 1 lb

Getting Acquainted

1–9

I

1.5 Safety Considerations

Crown Broadcast assumes the responsibility for providing you a safe product and safety guidelines during its use. “Safety” means protection to all individuals who install, operate, and service the transmitter as well as protection of the transmitter itself. To promote safety, we use standard hazard alert labeling on the product and in this manual. Follow the associated guidelines to avoid potential hazard.

1.5.1 Dangers

DANGER represents the most severe hazard alert. Extreme bodily harm or death will occur if DANGER guidelines are not followed.

1.5.2 Warnings

WARNING represents hazards which could result in severe injury or death.

1.5.3 Cautions

CAUTION indicates potential personal injury or equipment or property damage if the associated guidelines are not followed. Particular cautions in this text also indicate unauthorized radio-frequency operation.

Pictorial Indication of Hazard

WARNING

Severe shock hazard! Turn power off and

wait approximately 1 minute for capacitors to discharge before handling them.

Illustration 1–5 Sample Hazard Alert

Type of Hazard

Explanation of Hazard

1–10

FM500 User's Manual

®

Section 2—Installation

This section provides important guidelines for installing your transmitter. Review this information carefully for proper installation.

Installation

2–1

CAUTION

Possible equipment damage! Before operating the transmitter for

the first time, check for the proper AC line voltage setting and frequency selection as described in sections 2.3

and 2.4.

2.1 Operating Environment

You can install the FM transmitter in a standard component rack or on a suitable surface such as a bench or desk. In any case, the area should be as clean and wellventilated as possible. Always allow for at least 2 cm of clearance under the unit for ventilation. If you set the transmitter on a flat surface, install spacers on the bottom cover plate. If you install the transmitter in a rack, provide adequate clearance above and below. Do not locate the transmitter directly above a hot piece of equipment.

2.2 Remove PA Tray Spacers

The Crown FM 500 is shipped with spacers between the PA tray and the transmitter back panel. The spacers prevent damage to internal contacts during shipping. Remove and save the spacers and screws before installing the FM500.

#8

#6

Illustration 2-1 FM 500 PA Tray Mounting Screws

1. Remove screws and spacers from five locations.

2. Firmly push the PA tray into the FM 500 until the PA tray panel touches the back panel.

3. Locate the bag labeled 500 Hardware. Install four #8 screws and washers and one number #6 screw and washer. See photo for locations.

2–2

FM500 User's Manual

2.3 Power Connections

The FM500 operates on 100, 120, 220, or 240 volts AC (50 or 60 Hz; single phase). As shipped (factory default settings), the FM500 operates on 120 volts at 60 Hz.

If you are operating the transmitter at 120 volts you do not need to make any changes. To operate the FM500 at 100, 220, or 240 volts, a few changes are necessary.

To change the voltage setting, follow these steps:

1. Disconnect the power cord if it is attached.

2. To set the input voltage for 100 volts, skip to step 7.

3. Open the cover of the power connector assembly using a small, flat blade screwdriver. See Illustration 2–2.

4. Insert the screwdriver into the top slot of the voltage selection assembly (red) and pry out the assembly from the power connector.

5. If you are setting the input voltage for 220 or 240 volts, replace the installed fuses with 12 amp fuses (included in your package). See Illustration 2–3.

6. Replace the red fuse assembly so that the "230V" setting appears right side up in the window. Close the assembly window.

115V

Illustration 2–2

Opening the Power Connector Cover

Installation

115V

230V

Illustration 2–3

Removing the Voltage Selection (red) Assembly

2–3

7. Turn the transmitter upside down and remove the bottom cover.

Note: The front panel filter grill must be removed to expose all of the bottom

Power Distribution Board

front of transmitter

Illustration 2–4 Underside of Transmitter—Bottom Cover Removed

cover screws for bottom cover removal and installation.

8. Locate the power distribution circuit board on the left side next to the large transformer cover. See Illustration 2–4.

9. For 100 or 220 volt operation, change the jumper setting of P1 to the 100/ 220 V setting.

10. For 220 or 240 volt operation,

• remove the jumper connecting P6 and P7.

• remove the jumper connecting P4 and P5.

• use a jumper to connect P5 and P6.

11. Replace the bottom cover, and the front grill.

12. Connect the AC power cord.

For your reference, use 12 amp fuses for 220 or 240 volt operation and 20 amp fuses for 100 or 120 volt operation.

2–4

FM500 User's Manual

2.4 Frequency (Channel) Selection

You may select an operating frequency of 87 to 108 MHz in the FM broadcast band with 100 kHz channel spacing (10 kHz spacing is optional with the addition of a fifth rotary selector switch).

To adjust the operating frequency, follow these steps:

1. Remove the top cover by removing 15 screws.

2. Locate the RF Exciter board and identify the frequency selector switches which will be used to change the setting. See Illustrations 2–5 and 2–6.

Modulation Trim-pot

Audio Input

Frequency Selection Rotary Switches

RF Exciter

10

High

-6

-12

-18 Low

2

+6 dB

Wide Band

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 2–5 Top Cover Removed

Illustration 2–6 RF Exciter Board Frequency Selector Switches

Installation

MEGAHERTZ

.1 .01

2–5

3. Use small flat blade screwdriver or another suitable device to rotate the switches to the desired setting. (The selected number will appear directly above the white indicator dot on each switch.) See examples of selected frequencies in the illustration below.

= 88.1 MHz

= 107.9 MHz

Illustration 2–7 Two Sample Frequency Selections

4. If you have the receiver option, proceed to section 2.5 to set the incoming frequency. Otherwise, replace the top cover.

2.4.1 Modulation Compensator

The Modulation trim-potentiometer (see illustration 2–8) compensates for slight variations in deviation sensitivity with frequency. Set the trim-pot dial according to the following graph:

Modulation Compensation Pot Setting

90

80

70

60

50

40

30

20

10

0

75 80 85 90 95 100 105 110

Frequency (MHz)

Illustration 2–8 Modulation Compensator Settings

These compensator settings are approximate. Each mark on the potentiometer represents about 1.8% modulation compensation. For more exact settings, refer to section 5.2.2.

2–6

FM500 User's Manual

2.4.2 RF Tuning Adjustments

All the RF stages are broadband to cover the 88 to 108 MHz broadcast band. The RF amplifier stages require no tuning.

2.5 Receiver Frequency Selection

If you have a transmitter equipped with the receiver option, you will need to set the receiving or incoming frequency.

1. With the top cover removed, locate the receiver module and the two switches (labeled SW1 and SW2).

2. Use the table on the following pages to set the switches for the desired incoming frequency.

3. After setting the frequency, return to section 2.3.1 to set the modulation compensator.

Frequency Selection Switches SW1 & SW2

Stereo

Receiver

Generator

Module

Audio Input

High

-6

-12

-18 Low

2

High Band

Expand

Compress

2

Wide Band

+12 dB

+6 dB

Processing

Input Gain

Illustration 2–8 Receiver Module Switches

RF IN

RF Exciter

Carrier

Modulation

10

20

®

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono

RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Installation

2–7

Frequency S W1 SW2

87.9 0 0

88.0 80

88.1 0 1

88.2 8 1

88.3 0 2

88.4 8 2

88.5 0 3

88.6 8 3

88.7 0 4

88.8 8 4

88.9 0 5

89.0 85

89.1 0 6

89.2 8 6

89.3 0 7

89.4 8 7

89.5 0 8

89.6 8 8

89.7 0 9

89.8 8 9

89.9 0 A

90.0 8A

90.1 0 B

90.2 8 B

90.3 0 C

90.4 8 C

90.5 0 D

90.6 8 D

90.7 0 E

90.8 8 E

90.9 0 F

91.0 8F

91.1 1 0

91.2 9 0

91.3 1 1

91.4 9 1

91.5 1 2

91.6 9 2

91.7 1 3

91.8 9 3

91.9 1 4

92.0 94

92.1 1 5

92.2 9 5

92.3 1 6

92.4 9 6

92.5 1 7

92.6 9 7

92.7 1 8

92.8 9 8

92.9 1 9

Frequency SW1 SW2

93.0 99

93.1 1 A

93.2 9 A

93.3 1 B

93.4 9 B

93.5 1 C

93.6 9 C

93.7 1 D

93.8 9 D

93.9 1 E

94.0 9E

94.1 1 F

94.2 9 F

94.3 2 0

94.4 A 0

94.5 2 1

94.6 A 1

94.7 2 2

94.8 A 2

94.9 2 3

95.0 A3

95.1 2 4

95.2 A 4

95.3 2 5

95.4 A 5

95.5 2 6

95.6 A 6

95.7 2 7

95.8 A 7

95.9 2 8

96.0 A8

96.1 2 9

96.2 A 9

96.3 2 A

96.4 A A

96.5 2 B

96.6 A B

96.7 2 C

96.8 A C

96.9 2 D

97.0 AD

97.1 2 E

97.2 A E

97.3 2 F

97.4 A F

97.5 3 0

97.6 B 0

97.7 3 1

97.8 B 1

97.9 3 2

Frequency SW1 SW2

98.0 B2

98.1 3 3

98.2 B 3

98.3 3 4

98.4 B 4

98.5 3 5

98.6 B 5

98.7 3 6

98.8 B 6

98.9 3 7

99.0 B7

99.1 3 8

99.2 B 8

99.3 3 9

99.4 B 9

99.5 3 A

99.6 B A

99.7 3 B

99.8 B B

99.9 3 C

100.0 BC

100.1 3 D

100.2 B D

100.3 3 E

100.4 B E

100.5 3 F

100.6 B F

100.7 4 0

100.8 C 0

100.9 4 1

101.0 C1

101.1 4 2

101.2 C 2

101.3 4 3

101.4 C 3

101.5 4 4

101.6 C 4

101.7 4 5

101.8 C 5

101.9 4 6

102.0 C6

102.1 4 7

102.2 C 7

102.3 4 8

102.4 C 8

102.5 4 9

102.6 C 9

102.7 4 A

102.8 C A

102.9 4 B

Frequency SW1 SW2

103.0 CB

103.1 4 C

103.2 C C

103.3 4 D

103.4 C D

103.5 4 E

103.6 C E

103.7 4 F

103.8 C F

103.9 5 0

104.0 D0

104.1 5 1

104.2 D 1

104.3 5 2

104.4 D 2

104.5 5 3

104.6 D 3

104.7 5 4

104.8 D 4

104.9 5 5

105.0 D5

105.1 5 6

105.2 D 6

105.3 5 7

105.4 D 7

105.5 5 8

105.6 D 8

105.7 5 9

105.8 D 9

105.9 5 A

106.0 DA

106.1 5 B

106.2 D B

106.3 5 C

106.4 D C

106.5 5 D

106.6 D D

106.7 5 E

106.8 D E

106.9 5 F

107.0 DF

107.1 6 0

107.2 E 0

107.3 6 1

107.4 E 1

107.5 6 2

107.6 E 2

107.7 6 3

107.8 E 3

107.9 6 4

108.0 E4

2–8

Table 2–1 Receiver Frequency Selection

FM500 User's Manual

2.6 RF Connections

Connect the RF load, an antenna or the input of an external power amplifier, to the type-N, RF output connector on the rear panel. VSWR should be 1.5:1 or better.

WARNING

Severe shock hazard! Do not touch the inner

portion of the RF output connector when transmitter power is on.

The RF monitor is intended primarily for a modulation monitor connection. Information gained through this connection can supplement that which is available on the transmitter front panel displays.

If your transmitter is equipped with the receiver option, connect the incoming RF to the RF IN connector.

RF Output Connector

RF Output Monitor

RFInput Connector (receiver option only)

115V

Illustration 2–10 RF Connections

Installation

2–9

2.7 Audio Input Connections

Attach audio inputs to the Left and Right XLR connectors on the rear panel. (The Left channel audio is used on Mono.) Pin 1 of the XLR connector goes to chassis ground. Pins 2 and 3 represent a balanced differential input with an impedance of about 50 kΩ. They may be connected to balanced or unbalanced left and right program sources.

The audio input cables should be shielded pairs, whether the source is balanced or unbalanced. For an unbalanced program source, one line (preferably the one connecting to pin 3) should be grounded to the shield at the source. Audio will then connect to the line going to pin 2.

SCA IN

1

23

COMPOSITE IN

R

MONITOR

REMOTE I/O

RIGHT

L

LEFT/MONO

Audio Inputs

Illustration 2-10 XLR Audio Input Connectors

By bringing the audio return line back to the program source, the balanced differential input of the transmitter is used to best advantage to minimize noise. This practice is especially helpful if the program lines are fairly long but is a good practice for any distance.

If the program source requires a 600 Ω termination, install resistors on the 8–pin DIP socket on the motherboard (socket A501 located between the XLR connectors). See the motherboard schematic, on page 6–13.

2–10

FM500 User's Manual

2.8 SCA Input Connections

You can connect external SCA generators to the SCA In connectors (BNC-type) on the rear panel. The inputs are intended for the 60 kHz to 99 kHz range, but a lower frequency may be used if the transmitter is operated in Mono mode. (The 23 to 53 kHz band is used for stereo transmission.) For 7.5 kHz deviation (10% modulation), input of approximately 3.5–volts (peak-to-peak) is required.

SCA IN

1

23

COMPOSITE IN

R

MONITOR

REMOTE I/O

RIGHT

L

LEFT/MONO

SCA Inputs (BNC) Connectors

Illustration 2–12 SCA Input Connectors

2.9 Composite Input Connection

To use the Crown transmitter as an RF Exciter only ("E" version or when using the "T" version with composite input), it is necessary to use the Composite Input section of the transmitter. This will feed composite stereo (or mono audio) directly to the RF exciter. In the "T" version, this will bypass the internal audio processor and stereo generator. See Section 2.12 on the next page for caution in using the bypass option.

Input sensitivity is approximately 3.5–volt P-P for 75 kHz deviation.

1. Enable the Composite Input by grounding pin 9 of the Remote I/O connector (see Illustration 2–15).

2. Connect the composite signal using the Composite In BNC connector.

Installation

2–11

SCA IN

1

23

COMPOSITE IN

R

MONITOR

REMOTE I/O

RIGHT

L

LEFT/MONO

Composite Input (BNC) Connector

Audio Monitor (RCA) Jacks

Illustration 2–13 Composite In and Audio Monitor Connections

2.10 Audio Monitor Connections

Processed, de-emphasized samples of the left and right audio inputs to the stereo generator are available at the Monitor jacks on the rear panel. The signals are suitable for feeding a studio monitor and for doing audio testing. De-emphasis is normally set for 75 µsec; set to 50 µsec by moving jumpers, JP203 and JP204, on the Stereo Generator board.

2.11 Pre-emphasis Selection

Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the appropriate pins of header JP1 on the audio processor board. If you change the pre-emphasis, change the de-emphasis jumpers JP203 and JP204 on the Stereo Generator board to match.

2.12 Processor Bypass Option

You may bypass the audio processor in order to feed the left and right (preemphasized) audio directly to the stereo generator. The Normal-Bypass slide switch is near the left-rear corner of the motherboard. If the audio source is already processed and you do not desire further processing, use the Normal mode but turn the Processing control (on the front panel) to “0.” (See also section 3.5.)

CAUTION

In the BYPASS position, the pre-emphasis circuits and the filters that protect the pilot and stereo subcarrier are bypassed. As a result, the occupied bandwidth specifications of the transmitter could be compromised. The 15–Hz high-pass filters are also bypassed which may mean that modulation with frequencies below 10 Hz could cause the frequency synthesizer to unlock.

2–12

FM500 User's Manual

2.13 Program Input Fault Time-out

You can enable an automatic turn-off of the carrier in the event of program failure. To enable this option, see the table on the next page. The time between program failure and carrier turn-off is set by a jumper (JP701) on the voltage regulator board (see Illustration 6–4 for board location). Jumper pins 1 and 2 (the two pins closest to the edge of the board) for a delay of approximately 30 seconds; pins 3 and 4 for a 2–minute delay; pins 5 and 6 for a 4–minute delay, and pins 7 and 8 for an 8–minute delay.

2.14 Remote I/O Connector

Remote control and remote metering of the transmitter is made possible through a 15–pin, D-sub connector on the rear panel. (No connections are required for normal operation.)

SCA IN

1

23

COMPOSITE IN

MONITOR

R

REMOTE I/O

RIGHT

L

Remote I/O

Illustration 2–14 Remote I/O Connector

The following table summarizes the Remote I/O pin connections.

LEFT/MONO

Installation

2–13

Pin Number Function

1 Ground 2 (no connection) 3 Composite Out (sample of stereo generator output) 4 FSK In (Normally high; pull low to shift carrier

frequency approximately 7.5 kHz. Connect to open collector or relay contacts of user-supplied FSK keyer.)

5 /Auto Carrier Off (Pull low to enable automatic turnoff

of carrier with program failure.) 6 Meter Battery (unregulated DC volts; 5 volts = 50 VDC) 7 Meter RF Watts (1 volt = 100 watts) 8 Meter PA Volts (5 volts = 50 VDC) 9 /Ext. Enable (Pull low to disable internal stereo

generator and enable External Composite Input.) 10 a) 38 kHz Out (From stereo generator for power supply

synchronization.)

b) For transmitters equipped with tuner option, this pin

becomes the right audio output for an 8–ohm monitor

speaker. 38kHZ Out is disabled. 11 ALC 12 /Carrier Off (pull low to turn carrier off.) 13 Fault Summary (line goes high if any fault light is

activated.) 14 Meter PA Temperature (5 volts = 100 degrees C.) 15 Meter PA Current (1 volt = 10 amperes DC.)

Table 2–3 Remote I/O Connections

8

15

1

9

Illustration 2–15 Remote I/O Connector (outside view)

2–14

FM500 User's Manual

Section 3—Operation

This section provides general operating parameters of your transmitter and a detailed description of its front panel display .

Operation

3–1

3.1 Initial Power-up Procedures

These steps summarize the operating procedures you should use for the initial operation of the transmitter . More detailed information follows.

