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Crown FM500 User Manual

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Summary of Contents for Crown FM500

  • Page 2: Important Notices

    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.

  • Page 3: Table Of Contents

    Contents Contents Contents Contents Contents 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 Translator ...................... 1–5 1.2.6 Satellator ......................
  • Page 4 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 ..............
  • Page 5 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 ....................
  • Page 6 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..............

  • Page 7: Section 1-Getting Acquainted

    I NFORMATION Section 1—Getting Acquainted This section provides a general description of the FM500 trans- mitter and introduces you to safety conventions used within this document. Review this material before installing or operating the transmitter. Getting Acquainted 1–1...

  • Page 8: Your Transmitter

    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.

  • Page 9: Applications And Options

    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"...

  • Page 10: Stand-Alone

    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 configura- tion.

  • Page 11: Translator

    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.

  • Page 12: Satellator

    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 fre- quency in Morse Code. This option is intended for use in satellite-fed networks. Transmitters equipped in this fashion are often known as "satellators."...

  • Page 13: Transmitter/Exciter Specifications

    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) 50 Ω RF Output Impedance Frequency Stability Meets FCC specifications from 0-50 degrees C 50 kΩ bridging, balanced, or 600 Ω Audio Input Impedance Audio Input Level Selectable for –10 dBm to +10 dBm for...
  • Page 14 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...

  • Page 15: Receiver Specifications

    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 >...

  • Page 16: Safety Considerations

    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.

  • Page 17: Section 2-Installation

    Section 2—Installation This section provides important guidelines for installing your trans- mitter. Review this information carefully for proper installation. Installation 2–1...

  • Page 18: Operating Environment

    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. Illustration 2-1 FM 500 PA Tray Mounting Screws Remove screws and spacers from five locations.

  • Page 19: Power Connections

    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.
  • Page 20 Replace the bottom cover, and the front grill. 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...

  • Page 21: Frequency (Channel) Selection

    PA Temperature Power Stereo Supply DC Volts +6 dB +12 dB Voltmeter Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 2–5 Top Cover Removed MEGAHERTZ Illustration 2–6 RF Exciter Board Frequency Selector Switches Installation 2–5...

  • Page 22: Modulation Compensator

    Modulation Compensation Pot Setting 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...

  • Page 23: Rf Tuning Adjustments

    PA DC Volts Wide Band PA Temp PA DC Amps PA Temperature Power Stereo Supply DC Volts +6 dB +12 dB Voltmeter Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 2–8 Receiver Module Switches Installation 2–7...
  • Page 24 107.2 92.2 97.3 102.3 107.3 97.4 102.4 92.3 107.4 97.5 102.5 92.4 107.5 92.5 97.6 102.6 107.6 97.7 102.7 92.6 107.7 92.7 97.8 102.8 107.8 97.9 102.9 92.8 107.9 92.9 108.0 Table 2–1 Receiver Frequency Selection 2–8 FM500 User's Manual...

  • Page 25: Rf Connections

    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...

  • Page 26: Audio Input Connections

    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...

  • Page 27: Sca Input Connections

    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.

  • Page 28: Audio Monitor Connections

    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...

  • Page 29: Program Input Fault Time-Out

    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).
  • Page 30 Fault Summary (line goes high if any fault light is activated.) Meter PA Temperature (5 volts = 100 degrees C.) Meter PA Current (1 volt = 10 amperes DC.) Table 2–3 Remote I/O Connections Illustration 2–15 Remote I/O Connector (outside view) 2–14 FM500 User's Manual...

  • Page 31: Section 3-Operation

    Section 3—Operation This section provides general operating parameters of your transmitter and a detailed description of its front panel display. Operation 3–1...

  • Page 32: Initial Power-Up Procedures

    Set the Input Gain switches for mid-scale wideband gain reduction on an average program level (see section 3.4). Set the Processing control (see section 3.5; normal setting is “50”). Set the Stereo-Mono switch to Stereo (see section 3.6). Turn on the Carrier switch. 3–2 FM500 User's Manual...
  • Page 33 Check the following parameters on the front panel multimeter: RF Power should be 500–550 watts. SWR should be less than 1.25 (A reading greater than 1.25 indicates an antenna mismatch). ALC should be between 4.00 and 6.00 volts. PA DC Volts should be 46–56 volts. (Varies with antenna match, power, and frequency.) PA DC Amperes should be 12–16 amps.

  • Page 34: Power Switches

    (See section 2.12.) Carrier Switch Fault Modulation Carrier Over Lock Input PA DC PA Temp Power Stereo Pilot Mono RF Output FM500 FM BROADCAST TRANSMITTER Power Switch Illustration 3–2 Front Panel Power Switches 3–4 FM500 User's Manual...

  • Page 35: Front Panel Bar-Dot Displays

    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...

