Disc-Crown FM500 Manual

Disc-Crown FM500 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
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 ...................................................................................................... 1–6
1.3 Transmitter/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 Warnings .................................................................................................... 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 Tuning 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
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.15
iv
Part Numbering ................................................................................................. 4–2
Audio Processor Circuit Board .......................................................................... 4–3
Stereo Generator Circuit Board .......................................................................... 4–4
RF Exciter Circuit Board .................................................................................... 4–6
Metering Circuit Board ...................................................................................... 4–8
Motherboard ..................................................................................................... 4–9
Display Circuit Board ....................................................................................... 4–10
Voltage Regulator Circuit Board ...................................................................... 4–11
Power Regulator Circuit Boards ...................................................................... 4–12
RF Driver ......................................................................................................... 4–12
RF Amplifier .................................................................................................... 4–13
Chassis ........................................................................................................... 4–13
RF Output Filter & Reflectometer ..................................................................... 4–14
Receiver Circuit Board Option ......................................................................... 4–14
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 PA 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.
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
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
RF Exciter
Stereo Generator
Low-pass Filter
Metering
Audio Processor
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Pilot
Input Gain
Mono
Processing
®
RF Output
FM500
FM BROADCAST TRANSMITTER
Illustration 1–2 Standard (Transmitter) Configuration
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.
RF IN
Receiver Module
(option)
Stereo
Generator
Low-pass Filter
RF Out
RF Exciter
Metering
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
Pilot
FM500
FM BROADCAST TRANSMITTER
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).
Low-pass Filter
RF Out
FSK IDer
(option)
Stereo
Generator
Audio
Processor
RF Exciter
Metering
Modulation
Fault
Audio Input
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
Pilot
FM500
FM BROADCAST TRANSMITTER
Illustration 1–4 Transmitter with FSK IDer Option
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
1–8
29.5 kg (65 lbs);
31.8 kg (70 lbs) shipping weight
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.
Type of Hazard
WARNING
Severe shock hazard!
Pictorial Indication
of Hazard
Turn power off and
wait approximately 1
minute for capacitors
to discharge before
handling them.
Explanation of
Hazard
Illustration 1–5 Sample Hazard Alert
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
#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
115V
230V
Illustration 2–2
Opening the Power Connector Cover
Installation
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
Frequency Selection
Rotary Switches
RF Exciter
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
RF Output
Pilot
FM500
®
FM BROADCAST TRANSMITTER
Illustration 2–5 Top Cover Removed
MEGAHERTZ
.1
.01
Illustration 2–6 RF Exciter Board Frequency Selector Switches
Installation
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
RF IN
Stereo
Receiver
Generator
Module
RF Exciter
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
Pilot
FM500
FM BROADCAST TRANSMITTER
Illustration 2–8 Receiver Module Switches
Installation
2–7
Frequency
SW1 SW2
Frequency
SW1
SW2
Frequency
SW1
SW2
Frequency
SW1
SW2
87.9
88.0
88.1
88.2
88.3
88.4
88.5
88.6
88.7
88.8
88.9
89.0
89.1
89.2
89.3
89.4
89.5
89.6
89.7
89.8
89.9
90.0
90.1
90.2
90.3
90.4
90.5
90.6
90.7
90.8
90.9
91.0
91.1
91.2
91.3
91.4
91.5
91.6
91.7
91.8
91.9
92.0
92.1
92.2
92.3
92.4
92.5
92.6
92.7
92.8
92.9
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
0
8
1
9
1
9
1
9
1
9
1
9
1
9
1
9
1
9
1
9
1
93.0
93.1
93.2
93.3
93.4
93.5
93.6
93.7
93.8
93.9
94.0
94.1
94.2
94.3
94.4
94.5
94.6
94.7
94.8
94.9
95.0
95.1
95.2
95.3
95.4
95.5
95.6
95.7
95.8
95.9
96.0
96.1
96.2
96.3
96.4
96.5
96.6
96.7
96.8
96.9
97.0
97.1
97.2
97.3
97.4
97.5
97.6
97.7
97.8
97.9
9
1
9
1
9
1
9
1
9
1
9
1
9
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
2
A
3
B
3
B
3
9
A
A
B
B
C
C
D
D
E
E
F
F
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
A
B
B
C
C
D
D
E
E
F
F
0
0
1
1
2
98.0
98.1
98.2
98.3
98.4
98.5
98.6
98.7
98.8
98.9
99.0
99.1
99.2
99.3
99.4
99.5
99.6
99.7
99.8
99.9
100.0
100.1
100.2
100.3
100.4
100.5
100.6
100.7
100.8
100.9
101.0
101.1
101.2
101.3
101.4
101.5
101.6
101.7
101.8
101.9
102.0
102.1
102.2
102.3
102.4
102.5
102.6
102.7
102.8
102.9