CAUTION

Possible equipment damage! Before operating the transmitter for

the first time, check for the proper AC line voltage setting and frequency selection as described in sections 2.3

and 2.4.

1. Turn on the main power switch.

Carrier Switch

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Modulation

Over 100 90 80 70 60 50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Power

Power Switch

Illustration 3–1 Front Panel Power Switches

2. Verify the following: a. The bottom cooling fans runs continuously. b. The Lock Fault indicator flashes for approximately 5 seconds, then goes

off.

4. Set the Input Gain switches for mid-scale wideband gain reduction on an average program level (see section 3.4).

5. Set the Processing control (see section 3.5; normal setting is “50”).

6. Set the Stereo-Mono switch to Stereo (see section 3.6).

7. Turn on the Carrier switch.

3–2

FM500 User's Manual

8. Check the following parameters on the front panel multimeter: a. RF Power should be 500–550 watts. b. SWR should be less than 1.25 (A reading greater than 1.25 indicates an

antenna mismatch). c. ALC should be between 4.00 and 6.00 volts. d. PA DC Volts should be 46–56 volts. (Varies with antenna match, power,

and frequency.) e. PA DC Amperes should be 12–16 amps. (Varies with antenna match,

power , and frequency.) f. PA Temperature should initially read 20–35 degrees C (room tempera-

ture). After one hour the reading should be 35–50 degrees C. g. Supply DC Volts should display a typical reading of 65–70 V with the

carrier on and 80–85 V with the carrier off h. Voltmeter should be reading 0.0.

The remainder of this section describes the functions of the front panel indicators and switches.

Operation

3–3

3.2 Power Switches

3.2.1 DC Breaker

The DC breaker , on the rear panel, must be on (up) for transmitter operation, even when using AC power . Electrically, the DC breaker is located immediately after diodes which isolate the DC and AC power supplies.

3.2.2 Power Switch

The main on/off power switch controls both the 120/240 VAC and the DC battery power input.

3.2.3 Carrier Switch

This switch controls power to the RF amplifiers and supplies a logic high to the voltage regulator board, which enables the supply for the RF driver. In addition, the Carrier Switch controls the operating voltage needed by the switching power regulator .

A "Lock Fault" or a low pin 12 (/Carrier Off) on the Remote I/O connector will hold the carrier off. (See section 2.12.)

Carrier Switch

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Modulation

Over 100 90 80 70 60 50 40 30 20 Pilot

FM500

Carrier

Power

FM BROADCAST TRANSMITTER

Power Switch

Illustration 3–2 Front Panel Power Switches

3–4

FM500 User's Manual

3.3 Front Panel Bar-Dot Displays

Bar-dot LEDs show audio input levels, wideband and highband audio gain control, and modulation percentage. Resolution for the gain control and modulation displays is increased over a conventional bar-graph display using dither enhancement which modulates the brightness of the LED to give the effect of a fade from dot to dot. (See section 4.7.)

3.3.1 Audio Processor Input

T wo vertical, moving-dot displays for the left and right channels indicate the relative audio levels, in 3 dB steps, at the input of the audio processor . Under normal operating conditions, the left and right Audio Processor indicators will be active, indicating the relative audio input level after the Input Gain switches. During program pauses, the red Low LED will light.

With the receiver module option installed, the audio processor indicators are disabled.

3.3.2 Highband and Wideband Display

During audio processing, the moving-dot displays indicate the amount of gain control for broadband (Wide) and pre-emphasized (High) audio. These indicators are disabled if the receiver module option is installed.

As long as program material causes activity of the Wideband green indicators, deter mined by the program source level and Input Gain switches, the transmitter will be fully modulated. (See section 3.4.)

The Wideband indicator shows short-term “syllabic-rate” expansion and gain reduction around a long-term (several seconds) average gain set.

Program material and the setting of the Processing control determine the magnitude of the short-term expansion and compression (the rapid left and right movement of the green light).

High-frequency program content affects the activity of the Highband indicator . With 75–µsec pre-emphasis, Highband processing begins at about 2 kHz and increases as the audio frequency increases. Some programs, especially speech, may show no activity while some music programs may show a great deal of activity.

3.3.3 Modulation Display

A 10–segment, vertical peak-and-hold, bar graph displays the peak modulation percentage. A reading of “100” coincides with 75 kHz deviation. The display holds briefly (about 0.1 seconds) after the peak. The “Pilot” indicator illuminates when the transmitter is in the stereo mode.

T o verify the actual (or more precise) modulation percentage, connect a certified modulation monitor to the RF monitor jack on the rear panel.

Operation

3–5

3.4 Input Gain Switches

The “+6 dB” and “+12 dB” slide switches set audio input sensitivity according to the following table.

Nominal Input Switches

Sensitivity +6 dB +12 dB

+10 dBm Down Down

+4 dBm Up Down

-2 dBm Down Up

-8 dBm Up Up

Table 3–1 Input Gain Switches

Find, experimentally, the combination of Input Gain switch settings that will bring the Wideband gain-reduction indicator to mid scale for “normal” level program material. The audio processor will accommodate a fairly wide range of input levels with no degradation of audio quality.

3.5 Processing Control

T wo factors contribute to the setting of the Processing control: program material and personal taste. For most program material, a setting in the range of 40 to 70 provides good program density . For the classical music purist, who might prefer preservation of music dynamics over density, 10 to 40 is a good range. The audio will be heavily processed in the 70 to 100 range.

If the program source is already well processed, as might be the case with a satellite feed, set the Processing to “0” or “10”.

3.6 Stereo-Mono Switch

The Stereo-Mono slide switch selects the transmission mode. In Mono, feed audio only to the left channel. Although right-channel audio will not be heard as audio modulation, it will affect the audio processing.

3–6

FM500 User's Manual

3.7 RF Output Control

Set this control for the desired output power level. Preferably , set the power with an external RF wattmeter connected in the coaxial line to the antenna. You may also use the RF power reading on the digital multimeter .

The control sets the RF output voltage. Actual RF output power varies as the approximate square of the relative setting of the control. For example, a setting of “50” is approximately 1/4 full power . Operation below 100 watts is not recommended as instability can occur which could damage the transmitter .

CAUTION

Possible equipment damage!

Operation below 100 watts can cause oscillations and other problems that could damage the transmitter.

3.8 Digital Multimeter

The four-digit numeric display in the center of the front panel provides information on transmitter operation. Use the “Up” and “down” push-buttons to select one of the following parameters. A green LED indicates the one selected.

Audio Input

High

-12

-18 Low

Digital Multimeter Multimeter Functions

10

2

High Band

Expand

Compress

2

-6

Wide Band

+6 dB

20

+12 dB

ProcessingInput Gain

®

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Illustration 3–3 Digital Multimeter

Multimeter Push-buttons

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Modulation

Carrier

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

RF Power—Actually reads RF voltage squared, so the accuracy can be affected by VSWR (Voltage Standing-Wave Ratio). See section 5.4 for calibration. Requires calibration with the RF reflectometer being used.

SWR—Direct reading of the antenna standing-wave ratio (the ratio of the desired load impedance, 50 ohms, to actual load).

Operation

3–7

ALC—DC gain control bias used to regulate PA supply voltage. With the P A power supply at full output voltage, ALC will read about 6.0 volts. When the RF output is being regulated by the RF power control circuit, this voltage will be reduced, typically reading 4 to 5.5 volts. The ALC voltage will be reduced during PA DC overcurrent, SWR, or LOCK fault conditions.

PA DC V olts—Supply voltage of the RF power amplifier. PA DC Amps—Transistor drain current for the RF power amplifier. PA DC Temperature—T emperature of the RF power amplifier heatsink in degrees C. Supply DC Volts—Unregulated DC voltage at the input of the voltage regulators. For

battery operation, this reading is the battery voltage minus a diode drop. Voltmeter—Reads the voltage at a test point located on the front edge of the mother-

board. A test lead connected to this point can be used for making voltage measurements in the transmitter . The test point is intended as a servicing aid; an alternative to an external test meter . Remember that the accuracy is only as good as the reference voltage used by the metering circuit. Servicing a fault affected by the reference affects the Voltmeter reading. The metering scale is 0 to 199.9 volts.

3.9 Fault Indicators

Faults are indicated by a blinking red light as follows: SWR—Load VSWR exceeds 1.5:1. ALC voltage is reduced to limit the reflected RF

power. Lock—Frequency synthesizer phase-lock loop is unlocked. This indicator normally

blinks for about five seconds at power turn-on. Whenever this light is blinking, supply voltages will be inhibited for the RF driver stage as well as for the RF power amplifier .

Input—The automatic carrier-off circuit is enabled (see sections 2.11 and 2.12) and the absence of a program input signal has exceeded the preset time. (The circuit treats white or pink noise as an absence of a program.)

PA DC—Power supply current for the RF power output amplifier is at the preset limit. ALC voltage has been reduced, reducing the PA supply voltage to hold supply current to the preset limit.

PA Temp—PA heatsink temperature has reached 80–85° C (178–185° F). At about 83° C (181°F), ALC voltage begins to decrease, reducing the PA supply

voltage to prevent a further increase in temperature. By 85° C (185° F), the PA will be fully cut off.

3–8

FM500 User's Manual

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Section 4—Principles of Operation

This section discusses the circuit principles upon which the transmitter functions. This information is not needed for day-today operation of the transmitter but may be useful for advanced users and service personnel.

Principles of Operation

4–1

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4.1 Part Numbering

As this section refers to individual components, you should be familiar with the part numbering scheme used. Although parts on the various circuit boards and circuit board drawings may be marked with identical reference numbers, each component in the transmitter has a unique part reference number.

The circuit boards and component placement drawings use designators such as “R1”, “R2”, and “C1.” These numbers represent only a portion of the full part numbers (as shown on the schematic). To find the full number, refer to the chart below. R401, for instance, is marked “R1” on the Metering board and on its component placement drawing.

Circuit Name Part numbers

Audio Processor 0-199 Stereo Generator 200’s RF Exciter/Synthesizer 300’s Metering/Protection 400’s Motherboard 500’s Display 600’s Voltage Regulator 700’s Power Regulator 800’s RF Predriver 900’s Chassis Wiring 1000's RF Power Amplifier 1100's RF Low-Pass Filter 1200's

Illustration 4–1 Component Part Numbering

4–2

FM500 User's Manual

4.2 Audio Processor Circuit Board

The audio processor board provides the audio control functions of a compressor, limiter, and expander. Illustration 6–5 and accompanying schematic may be useful to you during this discussion.

Audio Processor

Carrier

Modulation

Audio Input

10

High

-6

-12

-18 Low

2

+6 dB

Wide Band

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Illustration 4–2 Audio Processor Board

This board also contains the pre-emphasis networks. Reference numbers are for the left channel. Where there is a right-channel counterpart, references are in parenthesis. One processor circuit, the eighth-order elliptical filter, is located on the stereo generator board.

Audio input from the XLR connector on the rear panel of the transmitter goes to differential-input amplifier, U1A (U2A).

Binary data on the +6 dB and +12 dB control lines sets the gain of inverting amplifier U1B (U2B). Analog switch, U3, selects one of four feedback points in 6 dB steps.

The output of U1B (U2B) goes to an eighth-order, elliptical, switched-capacitor, low-pass, 15.2 kHz filter. The filter finds its home on the stereo generator board to take advantage of the ground plane and proximity to the 1.52 MHz clock.

The circuit associated with U4B (U4A), along with R22/C8 (R58/C20), form third-order, low-pass filtering, attenuating audio products below 30 Hz.

The output level of analog multiplier U5 (U6) is the product of the audio signal at pin 13 and the DC voltage difference between pins 7 and 9. At full gain (no gain reduction) this difference will be 10 volts DC.

Principles of Operation

4–3

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When either the positive or negative peaks of the output of U5 (U6) exceeds the gain-reduction threshold, U13A generates DC bias, producing broadband gain reduction. Q5 is a precision-matched transistor pair. Q5 and U13B form a log converter, so that a given voltage change produces a given change in gain control dB of U5 (U6). The log conversion ensures uniform level-processing characteristics well beyond the 20 dB control range. The log conversion has an additional benefit; it allows a display of gain control on a linear scale with even distribution of dB.

Q1 (Q2) is a recover/expansion gate with a threshold about 18 dB below the normal program level. The amount of short-term expansion and gain reduction is controlled by R650, located on the front panel display board. (See section 3.5.)

Pre-emphasis, in microseconds, is the product of the capacitance of C10 (C22), multiplied by the gain of U8 (U9), times the value of R31 (R67). For a 75 µsecond pre-emphasis, the gain of U8 (U9) will be about 1.11. Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the appropriate pins on header JP1. Use trim pot R29 (R65) to make fine adjustments to the pre-emphasis. (See section 5.1.)

For highband processing, the peak output of U10B is detected and gain-reduction bias is generated, as with the broadband processor. The highband processing, however, shifts the pre-emphasis curve rather than affecting overall gain.

Peak audio voltages are compared to a plus and minus 5 volt reference, U17 and U18. This same reference voltage is used by the stereo generator, metering, and display boards.

For an explanation of on-board adjustments see section 5.1.

4.3 Stereo Generator Circuit Board

The stereo generator board (see Illustration 4–3) generates a composite stereo signal from left and right-channel audio inputs. The component side of the board is mostly a ground plane. Once again, the eighth-order, 15.2 kHz, elliptical, low-pass filters (U201 and U202) are on this board, but belong to the audio processor.

Illustration 6–6 and accompanying schematic complement this discussion. U207A and Y201 comprise a 7.6 MHz crystal oscillator from which the 19 kHz and

38 kHz subcarriers are digitally synthesized. U207F is a buffer. The 7.6 MHz is divided by 5 in U208A to provide 1.52 MHz at pin 6, used by filters U201 and U202.

3.8 MHz, 1.9 MHz, and 304 kHz are also derived from dividers in U208. Exclusive-OR gates, U210A and U210B, provide a stepped approximation of a 38 kHz

sine wave—a scheme described in the W. Sams &. Co., Inc., Indianapolis, IN, 1978).

With the resistor ratios used, the synthesized sine wave has very little harmonic energy below the 7th harmonic. U210C and D generate the 19 kHz pilot subcarrier. U211 is a dual, switched-capacitor filter, configured as second-order, low-pass filters,

4–4

CMOS Cookbook by Don Lancaster (Howard

FM500 User's Manual

Stereo Generator

Audio Input

10

High

-6

-12

-18 Low

2

+6 dB

Wide Band

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 4–3 Stereo Generator Board

each with a Q of 5. The 38 kHz and 19 kHz outputs of pins 1 and 20, respectively, are fairly pure sine waves. Harmonic distortion products are better than 66 dB down—THD of less than 0.05%.

U212 is a precision, four-quadrant, analog multiplier. The output of U212 is the product of 38 kHz applied to the “X” input and the difference of left and right audio (L-R signal) applied to the “Y” input. The resulting output is a double sideband, suppressed carrier—the L-R subcarrier.

The SCA subcarrier, the left, right, and left-minus-right subcarriers, and the 19 kHz pilot subcarrier are combined into the composite stereo signal by summing amplifier U206B.

Analog switch U205, at the input of U206B, provides switching of left and right audio for stereo and mono modes. In the mono mode, right channel audio is disabled, and the left channel audio is increased from 45% modulation to 100%.

MON L and MON R outputs go to the AF Monitor jacks on the rear panel. R208+R210 (R220+R222) and C207 (C211) comprise a 75 µsec de-emphasis network. Processed, de-emphasized (75 µsec) samples of the stereo generator input signals are used for a studio monitor and for audio testing. Option jumpers JP203 (JP204) allow you to select 50 µsec.

VR201 and VR202 supply +6 volts and –6 volts, respectively. A 5 volt reference from the audio processor board supplies the subcarrier generators.

For an explanation of on-board adjustments see section 5.2.

Principles of Operation

4–5

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4.4 RF Exciter Circuit Board

This board is also known as the Frequency Synthesizer board. The entire component side of the board is a ground plane. Rotary switches along the front edge of the board establish the operating frequency. The VCO (voltage-controlled oscillator) circuitry is inside a shielded cover.

Illustration 6–7 and accompanying schematic can be used as reference in this discussion. The following theory may apply to previous versions of the exciter board, but it is typical of the operation of the current board which has the latest technological improvements.

VCO, VCO61, operates at the synthesizer output frequency of 87 MHz to 108 MHz. The frequency is controlled by voltage-variable capacitors DV71 and DV72. U7A and U7B form an active filter to supply clean DC to the drain of Q71. They also serve as a common-base RF amplifier for Q71. A71 and A1 are hybrid RF amplifiers to provide buffering and gain.

A sample of the RF from the VCO goes to the input of A2. A2 amplifies the signal and feeds it back to the synthesizer IC, U6. This signal, available at pin 4 of U6, may be used with a high frequency receiver for deviation and frequency measurements. (See sections 5.2 and 5.3.)

U6 is a phase-locked-loop frequency synthesizer IC. The 10.24 MHz from the crystal oscillator is used by U6, along with ICs U1 through U3 and the frequency selector switches, to generate the frequencies of the transmitter.

RF Exciter

Carrier

Modulation

Audio Input

10

High

-6

-12

-18 Low

2

+6 dB

Wide Band

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

4–6

Illustration 4–4 RF Exciter Board

FM500 User's Manual

U6 is programmed with the four or five rotary switches. The binary output of the

0.1 MHz switch programs the “A” counter directly. BCD data from the 100’s, tens, and units rotary switches is converted to binary data by U3 to set the “N” counter. An optional fifth digit rotary switch for 10kHz spacing is available.

U5C is a differential amplifier and filter for the error signal. Audio that is out of phase with that appearing on the error voltage is introduced by U5A, allowing for greater loop bandwidth with less degradation of the low-frequency audio response. U5D is an integrator. U5B is a VCO input voltage clamp.

DV71 and DV72 are hyper-abrupt varactor tuning diodes with a square-law capacitance vs DC voltage curve, giving a straight-line frequency vs voltage curve in a LC oscillator where the varactors are the dominant source of capacitance.