  • Page 36: Processing Control

    Processing to “0” or “10”. 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...

  • Page 37: Rf Output Control

    Voltmeter Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 3–3 Digital Multimeter 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.

  • Page 38: Fault Indicators

    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...

  • Page 39: Section 4-Principles Of Operation

    ta ci n ha 'e n n ha ta ci 'e n n ha ta ci 'e n 'e n ta ci ta ci ta ci n ha 'e n ta ci Section 4—Principles of Operation This section discusses the circuit principles upon which the transmitter functions.

  • Page 40: Part Numbering

    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...

  • Page 41: Audio Processor Circuit Board

    Pilot Mono RF Output Input Gain Processing 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.

  • Page 42: Stereo Generator Circuit Board

    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 FM500 User's Manual...
  • Page 43 Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER 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%.

  • Page 44: Rf Exciter Circuit Board

    Wide Band PA Temp PA DC Amps PA Temperature Power Stereo Supply DC Volts +12 dB +6 dB Voltmeter Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 4–4 RF Exciter Board 4–6 FM500 User's Manual...
  • Page 45 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.

  • Page 46: Metering Circuit Board

    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...

  • Page 47: Motherboard

    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.

  • Page 48: Display Circuit 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...

  • Page 49: Voltage Regulator Circuit Board

    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.

  • Page 50: Power Regulator Circuit Boards

    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...

  • Page 51: Rf Amplifier

    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.

  • Page 52: Rf Output Filter & Reflectometer

    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...
  • Page 53 Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 4–6 Receiver Board (optional) 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;...
  • Page 54 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...

  • Page 55: Section 5-Adjustments And Tests

    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 proce- dure.

  • Page 56: Audio Processor Adjustments

    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...

  • Page 57: Stereo Generator Adjustments

    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.

  • Page 58: Frequency Synthesizer Adjustments

    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...

  • Page 59: Metering Board Adjustments

    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.

  • Page 60: Motherboard Adjustments

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

  • Page 61: Performance Verification

    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...

  • Page 62: Carrier Frequency

    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...

  • Page 63: Audio Frequency Response

    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.

  • Page 64: Main Channel Into Sub

    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...

  • Page 65: Section 6-Reference Drawings

    Section 6—Reference Drawings The illustrations in this section may be useful for making adjust- ments, taking measurements, troubleshooting, or understanding the circuitry of your transmitter. Reference Drawings 6–1...

  • Page 66: Views

    RF Output Composite Ground Audio Monitors Audio Inputs RF Output Monitor Input SCA IN COMPOSITE IN MONITOR RIGHT LEFT/MONO REMOTE I/O FUSE Power Amplifier SCA Inputs Remote I/O AC Power In and Cooling Illustration 6–2 Rear View 6–2 FM500 User's Manual...
  • Page 67 PA Temperature Power Stereo Supply DC Volts +6 dB +12 dB Voltmeter Pilot Mono RF Output Input Gain Processing FM500 ® FM BROADCAST TRANSMITTER Illustration 6–3 Chassis Top View Power Amp Fans Power Transformer Voltage Regulator Power Board Distribution Board...