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
3
B
4
C
4
C
4
C
4
C
4
C
4
C
4
C
4
C
4
C
4
C
4
C
4
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
A
B
B
C
C
D
D
E
E
F
F
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
A
B
103.0
103.1
103.2
103.3
103.4
103.5
103.6
103.7
103.8
103.9
104.0
104.1
104.2
104.3
104.4
104.5
104.6
104.7
104.8
104.9
105.0
105.1
105.2
105.3
105.4
105.5
105.6
105.7
105.8
105.9
106.0
106.1
106.2
106.3
106.4
106.5
106.6
106.7
106.8
106.9
107.0
107.1
107.2
107.3
107.4
107.5
107.6
107.7
107.8
107.9
108.0
C
4
C
4
C
4
C
4
C
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
5
D
6
E
6
E
6
E
6
E
6
E
B
C
C
D
D
E
E
F
F
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
A
B
B
C
C
D
D
E
E
F
F
0
0
1
1
2
2
3
3
4
4
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
A
B
B
C
C
D
D
E
E
F
F
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
Table 2–1 Receiver Frequency Selection
2–8
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
RFInput Connector
(receiver option only)
RF Output
Monitor
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
RIGHT
MONITOR
COMPOSITE IN
R
LEFT/MONO
L
REMOTE I/O
1
2
3
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
RIGHT
MONITOR
COMPOSITE IN
R
LEFT/MONO
L
REMOTE I/O
1
2
3
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
RIGHT
MONITOR
COMPOSITE IN
R
LEFT/MONO
L
REMOTE I/O
1
2
3
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
RIGHT
MONITOR
COMPOSITE IN
R
LEFT/MONO
L
REMOTE I/O
1
2
3
Remote I/O
Illustration 2–14 Remote I/O Connector
The following table summarizes the Remote I/O pin connections.
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
1
8
15
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
Modulation
Fault
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
Carrier
Power
50
Stereo
40
30
20
Mono
RF Output
Pilot
FM500
FM BROADCAST TRANSMITTER
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 temperature). 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
Modulation
Fault
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
Carrier
Power
50
Stereo
40
30
20
Mono
RF Output
Pilot
FM500
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
Two 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, determined 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.
To 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
Sensitivity
+10 dBm
+4 dBm
-2 dBm
-8 dBm
Switches
+6 dB
+12 dB
Down
Down
Up
Down
Down
Up
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
Two 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.
Digital Multimeter Multimeter Functions
Modulation
Fault
Audio Input
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Multimeter Push-buttons
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
RF Output
®
Pilot
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.
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 PA 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 Volts—Supply voltage of the RF power amplifier.
PA DC Amps—Transistor drain current for the RF power amplifier.
PA DC Temperature—Temperature 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 motherboard. 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
uesto mondo,
in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
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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
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
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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in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
madiciamo che
se scrivendo con
ma
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 CMOS Cookbook by Don Lancaster (Howard
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
FM500 User's Manual
Stereo Generator
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
RF Output
®
Pilot
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%.
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
uesto mondo,
in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
madiciamo che
se scrivendo con
ma
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
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
RF Output
®
Pilot
FM500
FM BROADCAST TRANSMITTER
Illustration 4–4 RF Exciter Board
4–6
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
uesto mondo,
in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
madiciamo che
se scrivendo con
ma
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
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
Pilot
FM500
FM BROADCAST TRANSMITTER
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
uesto mondo,
in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
madiciamo che
se scrivendo con
ma
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
uesto mondo,
in rqse, uno si dice
fo diciamo che
se scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
ma
scrivendo con
maquesto mondo,
in se, uno si dice
for diciamo che
se scrivendo con
a
m
scrivendo con
maquesto mondo,
in se, uno si dice
for
diciamo che
se scrivendo con
madiciamo che
se scrivendo con
ma
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
RF IN
Receiver Module
(option)
Stereo
Generator
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
®
RF Output
Pilot
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; 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
Trim 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
19 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. (Do not connect to the 10.24–MHz clock
circuit.)