Lock and unlock status signals are available at the outputs of U4E and U4F, respectively. Modulation is introduced to the VCO through R17 and R71 to R75. About 4.1 millivolts across R75 produces 75 kHz deviation.

An FSK signal (used for automatic identification of FM repeaters) shifts the frequencies of the 10.24 MHz crystal reference and the VCO. With keying, diodes D9 and D10, are reverse biased, increasing the crystal reference frequency. At the same time, current through R72 increases the VCO frequency. See section 5.3.4.

Principles of Operation

4–7

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4.5 Metering Circuit Board

The ALC and metering circuitry is on the metering board (see Illustration 4–4). This board processes information for the RF and DC metering, and produces ALC (RF level-control) bias. It also provides reference and input voltages for the digital panel meter, voltages for remote metering, fan control, and drive for the front-panel fault indicators.

Illustration 6–8 and accompanying schematic complement this discussion. PA voltage and current come from a metering shunt on the power regulator board.

The PAI input is a current proportional to PA current; R405 converts the current to voltage used for metering and control. A voltage divider from the PAV line is used for DC voltage metering.

Metering

Audio Input

10

High

-6

-12

-18

Low

2

+6 dB

Wide Band

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 4–5 Metering Board

U406A, U406B, and U407A, with their respective diodes, are diode linearity correction circuits. Their DC inputs come from diode detectors in the RF reflectometer in the RF low-pass filter compartment.

U407B, U407C, Q405, and Q406 are components of a DC squaring circuit. Since the DC output voltage of U407C is proportional to RF voltage squared, it is also proportional to RF power.

U404C, U404A, U403A, and U404D are level sensors for RF power, reflected RF power, PA temperature, and external PA current, respectively. When either of these parameters exceeds the limits, the output of U404B will be forced low, reducing the ALC (RF level control) voltage, which, in turn, reduces the PA supply voltage.

4–8

FM500 User's Manual

The DC voltage setpoint for U404A (reflected RF voltage) is one-fifth that of U404C (forward RF voltage). This ratio corresponds to an SWR of 1.5:1 [(1+.2)/(1–.2)=1.5]. The U405 inverters drive the front panel fault indicators.

To get a direct reading of SWR, the reference input of the digital panel meter is fed from a voltage proportional to the forward-minus-reflected RF voltage, while forward-plus-reflected is fed to the digital panel meter input. The panel meter provides the divide function.

U408 & U409 function as data selectors for digital panel meter input and reference voltages. Binary select data for U408 & U409 comes from the display board.

The output voltage of U403D goes positive when the temperature exceeds about 35 degrees C (set by R426) providing proportional fan control.

When the Carrier switch is off or the RF power is less than about 5 watts, the SWR automatically switches to a calibrate-check mode. U406C provides a voltage that simulates forward power, while Q403 shunts any residual DC from the reflectedpower source. The result is a simulation of a 1.0 to 1 SWR. (See section 5.4.)

4.6 Motherboard

The motherboard is the large board in the upper chassis interconnecting the audio processor, stereo generator, RF exciter, and metering boards. The motherboard eliminates the need for a wiring harness, and provides input/output filtering, test points, and modular customization.

Motherboard components are passive with the exception of the fan driver transistor, power FET Q501.

With Normal-Bypass slide switch SW501, it is possible to bypass the audio processor, connecting the left and right audio inputs directly to the inputs of the stereo generator.

CAUTION

In the BYPASS position, the pre-emphasis circuits and the filters that protect the pilot and stereo subcarrier are bypassed. As a result, the occupied bandwidth specifications of the transmitter could be compromised. The 15–Hz high-pass filters are also bypassed which may mean that modulation with frequencies below 10 Hz could cause the frequency synthesizer to unlock.

If the audio source is already processed, and further processing is not desired, use the Normal mode instead of Bypass and turn the Processing control on the front panel to “0”.

If it is necessary to provide resistive terminations at the audio inputs (either lineto-line or line-to-ground), you may place resistors directly into the 8–pin DIP socket, A501, located between the XLR input connectors. See Illustration 6–9 and accompanying schematic for the socket pin-out.

Principles of Operation

4–9

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4.7 Display Circuit Board

The front-panel LEDs, the numeric display, the slide switches, and the processing and RF level controls are mounted on the display circuit board. To access the component side of the board, remove the front panel by removing 12 screws. The board contains circuits for the digital panel meter, modulation peak detector, and LED display drivers, as well as indicators and switches mentioned above.

Illustration 6–10 and accompanying schematic complement this discussion. Left and right audio from input stages of the audio processor board (just after the

Input Gain attenuator) go to the L VU and R VU input on the display board. Peak rectifiers U601A and U601B drive the left and right Audio Input displays. The LED driver gives a 3 dB per step display. The lowest step of the display driver is not used; rather a red LOW indicator lights when audio is below the level of the second step. Transistors Q601 and Q602 divert current from the LOW LEDs when any other LED of the display is lit.

Resolution of the linear displays, High Band, Wide Band, and Modulation, has been improved using dither enhancement. With dither, the brightness of the LED is controlled by proximity of the input voltage relative to its voltage threshold. The effect is a smooth transition from step to step as input voltage is changed. U606A, U606B, and associated components comprise the dither generator. Dither output is a triangular wave.

Composite stereo (or mono) is full-wave detected by diodes D605 and D606. U607, U613, Q603, and Q604 are components of a peak sample-and-hold circuit.

Oscillator, U609F, supplies a low-frequency square wave to the Fault indicators, causing them to flash on and off.

Digital multimeter inputs are selected with push buttons located to the right of the multimeter menu. Signals from the push buttons are conditioned by U609A and U609B. U610 is an up/down counter. Binary input to U611 from U610 selects a green menu indicator light, and lights the appropriate decimal point on the numeric readout. The binary lines also go to analog data selectors on the ALC/ metering board.

Processing control, R650, is part of the audio processor. (See section 4.2.) The DPM IN and DPM REF lines are analog and reference voltage inputs to digital

multimeter IC U612. They originate from analog data selectors on the ALC/ metering board.

4–10

FM500 User's Manual

4.8 Voltage Regulator Circuit Board

The voltage regulator board is the longer of two boards mounted under the chassis toward the front of the unit. It has switch-mode voltage regulators to provide +12, –12, and 24 volts. It also contains the program detection and automatic carrier control circuits.

Illustration 6–11 and accompanying schematic complement this discussion. U703E and U703F convert a 38 kHz sine wave from the stereo generator into a

synchronization pulse. In the transmitter, synchronization is not used, thus D709 is omitted.

U704 and U705 form a 24 volt switching regulator running at about 35 kHz. U704 is used as a pulse-width modulator; U705 is a high-side driver for MOSFET switch Q701. Supply voltage for the two IC’s (approximately 15.5 volts) comes from linear regulator DZ702/Q705. Bootstrap voltage, provided by D710 and C714, allows the gate voltage of Q701 to swing about 15 volts above the source when Q701 is turned on. Current through the FET is sensed by R738 and R738A. If the voltage between pin 5 and 6 of U705 exceeds 0.23 volts on a current fault, drive to Q701 is turned off. Turn-off happens cycle by cycle. The speed of the turn-off is set by C713.

U706 is a switching regulator for both +12 volts and –12 volts. It runs at about 52 kHz. Energy for –12 volts is taken from inductor L702 during the off portion of the switching cycle. The –12 volts tracks the +12 volts within a few tenths of a volt. There will be no –12 volts until current is drawn from the +12 volts.

Q702, Q703, and Q704 form an active filter and switch, supplying DC voltage to the RF driver, when the Carrier switch is on.

The program detection circuit is made up of U701 and U702. U701A and U701D and associated circuitry discriminate between normal program material and white noise (such as might be present from a studio-transmitter link during program failure) or silence. U701A and surrounding components form a band-pass filter with a Q of 3 tuned to about 5 kHz. U701D is a first-order low-pass filter. Red and green LEDs on the board indicate the presence or absence of program determined by the balance of the detected signals from the two filters. U702 and U701C form a count-down timer. The time between a program fault and shutdown is selected by jumpering pins on header JP701. For times, see section 5.7. The times are proportional to the value of R721 (that is, times can be doubled by doubling the value of R721).

Principles of Operation

4–11

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4.9 Power Regulator Circuit Boards

The power regulator boards are the two boards mounted under the chassis on either side of a pair of 15,000 µf filter capacitors toward the front of the unit. Each board has the switch-mode voltage regulator for a RF power amplifier, and circuitry for PA supply current metering.

Illustration 6–12 and accompanying schematic complement this discussion. Diode D804, in series with the battery input, together with the AC-supply diode

bridge, provides diode OR-ing of the AC and DC supplies. U801 and U802 form a switching regulator running at about 35 kHz. U801 is used

as a pulse-width modulator; U802 is a high-side driver for MOSFET switch Q801. Power for the two IC’s comes from the 24 volt supply voltage for the RF driver (available when the Carrier switch is on). The voltage is controlled at 16 volts by zener diode DZ801. Bootstrap voltage provided by D802 and C809 allows the gate voltage of Q801 to swing about 16 volts above the source when Q801 is turned on. Current through the FET is sensed by R812 and R812A. If the voltage from pin 5 to 6 of U802 exceeds 0.23 volts on a current fault, drive to Q801 is turned off. This happens on a cycle-by-cycle basis. The speed of the turnoff is set by C805.

In the transmitter, synchronization is not used, thus D801 is omitted. U803 and Q802 are used in a circuit to convert the current that flows through

metering shunt, R819, into a current source at the collector of Q803. Forty millivolts is developed across R819 for each amp of supply current (.04 ohms x 1 amp). Q803 is biased by U803 to produce the same voltage across R816. The collector current of Q803 is the same (minus base current) as that flowing through R822 resulting in 40 microamperes per amp of shunt current. R405 on the metering board converts Q803 collector current to 0.1 volt per amp of shunt current (.04 ma X 2.49 k). (See section 5.4.)

4.10 RF Driver

The RF Driver module is mounted next to the heat sinks on the bottom of the RF Amplifier/Combiner sub chassis. The driver amplifies the approximate 20 milliwatts from the frequency synthesizer to about 15 watts to drive the RF power amplifiers. A CA2832 hybrid, high-gain, wideband amplifier, operating at about 20 volts, provides about one watt of drive to a single MRF137 MOSFET amplifier. The MRF137 stage operates from a supply voltage of approximately 15 to 16 volts.

The circuit board has components for input and output coupling and for power supply filtering.

4–12

FM500 User's Manual

4.11 RF Amplifier

The two RF power amplifier modules are mounted on a combiner board, heat sink, slide rail assembly which slides into the main chassis at the rear, and is fastened to the back panel with six screws. RF power, DC power, and control voltages enter the PA assembly through a 72–pin edge connector that it slides into at the front of the chassis.

The amplifier is built around two Phillips BLF278, dual-power MOSFETs rated for 50 volts DC and a maximum power of about 300 watts. When biased for class B, the transistor has a power gain of 20 dB. (It is biased below class B in the transmitter.)

Input transformer, T1111, is made up of two printed circuit boards. The four-turn primary board is separated from the one-turn secondary by a thin dielectric film. R1112–R1117 are for damping. Trim pot R1111 sets the bias.

Output transformer, T1121, has a one-turn primary on top of the circuit board and a two-turn secondary underneath. Inductors L1121 and L1122 provide power line filtering.

The amplifiers are surrounded by a 50 Ω impedance, input/output combiner board which takes the 15 watts input and divides it equally to each power amp. Then the output from each amplifier is combined to form a single output.

4.12 Chassis

The AC power supply components, as well as the bridge rectifier and main filter capacitor are mounted on the chassis. Changing the jumpers on the AC distribution board (located beside the transformer assembly on the bottom of the transmitter), configures the power transformer for 100, 120, 220, or 240 VAC; see section 2.2 for switching and fuse information. The board also includes MOV voltage-surge suppressors and in-rush current limiters as well as a 12 volt power supply for the PA assembly cooling fans.

The main energy-storage/filter capacitors are located between the two power regulator boards. The DC voltage across each capacitor will be 65 to 70 volts when the carrier is on.

WARNING

Shock hazard! Do not attempt to short the capacitor

terminals. A bleeder resistor will discharge the capacitor in approximately one minute after shutdown.

Principles of Operation

4–13

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4.13 RF Output Filter & Reflectometer

The RF low-pass filter/reflectometer are located beside the motherboard in the right-hand compartment on the top of the chassis. See Illustration 6–14 and accompanying schematic for more information.

A ninth-order, elliptic, low-pass filter attenuates harmonics generated in the power amplifier. The capacitors for the filter are circuit board pads.

The reflectometer uses printed circuit board traces for micro-strip transmission lines. Transmission line segments (with an impedance of about 82 ohms) on either side of a 50 ohm conductor provide sample voltages representative of the square root of forward and reverse power.

DC voltages, representative of forward and reflected power, go through a bulkhead filter board to the motherboard, then to the metering board, where they are processed for power control, metering, and for SWR metering and protection.

4.15 Receiver Circuit Board Option

This option allows the transmitter to be used as a translator. The receiver board receives terrestrially fed RF signal and converts it to composite audio which is then fed into the exciter board. Microprocessor controlled phase lock loop technology ensures the received frequency will not drift, and multiple IF stages ensure high adjacent channel rejection. Refer to illustrations 4–6, 6–16 and its schematic for the following discussion.

The square shaped metal can located on the left side of the receiver board is the tuner module. The incoming RF signal enters through the BNC connector (top left corner) and is tuned through the tuner module. Input attenuation is possible with jumper J1 on the top left corner of the receiver board. Very strong signals can be attenuated 20 dB automatically by placing the jumper on the left two pins (“LO” position). An additional 20 dB attenuation is also available with the jumpers in the top left corner of the board. The frequencies are tuned by setting switches SW1 and SW2 (upper right corner). These two switches are read upon power up by the microprocessor (U4). The microprocessor then tunes the synthesizer IC SA1057 (U3) to the selected frequency. The switches frequency range is 87.9 Mhz at setting “00” to 107.9 Mhz at setting “64”. Other custom ranges are available.

The synthesizer chip works on a phase lock loop system. It receives the frequency information from pin 6 of the tuner module, then goes through a FET buffer amplifier (Q2) on its way to synthesizer IC (U3). The synthesizer feeds back a DC voltage through two resistors to pin 4 of the tuner module. Different frequencies cause different tuning voltages to go to the tuner module to tune it on frequency. The frequency synthesizer locks on to the exact frequency needed and adjusts the DC voltage accordingly. The microprocessor tunes the frequencies of the synthesizer IC, but the DC tuning voltage is somewhat dependent on the tuner module.

4–14

FM500 User's Manual

Receiver Module (option)

Audio Input

High

-6

-12

-18

Low

Illustration 4–6 Receiver Board (optional)

Stereo Generator

2

High Band

Expand

Compress

2

Wide Band

+12 dB

+6 dB

ProcessingInput Gain

RF IN

Carrier

Modulation

10

20

®

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Generally, the voltage is around 0.5 volt DC for tuning 88.1 MHz, and from 5.5 to

6.5 volts DC for tuning 107.9 MHz. The 10.7 MHz IF frequency comes out of the tuner module on pin 5 and is coupled into the first filter FL1; passes through FL1 and into the IF decoder system of IC LM1865 (U1). The FL1 filter sets the bandwidth or everything outside of the bandwidth depending on the filter that is selected. It could be a bandwidth of 180 kHz where everything outside of that is filtered out depending on the filter characteristics. A second filter (F3) is available when the signal has a great amount of interference from an adjacent signal. In such a case, remove the jumper cap that is in the F3 position, then remove the ceramic filter that is in the F4 storage position and place it into the F3 position.

Then the signal goes to a buffer gain stage at pin 1 of LM1865 (U1). From there the signal passes through F2, which is a second filter for further removal of unwanted products, and then it goes on to the IF of that chip. The quadrature coil L4 is tuned to 10.7 MHz as per calibration procedures. This results in a low distortion of around 0.2 to 0.3% on the audio. The audio, still a composite at this point, will come out of pin 15 of that IC (U1) and go to the first buffer U9. Then it goes through a compensation network R54 and C26, and on to the stereo decoder chip at pin 2 of U5.

When a stereo signal is present, Led 1 illuminates which indicates that left and right audio is available. Then the stereo signals go to gain stages U6A and U6B and out to the RCA jacks on the back of the cabinet. These can be used for off-air monitoring of the audio signal. Incoming frequency can be monitored from the frequency monitor BNC jack on the back. The stereo buffer U9, stereo decoder U5, and gain stages U6A and U6B have no effect on the signal that goes through the transmitter. This section along with the composite signal coming out of pin 15 of LM1865 (U1) is totally separate from the transmitter section.

Principles of Operation

4–15

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A muting circuit, consisting of C22, a 1N914 diode, R14, and varible resistor R15 mutes the output when a signal is too weak to be understood. The strength of the signal muted is determined by the adjustment of R15. Any signal below the setting of R15 is shorted to +VCC through C22 by the current drawn through R14 and the diode. The audio signal above this setting goes through C17 to the connector P3.

The P3 connector block allows jumpering to either internal circuitry or to external signal processing such as advertisement injection or other forms of altering the signal. If the jumper is installed for internal circuitry, the signal will go through R39 to the input of U2A. This is a buffer that drives the R20 pot located on the top left hand corner of the board. R20 sets signal gain for 100% modulation if adjusted correctly with a full incoming 75 kHz deviation signal. Then the signal goes through R21, R22, and C20 which, along with adjustable pot R24 and C21, forms a compensation network with some phase shifting. This allows the best stereo separation possible by adjusting and compensating for differences in FM exciter boards. The signal is buffered through U2B and finally reaches the output connectors P1 and P2, and on to the transmit circuitry.

The power supply is fairly straight forward. The incoming 12 volt supply goes to a 7809, 9 volt regulator (VR1) which supplies all 9–volt needs on the board. The 9 volts also supplies a 7805, 5 volt regulator (VR2) which supplies all 5–volt needs on the board. Plus and minus 12 volts from the motherboard is filtered and supplies various needs on the board. Finally there is a precision reference voltage supplied through R50 by U7 and U8. These two 2.5 volt reference shunts act very much like a very accurate zenor diode to provide precision 5 volts to the metering board.