  • Page 68: Board Layouts And Schematics

    Board Layouts and Schematics Illustration 6–5 Audio Processor Board 6–4 FM500 User's Manual...
  • Page 69 R9 1K L VU GAIN REDUCTION VOLTS P-P THRESHOLD 24.9K 10DB 24.9K GAIN: U5, Pin 2 to U8, Pin 2 20DB (No Hi-band gain reduction) L IN1 +12V 30.1K TL072 .047 FLAT +12V L LP2 25uSEC A=0.33 AD632 50uSEC A=0.67 100PF 100K L LP1...
  • Page 70 Illustration 6–6 Stereo Generator Board 6–6 FM500 User's Manual...
  • Page 71 +12V R54 24.9K 1% R55 24.9K EXT RTN EXTERNAL COMPOSIT IN (3.5V P-P for 75KHz) 3.9K 24.9K 1% EXT IN TL072 24.9K -12V (3.5V P-P for 7.5KHz) 0 OHM .0027 SCA IN POLY 15.2 KHz LOW-PASS FILTER 0 OHM 100PF (8th ORDER ELLIPTICAL) INPUT L +12V...
  • Page 72 SEE NOTE 10 TOP SIDE COMPONENT MAP, FM-VFM EXCITER M200440PT-A.DOC PWB: 200440-PWB-A.PCB UNCONTROLLED SIZE DWG. NO. 200440-PWA THESE DRAWINGS, SPECIFICATIONS AND ASSOCIATED UNLESS OTHERWISE MARKED IN RED BY CM AS A ELECTRONIC FILES ARE THE PROPERTY OF INTERNATIONAL CONTROLLED COPY, COPIES OF THESE DOCUMENTS AND RADIO AND ELECTRONICS CORP., AND SHALL NOT BE REPRODUCED, COPIED, OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF ASSOCIATED ELECTRONIC FILES ARE UNCONTROLLED AND...
  • Page 73 REV. DWG. NO. 200440-SCH REVISION HISTORY APPROVALS E . C . N. DESCRIPTION DATE FOR PROTOTYPE 01-04-02 MODIFIED PER MIKE SENEKI 02-06-02 CHG'D R18 PER EAD MRH01. R18 WAS 91K OHM. U5 WAS C 6900-5 06-24-02 246 A-G R8 WAS 1.0K OHM. 05-23-03 PRODUCTION RELEASE 01-29-04...
  • Page 74 Illustration 6–8 RF Metering Board (Add 400 to component designators for schematic reference) 6–10 FM500 User's Manual...
  • Page 75 +12V D416 POWER CAL C426 -6.9V 1.0UF TL074 LM394 1.0UF C429 1.0UF R417 D415 R472 (2.5VDC at 100W) R469 3.3K FM500 1N6263 10K POT H -12V U407C (.135V) C427 METERING R473 C428 U406C J2-9 Q406 TL074 R479 1.0UF C419 R471 TL074 1.0UF...
  • Page 76 6 - 12 FM30/FM100/FM250 User's Manual...
  • Page 77 DWG. NO. REV. 201207-SCH REVISION HISTORY APPROVALS E . C . N. DESCRIPTION DATE FOR PROTOTYPE 02-05-05 +12V AUDIO PROCESSOR SHUNT FAN- 4.7K +12V ALC / METERING RF EXCITER +12V HEADER 2 .156 +5.00V +12V TL072 OPEN TEMP Vout -12V HEADER 6X1 .156 REF02 OPEN...
  • Page 78 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 Short Short Short...
  • Page 79 D 8167-5 Illustration 6–10 Display Board (Add 600 to component designators for schematic reference) 6–14 FM500 User's Manual...
  • Page 80 U602 DL601-610 JP601 LM3915 +12V MODE U613B +12V R602 TL072 100K +12V R604 RADJ R645 Q604 C611 1.2K 2N5087 DL621-625 +12V ROUT D601 DL648-658 R601 C628 C626 1N4148 JP603 5.00V 1.0UF R644 R603 1.0UF L VU JUMPER 50mA R646 U608 FOR BAR R652 LM3914...
  • Page 81 6 - 17 Reference Drawings...
  • Page 82 CARR SW R701 U703C 4.7K R702 CROWN INTERNATIONAL, INC. /CARRIER OFF +12V 1718 WEST MISHAWAKA ROAD ELKHART, IN. 46517 PHONE (219) 294-8000 R733 74HC14 4.7K R723 R703 D701 4.7K FM VOLTAGE REGULATOR 1N4148 U703A U703B D702 R704 1N4148 /AUTO CARRIER DRAWN 8-25-97 APPROVED BY :...
  • Page 83 Illustration 6–12 Power Regulator Board 6–18 FM500 User's Manual...
  • Page 84 R804 OPEN Q803 10.0K 1% 2N5087 C818 R822 .1UF DZ802 1N966B 16V UNIT CONFIGURATION 22.0K NOTES: JUMPER FM30 FM100 FM250 FM500 EURO HARRIS M1 HARRIS M2 UNLESS OTHERWISE Q802 OPEN OPEN OPEN OPEN SHORT OPEN OPEN SHORT SPECIFIED: R814 MPSA56...
  • Page 85 Illustration 6–13 Power Amplifier (Add 1100 to component designators for schematic reference) 6–20 FM500 User's Manual...
  • Page 86 Q1101 BLF278 R1116 C1113 C1112 T1111P 0.01 0.01 C1125 R1119 C1116 R1117 60PF 27PF T11S C1138 C1123 C1124 0.068 0.01 0.01 T1121 C1114 C1115 0.01 0.01 R1114 R1115 PA INPUT BD PA OUTPUT BD FM500 POWER AMPLIFIER Reference Drawings 6–21...
  • Page 87 Illustration 6–14 RF Output Filter (Add 1200 to component designators for schematic reference) 6–22 FM500 User's Manual...
  • Page 88 (455MHz) (195MHz) (176MHz) (252MHz) C1211 C1206 C1208 C1204 C1202 47PF NP0 R1203 R1202 9.3PF 5.13PF 1.35PF 7.1PF RF OUT RF IN L1202 L1203 L1205 L1204 C1209A L1201 90.5NH 94.1NH 87.5NH 77.9NH 250NH R1205 R1204 C1201 C1203 C1205 C1209 C1207 C1219 15.4PF 40.9PF 37.7PF...
  • Page 89 6 - 25 Reference Drawings...
  • Page 90 0.01 OPEN OPEN OPEN OPEN FOR FM30: 33uH Vout 20VDC INPUT APPLIED HERE. FOR FM100 AND FM250: 18V OPEN FOR FM500: 20V FOR FM30: FEED POINT FROM PWR. REGULATOR PWB. OPEN +24VDC OPEN 4.7K OPEN 1/2W 2.7K NTC 1N753A 0.01...
  • Page 91 FM500 CHASSIS WIRING Mother Board Voltage Regulator Unreg Board FM500 Chassis Wiring C.Donner 2-23-98 CROWN BROADCAST HD505 Metering Ribbon Cable Board HD701 HD 502 HD503 HD504 J 403 HD561 HD702 Ribbon Ribbon J 602 J 601 Display Board Reflectometer Feed-Thru...
  • Page 92 Illustration 6–16 Receiver Board Reference Drawings 6–27...
  • Page 93 Receiver 6–28 FM500 User's Manual...