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 carrier turned off, look at the DC voltage at the right end of R413 on 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.
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
Take 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.
Test 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
Digital Multimeter
Modulation
Fault
Audio Input
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
+6 dB
+12 dB
Carrier Switch
Carrier
Power
50
Stereo
Supply DC Volts
-12
Modulation
Indicators
Multimeter Select
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
Pilot
RF Output
FM500
®
FM BROADCAST TRANSMITTER
Audio Processor
Processing Control
Input Level
Indicators Input Gain
Stereo/Mono Switch
Switches
Fault Indicators
Power Switch
Relative RF
Voltage Out
Illustration 6–1 Front View
RF Output
RF Output
Monitor
Composite
Input
Ground
SCA IN
Audio Monitors
MONITOR
COMPOSITE IN
R
Audio Inputs
RIGHT
LEFT/MONO
L
REMOTE I/O
1
2
3
FUSE
Power Amplifier
and Cooling
AC Power In
SCA Inputs
Remote I/O
Illustration 6–2 Rear View
6–2
FM500 User's Manual
RF Exciter
Stereo Generator
Low-pass Filter
Metering
Audio Processor
10
2
High Band
RF Power
High
Expand
2
Compress
SWR
20
ALC
PA DC Volts
Wide Band
PA DC Amps
-6
SWR
Over
Lock
100
Input
90
PA DC
80
PA Temp
70
60
PA Temperature
Supply DC Volts
-12
Modulation
Fault
Audio Input
+6 dB
+12 dB
Carrier
Power
50
Stereo
40
Voltmeter
30
-18
20
Low
Input Gain
Mono
Processing
RF Output
Pilot
FM500
®
FM BROADCAST TRANSMITTER
Illustration 6–3 Chassis Top View
Power Amp
Fans
Power Transformer
Voltage Regulator
Board
Power
Distribution
Board
Power Regulator
Boards
Filter Capacitors
front of transmitter
Illustration 6–4 Chassis Bottom View
Reference Drawings
6–3
6.2
Board Layouts and Schematics
Illustration 6–5 Audio Processor Board
6–4
FM500 User's Manual
R9 1K
L VU
L IN1
R4
24.9K
1
C3
1.0
R2
1K
R6
24.9K
1
+12V
C1
100PF
L IN2
R8
30.1K
1
C4
1.0
L LP2
7
5
X
3
Y
16
8
20K
R IN1
C15
1.0
R40
1K
R42
24.9K
R IN2
C16
1.0
R41
1K
2
R43
24.9K
8
C18
.047
2
U4A
TL072
1
3
7
4
3
7
9
4
1
C14
100PF
R45
24.9K
U2B
TL072
R33
10K
2
U6
13
12
-12V
10
11
D8
R58
11.3K
1
3
PRE-EMP.
R123
50K
11
3
R88
10M
-5VDC at 0DB GR
4.1V at 20 DB GR
2
IN
U17
4
GND
C38
1.0
5
TRM
+5V
C46
0.1
R121
10.0K
1
R122
100
VSS
-5V
C39
1.0
8
7
6
5
8 C1
7 B2
6 E3
4
5
1
2
3
4
D13
8
2
C48
0.1
C41
1.0
2
4
6
8
10
12
14
16
18
20
J2
L LP1
L LP2
R LP1
R LP2
RECEPT 10X2
L OUT
10
8
6
4
2
RECEPT 5X2
9
7
5
3
1
R105
1M
8
R101
10K
D16
2
1
3
U14A
TL072
1K
4
R106
1K
R76
10K
C30
1.0
D15
D14
YEL
4
C35
1.0
D17
D18
560
TEST
.25V/DB
R99
Q3
R77
3.3K
2N5210
R107
10K
-12V
D21
-12V
3.3K
-5V
R111
49.9K
1
J3
R OUT
3mV/DB