4–16

FM500 User's Manual

Section 5—Adjustments and Tests

This section describes procedures for (1) advanced users who may be interested in customizing or optimizing the performance of the transmitter and (2) service personnel who want to return the transmitter to operational status following a maintenance procedure.

Adjustments and Tests

5–1

5.1 Audio Processor Adjustments

5.1.1 Pre-Emphasis Selection

Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the appropriate pins of header JP1 on the audio processor board. (See section 2.9.) If you change the pre-emphasis, change the de-emphasis jumpers, JP203 and JP204 on the Stereo Generator board, to match. (See section 2.8.)

5.1.2 Pre-Emphasis Fine Adjustment

T rim potentiometers, R29 and R65, (for left and right channels, respectively) provide for fine adjustment of the pre-emphasis. Set the potentiometers to bring the de-emphasized gain at 10 kHz equal to that of 400 Hz. (At the proper setting,

15.0 kHz will be down about 0.7 dB.) When making these adjustments, it is important that you keep signal levels below

the processor gain-control threshold. A preferred method is to use a precision de-emphasis network in front of the audio

input. Then, use the non-de-emphasized (flat) output from the FM modulation monitor for measurements.

5–2

FM500 User's Manual

5.2 Stereo Generator Adjustments

5.2.1 Separation

Feed a 400 Hz sine wave into one channel for at least 70% modulation. Observe the classic single-channel composite stereo waveform at TP1 on the RF Exciter circuit board. Adjust the Separation control for a straight centerline.

Since proper adjustment of this control coincides with best stereo separation, use an FM monitor to make or confirm the adjustment.

5.2.2 Composite Output

Adjust the composite output with a modultion monitor following the steps below:

1. Set the Stereo-Mono switch to Mono.

2. Check that the setting of the Modulation compensation control, R17 on the RF Exciter circuit board, falls within the range specified for the frequency of operation. (See section 2.3.1.)

3. Feed a sine wave signal of about 2.5 kHz into the left channel at a level sufficient to put the wideband gain-reduction indicator somewhere in the middle of its range.

4. Set the Composite level control to produce 90% modulation as indicated on an FM monitor.

5. Apply pink noise or program material to the audio inputs and confirm, on both Mono and Stereo, that modulation peaks are between 95% and 100%.

5.2.3 19 kHz Level

Adjust the 19 kHz pilot for 9% modulation as indicated on an FM modulation monitor . (The composite output should be set first, since it follows the 19 kHz Level control.)

5.2.4 1 9 kHz Phase

1. Apply a 400 Hz audio signal to the left channel for at least 70% modulation.

2. Look at the composite stereo signal at TP301 on the RF Exciter circuit board with an oscilloscope, expanding the display to view the 19 kHz component on the horizontal centerline.

3. Switch the audio to the right-channel input. When the 19 kHz Phase is properly adjusted, the amplitude of the 19 kHz will remain constant when switching between left and right.

4. Recheck the separation adjustment as described in section 5.2.1.

Adjustments and Tests

5–3

5.3 Frequency Synthesizer Adjustments

5.3.1 Frequency (Channel) Selection

Refer to section 2.3.

5.3.2 Modulation Compensator

Refer to section 2.3.

5.3.3 Frequency Measurement and Adjustment

Next to the 10.24–MHz crystal on the RF Exciter board is a 1–11 pF piston trimmer capacitor (C3). Use C3 to set the frequency of the 10.24–MHz crystal while observing the output frequency of the synthesizer .

Use one of these methods for checking frequency:

❑ Use an FM frequency monitor . ❑ Couple a frequency counter of known accuracy to the output of the synthesizer

and observe the operating frequency. circuit.)

(Do not connect to the 10.24–MHz clock

5.3.4 FSK Balance Control

An FSK signal (used for automatic identification of FM repeaters) shifts the frequencies of the 10.24–MHz crystal reference oscillator and the VCO.

Use an oscilloscope to observe the cathode end of D4. With no program, the pulse will be less than 1 µsec wide. With an FSK input (a 20–Hz square wave at the FSK input will work), set trim pot R45 for minimum pulse width.

The setting will vary slightly with operating frequency.

5–4

FM500 User's Manual

5.4 Metering Board Adjustments

5.4.1 Power Calibrate

While looking at RF Power on the digital panel meter , set the Power Calibrate trim potentiometer to agree with an external RF power meter .

5.4.2 Power Set

With the front panel RF Output control fully clockwise, adjust the Power Set trim pot to 10% more than the rated power (33 W for FM30, 110 W for FM100, 275 W for FM250, 550 W for FM500) as indicated on an accurate external watt meter. If the authorized power is less than the maximum watts, you may use the Power Set to limit the range of the RF Output control. Operation below 100 watts is not

recommended as instability can occur which could damage the transmitter .

CAUTION

Possible equipment damage!

Operation below 100 watts can cause oscillations and other problems that could damage the transmitter.

5.4.3 SWR Calibrate

When the Carrier switch is off, or the RF power is less than about 5 watts, the SWR circuit automatically switches to a calibrate-check mode. (See section 4.5 for more information.)

Set the digital panel meter to read SWR. With the Carrier switch off, set the SWR CAL trim pot to read 1.03.

5.4.4 PA Current Limit

Since it may not be practical to increase the PA current to set the PA Current Limit control, you may use this indirect method.

With the Metering board. The current limit, in amperes, will be 0.35 amps higher than ten times this voltage. Set the current limit for 16.5 amps or 1.615 volts at R413.

carrier turned off, look at the DC voltage at the right end of R413 on the

Adjustments and Tests

5–5

5.5 Motherboard Adjustments

For Normal-Bypass switch setting, see section 2.10.

5.6 Display Modulation Calibration

The Modulation Calibrate trim pot sets the sensitivity of the front panel Modulation bar graph display.

This adjustment may be made only after the Output trim pot on the Stereo Generator board has been set. (See section 5.2.4.)

1. Set the Stereo-Mono switch to Mono.

2. Feed a sine wave source of about 2.5 kHz into the left channel at a level sufficient to put the wideband gain-reduction indicator somewhere in the middle of its range.

3. Set the Modulation Calibrate trim pot so that the “90” light on the front panel Modulation display just begins to light.

5.7 Voltage Regulator Adjustments

JP701, a 10–pin header on the Voltage Regulator board, sets the time between program failure and carrier turnoff. Pins 1 and 2 are the two pins closest to the edge of the board. The times are approximate. Sections 2.11, 2.12, and 4.8 contain further information.

1. Short pins 1 and 2 for a 30–second delay.

2. Short pins 3 and 4 for a 2–minute delay.

3. Short pins 5 and 6 for a 4–minute delay.

4. Short pins 7 and 8 for an 8–minute delay.

You may select other times by changing the value of R721. The time is proportional to the resistance.

5.8 Bias Set (RF Power Amplifier)

The Bias Set trim pot is located on the PA module on the input circuit board. Set the trim pot to its midpoint for near-optimum bias.

5–6

FM500 User's Manual

5.9 Performance Verification

Measure the following parameters to receive a comprehensive characterization of transmitter performance:

❑ Carrier frequency ❑ RF output power ❑ RF bandwidth and RF harmonics (see section 5.12) ❑ Pilot frequency, phase, and modulation percentage ❑ Audio frequency response ❑ Audio distortion ❑ Modulation percentage ❑ FM and AM noise ❑ Stereo separation between left and right ❑ Crosstalk between main channel and subcarrier ❑ 38–kHz subcarrier suppression

In addition to the above tests, which pertain to signal quality, a complete check of the unit will include items listed in section 5.21.

5.9.1 Audio Proof-of-Performance Measurements

References to “100%” modulation assume 9% pilot and 91% for the remainder of the composite stereo signal.

Because the audio processing threshold is at 90% modulation, it is not possible to make audio proof-of-performance measurements at 100% modulation through the audio processor. Instead, audio data for 100% modulation is taken from the input of the stereo generator (SW501 on Motherboard set for Bypass). Then, data, including the audio processor (SW501 set for Normal), is taken at a level below the audio processing threshold.

5.9.2 De-emphasis Input Network

A precision de-emphasis network, connected between the test oscillator and the audio input of the transmitter, can be very helpful when making the audio measurements. Note that the input impedance of the transmitter or the source impedance of the test oscillator can affect network accuracy. With the de-emphasis network, oscillator level adjustments need only accommodate gain errors, instead of the whole pre-emphasis curve.

Adjustments and Tests

5–7

5.10 Carrier Frequency

Carrier frequency is measured at the output frequency with a frequency monitor or suitable frequency counter .

To adjust frequency, see section 5.3.3. (FCC tolerance +/– 2000 Hz per FCC Part

73.1540 and 73.1545.)

5.11 Output Power

The output power reading on the front panel display should be 90–105% of the actual value. For a more precise measurement, use a watt meter in the RF output line. See sections 5.4.1 and 5.4.2 for setting power.

5.12 RF Bandwidth and RF Harmonics

You can observe RF bandwidth and spurious emissions with an RF spectrum analyzer .

In the Stereo mode, feed a 15.0 kHz audio signal into one channel to provide 85% modulation as indicated on a monitor. Doing so produces 38% main, 38% stereo subcarrier, and 9% pilot per FCC Part 2.989. As an alternative, use pink noise into one channel.

Using a spectrum analyzer, verify the following (per FCC 73.317):

1. Emissions more than 600 kHz from the carrier are at least 43 + 10log(power, in watts) dB down (70 dB for 500 watts). The scan should include the tenth harmonic.

2. Emissions between 240 kHz and 600 kHz from the carrier are down at least 35 dB.

3. Emissions between 120 kHz and 240 kHz from the carrier are down at least 25 dB.

5.13 Pilot Frequency

The pilot frequency should be within 2 Hz of 19 kHz. (FCC Part 73.322.) Using a frequency counter , measure 1.9 MHz at pin 1 of U209 on the Stereo Generator board. A 200-Hz error here corresponds to a 2-Hz error at 19 kHz. If the frequency is off by more than 50 Hz, you may change the value of C213. (Changing C213 from 56 pF to 68 pF lowers the 1.9 MHz by about 35 Hz.)

5–8

FM500 User's Manual

5.14 Audio Frequency Response

For the response tests, take the readings from an FM modulation monitor . Make audio frequency response measurements for left and right channels at

frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See sections 5.9.1 and 5.9.2.

5.15 Audio Distortion

Make distortion measurements from the de-emphasized output of an FM modulation monitor .

Make audio distortion measurements for left and right channels at frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See sections 5.9.1 and

5.9.2.

5.16 Modulation Percentage

While feeding an audio signal into the left channel only, confirm that the total modulation percentage remains constant when switching between Mono and Stereo.

Measure modulation percentage with an FM modulation monitor , or by using an HF receiver and Bessel nulls. See section 5.2.2.

19–kHz pilot modulation should be 9%.

5.17 FM and AM Noise

T ake noise readings from a de-emphasized output of a modulation monitor.

5.18 Stereo Separation

Make left-into-right and right-into-left stereo separation measurements with an FM modulation monitor for frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz.

5.19 Crosstalk

For stereo crosstalk measurements, both left and right channels are fed at the same time. For best results, there needs to be a means of correcting small imbalances in levels and phase. The balance is made at 400 Hz.

Adjustments and Tests

5–9

5.19.1 Main Channel Into Sub

Feed the left and right channels in phase with audio (L+R) at 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz at 100% modulation, while observing the stereo subcarrier (L-R) level on an FM modulation monitor .

5.19.2 Sub Channel Into Main

Feed the audio into the left and right channel as above, with the exception of reversing the polarity of the audio of one channel (L-R input). Using the frequencies of 5.19.1 above, observe the main channel (L+R) level with a modulation monitor .

5.20 38 kHz Subcarrier Suppression

With no modulation, but in the Stereo mode, the 38 kHz subcarrier , as indicated on an FM modulation monitor, should be down at least 40 dB.

5.21 Additional Checks

In addition to the tests and adjustments mentioned in this section, the following checks ensure a complete performance appraisal of the transmitter:

1. Perform a physical inspection, looking for visible damage and checking that the chassis hardware and circuit boards are secure.

2. Check the functionality of switches and processing control.

3. Verify that all indicators function.

4. Check the frequency synthesizer lock at 80 MHz and 110 MHz.

5. Measure the AC line current with and without the carrier on.

6. Perform a functional test of the SCA input, Monitor outputs, and the monitor and control function at the 15–pin, D-sub connector .

7. T est the functionality of the FSK circuit.

8. Check the operation and timing of the automatic carrier-off circuitry associated with program failure.

9. Check all metering functions.

10. Test ALC action with PA current overload, SWR, and PLL lock.

NOTE:

FCC type acceptance procedures call for testing the carrier frequency over the temperature range of 0–50 degrees centigrade, and at line voltages from 85% to 115% of rating. (See FCC Part 2.995.)

5–10

FM500 User's Manual

Section 6—Reference Drawings

The illustrations in this section may be useful for making adjustments, taking measurements, troubleshooting, or understanding the circuitry of your transmitter.

Reference Drawings

6–1

6.1 Views

Gain Reduction/Expansion

Indicators

Audio Input

High

-6

-12

-18 Low

High Band

2

Wide Band

+6 dB

Audio Processor

Input Level

Indicators

Input Gain

2

Expand

Compress

+12 dB

ProcessingInput Gain

Switches

10

20

®

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Processing Control

Stereo/Mono Switch

Illustration 6–1 Front View

Modulation

Indicators

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Fault Indicators

Carrier SwitchDigital Multimeter Multimeter Select

Modulation

Over 100 90 80 70 60 50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Power Switch

Relative RF

Voltage Out

Carrier

Power

RF Output

FUSE

AC Power In

RF Output

Monitor

Power Amplifier

and Cooling

Ground

1

Composite

Input

SCA IN

23

COMPOSITE IN

SCA Inputs

Illustration 6–2 Rear View

MONITOR

R

REMOTE I/O

Remote I/O

Audio InputsAudio Monitors

RIGHT

L

LEFT/MONO

6–2

FM500 User's Manual

Stereo Generator

RF Exciter

Low-pass Filter

Audio Processor

Power Transformer

Audio Input

Metering

10

High

-6

-12

-18 Low

2

Wide Band

+6 dB

Expand

Compress

20

+12 dB

ProcessingInput Gain

®

2

High Band

RF Power SWR ALC PA DC Volts PA DC Amps PA Temperature Supply DC Volts Voltmeter

Fault

SWR Lock Input PA DC PA Temp

Stereo

Mono RF Output

Over 100 90 80 70 60

Power

50 40 30 20 Pilot

FM500

FM BROADCAST TRANSMITTER

Carrier

Modulation

Illustration 6–3 Chassis Top View

Power Amp

Fans

Power Distribution Board

Power Regulator Boards

Voltage Regulator

Board

Filter Capacitors

front of transmitter

Illustration 6–4 Chassis Bottom View

Reference Drawings

6–3

6.2 Board Layouts and Schematics

6–4

Illustration 6–5 Audio Processor Board

FM500 User's Manual

6–5

Reference Drawings

L OUT

+5V

-5V

D3

D4

FLAT A=0

75uSEC A=1.0

50uSEC A=0.67

25uSEC A=0.33

GAIN: U5, Pin 2 to U8, Pin 2

(No Hi-band gain reduction)

C11

220PF

R35 240K

+12V

C12

0.1

R26 100K

R38

1K

R31

24.9K 1

R34

24.9K 1

(+/-5.0V PK)

GAIN REDUCTION VOLTS P-P

THRESHOLD 1.1

10DB 3.5 20DB 11

D2

R17 360K

L LP2 L LP1

+12V

-12V

C6

.047

7

9

1

12

13

2

10

1

4

31

1

U5

AD632

R1 100

R22

11.3K 1

6 5

7

U4B

TL072

R24

24.9K 1

C5

.047

R20 75K

1

R13

2.0K 1

R23

100K 1

L VU

L IN1

L IN2

+12V

-12V

C3

1.0

C1

100PF

C2

100PF

R2

1K

R3 1K

R9

1K

R4

24.9K 1

R5

24.9K

1

R6

24.9K 1

C4

1.0

R7

24.9K 1

2 3

1

8

4

U1A

TL072

6 5

7

U1B

TL072

R8

30.1K 1

16 7 8

R44

24.9K

R42

24.9K

R43

24.9K

R45

24.9K

/+6DB

/+12DB

R VU

R IN1

R IN2

+5V

+12V

-12V

+5V

-5V

C16

1.0

C15

1.0

C13

100PF

C14

100PF

R40

1K

R41

1K

R48

1K

2 3

1

8

4

U2A TL072

6 5

7

U2B

TL072

R12

20K 1

R49

20K 1

R47

30.1K 1

X0

12

X1

14

X2

15

X3

11

Y0

1

Y1

5

Y2

2

Y3

4

INH

6

A

10

B

9

X

13

Y

3

U3

74HC4052

R10 47K

R11

47K

(+/-5.0V PK)

R60

24.9K

2 3

1

8

4

U7A

TL072

R61

24.9K

C50 47PF

R LP2 R LP1

+12V

-12V

C8

1.0 POLY

C20

1.0

POLY

R59

100K 1

R58

11.3K 1

D1

D7

D8

2 3

1

8

4

U4A

TL072

R14

1.0K 1

R15 499

1

R98 100

R51

1.0K

1

R52

499

1

6 5

7

U7B

TL072

R25

24.9K 1

C17 .047

C18

.047

R46

360K

7 9

1

12

13

2

10

1

4

31

1

U6

AD632

R16 499

1

R53 499

1

R56 75K

1

R50

2.0K 1

R87

3.3K

2

1 3

SW1A

R123

50K

PRE-EMP.