  • Page 94: Section 7-Service And Support

    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...

  • Page 95: 7.1 Service

    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.
  • Page 96 (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.
  • Page 97 Notes: 7–4 FM500 User's Manual...

  • Page 98: Factory Service Instructions

    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:...

  • Page 99: Appendix

    Appendix Transmitter Output Efficiency FM500 User's Manual Appendix–1...
  • Page 100 Transmitter efficiency output RF Power Output Efficiency-FM500 PADC Volts PADC Amps RF Power Efficiency 51.3 13.91 48.3 13.29 45.5 12.74 42.7 12.14 39.4 11.46 36.0 10.68 33.0 10.00 29.6 9.25 25.4 8.28 21.1 7.29 Power measurements were made at 97.1 MHz. Voltage and current measurements were taken from the unit's built-in metering.

  • Page 101: Glossary

    Glossary The following pages define terms and abbreviations used throughout this manual. Glossary G–1...
  • Page 102 The unwanted changes in signal wave shape that occur during transmission between two points. Digital Panel Meter EPROM Erasable Programmable Read Only Memory Electrostatic Discharge; a discharge that is potentially destructive to sensitive electronic components. G–2 FM500 User's Manual...
  • Page 103 exciter (1) A circuit that supplies the initial oscillator used in the driver stage. (2) A transmitter con- figuration which excludes stereo generation and audio processing. Field-Effect Transistor frequency synthesizer A circuit that generates precise frequency signals by means of a single crystal oscillator in conjunc- tion with frequency dividers and multipliers.
  • Page 104 (or vice versa). subcarrier A carrier signal which operates at a lower fre- quency than the main carrier frequency and which modulates the main carrier. suppression The process used to hold back or stop certain frequencies. G–4 FM500 User's Manual...
  • Page 105 Standing-Wave Ratio; on a transmission line, the ratio of the maximum voltage to the minimum voltage or maximum current to the minimum current; also the ratio of load impedance to intended (50 ohms) load impedance. Total Harmonic Distortion translator A transmitter designed to internally change an FM signal from one frequency to another for retransmission.

  • Page 106: Index

    Index Symbols bias set 5–6 booster 19–kHz transmitter use 1–4 level adjustment 5–3 broadband. See audio: broadband phase adjustment 5–3 bypass audio processor 2–12, 4–9 AC. See power: input ALC 3–3, 3–8, 4–8 cables altitude audio input 2–10 operating range 1–8 carrier 4–9, 5–8 amperes automatic turnoff 2–13, 3–8, 5–6, 5–...
  • Page 107 3–5 wideband 3–5, 5–6 control 4–9 input fault audio connections 2–10 indicators 4–10 composite 2–11 input 3–8 fault 3–8 lock 3–8 gain switches 3–5 power 3–8 program servicing 3–8 fault 2–13 SWR 3–8 SCA connection 2–11 Index–2 FM500 User's Manual...
  • Page 108 pilot indicator 3–5 power labels 1–10 AC supply 4–13 LEDs 3–5, 4–10 AC voltage selection 2–3 line voltage 2–3 amplifier lock reference drawings 20 status 4–7 fault 3–8 lock fault 3–8 input 1–8, 2–3 FCC guidelines 5–10 output 1–3, 1–7, 5–8 display 3–7 metering 1–2 output filter 4–14...
  • Page 109 3–5, 5–6 circuit description 4–4 reference drawings 6 subcarrier 5–10 XLR connectors 2–10 38–kHz 5–10 suppression subcarrier 1–7 switches carrier 3–2, 3–4, 5–5 input gain 3–5, 3–6 Normal-Bypass 2–12, 4–9 power 3–4 receiver 2–7 stereo-mono 3–2, 3–6 Index–4 FM500 User's Manual...

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