R100
120
D20
C25
100PF
J1
1
3
5
7
9
11
13
15
17
19
8
7
6
5
C20A
OPEN
-12V
L IN1
L IN2
R IN1
R IN2
1 C8
2 B7
3 E6
4
5
R93
10K
R92
3
U13A
TL072
C45
0.1
-12V
C32
100PF
R96
20.0K
1
1
2
3
4
R91
10M
R75
2.4K
C8A
OPEN
2
4
6
8
+12V
3mV/DB
R80
3.3K
C43
0.1
1
3
5
7
R104
OPEN
R97
49.9K
1
+12V
1
C44
0.1
C42
0.1
R103
3.3K
C34
OPEN
R95
20.0K
1
Q7
LM394
+12V
C40
1.0
JP1
HEADER 4X2
FLAT
25uS
50uS
75uS
6
R82
120
+12V
POT LOCATED
ON DISPLAY PCB
4
R79
49.9K
1
-5V
5
U18B
TL072
C33
.047
R94
20.0K
1
PROC C
Q5
LM394
7
7
D12
R109
3.3K
C26
100PF
VEE
C37
.01
6
SW1B
5
C47
0.1
R78
91K
R118
10.0K
1
D11
C49
47PF
R650
100K
R86
3.3M
C28
1.0
POLY
-12V
REF02
4
U18A
TL072
4
LIGHT
+5V
VDD
+5V
R120
100
1
3
+5V
+5.00V
8
3
6
VO
U12A
TL072
-12V
PROC B
R89
330K
D19
8
2
-12V
PROC A
10K
C36
.01
+12V
HEAVY
R85
3.3K
R83
+12V
U10A
4 TL072
R68
12K
R69
10K
-5V
C27
.047
R73
24.9K
R72
24.9K
1
-12V
C29
0.1
R87
3.3K
SW1A
8
2
R90
1K
TL072
1
R119
4.7K
3
1
-12V
C50
47PF
-5V
3
10
R66
49.9K
1
U7A
+12V
R81
1K
2
U9
Q2
2N5087
2
C22
.0027
POLY
1
13
12
R65
10K
8
3
R OUT
R71
240K
D10
7
9
R61
24.9K
+12V
R74
1K
C23
220PF
14 AD632
R64
OPEN
D7
C20
1.0
POLY
C24
0.1
R70
24.9K
+12V
R62
100K
R60
24.9K
-12V
R53
499
1
1
D6
D5
D9
2
2
U12B
TL072
7
6
-12V
R67
24.9K
4
-12V
U10B
TL072
5
(+/-5.0V PK)
5
U2A
TL072
R37
24.9K
+5V
R52
499
1
6
5
R32
12K
R59
100K
1
14 AD632
R50
2.0K
1
R47
30.1K
1
7
+12V
1
R51
1.0K
1
8
R30
49.9K
1
D4
R36
24.9K
6
10
3
L OUT
R35
240K
-5V
R39
1K
2
11
7
R46
360K
+12V
C13
100PF
R25
24.9K
1
1
U8
13
12
U7B
TL072
R LP1
R44
24.9K
R29
10K
5
R LP2
1
R28
OPEN
Q1
2N5087
C10
.0027
POLY
D3
R38
1K
+12V
C17
.047
1K
7
9
PRE-EMP.
D1
C12
0.1
1
C11
220PF
1 4 AD632
6
R98
100
R VU
R31
24.9K
1
+12V
R26
100K
R24
24.9K
1
-12V
R49
R48
D2
R22
11.3K
1
3
R56
75K
1
74HC4052
/+12DB
/+6DB
R34
24.9K
10
R17
360K
R16
499
1
1
5
2
4
6
10
9
Y0
Y1
Y2
Y3
INH
A
B
7
R11
47K
R10
47K
12
14
15
11
X0
X1
X2
X3
+5V
-5V
U5
C8
1.0
POLY
R15
499
1
U3
13
1
2
R14
1.0K
1
R12
20K
1
FLAT A=0
25uSEC A=0.33
50uSEC A=0.67
75uSEC A=1.0
(+/-5.0V PK)
11
C6
.047
R23
100K
1
13
12
5
R13
2.0K
1
-12V
+5V
7
9
7
R1
100
+5V
AD632
14
6
U1A
TL072
4
GAIN: U5, Pin 2 to U8, Pin 2
(No Hi-band gain reduction)
U4B
TL072
L LP1
1
3
VOLTS P-P
1.1
3.5
11
+12V
2
R7
24.9K
1
C2
100PF
R20
75K
1
C5
.047
6
8
R5
24.9K
1
R3
1K
U1B
TL072
GAIN REDUCTION
THRESHOLD
10DB
20DB
1
3
5
7
9
11
13
15
17
19
21
23
25
2
4
6
8
10
12
14
16
18
20
22
24
26
RECEPT 13X2
+12V
-12V
/+6DB
/+12DB
L VU
R VU
+5.00V
PROC A
PROC B
PROC C
BR GR
HI GR
TEST
R112
49.9K
1
C31
100PF
R115
49.9K
1
+12V
8
2
6
7
6
1
5
U13B
TL072
5
U15B
TL072
R113
100
R84
49.9K
1
6
.25V / DB
BR GR
8
6
7
5
U14B
TL072
U15A
TL072
1
-12V
R110
49.9K
1
NOTES :
1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.