D6

D11 D12

R73

24.9K

6 5

7

U10B TL072

R67

24.9K

R70

24.9K

R72

24.9K

R36

24.9K

R37

24.9K

D5

Q1

2N5087

R64

OPEN

R28

OPEN

C23

220PF

R71 240K

C49 47PF

+12V

-12V

-5V

-12V

C24

0.1

C29

0.1

C22

.0027

POLY

Q2

2N5087

R62 100K

R29 10K

R65 10K

R33 10K

R69 10K

R32 12K

7 9

1

12

13

2 10

1

4

31

1

U8

AD632

R68 12K

7 9

1

12

13

2 10

1

4

31

1

U9

AD632

2 3

1

8

4

U10A

TL072

R39 1K

R74

1K

R81 1K

R90 1K

2 3

1

8

4

U12A

TL072

6

5

7

U12B

TL072

R30

49.9K 1

R66

49.9K 1

C10

.0027

POLY

D10

D9

R OUT

+5V

-5V

R109

3.3K

-5V

C35

1.0

R107

10K

R106

1K

R105

1M

D18 560

LIGHT

3mV/DB

HEAVY

.25V/DB

E

B

C

R650

POT LOCATED ON DISPLAY PCB

FLAT 25uS 50uS 75uS

D16

D17

R77

3.3K

100K

1

2

3

4

8

7

6

5

Q7

LM394

Q3

2N5210

PROC A

PROC B

PROC C

TEST

+5V

+12V

-12V

C33 .047

C34

OPEN

C30

1.0

C31

100PF

C32

100PF

R76 10K

R93 10K

R101

10K

R100 120

R92

1K

D15

2 3

1

8

4

U14A TL072

R104 OPEN

R99

3.3K

D21

R75

2.4K

R94

20.0K 1

R95

20.0K 1

R96

20.0K 1

R97

49.9K 1

R112

49.9K 1

R115

49.9K 1

R116

49.9K 1

1 2 3 4 5 6 7 8

JP1

HEADER 4X2

R103

3.3K

3mV/DB

-5VDC at 0DB GR

4.1V at 20 DB GR

7

E

B

C

D19

R89 330K

D13

1

2

3

4

8

7

6

5

Q5

LM394

+5V

-5V

+5.00V

+5V

+12V

-12V

+5V

-5V

VDD

VSS

VEE

C46

0.1

C47

0.1

C48

0.1

C25

100PF

C26 100PF

R78 91K

R88

10M

R91 10M

R82

120

C28

1.0

POLY

2 3

1

8

4

U13A TL072

C27

.047

R86

3.3M

D20

R80

3.3K

R111

49.9K 1

C38

1.0

C39

1.0

D14 YEL

R85

3.3K

R79

49.9K 1

R83 10K

5

4 6

SW1B

IN

2

GND

4

VO

6

TRM

5

U17

REF02

2 3

1

8

4

U18A TL072

+12V

-12V

+12V

-12V

+12V

-12V

C36 .01

C37 .01

C42

0.1

C43

0.1 C45

0.1

C44

0.1

R121

10.0K 1

R122

100

6 5

7

U18B

TL072

R119

4.7K

R120

100

C40

1.0

C41

1.0

R118

10.0K 1

6 5

7

U13B TL072

6 5

7

U15B TL072

C20A OPEN

C8A OPEN

R84

49.9K 1

R110

49.9K 1

.25V / DB

0.25V / DB

2 3

1

8

4

U16A TL072

2 3

1

8

4

U15A TL072

BR GR

+12V

-12V

6 5

7

U14B

TL072

6 5

7

U16B

TL072

R113

100

R117

100

R102

49.9K 1

R114

49.9K 1

NOTES :

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROF ARADS UNLESS O THER WISE SPECIFIED .

SCM, FM AUDIO PROCESSOR

HI GR

3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED.

103202

L OUT

R OUT

12

34

56

78

910

J2

RECEPT 5X2

+12V

-12V /+6DB /+12DB

R VU

L VU +5.00V

PROC A PROC B PROC C BR GR HI GR TEST

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

J3

RECEPT 13X2

L IN1 L IN2 R IN1 R IN2

L LP1 L LP2 R LP1 R LP2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

J1

RECEPT 10X2

AUDIO PROCESSOR

6–6

FM500 User's Manual

Illustration 6–6 Stereo Generator Board

6–7

Reference Drawings

STEREO GENERATOR

OUTPUT

+12V

+6V

+12V

-12V

2 3

1

8

4

U4A TL072

R12

10.0K 1%

R11 100

D3

R58

3.9K

R55

24.9K

C26

1.0

2

3

1

8

4

U6A TL072

C27

1.0

R57

24.9K

R9

2K

1%

R56

24.9K 1%

R54

24.9K 1%

C3

100PF

R3

0 OHM

C4

0 OHM

R5 1K

(SELECTABLE BY TEST, USE

EXTERNAL COMPOSIT IN

(3.5V P-P for 7.5KHz)

(3.5V P-P for 75KHz)

+12V

-12V

C1

.0027

POLY

R38

1M

R6

499

1%

3

1

2

JP1

C5

.0027

POLY

R7

3.65K 1%

C6

1030PF

2 3

1

8

4

U3A TL072

R1

330

15.2 KHz LOW-PASS FILTER (8th ORDER ELLIPTICAL)

LPIN L

+6V

-6V

1 2 3 4 5 6 7

14 13 12 11 10

9 8

U1

LTC1064-1

14

7

+6V

R26 1K

Y1

7.6MHZ

C13

56PF

NPO

R25 1M

1

2

U7A

74HC04

C14 33PF NPO

C29

1.0

R27 100

CK

1

CK

4

CLR

2

Q

3

Q

5

QC

6

QD

7

U8A

74HC390

13

12

U7F

C24

1.0

D1 1N5818

C23

1.0

D2 1N5818

1 2 3 4 5 6 7

14 13 12 11 10 9 8

U2

LTC1064-1

1.52 MHz

3.8 MHz

14

8

16

14

50 75

LPOUT R

INPUT R

+6V

+5.00V

CK

15

CK

12

CLR

14

QA

13

QB

11

QC

10

QD

9

U8B

74HC390

A

13

Q

11

Q

10

QC

9

QD 8CLR

12

U9B

74HC393

4 5

6

U10B

R29

100K

1%

C15

0.1

L P A

1

L P B

2 0

B P A

2

H P A

3

I N V A

4

S 1 A

5

B P B

1 9

H P B

1 8

I N V B

1 7

S 1 B

1 6

S A / B

6

V A +

7

V D +

8

L S H

9

C L K A

1 0

A G N D

1 5

V A

1

4

V D

1

3

5 0 / 1 0 0

1 2

C L K B

1 1

U11

LMF100

R33

10.0K

1%

C11

.01

POLY

C31

1.0

R28

243K

1%

C30

1.0

C2

.0027

POLY

R2

330

3

1

2

JP2

R18 499 1%

C9

.0027

POLY

R19

3.65K

1%

C10

1030PF

R39

1M

6 5

7

U3B

TL072

3 1

2

JP4

R8

4.99K

1%

3

1

2

JP3

C7

.01

POLY

R34

49.9K 1%

R20

4.99K

1%

R10

2.49K

1%

R22

2.49K 1%

1

2

3

U10A

74HC86

38 KHz

3.0VP-P

8

7

16

SEPARATION

(•3.85V P-P)

R204 1K

+12V

-12V

MON L

MON R

COMP METER

SYNC OUT

MONO/STEREO

/EXT ENABLE

+12V

+6V

-12V

-6V

-12V

C17

0.1

R37 1K

C18

.0027

POLY

R40 10K

7 9

1

12

13

2 10

14

311

U12 B-B 4214

R32 10K

C21

0.1

R47 20K

C37

OPEN

R48

4.3K

R17 100

R21 10K

R53

10K

6 5

7

U4B

TL072

R24 100

D6

X0

12

X1

13

Y0

2

Y1

1

Z0

5

Z1

3

INH

6

A

11

B

10

C

9

X

14

Y

15

Z

4

U5

74HC4053

C28

1.0

6

5

7

U6B

TL072

R16 100

R14

1K

R15

4.02K 1%

R13

24.9K

1%

R23

24.9K

1%

4.12K OR 4.15K IF NEEDED)

12

34

56

78

910

J3

RECEPT 5X2

19 KHz

3.3VP-P

19 KHZ LEVEL

STEREO

X1

EXTERNAL COMPOSITE

U205 Connections

X

SCA IN COMP OUT COMP METER

/EXT ENABLE

EXT IN EXT RTN

GND

MONO/STEREO

U5Y

R43 33K

R41 510

1 2 3 4 5 6 7 8

9 10 11 12

J1

RECEPT 12X1

C19

0.1

C20

.0027

POLY

1.9MHz

304 Khz

7

+12V

-6V

+12V

+6V

C33

1.0UF

C34

1.0UF

R49 240

IN

1

C

2

OUT

3

VR1 LM317

C16

0.1

C32

1.0

R30

243K

1%

9

10

8

U10C

74HC86

12 13

11

U10D

A 1QA

3

QB

4

QC

5

QD

6

CLR

2

U9A

74HC393

R35

10.0K

1%

R36

49.9K 1%

R31

100K

1%

R50 910

7.6 MHz

CLK

QA

QB

QC

QD

QB XOR QD

QC XOR QD

QB XOR QC

QA XOR QC

Current at U211 pin 4.

Current at U211 pin 17.

-12V

-12V -6V

C35

1.0

IN

1

C

2

OUT

3

VR2 LM337

R52 910

R51 240

11

10

U7E 74HC04

9

8

U7D 74HC04

5

6

U7C 74HC04

3

4

U7B 74HC04

C36 47UF

MONO

STEREO/MONO

Z

C

X0

B

Y

A

Y1

Y0

Z1

Z0

MON L MON R

+5.00V SYNC OUT

INPUT L INPUT R

GND

LPIN L LPOUT L LPIN R LPOUT R

+5.00V

1 2 3 4 5 6 7 8

9 10 11 12

J2

RECEPT 12X1

U5X

U5Z

U206, pin6

/EXT EN

NOTES : _______

_______

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROFARADS UNLESSOTHERWISE SPECIFIED.

CROWN INTERNATIONAL, INC.

1718 WEST MISHAWAKA ROAD ELKHART, IN. 46517 PHONE (219) 294-8000

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A

SCM, FM STEREO GENERATOR

7-28-97

MLOWCM0

103203

103203A.SCM

3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED.

COMP OUT

LPIN R

LPOUT L

R242 1K

R244 10K

INPUT L

C12

5.5—18PF

EXT RTN

EXT IN

SCA IN

D4

D5

19 KHZ PHASE

R46 10K

JB

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TOP SIDE COMPONENT MAP, FM-VFM EXCITER

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1 OF 1

PWB: 200440-PWB-A.PCB

M200440PT-A.DOC

REV

A

THESE DRAWINGS, SPECIFICATIONS AND ASSOCIATED

ELECTRONIC FILES ARE THE PROPERTY OF INTERNATIONAL RADIO AND ELECTRONICS CORP., AND SHALL NOT BE REPRODUCED, COPIED, OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

SEE NOTE 10

DWG. NO.

REV.

A

200440-SCH

H

G

F

E

D

C

B

A

1 2 3 4 5 6 7 8 9 10 11 12

H

G

F

E

D

C

B

A

1 2 3 4 5 6 8 9 10 11 12

E . C . N. REV DESCRIPTION

APPROVALS

PECHK CMDATE DWN

REVISION HISTORY

THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF INTERNATIONAL RADIO CORP. AND SHALL NOT BE REPRODUCED, COPIED OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

SHEET

OF

SCALE : NONE PROJ NO.FILENAME:

DWG . NO .

REV

A

200440-SCH

TITLE:

UNCONTROLLED

UNLESS OTHERWISE MARKED IN RED INK BY CM AS A CONTROLLED COPY, COPIES OF THESE DOCUMENTS INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS ARE FOR REFERENCE ONLY.

APPROVALS

DWN CHK

CM PE

DISTRIBUTION

K

SIZE

C

C_L_SHT1_A.DOT REV. A

INTERNATIONAL RADIO AND ELECTRONICS CORP. 25166 LEER DRIVE ELKHART, IN. 46514 574-262-8900

WWW.IREC1.COM

IREC

+12V

/LOCK

LOCK

+12V

GND

+5V

FSK-R

LOCK

COMPOSITE IN

TP1

+12V

RF OUT

+8V

FSK-R

88-108 MHZ

COMPOSITE IN

+8V

-12V-12V

CLK

DATA

LOAD

8.26V

+8V

+5V

DATA LOAD

CLOCK

GND

+5V

REMOTE FREQUENCY CONTROL

FSK BAL.

LF SEP.

CLOCK

DATA

/ENABLE

OSC in OSC out

Fin

VDD

+5V

+12V

VVCO

FSK

+5V

CH. SEL.

DIRECT FSK

+5V

LOCK DET.

+5V

VU5

+12V

FSK

Local/Remote

Frequency Select

ID

AUTO ID

BAND LIMIT

FSK-ID-CHAN

TP

NOTES :

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL.

2. ALL CAPACITORS ARE IN MICROFARADS.

DL1

GREEN

DL2 RED

IN

3

C

2

OUT

1

VR3

LM317

12

34

56

78

910

1112

1314

1516

1718

1920

2122

2324

2526

J1

RECEPT 13X2

12345

SW1

12345

SW3

12345

SW2

12345

SW4

12345

SW5

IN

3

C

2

OUT

1

VR2

LM78L05

PB1 RESET

SER10A11B12C13D14E3F4G5H

6

QH

9

CLK

2

QH

7

INH15SH/LD

1

U2

74HC165

SER10A11B12C13D14E3F4G5H

6

QH

9

CLK

2

QH

7

INH15SH/LD

1

U1

74HC165

12345678910

HD1

HEADER 5X2

1

2

3

4

5

6

7

8

9

10

RP1

100K RPACK

1

2

3

4

5

6

7

8

9

10

RP2

100K RPACK

R1

10.0K

RA2

1

RA3

2

RTC

3

CLR

4

VSS

5

RB0

6

RB1

7

RB2

8

RB39RB4

10

RB5

11

RB6

12

RB7

13

VDD

14

OSC2

15

OSC1

16

RA0

17

RA1

18

U3

PIC16C61

R2

10.0K

R17

1K BECKMAN

R18 68K

R19 25K

R24 150

R25 680

R26 680

R44

10.0K

R45 10K

R46 39K

R47

1.0K

R48

1.0K

R51 237

R52

1.27K

C1

33PF NPO

C2

39PF NPO

C3

1-10PF

C5 .001 POLY

C6

100PF

C7

.001

C9 .001

C10 .001

C13

3900PF

C19

.001

C23 .001

C26 .001

C31 .001

C32

.001

C33

33pF

C35 .001

D1

1N4148

D2

1N4148

D3

1N4148

D4

1N4148

D5 1N4148

D9

1N4148

D10

1N4148

R5

1.0K

R16 100K

R15 100K

D8

1N4148

C41 100PF

9 8

U4D

74HC14

5 6

U4C

74HC14

13 12

U4F

74HC14

11 10

U4E

74HC14

34

U4B

74HC14

12

U4A

74HC14

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

U6

MC145170

R4 100K

Y1

10.24MHZ

D7

1N4148

2 1

3

A2

MAR-6

C22 .001

R63 39

123456

78

VCO61 POS-150

DL3

AMBER

1 2

3 4

5 6

7 8

9 10

HD2 HEADER 5X2

R30 10

R43

1.0K

12345678910

PL1

HEADER 5X2

C24

33pF NPO

R7 10

C42 .001

C11 .001

C12

1

C14

.001 POLY

R6

100K

R9

100K

R10

100K

R11 100K

R13 100K

R14 100K

R21

100K

R12

1.0K

R62

100

R65

100K

R61

10.0K

R20 1M

R41 10.0K

R28 10.0K

R27 10.0K

R42 10.0K

R40 10.0K

R23 1M

R22

200K

C15

0.01

R35 499K

D12

1N4148

R3 150K

D6

1N4148

R66 150

R67

15

R68 499K

21

3

A1

MAR-6

R38

15

R39 100

R33 100

D11 1N4148

C62

220pF

R64 4.99K

2 3

1

411

U5A

MC33284P

6 5

7

U5B

MC33284P

9

10

8

U5C

MC33284P

13 12

14

U5D

MC33284P

2 3

1

84

U7A

NE5532

5 6

7

U7B

NE5532

+5V

GND

RF OUT

8

9

C4

1

C29 1

C43 1

C8

1

C44

1

C40

1

C28 1

509

2

3

1

8 4

U8A

TL072

5

6

7

U8B

TL072

C76

0.1

C77

0.1

C78 0.1

-12V

+12V

R85

2K

PWR. CNTRL. OFFSET

C79 0.1

-12V

R87 10K

Q72

IRFD9120

G

S

D

D13

3.9V

TP2

4.5 - 8.0V

1

2

JP1 JUMPER

C82 .01

PWR. CNTRL TILT

+8V

SCH, FM-VFM RF EXCITER

DW

01-04-02

R80

24.3K 1%

R88

30.1K 1%

R89

26.7K 1%

R82

24.3K 1%

R90

499 1%

R86

680.0

D14

6.2V 1N753A

R81

10.0K

C81

1000pF

R83

5.11K 1%

R84

5.11K 1%

C80

0.1

1 FOR PROTOTYPE 01-04-02 DW

02-06-02 DW2 MODIFIED PER MIKE SENEKI 06-24-02 DW3 CHG'D R18 PER EAD MRH01. R18 WAS 91K OHM. U5 WAS C 6900-5

1%

+

C61

47/20V

TANT.

+

C21 10/35V

TANT.

+

C27

10/35V

TANT.

+

C30

10/35V

TANT.

+

C36

10/35V

TANT.

+

C37

10/35V

TANT.

+

C38 10/35V

TANT.

+

C39 10/35V

TANT.

POLY

UNLESS OTHERWISE SPECIFIED:

1 1

REFERENCE DESIGNATORS NOT USED:

C16, C17, C18, C20, C25, C34, C45-60, C63-75, Q1-71, R29, R31, R32, R34, R36, R37, R49, R50, R53-60, R69-79, VCO1-VCO60.

R8

100

05-23-03 DW4 R8 WAS 1.0K OHM.

246 A-G

01-29-04 DWA PRODUCTION RELEASE

277

DW DP

DJ

01-05-02

DW

01-05-02

DP

01-05-02

6–10

FM500 User's Manual

Illustration 6–8 RF Metering Board

(Add 400 to component designators for schematic reference)

D 8169-1

6–11

Reference Drawings

METERING

FAULT SUM

SWR LAMP

PADC LAMP

LOCK LAMP

+5V

PATEMP LAMP

R450

10K

D411

J2-1

J4-8

J3-18

J3-12

J3-14

J3-20

/+28V INH

11

10

U405E

74HC14

/LOCK

+5V

D406

D407

D408

D409

D410

U5

R416 100K

9

8

U405D

74HC14

13

12

U405F

74HC14

1

2

U405A

74HC14

3

4

U405B

74HC14

5

6

U405C

74HC14

R432 100K

R492 10K

+5V

J4-1

PAI LIMIT

+12V

1.00V = 10.0A

1.00V = 10VDC

FAN

REM PADCV

REM PADCA

R415 120K

C407

.001

C409 .001

D401

U3

U4

U2

-12V

J2-7

J4-4

-12V

+12V

-12V

+12V +5.00V

6 5

7

U402B TL072

2 3

1

8

4

U402A TL072

R410

100

R409

100

R412

10K POT H

R411

15K

R413

33K

13 12

14

U404D TL074

C405 .001

D402

R431 120K

2 3

1

4

1

U403A TL074

13 12

14

U403D TL074

2 3

1

4

1

U404A TL074

R427 240K

R437

1M

R425 1M

R428 10K

R429

220K

R430 100K

C408

1.0UF

J4-3

R414

2.2M

R424 100k

R426

30.1K 1

5.00V = 100 deg. C

TEMP OUT

REM PATEMP

R418 1K

R420

100K 1

R421 100

R419

24.9K

U3

-12V

J2-4

J2-3

J2-6

J4-6

C421

.001

R407

10.0K 1

R406

100K 1

R423 240K

9

10

8

U403C TL074

R408

1.1K 1

Parts not loaded:

R402, 403, 404

C403, 404

Q401, 402

DZ401

(Jumper under board)

C401 .01

U401

R405

2.49K 1

C431

0.1

PAV

LB401

R401

1N4148

C406 .01

PAI

50mv per degree C.

R422

75k

DC SUPPLY

SWR LIMIT=

(R435+R436)+R436 (R435+R436)-R436

---------------- = ----

150K 100K

= 1.5:1

VOLTMETER

10mV/Deg. C

REM BATT

R456

1K 1

U3

J2-2

J2-8

J4-7

R453

1.1K 1

R452 10K 1

R451 100K 1

R454 100

6 5

7

U403B TL074

C412

0.1

C413

0.1

R455

100K 1

-12V

POWER SET

.001V per Watt

1mV/Degree C

10mV/Volt 100mV/Amp

10mV/Volt

RF LEVEL

C410

0.1

R441

1M

D403

U4

J3-8

R438 120K

R435 100K

R436

24.9K

R440

33K

R434

10K POT H

9

10

8

U404C TL074

D404

(VFWD+VREFL)/40

RF POWER (RFV SQUARED) RF POWER

SWR ALC PA DCV PA DCI PA TEMPERATURE SUPPLY DC VOLTS VOLTMETER

INPUT

R467

1K POTH

D412

C411

0.1

U4

-12V

J2-12

R445 100K

R446

10K

6 5

7

U404B TL074

D405

R439 100K

R442

51K

R444 200K

R443 51K

ALC

DPM IN

+5V

16

FULL SCALE 1999 WATTS

19.99

19.99V

199.9V

19.99A

199.9V

199.9 Deg. C

(1.999V reads "1999")

INPUT LAMP

U8

J3-19

GND

J3-16

R449 11K 1

R448 100K 1

R447

1K

C422

0.1

X0

13

X1

14

X2

15

X3

12

X4

1

X5

5

X6

2

X7

4

INH

6

A

11

B

10

C

9

X

3

U408 74HC4051

J4-2

1.00V

SEL A SEL B SEL C

DPM REF

+5V

VCC

VSS

VDD

VEE

8

+5V

16

R1-91

NUMBERS USED:

C1-29

U9

J3-2 J3-4 J3-6

J3-17

-12V

U8,9 pin 7

R417

3.3K

+5.00V

(C2)

DZ402 LM329DZ

-6.9V

X0

13

X1

14

X2

15

X3

12

X4

1

X5

5

X6

2

X7

4

INH

6

A

11

B

10

C

9

X

3

U409 74HC4051

C423

0.1

R490

10.0K 1

R491

2.49K 1

C429

1.0UF

C426

1.0UF

+12V

-12V

+12V

-12V

SWR CAL

(VFWD-VREFL)/4

+5V

R466

56K

R468

1K

R488

24.9K

R483

1M

R485

100K

U6

J3-9,10

C424

1.0UF

C425

1.0UF

C428

1.0UF

+5.00V

13 12

14

U406D TL074

R486 100K

R487

100K

R489

24.9K

Q403 2N5210

R484

10K

D417

R481

39K

9

10

8

U406C TL074

R482

1K

D418

C427

1.0UF

IN

1

C

2

OUT

3

VR401 78L05

J4-12

C B E

(2.5VDC at 100W)

(.135V)

R474

3.3K

R476

49.9K

U7

R465

56K

9 10

8

U407C TL074

R477

7.5K

R460

1K

R464

1K

1

2

3

4

8

7

6

5

Q405

LM394

1

2

3

4

8

7

6

5

Q406

LM394

RFV

RF REV

RF FWD

-12V

+12V

-12V

+12V

POWER CAL

R457 10K

R458 22K

R459 100K

R461 10K

R462 22K

R463 100K

R469

10K

R471 100K

C414

.01

C416

.01

C418

.01

D416

U6

U7

D413

1N6263

J2-9

J2-10

J2-11

2 3

1

4

1

U406A TL074

C415 .001

6 5

7

U406B TL074

C417 .001

D414

1N6263

2 3

1

4

1

U407A TL074

C419 .001

D415

1N6263

R472

10K POT H

6 5

7

U407B TL074

C420

.01

R473 10K

R470 22K

R480 100

U7

-6.9V

R478

10.0K 1 13

12

14

U407D TL074

R479

1.1K 1

R475

49.9K

(Clamp SWR reading below 5W.)

(1.00V at 100W)

REM RFWATTS

J4-5

FM500

METERING

103204A

-12V -12V +12V+12V

12

34

56

78

910

J401

RECEPT 5X2

/LOCK

ALC

FAULT SUM

+5.00V

REM PATEMP

REM PADCV

REM PADCA

REM RFWATTS

REM BATT

J4

1

2

3

4

5

6

7

8

9

10

11

12

J404

RECEPT 12X1

SEL A SEL B SEL C

DPM REF

SWR LAMP

PADC LAMP LOCK LAMP

+5.00V

DPM IN

INPUT LAMP

PATEMP LAMP

RF LEVEL

J3

+5.00V

12 34 56 78

910 1112 1314 1516 1718 1920

HD403

HEADER 10X2

RFV

DC SUPPLY

RF FWD

RF REV

FAN TEMP OUT

VOLTMETER

/+28V INH

J2

INPUT

1

2

3

4

5

6

7

8

9

10

11

12

J402

RECEPT 12X1

PAV PAI

1 2 3 4 5 6 7 8 9 10 11 12

A

B

C

D

E

F

G

H

121110987654321

H

G

F

E

D

C

B

A

DWG. NO. REV.

1

201207-SCH

E . C . N. REV DESCRIPTION

APPROVALS

PECHK CMDATE DWN

REVISION HISTORY

65

THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF INTERNATIONAL RADIO AND ELECTRONICS CORP. AND SHALL NOT BE REPRODUCED, COPIED OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

1 1SHEET OF

SCALE : NONE

PROJ NO.

FILENAME:

DWG . NO .

REV

1

201207-SCH

TITLE:

SCH, FM/IBOC MOTHER BOARD

UNCONTROLLED

UNLESS OTHERWISE MARKED IN RED INK BY CM AS A CONTROLLED COPY, COPIES OF THESE DOCUMENTS INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS ARE FOR REFERENCE ONLY.

APPROVALS

DWN

CHK CM PE

DISTRIBUTION

K

SIZE

D

Error : logo3A.jpg file not found.

INTERNATIONAL RADIO AND ELECTRONICS CORP. 25166 LEER DRIVE ELKHART, IN. 46514 574-262-8900

WWW.IREC1.COM

IREC

1 FOR PROTOTYPE 02-05-05 DW DW

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

J4

DB15

C17

.01

C18 .01

C19 .01

C20 .01

C21 .01

C22 .01

C23 .01

C24 .01

R24 220

C38

OPEN

C39

OPEN

C40

OPEN

R13 390

R14

390

R12 1K R11 220

R15 100

R16 220

C11

.01

C12 OPEN

C13

.001

C14

.001

C15

.01

C16

.01

C30

.01

C31

.01

C32

.01

C33

.01

C34

.01

C35

.01

C36

.01

1 2 3

HD5

HEADER 3X1

123

J2

OPEN

C3

220pFC4220pF

C5

220pF

C6

220pF

C7

220pF

C8

220pF

C9

220pF

R3

1K

R4 1K

R51KR61KR7

1K

R81KR9

1K

R10 240

12345

HD6

OPEN

2

3

1

REF. FOR XLR CON.

HI LO GND

SCA

EXT_RTN

EXT_IN

MON_L

MON_R

-12V

+12V

12345678910111213141516171819202122232425

26

HD31

26 HEADER

J5 MCXJ6MCX

J1

12345678910111213141516171819202122232425

26

RFX OUT

1234567891011

12

HD42

HEADER 12

1234567891011

12

HD44

HEADER 12

J2J4

1234567891011

12

+5.00V

D1 1N4148

123456789

10

HD41

HEADER 5 x 2

J1

V+

TEMP

GND

R27

1K

R28 1K

R29

1K

1 2 3 4 5 6 7 8 9

10

HD4

HEADER 5 x 2

1 2 3 4 5 6 7 8 9 10 11 12

HD21

HEADER 12

1 2 3 4 5 6 7 8 9 10 11 12

HD22

HEADER 12

+5.00V

LEFT

RIGHT

R IN2

R IN1

L IN2

L IN1

LPIN L

LPOUT L

LPIN R LPOUT R

+12V

-12V

L VU

+5.00V

PROC A PROC B

PROC C

R VU

BR GR HI GR

1234567891011

12

ALC / METERING

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20

HD3

HEADER 10 x 2

+12V

123456789

10

+12V

-12V

C41 .001

C42 .001

C43 .001

RF EXCITER

C10

.01

R26

1K

TP1

VOLTMETER

1

2

3

4

5

6

HD2

HEADER 6X1 .156

+12V

1

2

HD7

HEADER 2 .156

C25

.01

C26

.01

C27

.01

R25

OPEN

Q1

IRF541

R4A 300

R3A 300

Z8

OPEN

Z7

OPEN

123

J1

XLR

C1

220pFC2220pF

R1 1K

R2 1K

R2A

300

R1A

300

Z3

OPEN

Z5

OPEN

Z4 OPEN

Z6 OPEN

Z1

JUMPERZ2JUMPER

J1

1 2 3 4 5 6 7 8 9 10 11 12

STEREO GENERATOR

J2

1 2 3 4 5 6 7 8 9 10 11 12 1

2 3 4 5 6 7 8 9

10

HD23

HEADER 5 x 2

J3

1 2 3 4 5 6 7 8 9 10

+12V

-12V

SCA IN

EXT RTN

EXT IN

/EXT ENABLE

COMP OUT

RIGHT

LEFT

MON R

MON L

LPIN L LPOUT L LPIN R LPOUT R

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

HD11

HEADER 10 x 2

J1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

AUDIO PROCESSOR

1 2 3 4 5 6 7 8 9 10

HD12

HEADER 5 x 2

J2

1 2 3 4 5 6 7 8 9 10

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

HD13

HEADER 13 x 2

J3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

+12V

-12V

/+6DB

/+12DB

+5.00V

COMP METERCOMP METER

STEREO/MON

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

HD61

HEADER 10 x 2

ALC

FAN

TP2

+12V

TP3

-12V

+12V

TP4

+12V

+5.00V

TP5

GND

2

3

1

U1A

TL072

C48

1.0

+12V

C49

1.0

-12V

R33

24.9K 1%

R34 24.9K 1%

R36

24.9K 1%

R35

24.9K 1%

Z11

OPEN

EXT RTN

Z10

OPEN

R37

3.9K

5

6

7

U1B

TL072

R32

1K

EXT IN

R41 1K

Z14

OPEN

SCA IN

D2

1N4148

D3

1N4148

R38

4.02K 1%

R39 100

R40 100

Z12

OPEN

Z13

OPEN

COMP METER

COMP OUT

STEREO GENERATOR SHUNT

NC

1

Vin

2

TEMP

3

GND4TRM

5

Vout

6

NC

7

NC

8

U2

REF02

+12V

C54

1.0

2

3

1

U3A

TL072

C50

1.0

+12V

C51

1.0

-12V

5

6

7

U3B

TL072

R43 100

C52 .01

R42

4.7K

C54

1.0

Z9

OPEN

+5.00V

AUDIO PROCESSOR SHUNT

_METER PAV

_METER PAI

_METER RFW _METER PA TEMP

_METER BATT

_FAULT SUM _/AUTO CAR. OFF

_/CARRIER OFF

_FSK IN _ALC

_COMPOSITE OUT

_38 KHZ OUT

_/EXT ENABLE

L IN1

L IN2

R IN1

R IN2

R IN1

L IN2

JMP1 OPEN

JMP2 OPEN

R23 220

R22 220

R21 220

R20 220

R19 220

R18 220

R17 220

FAULT SUM

METER BATT

METER PATEMP

METER RFW

METER PAI

METER PAV

ALC

FSK IN

NC NC

PAI

PAV

/LOCK FAULT

C28 .001

C29 .001

DC SUPPLY

TEMP

INPUT

FAN+12V

FAN

V-METER

RFV

RF FWD

RF REV

/LOCK

NC

38KHZ38KHZ

NC

NOTES: UNLESS OTHERWISE SPECIFIED:

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL.

2. ALL CAPACITORS ARE IN MICROFARADS.

DW 11-23-04

/EXT ENABLE

COMP METER

INPUT CONFIGURATION CHART

NON-OMNIA BOARD INPUT IMPEDENCE

Z1, Z2 ON Z3, Z5, Z7, Z8 OFF Z4, Z6 OFF

50 KOHM

Z1, Z2 ON Z3, Z5, Z7, Z8 ON Z4, Z6 OFF

600 OHM

OMNIA BOARD AES/EBU INPUT

Z1, Z2 OFF Z3, Z5, Z7, Z8 OFF Z4, Z6 ON

ANALOG LEFT/RIGHT

LEFT IN 1 LEFT IN 2

Z32

OPEN

Z33

OPEN

Z31

OPEN

ADD FOR M2HD-S

MOTHERBOARD ONLY

INSTALLED WHEN USING AUDIO PROC. SHUNT CKT.

Z15 OPEN

Z16 OPEN

Z17 OPEN

Z18 OPEN

Z19 OPEN

Z20 OPEN

Z21 OPEN

Z22 OPEN

Z23

JUMPER

Z24

JUMPER

Z25

JUMPER

Z26

JUMPER

Z27

JUMPER

Z28

JUMPER

Z29

JUMPER

Z30

JUMPER

Jumper FMA "E" FMA "T" FMA"T" FMA "R" FMA "Omnia" FMA "Omnia" FMX "E" FMX "T" FMX "T" FMX "R" FMX "Omnia" FMX "Omnia" FMX

50K input 600 input Analog input AES input 50K input 600 input Analog input AES input RMS Z1 Short Short Short Short Short Open Short Short Short Short Short Open Z2 Short Short Short Short Short Open Short Short Short Short Short Open Z3 Open Open Short Open Open Open Open Open Short Open Open Open Z4 Open Open Open Open Open Short Open Open Open Open Open Short Z5 Open Open Short Open Open Open Open Open Short Open Open Open Z6 Open Open Open Open Open Short Open Open Open Open Open Short Z7 Open Open Short Open Open Open Open Open Short Open Open Open Z8 Open Open Short Open Open Open Open Open Short Open Open Open Z9 Short Open Open Open Open Open Short Open Open Open Open Open Z10 Short Open Open Open Open Open Short Open Open Open Open Open Z11 Short Open Open Open Open Open Short Open Open Open Open Open Z12 Short Open Open Open Open Open Short Open Open Open Open Open Z13 Short Open Open Open Open Open Short Open Open Open Open Open Z14 Short Open Open Open Open Open Short Open Open Open Open Open Z15 Open Open Open Open Open Open Open Open Open Open Open Open Short Z16 Open Open Open Open Open Open Open Open Open Open Open Open Short Z17 Open Open Open Open Open Open Open Open Open Open Open Open Short Z18 Open Open Open Open Open Open Open Open Open Open Open Open Short Z19 Open Open Open Open Open Open Open Open Open Open Open Open Short Z20 Open Open Open Open Open Open Open Open Open Open Open Open Open Z21 Open Open Open Open Open Open Open Open Open Open Open Open Open Z22 Open Open Open Open Open Open Open Open Open Open Open Open Open Z23 Short Short Short Short Short Short Short Short Short Short Short Short Open Z24 Short Short Short Short Short Short Short Short Short Short Short Short Open Z25 Short Short Short Short Short Short Short Short Short Short Short Short Open Z26 Short Short Short Short Short Short Short Short Short Short Short Short Open Z27 Short Short Short Short Short Short Short Short Short Short Short Short Open Z28 Short Short Short Short Short Short Short Short Short Short Short Short Short Z29 Short Short Short Short Short Short Short Short Short Short Short Short Short Z30 Short Short Short Short Short Short Short Short Short Short Short Short Short Z31 Open Open Open Open Open Open Open Open Open Open Open Open Z32 Short Open Open Open Open Open Short Open Open Open Open Open Z33 Short Open Open Open Open Open Short Open Open Open Open Open JMP1 Open Open Open Open Open Open Open Open Open Open Open Open Open