U16B
TL072
R117
100
0.25V / DB
HI GR
3
7
5
4
+12V
2
3
7
R116
49.9K
1
R102
49.9K
1
R114
49.9K
1
4
-12V
U16A
TL072
SCM, FM AUDIO PROCESSOR
103202
2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED.
3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED.
AUDIO PROCESSOR
Reference Drawings
6–5
Illustration 6–6 Stereo Generator Board
6–6
FM500 User's Manual
+12V
R54 24.9K 1%
EXT RTN
R55 24.9K
C26
1.0
EXTERNAL COMPOSIT IN
(3.5V P-P for 75KHz)
EXT IN
8
2
R56
24.9K
1%
4
R57
24.9K
C5
.0027
POLY
15.2 KHz LOW-PASS FILTER
(8th ORDER ELLIPTICAL)
1
2
3
4
5
6
7
LPIN L
+6V
U1
3
R7
3.65K
1%
-6V
R1
330
R38
1M
2
8
R5
1K
R12
10.0K
1%
U3A
TL072
1
3
C6
1030PF
R9
2K 1%
+12V
4
R6
499
1%
LPOUT L
C1
.0027
POLY
C4
0 OHM
+12V
2
14
13
12
11
10
9
8
D4
C3
100PF
R3
0 OHM
JP1
1
INPUT L
LTC1064-1
D3
C27
1.0
-12V
(3.5V P-P for 7.5KHz)
SCA IN
R58
3.9K
1
U6A
TL072
3
-12V
2
R10
2.49K 1%
R8
4.99K 1%
1
C9
.0027 POLY
8
4
3
U5
74HC4053
D5
-12V
75
1
2
3
4
5
6
7
LPIN R
U2
1
INPUT R
C7
.01 POLY
3
2
14
13
12
11
10
9
8
R19
3.65K 1%
R2
330
R39
1M
5
C10
1030PF
R22
2.49K
1%
R20
4.99K
1%
7
C23
1.0
D1
1N5818
3
D2
1N5818
+5.00V
U4B
TL072
JP4
14
R28
243K 1%
1
+6V
2
3
U10A
R204
1K
R33
10.0K 1%
1.52 MHz
R27
100
C29
1.0
5
R23
24.9K
R37
1K
R29
100K 1%
R25
1M
3.8 MHz
Y1
7.6MHZ
2
1
C13
56PF
NPO
C12
5.5—18PF
C14
33PF
NPO
R34
49.9K
1%
13
U7F
14
7
U7A
74HC04
U8A
74HC390
12
1
4
2
CK
CK
CLR
1
0
16
Q
Q
QC
QD
15
12
3
5
6
7
14
13
11
10
9
QA
QB
QC
QD
CK
CK
CLR
U9B
74HC393
13
8
U8B
74HC390
12
304 Khz
C
L
K
A
14
A
11
10
9
8
Q
Q
QC
QD
CLR
7.6 MHz
CLK
QA
QA
QB
QC
QD
5
0
/
A
1 V V G
0 D A N
0 - - D
1
1
1.9MHz
U9A
74HC393
3
4
5
6
L V V S
S D A A
H + + /
B
C
L
K
B
7
9 8 7 6
1 1 1 1
2 3 4 5
5
4
3
2
S
1
A
I
N
V
A
H
P
A
B
P
A
L
P
A
S
1
B
I
N
V
B
H
P
B
B
P
B
L
P
B
C18
.0027
POLY
1
7
1
8
1
9
R48
4.3K
J1
10
11
-12V
R32
10K
R47
20K
CLR
9
2
8
U10C
R36
49.9K
1%
13
QC
11
U10D
R35
10.0K 1%
C16 0.1
U7B
74HC04
+12V
U7C
74HC04
QD
9
VR1
LM317
1
+12V
OUT
IN
+6V
3
C
C33
1.0UF
6
R49
240
2
R244 10K
U7D
74HC04
1
C35
1.0
IN
OUT
C
X
DRAWN
ELKHART, IN. 46517
Z1
U5X
C36
47UF
MONO
JFL
7-28-97
JB
1
ME
SUPERSEDES
SCALE
NONE
EE
E.C.