JMP2

Open

6–14

FM500 User's Manual

Illustration 6–10 Display Board

(Add 600 to component designators for schematic reference)

R27

D 8167-5

6–15

Reference Drawings

"110"

RED

GRN

+5V

+12V

5.00V

+12V

C628

1.0UF

L2

18

L3

17

L4

16

L5

15

L6

14

L7

13

L8

12

L9

11

L1010MODE

9

RADJ

8

ROUT

7

DHI

6

L1

1

V-

2

V+

3

DLO

4

IN

5

U608

LM3914

YEL

6 5

7

U613B TL072

FOR BAR

DL648-658

JP603

JUMPER

2 3

1

8

4

U613A TL072

R647

1K

R648

1K

R627

2.7K

R652

5.6K

COMPOSITE

-12V

C611

0.1

+12V

R646

10M

Q603 2N5210

Q604

2N5087

R644 33K

R645

100

+12V

R653

1K

2 3

1

8

4

U607A TL072

D606

1N6263

D618

C626

1.0UF

R623

10.0K

D605

1N6263

6 5

7

U607B TL072

R643

3.3M

R622

10.0K

50mA

RED

GRN GRN

GRN

RED

+5V

+12V

5.00V

L 2

1 8

L 3

1 7

L 4

1 6

L 5

1 5

L 6

1 4

L 7

1 3

L 8

1 2

L 9

1 1

L 1 0

1 0

M O D E

9

R A D J

8

R O U T

7

D H I

6

L 1

1

V

2

V +

3

D L O

4

I N

5

U604 LM3914

HI GR

G GG G Y

YEL

DL621-625

DL601-610

R614

1.2K

Q601

MPS-A56

R605

1K

R613

1K

R606

330

C602

1.0UF

L VU

+12V

5.00V

+12V

-12V

D601

1N4148

D602 1N4148

JP601

R602 100K

R601

68K

C601

1.0UF

2 3

1

8

4

U601A TL072

R603

1K

L2

18

L3

17

L4

16

L5

15

L6

14

L7

13

L8

12

L9

11

L1010MODE

9

RADJ

8

ROUT

7

DHI

6

L1

1

V-

2

V+

3

DLO

4

IN

5

U602

LM3915

R604

1.2K

C604

1.0UF

R609

1K

R VU

+12V

5.00V

+12V

+5V

R607 68K

C603

1.0UF

D604 1N4148

D603

1N4148

R608 100K

JP602

R610

1.2K

6 5

7

U601B TL072

L2

18

L3

17

L4

16

L5

15

L6

14

L7

13

L8

12

L9

11

L1010MODE

9

RADJ

8

ROUT

7

DHI

6

L1

1

V-

2

V+

3

DLO

4

IN

5

U603

LM3915

50mA

DL11-20

RED

GRN GRN GRN GRN GRN GRN GRN

RED

C607

0.1

C608 .001

R617

1K

DITHER

+5V

+12V

5.00V

L 2

1 8

L 3

1 7

L 4

1 6

L 5

1 5

L 6

1 4

L 7

1 3

L 8

1 2

L 9

1 1

L 1 0

1 0

M O D E

9

R A D J

8

R O U T

7

D H I

6

L 1

1

V

2

V +

3

D L O

4

I N

5

U605 LM3914

BR GR

R618

1.2K

Y Y G G G

G G G Y

YEL

R615

33K

R616

33K

C606

0.1

R611

1K

C605 .001

Q602

MPS-A56

R612

330

D607

-12V

MOD. CAL.

C610

0.1

R655

4.7K

R649 10K POT H

C612 .001

DL626-635

R624

1M

RED

R625

10K

"PILOT"

GRN GRN

GRN

ST/MON

/+6DB

/+12DB

+5V

DITHER

C625

0.1

-12V

STEREO

MONO

R626 33K

5.00V

RF LEVEL

R629 680

SW603

SW601

SW602

C634

1.0UF R657

1K BECKMAN

DP10 DP100

-12V

R651

2.2K

UNITSTENS100's1000

+5V

1234567891011121314151617181920

212223242526272829303132333435363738394

0

DL101

DISPLAY

1234567891011121314151617181920

212223242526272829303132333435363738394

0

U612

ICL7107

C614

0.1

C615

0.1

R638 100K

DPM IN

DPM REF

C617

0.1

R637

470K

C616

0.1 POLY

C618

0.1

C619

100PF

R635 100K

R636 100K

C627

1.0UF

DZ601

6.2V

SCM, FM DISPLAY

103206

SWR

SWR LAMP

PADC LAMP

LOCK LAMP

R619

510

DL644-647, 659

INPUT

LOCK

INPUT

PA DC

DL644

RED

DL645

RED

DL646

RED

DL647

RED

1312

U609F 74HC14

R620 220K

C609

1.0UF

PATEMP LAMP

PA TEMP

DL659

RED

+5V

VCC

16

U10 U11

8

VEE VSS

VDD

-12V

+12V

-12V

14

U9

7

C630

1.0UF

C631

1.0UF

C622

1.0UF

C624

1.0UF

C629

1.0UF

C623

1.0UF

IN

1

C

2

OUT

3

VR601 7805

+12V

2 3

1

8

4

U606A TL072

R631

5.6K

D616

D617

10V P-P DITHER

DITHER

6 5

7

U606B TL072

R633

33K

C613

.01

R634

5.1K

-12V

R632

620

5

6

U609C 74HC14

9

8

U609D 74HC14

11

10

U609E 74HC14

R630 150

X0

13

X1

14

X2

15

X3

12

X4

1

X5

5

X6

2

X7

4

INH

6

A

11

B

10

C

9

X

3

U611

74HC4051

SWR

ALC

RF POWER

PA DC VOLTS

PA DC AMPS

SUPPLY DC VOLTS

19.99

199.9

19.99

F.S.

DECIMAL POINT

GRN

DP100

DP10

GRN

+5V

1999

R656

220

DL636-643

PA TEMPERATURE

199.9VOLTMETER

UP

DOWN

R639 100K

R640 100K

+5V

SW605

SW606

R628

1K

R654

1K

+5V

1 2

U609A

74HC14

3

4

U609B

74HC14

A15QA

3

B1QB

2

C10QC

6

D9QD

7

UP

5

CO

12

DN

4

BO

13

LOAD

11

CLR

14

U610

74HC193

C620

.01

C632

.001

C621

.01

C633

.001

R641 10K

R642 10K

SEL A SEL B SEL C

PROC A

R650 100K BECKMAN

PROC B

PROC C

L VU R VU

HI GR

BR GR

PROC A PROC B PROC C

/+6DB

/+12DB

DPM IN

DPM REF

MON/ST

SWR LAMP

PADC LAMP LOCK LAMP

COMPOSITE

-12V

RF LEVEL

+12V

-12V

5.00V

GND

5.00V

SEL A SEL B SEL C

+12V

INPUT

PATEMP LAMP

Pin 1, upper left from front of unit.

12 34 56 78

910 1112 1314 1516 1718 1920

J601

HEADER 10X2

12

34

56

78

910 1112 1314 1516 1718 1920

J602

HEADER 10X2

NOTES :

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROF ARADS UNLESS O THER WISE SPECIFIED .

DISPLAY

6–17

Reference Drawings

VOLTAGE REGULATOR

+6V

VDD

VSS

+12V

VCC

R723 1K

DZ701 1N4735

6.2V

R722 100K

R713 100K

D706

1N4148

+12V

R709

1K

R716

10K

D707

1N4148

PI

11

RST

12

Q4

7

Q5

5

Q6

4

Q7

6

Q8

14

Q9

13

Q10

15

Q12

1

Q13

2

Q14

3

PO

9

PO

10

U702

74HC4060

D702

1N4148

D701

1N4148

6 5

7

U701B TL074

+12V

/CARRIER OFF

C703

.001

Fo=5KHZ BPF; Q=3

/AUTO CARRIER

VDD

5

6

U703C

74HC14

3

4

U703B

74HC14

1

2

U703A

74HC14

R702

10K

R704

10K

R707 180K

C702 .001

R705

91K

R701

4.7K

R703

4.7K

R733

4.7K

CARR SW

2 3

1

4

1 1

U701A TL074

-12V

PROGRAM DETECT

VDD VDD

R725 100K

COMP2

AUDIO or COMPOSITE

R748 10K

D703

1N6263

R706

5.1K

R711

100K

C701 .01

C704 .001

13

12

U703F

74HC14

11

10

U703E 74HC14

D704

1N626313

12

14

U701D TL074

R710

75K

1

1 2 3 4

+IN OSC GND

-IN

LM3578

U1

+UNREG

0.5 2 4

R715

2.2K

VDD

R720 10K

INPUT FAULT

R708 100K

R714 220

DL701 GREEN

R718 100K

12 34 56 78 910

JP701

HEADER 5X2

D708

1N4148

R717

10K

1

2

3

4

8

7

6

5

U705

IR2125

1

2

3

4

8

7

6

5

U704

LM3578

D710

1N4148

R735

51

C714

0.1

R724

100

R734

10K

TIME-OUT

SELECT

MINUTES

P701

8

Q701 IRF540

C723

330

100V

DZ702 1N9661B 16V

R712

1M

C706

1.0

POLY

C712

1.0

R719

10K

C705

1.0

POLY

Q705

MPSA06

DL702 RED

9 10

8

U701C TL074

R721

24.9K 1

1 2 346

7

8VB

5

U2

6

7

8V+

5

CS

C E

IR2125

VCC IN ERR ESS VS

CS

OUT

28V ENABLE

9

8

U703D

74HC14

DRVR V+

+12V

-12V

+12V

R743

220

R739

510

R742

1K

Q704

MJE15028

R741 1K

(+13.5V)

(+12.5V)

DZ703

ICTE-12

DZ704

ICTE-12

C720 220UF

50V

C722 3300UF 16V

L702

960UH

C718

220 63V

C725

220 63V

R740

10

C719 1000

35V

Q702 MPSA06

Q703

MPSA56

C717 1UF

SYNC

ALC

DRVR V+

+UNREG

+12V

(TO POWER REG. BOARD)

R730

2.2K

R750

100

-12V PAV

PAI

1

2

3

4

5

6

HD704

HEADER 6

L701

380UH

C711

.01

R728

68K

R729

4.12K 1

C713

100PF

R738A

1.0

0.5W

R738A

1.0

0.5W

R737

4.3K

R736

2K

C715

0.1

C724

47

20V

R751

JUMPER

A10124-22

D711 MUR110

D714

1N5822

R732

82.5K 1

/LOCK FAULT

METER UNREG

+12V

-12V

DRVR V+

INPUT FAULT

D715 1N4004

CARR SW

C709

2200PF

POLY

C710 56PF

NPO

123456

HD701

123456789

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

1 9

2 0

HD702

c 8667-5

38KHZ

COMP2 /CARRIER OFF

/AUTO CARRIER

FAN

L703

960UH

1 2 3

HD703

-12V

NOTES : _______

_______

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED.

THESE DRAWINGS AND SPECIFICATIONS ARE THE SHALL NOT BE REPRODUCED, COPIED, OR USED

AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

PROPERTY OF CROWN INTERNATIONAL, INC. AND

CROWN INTERNATIONAL, INC.

1718 WEST MISHAWAKA ROAD ELKHART, IN. 46517 PHONE (219) 294-8000

DO NOT SCALE PRINT

SUPERSEDES

REV

ME

EE

PE

APPROVED BY :DRAWN

CHECKED

SCALE NONE

PROJ #

DWG. NO.

E.C.

JFL

NEXT ASM:FILENAME: 10.SCM

A

103207

8-25-97

MLOWCMO

FM VOLTAGE REGULATOR

Inductor Data

L Wire Turn s

960uH

165

#26

380uH #22 80

L701 L702-703

Micrometals T90 core

Remove:

U706 L704 R745 R744 C724 D713

D714 1N5822 to MUR110

Change: R732 100K to 49.9K

(C707) (R726) (R708) (R749)

Add: 1UF/100V between L701 and L703 under board.

Modifications for use

with 12.5V RF driver.

DZ703 1.5KE36A to ICTE-12 C721, C722 3300UF to 220UF/50V

7912 regulator, using "L704" pads. Jumper "U706" pads 1 and 2. DZ705

C708 220 Pf

C707 .001

R726 100K

R749

1.5K

D709

OPEN

R727 620

1 2 3 4 5

LM2576–ADJ

U706

R745 10K 1%

D713 1N5822

R744

1.1K 1%

C721 3300UF 16V

L704

960UH

6–18

FM500 User's Manual

Illustration 6–12 Power Regulator Board

DWG. NO. REV.

200915-SCH

C

1 2 3 4 7 8

A

B

C

D

E

F

1 2 3 4 6 7 8

A

B

C

E

F

5

THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF INTERNATIONAL RADIO AND ELECTRONICS CORP. AND ARE NOT TO BE REPRODUCED, COPIED OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

1 1

SHEET

OF

SCALE : NONE

PROJ NO.

FILENAME:

DWG . NO .

REV.

C

200915-SCH

TITLE:

SCH, FM POWER REGULATOR

UNCONTROLLED

UNLESS OTHERWISE MARKED IN RED INK BY CM AS A CONTROLLED COPY, COPIES OF THESE DOCUMENTS INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS ARE FOR REFERENCE ONLY.

APPROVALS DWN CHK

CM

PE

DISTRIBUTION

E . C . N. REV DESCRIPTION

APPROVALS

PECHK CMDATE DWN

REVISION HISTORY

65

SIZE

B

Error : logo3A.jpg file not found.

B_L_SHT1_A.DOT REV. A

INTERNATIONAL RADIO AND ELECTRONICS CORP. 25166 LEER DRIVE ELKHART, IN. 46514 574-262-8900

WWW.IREC1.COM

IREC

~

-

+

DC INPUT

TP1

TP2

ON CHASSIS

NOTES: UNLESS OTHERWISE

SPECIFIED:

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL.

2. ALL CAPACITORS ARE IN MICROFARADS.

533

BATTERY

CIRCUIT BREAKER

110V

DW 09-30-03

R801B

24.9K

R801A

27.4K

1 2

Z7

1 2

Z6

1 2

Z9

1 2

Z8

12

Z1

12

Z2

R806A

330K

R805A

330K

R806B

200K

R805B

200K

D805

1N4148

R820 100K

R804

10.0K 1%

123

D803 BYV72EW-150

123

D804 BYV72EW-150

D802 1N4148

R811

ESS

4

ERR

3

IN

2

VCC1VB

8

OUT

7

CS

6

VS

5

U2

IR2125

GND

4

OSC

3

+IN

2

-IN1V+

8

CS

7

C

6

E

5

U801

LM3578AN

1

2

3

R802

10K

DZ801

1N966B 16V

DZ802

1N966B 16V

1 2

Z4

1 2

Z5

L801 30UH

L803 30UH

L802

*

Q801 IRF540

R808

1.0K

R809

51.0

R807

2.2K

R803

82K

R810

2.0K

R812A

0.1

R812B

0.1

DZ803 1N4735 6.2V

R821

10.0K

R818A

2.0K

R818B

2.0K

+

C815

330/100V

+

C816

330/100V

+

C817 330/100V

+

C810

330/100V

+

C811

330/100V

Q804 MPSA06

3

2

6

1

8

74

U803 OP-27GNB

Q802 MPSA56R814

22.0K

Q803

2N5087

R822

22.0K

R816

1.0K 1%

R813

1.0K

R815

100.0

R819

.04 OHM 15W 3%

R817B

2K

R817A

100

C1001

0.015F

C802

2200PF POLY

C801 220PF

C814 1/50V

C804

.01

C803 56PF

C813

.01UF

C819 .01UF

C820

0.01UF DISK

C809

.1

C818

.1UF

C805 100PF

C812

1/50V

C808 .0027

+

C806

4.7UF/63V

1 2 3 4 5 6

HD1

C 7527-2_6 HDR

P801

FASTON TAB

P802

FASTON TAB

P806 FASTON TAB

P803

FASTON TAB

P804

FASTON TAB

P805

FASTON TAB

P807 FASTON TAB

P808

FASTON TAB

PA-DC OUT

+ UNREG IN

C10582-2C10582-2C10582-2C10582-2

PWB_REV.G PWB_100969-1

A PRODUCTION RELEASE 10-31-03 DW

R827

1.0K

1 2

Z3

DZ806

1N4735 6.2V

2W

5W 5W

DZ807

1N966B 16V

R828 30K

REF DES

FM1

UNIT CONFIGURATION

SHORT

FM30 FM100 FM250 FM500

L802

OPEN

OPEN OPEN

OPEN

OPEN OPEN

SHORT

OPEN OPEN OPEN OPEN OPEN SHORT SHORT SHORT SHORT SHORT OPEN OPEN OPEN SHORT SHORT SHORT SHORT OPEN OPEN

OPEN

OPEN SHORTOPEN

H43608-1 H43395-5 H43533-1

H43533-1 H43533-1

*

* *

*

2W

*

PA VOLTAGE SET

JUMPER

Z1

SHORT SHORT SHORT

Z2

SHORT

Z9

SHORT SHORT SHORT

Z8 Z7 Z6 Z4 Z5

Z3

SHORT SHORT SHORT SHORT SHORT

EURO

SHORT

OPEN

OPEN SHORT

SHORT

H43533-1

HARRIS M1

SHORT

OPEN

OPEN SHORT

SHORT

OPEN

H43533-1 R811 5.11K 1%3.3K 3.3K 3.3K3.3K3.3K R827 R828 DZ806 DZ807

OPEN OPEN OPEN OPEN

INSTALLED

3.3K

HARRIS M2

OPEN

SHORT

OPEN

SHORT SHORT

SHORT

OPEN

H43533-1

3.3K

INSTALLED INSTALLED INSTALLED INSTALLED INSTALLED INSTALLED INSTALLED

DW 09-30-03 DP 09-30-03

200915-SCH

DW DP B CORRECTED Z3 AND Z6 UNIT STATUS FOR M2 AND FM100 01-29-04 DW DW DP274 C SWAPPED Z1, Z2 TO MATCH PWB 08-10-04 DW DW323 DP

6–20

FM500 User's Manual

Illustration 6–13 Power Amplifier

(Add 1100 to component designators for schematic reference)

R20

R19

6–21

Reference Drawings

FM500 POWER AMPLIFIER

J2

L902

R903

4.7K

C904

0.01

R904

51

T900

C900

0.01

R901 51

C901

0.01

R900

51

C903

0.01

U900

CA2832

L900 33uH

R902

2.7 5W

RF DRIVER BD

C908 27PF

C907 5PF

L904

23.2uH

C910 36PF

C906 36PF

L903

10.4uH

C905 10PF

C909

680PF

C902

0.01

D900 1N753A

6.2V

J3

DZ1110 1N4735

6.2V

R1119

200

3W

J5

R1120

2.7K

C1121

0.01 DISC

R1112

5.6 2W

R1113

5.6 2W

R1101 15K

C1126

0.1

R1110

10K

R1117

24

3W

C1138

0.068

C1112

0.01

C1113

0.01

C1114

0.01

C1115

0.01

R1116

10K

C1116 27PF

C1110

0.01

C1111

0.01

TEMP SENSE

C1122

0.01 DISC

L1122 50NH

L1121 50NH

C1125

60PF

C1123

0.01

C1124

0.01

123

LM35DZ

C1133

0.1

C1127

0.1

C1128

0.1

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72

J1

C1137

0.1

C1136

0.1

C1132

0.1

C1134

0.1

C1135

0.1

+

_

B1

J2

C1131

0.1

C1130

0.1

PA OUTPUT BD

T1121

L1125A

L1125B

C1122

0.01 DISC

L1122 50NH

L1121

50NH

C1125

60PF

L1126

C1129

0.1

T11S

R1114

5.6 2W

R1115

5.6 2W

R1110

10K

R1120

2.7K

C1121

0.01 DISC

R1112

5.6

2W

R1113

5.6 2W

R1101

15K

R1117

24

3W

C1112

0.01

C1113

0.01

R1116

10K

C1110

0.01

C1111

0.01

PA INPUT BD

L1124A

L1124B

L1123

DZ1110 1N4735

6.2V ZENER

R1119

200

3W

PA INPUT BD

R1114

5.6 2W

R1115

5.6 2W

C1116

27PF

C1114

0.01

C1115

0.01

C1138

0.068

PA OUTPUT BD

T1121

C1123

0.01

C1124

0.01

B3

B2

CROWN INTERNATIONAL, INC.