PROJ #
MLOWCM0
PE
CHECKED
B
-6V
3
R51
240
2
+5.00V
PHONE (219) 294-8000
X1
X0
VR2
LM337
-12V
LPIN L
LPOUT L
LPIN R
LPOUT R
+5.00V
SYNC OUT
SCM, FM STEREO GENERATOR
STEREO
-12V
Current at U211 pin 17.
1718 WEST MISHAWAKA ROAD
U5Y
10
GND
RECEPT 12X1
CROWN INTERNATIONAL, INC.
U205 Connections
U7E
74HC04
11
NOTES :
_______
_______
MON L
MON R
-6V
C34
1.0UF
R50
910
8
19 KHz
3.3VP-P
1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.
2. ALL CAPACITORS ARE IN MICROFARADS UNLESSOTHERWISE SPECIFIED.
3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED.
EXTERNAL COMPOSITE
QB XOR QD
QC XOR QD
C20
.0027
POLY
C32
1.0
4
1
2
3
4
5
6
7
8
9
10
11
12
R43
33K
R41
510
C19
0.1
R31
100K
1%
7
5
EXT IN
EXT RTN
SCA IN
COMP OUT
COMP METER
MONO/STEREO
/EXT ENABLE
GND
INPUT L
INPUT R
J2
19 KHZ LEVEL
19 KHZ PHASE
R242 1K
Current at U211 pin 4.
SEPARATION
2
0
R30
243K
1%
74HC86
12
3
1
2
3
4
5
6
7
8
9
10
11
12
3
R46
10K
C21
0.1
9
7
5
3
1
RECEPT 12X1
A
QB
QB XOR QC
-12V
+12V
1
10
QA XOR QC
J3
10
8
6
4
2
RECEPT 5X2
1
13
12
R40
10K
U11
LMF100
1
6
7
9
2
1
1%
U12
B-B 4214
14
38 KHz
3.0VP-P
COMP METER
C37
OPEN
+12V
6
U10B
R17
100
-6V
R13
24.9K 1%
4
R26
1K
7
8
SYNC OUT
C17
0.1
COMP OUT
(•3.85V P-P)
U6B
TL072
R21
10K
C31
1.0
C15
0.1
7
INH
A
B
C
/EXT ENABLE
+6V
R16
100
6
4
5
R53
10K
C11
.01 POLY
C30
1.0
74HC86
+6V
15
Z
Z0
Z1
9
75
14
Y
6
11
10
MONO/STEREO
MON R
5
2
50
R24
100
6
X
Y0
Y1
5
3
1
C24
1.0
X0
X1
2
1
D6
7
U3B
TL072
R18
499
1%
LPOUT R
C2
.0027
POLY
6
R15 (SELECTABLE BY TEST, USE
4.12K OR 4.15K IF NEEDED)
4.02K
1%
R14 1K
16
12
13
JP2
LTC1064-1
OUTPUT
C28
1.0
MON L
U4A
TL072
JP3
2
50
+6V
R11
100
1
3
U206, pin6
Z0
Y
Y0
C
/EXT EN
FILENAME:
STEREO/MONO
A
DO NOT SCALE PRINT
U5Z
Z
Y1
APPROVED BY :
103203A.SCM
NEXT ASM:
REV
DWG. NO.
103203
A
R52
910
STEREO GENERATOR
Reference Drawings
6–7
SEE NOTE 10
TOP SIDE COMPONENT MAP, FM-VFM EXCITER
UNCONTROLLED
UNLESS OTHERWISE MARKED IN RED BY CM AS A
CONTROLLED COPY, COPIES OF THESE DOCUMENTS AND
ASSOCIATED ELECTRONIC FILES ARE UNCONTROLLED AND
ARE FOR REFERENCE ONLY.