1718 WEST MISHAWAKA ROAD

DRAWN

CHECKED

SCALE

PROJ #

JFL

FILENAME: 1001771A.SCM

FM500 P.A.

ELKHART, IN. 46517 PHONE (219) 294-8000

DO NOT SCALE PRINT

SUPERSEDES

REV

ME

EE

PE

APPROVED BY :

NONE

DWG. NO.

E.C.

R103

NEXT ASM:

7-12-96

100177

A

THESE DRAWINGS AND SPECIFICATIONS ARE THE SHALL NOT BE REPRODUCED, COPIED, OR USED

AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

PROPERTY OF CROWN INTERNATIONAL, INC. AND

+

_

+

_

NOTES :

_______

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED.

9875321

Q1101 BLF278

Q1101

BLF278

T1111P

T11S

T1111P

R1111

10K POT V

R1111

10K POT V

R905 10K

R900 MRF 137

6–22

FM500 User's Manual

Illustration 6–14 RF Output Filter

(Add 1200 to component designators for schematic reference)

P10421-9

6–23

Reference Drawings

RF OUTPUT FILTER & REFLECTOMETER

103209

RF OUT

C1211

47PF NP0

R1203

10

*

R1202

75

C1204

7.1PF

C1206

9.3PF

C1208

5.13PF

L1203

94.1NH

L1204

87.5NH

(195MHz) (176MHz) (252MHz)

C1209A

2PF

L1205

77.9NH

RF IN

C1202

1.35PF

L1202

90.5NH

(455MHz)

C1201

15.4PF

C1203

40.9PF

L1201

250NH

C1201A

10PF

C1218

47PF SM

R1201

100

C1217

3.5PF

C1205

38.9PF

C1207

37.7PF

C1209

14.1PF

C1219 47PF SM

with 200W RF in.

Approx. 7V RMS

1 2 3

HD1201

RF MONITOR

F W D

R E F L

C1212 47PF NP0

C1213

.001

C1215

.01

C1214

.01

D1201

1N6263

R1204

10

R1207

100K

R1206

1K

C1216 .001

*

D1202

1N6263

R1209

1K

R1205

75

R1208

20K

1 2 3 4 5

HD1202 HEADER 5

RFV

C1220 .01

R1210

10K

R1211 100K

14

3 3 3 3

LENGTH

0.7"

0.6"

GUAGE #17

#12 #12 #12 #12

D1203

1N6263

0.6"

0.5"

0.7"

L1201 L1202 L1203 L1204 L1205

I.D. TURNS

0.25"

0.5"

0.4375"

INDUCTORS

*

50-OHM LOAD. R1205 = R1202

IF NECESSARY, SELECT R1202 FOR

SWR READING OF 1.1 OR BETTER WITH R1202,R1203,C1211,D1202,C1216

ON UNDERSIDE OF CIRCUIT BOARD.

EXACT COIL LENGTHS ARE FACTORY-SET.

3. C1201-1209A,1217 are circuit board pads.

NOTES :

_______

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.

2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED.

DWG. NO. REV.

Q43310-4

P

1 2 3 4 7 8

A

B

C

D

E

F

1 2 3 4 6 7 8

A

B

C

E

F

5

THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF INTERNATIONAL RADIO AND ELECTRONICS CORP. AND ARE NOT TO BE REPRODUCED, COPIED OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR DEVICES WITHOUT PERMISSION.

1 1

SHEET

OF

SCALE : NONE

PROJ NO.

FILENAME:

DWG . NO .

REV.

P

Q43310-4

TITLE:

FM RF DRIVER

UNCONTROLLED

UNLESS OTHERWISE MARKED IN RED INK BY CM AS A CONTROLLED COPY, COPIES OF THESE DOCUMENTS INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS ARE FOR REFERENCE ONLY.

APPROVALS DWN CHK

CM

PE

DISTRIBUTION

E . C . N. REV DESCRIPTION

APPROVALS

PECHK CMDATE DWN

REVISION HISTORY

65

SIZE

B

B_L_SHT1_A.DOT REV. A

INTERNATIONAL RADIO AND ELECTRONICS CORP. 25166 LEER DRIVE ELKHART, IN. 46514 574-262-8900

WWW.IREC1.COM

IREC

L1 33uH

J1

RF IN

L2

OPEN

R10 10K

IN1GND2GND3N/C4VCC5N/C6GND7GND8OUT

9

XU1

MHW6342T

R1 OPEN

C6

0.01

C7

0.01

T1

Q1

BLF245

R2

OPEN

C15 680pF

L3

C10

10pF

C11

36pF

C12

36pF

C13

5pF

L4

10.4uH

L5

23.2uH

C14 27pF

J2

RF OUT

C9

OPEN

R11

4.7K

R9

51

C17

0.01

+24VDC

C16

0.01

C18

OPEN

1/2W

3 2

1

84

U2A

OPEN

5 6

7

U2B

OPEN

R15 OPEN

R14

OPEN

G

S

D

1

J3

1

J4

R13 OPEN

R12

OPEN

R8

*

D3 1N753A

6.2V

DW 08-28-03

533

1

J5

R7 OPEN

C8

OPEN

2

1

3

D1

OPEN

C1

.01

Vin

1

GND

2

Vout

3

VR1 OPEN

R16

OPEN

C2

OPEN

R4 OPEN

R3 OPEN

2

1

3

D2

OPEN

C3

.01

R6 OPEN

+5V

R5

OPEN

C4 OPEN

UNLESS OTHERWISE SPECIFIED:

NOTE:

1. ALL RESISTORS ARE IN OHMS, 1/4 WATT +/- 5% TOL.

2. ALL CAPACITORS ARE IN MICROFARADS.

L6

OPEN

R17 51

DW 10-30-03 DP 10-30-03

C19

OPEN

RT1

2.7K NTC

OPEN

T

L7

OPEN

C20

OPEN

C21 OPEN

C22

OPEN

R18

0

FM30 FM100 FM250 FM500

R8 POWER LEVEL CONFIGURATION

OPEN 3 OHM 5W 2.7 OHM 5W3 OHM 5W

FOR FM100 AND FM250: 18V FOR FM500: 20V FOR FM30: FEED POINT FROM PWR. REGULATOR PWB.

FOR FM30: 20VDC INPUT APPLIED HERE.

C5

22

C23

.01

C24

.01

ADDED TO PWB (200922-PWB-D IN LOCATION

SHOWN, AND DEPICTED ON COMPONENT MAP.

M PRODUCTION RELEASE 12-10-03

DW

DW DP264

N XU1 WAS 200479-TERM-10 01-29-04

DW

DW MH279

O PWB CHG'D TO REV. C 06-14-04

DW

DW DP316

P PWB CHG'D TO REV. D 03-22-05

DW

DW DP361

6–26

FM500 User's Manual

FM500 CHASSIS WIRING

FM500 Chassis Wiring C.Donner 2-23-98 CROWN BROADCAST

AC Input, Fuse, & Filter

A

B

C

D

A

Gnd

Red

Blk

Red/Wht

Brn/Wht

Brn

Wht

S1A S1B

P1

100V 220V

120V 240V

P7 P6

P5 P4

Blk/Wht

P801

P802

P803

P804

P806

P805

P807

P808

Right Power

Regulator Board

P801

P802

P803

P804

P806

P805

P807

P808

Red

Blk

Fan

1

2

3

4

6

7

8

9

10

1

2

3

4

5

6

HD701

P1 Unreg

Carrier Switch

V+

Gnd

Power Transformer

RED / WHT

RED

WHT / BLK WHT

BLK

BRN

BRN / WHT

BLU / WHT

BLU

1

3

4

5

6

2

1

2

3

4

5

6

1

2

3

4

5

6

P3

Ribbon Cable

+

Bridge Rectifier

AC Power Switch

Ribbon Cable

On

Off

1 2

4 5 6

8 9

12 13 14 15

17 18

20

19

22 23 24 25

28 29

31 32 33

35 36

Driver input

BNC

PA 1 DC Input

PA RF Output

BNC

37 38

40 41 42

44 45 46 47

54 55 56 57

52 53

62 63 64 65

67 68 69

71 72

PA 2 DC Input

P1

P2

Outer Fans

Inner Fan

Driver DC Input

Mother Board

Voltage Regulator

Board

1

3

1

2

3

4

5

6

1

2

3

4

6

7

8

9

10

Header Socket

Power Amp Interconnect

Board

J1

Bus

DC

AC Distribution Board

Temp Sensor

Back view

*

Jumpered for 120VAC

On

Off

Display Board

HD561

J 601

J 602

Metering

Board

J 403

Ribbon Ribbon

HD504

HD1202

RF Output

Filter & Reflectometer Board

RF Out

RF In

HD505

Reflectometer Feed-Thru

P3

55

HD 502

HD503

2

Temp

HD702

Left Power

Regulator Board

120 VAC

20 VAC

100 VAC

57 VAC

12.5 VAC

CHASSIS WIRING

6–27

Reference Drawings

Illustration 6–16 Receiver Board

6–28

FM500 User's Manual

Receiver

Section 7—Service and Support

We understand that you may need various levels of support or that the product could require servicing at some point in time. This section provides information for both of these scenarios.

Service and Support

7–1

7.1 Service

The product warranty (see opposite page) outlines our responsibility for defective products. Before returning a product for repair or replacement (our choice), call our Customer Service department using the following telephone number:

(866) 262-8917

Our Customer Service Representative will give you further instructions regarding the return of your product. Use the original shipping carton or a new one obtained from Crown. Place shipping spacers between the slide-out power amplifier assembly and the back panel.

Please fill out the Factory Service Instructions sheet (page 7–5) and include it with your returned product.

7.2 24–Hour Support

In most instances, what you need to know about your product can be found in this manual. There are times when you may need more in-depth information or even emergency-type information. We provide 24–hour technical assistance on your product via a toll telephone call.

For emergency help or detailed technical assistance, call

(866) 262-8917

You may be required to leave a message at this number but your call will be returned promptly from our on-call technician.

7.3 Spare Parts

To obtain spare parts, call Crown Broadcast Sales at the following number.

(866) 262-8917

You may also write to the following address:

Service Manger

International Radio and Electronics Company, Inc.

25166 Leer Drive

Elkhart, Indiana, U.S.A. 46514-5425

7–2

FM500 User's Manual

Three-Year Limited Warranty

North America Only

SUMMARY OF WARRANTY

We, Crown Broadcast, a business unit of International Radio and Electronics Company, Inc., 25166 Leer Drive, Elkhart, Indiana 46515–2000 warrant to the ORIGINAL PURCHASER of a NEW Crown Broadcast product, for a period of three (3) years from the date of purchase by the original purchaser (the “warranty period”) that the new Crown Broadcast product is free of defects in materials and workmanship and will meet or exceed all advertised specifications for such a product. This warranty does not extend to any subsequent purchaser or user, and automatically terminates upon sale or other disposition of our

product.

ITEMS EXCLUDED FROM THIS CROWN BROADCAST

We are not responsible for product failure caused by misuse, accident, or neglect. This warranty does not extend to any product on which the serial number has been defaced, altered, or removed. It does not cover damage to loads or any other products or accessories resulting from Crown Broadcast product failure. It does not cover defects or damage caused by use of unauthorized modifications, accessories, parts, or

service.

WHAT WE WILL DO

We will remedy any defect, in material or workmanship (except as excluded), in our sole discretion, by repair, replacement, or refund. If a refund is elected, then you must make the defective or malfunctioning component available to us free and clear of all liens or other encumbrances. The refund will be equal to the actual purchase price, not including interest, insurance, closing costs, and other finance charges less a reasonable depreciation on the product from the date of original purchase. Warranty work can only be performed at our authorized service centers or at our factory. Expenses in remedying the defect will be borne by Crown Broadcast, including two-way surface freight shipping costs within the United States. (Purchaser must bear the expense of shipping the product between any foreign country and the port of

entry in the United States and all taxes, duties, and other custom’s fee(s) for such foreign shipments.)

HOW TO OBTAIN WARRANTY SERVICE

You must notify us of your need for warranty service not later than ninety (90) days after the expiration of the warranty period. We will give you an authorization to return the product for service. All components must be shipped in a factory pack or equivalent which, if needed, may be obtained from us for a nominal charge. Corrective actions will be taken within a reasonable time of the date of receipt of the defective

product by us. If the repairs made by us are not satisfactory, notify us immediately.

DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES

You are not entitled to recover from us any consequential or incidental damages resulting from any defect in our product. This includes any damage to another product or products resulting from such a defect.

WARRANTY ALTERATIONS

No person has the authority to enlarge, amend, or modify this warranty. The warranty is not extended by the length of time for which you are deprived of the use of the product. Repairs and replacement parts

are provided under the terms of this warranty shall carry only the unexpired portion of this warranty.

DESIGN CHANGES

We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in products previously manufactured.

LEGAL REMEDIES OF PURCHASER

There is no warranty which extends beyond the terms hereof. This written warranty is given in lieu of any oral or implied warranties not contained herein. We disclaim all implied warranties, including without limitation any warranties of merchantability or fitness for a particular purpose. No action to enforce this

warranty shall be commenced later than ninety (90) days after expiration of the warranty period.

Crown Broadcast, International and Radio Company, Inc.

25166 Leer Drive, P.O. Box 2000, Elkhart, Indiana 46515–2000

Service and Support

Revised August 2001

7–3

Notes:

7–4

FM500 User's Manual

Factory Ser vice Instructions

To obtain factory service, complete the bottom half of this page, include it with the unit, and ship to:

International Radio and Electronics Company, Inc.

25166 Leer Drive

Elkhart, Indiana, U.S.A. 46514-5425

For units in warranty (within 3 years of purchase from any authorized Crown Dealer): We pay for ground UPS shipments from anywhere in the continental U.S. and Federal Express Second Day service from Hawaii and Alaska to the factory and back to you. Expedited service/shipment is available for an additional charge. You may ship freight collect (COD for cost of freight) or forward your receipt for shipping charges which we will reimburse. We do not cover any charges for shipping outside the U.S. or any of the expenses involved in clearing customs.

If you have any questions about your Crown Broadcast product, please contact Crown Broadcast Customer Service at:

Telecphon: (574) 262-8900

Fax: (574) 262-5399

Name: Company:

Shipping Address: Phone Number: Fax:

Model: Serial Number: Purchase Date:

Nature of the Problem

(Describe the conditions that existed when the problem occurred and what attempts were made to correct it.)

Other equipment in your system: If warranty has expired, payment will be: Cash/Check VISA Mastercard COD

Please Quote before servicing

Card Number: Exp. Date: Signature:

Service and Support

7–5

Appendix

Transmitter Output Efficiency

FM500 User's Manual

Appendix–1

T ransmitter efficiency output

RF Power Output Efficiency-FM500

PADC V olts PADC Amps RF Power Efficiency

51.3 13.91 550 77%

48.3 13.29 500 78%

45.5 12.74 450 77%

42.7 12.14 400 77%

39.4 11.46 350 78%

36.0 10.68 300 78%

33.0 10.00 250 76%

29.6 9.25 200 73%

25.4 8.28 150 71%

21.1 7.29 100 6 5 %

Power measurements were made at 97.1 MHz. Voltage and current measurements were taken from the unit's built-in metering. The accuracy of the internal metering is better than 2%. Return loss of the RF load was greater than -34dB at test frequency.

Appendix–2

FM500 User's Manual