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.
M200440PT-A.DOC
PWB: 200440-PWB-A.PCB
SIZE DWG. NO.
B
SCALE:
N/A
REV
200440-PWA
PROJECT #:
509
A
SHEET:
1 OF 1
1
2
3
4
5
DWG. NO.
6
REV.
200440-SCH
A
8
9
E . C . N.
10
11
REVISION HISTORY
DESCRIPTION
REV
12
DATE
DWN
1
FOR PROTOTYPE
01-04-02
DW
2
MODIFIED PER MIKE SENEKI
02-06-02
DW
3
CHG'D R18 PER EAD MRH01. R18 WAS 91K OHM. U5 WAS C 6900-5
06-24-02
DW
246 A-G
4
R8 WAS 1.0K OHM.
05-23-03
DW
277
A
PRODUCTION RELEASE
01-29-04
DW
H
APPROVALS
CHK
CM
PE
H
DW
DP
88-108 MHZ
+8V
+12V
R24
150
+12V
2
MAR-6
C7
.001
R30
10 1
VU5
3
/LOCK
DL1
GREEN
R25
680
+5V
5
37
R33
100
1%
13
12
FSK-R
C1
33PF NPO
C11
C4
1
.001
C13
3900PF
R11
100K
1%
8
U5C
10
R10
100K
1%
MC33284P
13
12
7
9
TP
RA2
RA3
RTC
CLR
VSS
RB0
RB1
RB2
RB3
R1
10.0K
1%
10
9
8
7
6
5
4
3
2
1
D
D2
1N4148
LOAD
DATA
CLK
RP1
100K RPACK
1
2
3
4
5
6
7
8
9
10
9
8
7
6
5
4
3
2
1
R3
150K
18
17
16
15
14
13
12
11
10
RA1
RA0
OSC1
OSC2
VDD
RB7
RB6
RB5
RB4
R13
100K
1%
5
D7
1N4148
+ C27
10/35V
D8
1N4148
C28
R63
39
+8V
R81
10.0K
1%
3
C76
0.1
JP1
JUMPER
C81
1000pF
1
U8A
TL072
2
R83
5.11K 1%
6
5
C78 0.1
E
R84
5.11K 1%
-12V
D5 1N4148
U8B
TL072
7
S
G
Q72
IRFD9120
D
D13
3.9V
+12V
1
PB1
RESET
47/20V
C77
0.1
R80
24.3K 1%
F
TANT.
R14
100K
1%
C5
.001 POLY
R21
100K
1%
C26
.001
+ C61
R65
100K
1%
TANT.
U3
PIC16C61
8
U5B
MC33284P
POLY
9
R20
R18
68K
VU5
U5A
3
1
R82
24.3K 1%
C80
0.1
TP2
-12V
4.5 - 8.0V
680.0
11
MC33284P
D
R87
10K
PWR. CNTRL TILT
R86
C43
1
2
D4
1N4148
RP2
100K RPACK
R89
26.7K 1%
1M
4
QH
CLK
QH
INH
SH/LD
2
15
1
7
CLK
QH
INH
SH/LD
SER
A
B
C
D
E
F
G
H
10
11
12
13
14
3
4
5
6
10
11
12
13
14
3
4
5
6
D1
1N4148
6
7
RF OUT
2
R67
15
1%
R15
100K
1%
A1
C24
33pF NPO
R62
100
1%
C62
220pF
MAR-6
1
R66
150
R64 4.99K
VDD
R2
10.0K
1%
R39
100
1%
C23
.001
VCO61
POS-150
R61
10.0K
1%
C15
0.01
+5V
+5V
U2
74HC165
2
15
1
QH
SER
A
B
C
D
E
F
G
H
9
7
5
3
1
10
8
6
4
2
HEADER 5X2
E
9
U1
74HC165
U5D
R16
100K
1%
D12
1N4148
DATA
HD1
14
C14
.001 POLY
/ENABLE
+5V
R12
1.0K
1%
MC33284P
R8
100
1%
CLOCK
C82
.01
POLY
9
R6
100K
1%
U4E
74HC14
7
5
3
1
R7 10
MC145170
C3
1-10PF
C2
39PF NPO
VDD
C10
.001
C19
.001
1
10.24MHZ
Y1
16
15
14
13
12
11
10
9
16
15
14
13
12
11
10
9
R26
680
3
R4 100K 1%
F
1
2
3
4
5
6
7
8
U4F
74HC14
DL2
RED
LOCK
10
4
1
2
3
Fin 4
5
6
7
8
R38
15
TANT.
8
6
4
2
U6
OSC in
OSC out
11
8
R5
1.0K
1%
C12
1
G
C22
.001
D11
1N4148
+ C21
R88
30.1K 1%
REMOTE FREQUENCY CONTROL
R9
100K
1%
R35 499K
1%
10/35V
C8
1
D6
1N4148
+8V
6
NE5532
VVCO
9
7
5
3
1
LOCK DET.
10
8
6
4
2
PL1
HEADER 5X2
U7B
NE5532
C9
.001
R23
1M
R22
200K
R68
499K
1%
2
U7A
4
G
+5V
2
GND
DATA
CLOCK
LOAD
+5V
1
A2
C44
1
8
C6
100PF
5
4
3
2
1
5
4
3
2
1
SW3
SW4
SW5
C29
1
R90
5
4
3
2
1
SW2
SW1
R19
25K
LF SEP.
+ C30
R17
1K BECKMAN
TP1
10/35V
499 1%
5
4
3
2
1
5
4
3
2
1
C79 0.1
R85
2K
PWR. CNTRL. OFFSET
D14
6.2V 1N753A
TANT.
VR3
LM317
COMPOSITE IN
C41
100PF
+12V
3
R27 10.0K 1%
U4B
74HC14
4
U4A
74HC14
3
2
10/35V
1
R43
1.0K
1%
9
8
5
6
U4D
74HC14
U4C
74HC14
-12V
+12V
Local/Remote
/LOCK
LOCK
FSK-ID-CHAN
C31
.001
C33
33pF
VR2
LM78L05
FSK-R
3
-12V
R45
10K
FSK
+12V
C35
.001
D10
1N4148
UNCONTROLLED
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.
UNLESS OTHERWISE MARKED IN RED INK BY CM AS A
CONTROLLED COPY, COPIES OF THESE DOCUMENTS
INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS
ARE FOR REFERENCE ONLY.
C_L_SHT1_A.DOT REV. A
5
6
7
8
DWN
CHK
CM
PE
DW
01-04-02
DJ
01-05-02
DW
01-05-02
DP
01-05-02
INTERNATIONAL RADIO AND ELECTRONICS CORP.
25166 LEER DRIVE ELKHART, IN. 46514
574-262-8900
WWW.IREC1.COM
TITLE:
SIZE
DISTRIBUTION
9
B
IREC
SCH, FM-VFM RF EXCITER
DWG . NO .
C
K
FILENAME:
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.
C40
1
TANT.
APPROVALS
BAND LIMIT
A
4
+ C39
FSK BAL.
ID
3
+5V
10/35V
AUTO ID
2
REFERENCE DESIGNATORS NOT USED:
1
R46
39K
CH. SEL.
DIRECT FSK
1
OUT
D3
1N4148
GND
GND
RECEPT 13X2
IN
C
C42
.001
R48
1.0K
1%
NOTES :
1. ALL RESISTORS ARE IN OHMS,
1/4W, 5% TOL.
2. ALL CAPACITORS ARE IN MICROFARADS.
2
2
4
6
8
10
R44
10.0K
1%
HD2
HEADER 5X2
1
3
5
7
9
COMPOSITE IN
Frequency Select
TANT.
UNLESS OTHERWISE SPECIFIED:
J1
RF OUT
+ C38
D9
1N4148
C32
.001
Local/Remote
C
10/35V
TANT.
R47
1.0K
1%
+8V
R52
1.27K
1%
10/35V
R40 10.0K 1%
25
23
21
19
17
15
13
11
9
7
5
3
1
R51
237
1%
TANT.
R41 10.0K 1%
+5V
8.26V
1
+ C37
FSK
26
24
22
20
18
16
14
12
10
8
6
4
2
OUT
+ C36
DL3
AMBER
R28 10.0K 1%
R42 10.0K 1%
B
IN
C
+5V
2
C
SCALE :
10
NONE
A
REV
A
200440-SCH
PROJ NO.
11
509
SHEET
1
12
OF
1
D 8169-1
Illustration 6–8 RF Metering Board
(Add 400 to component designators for schematic reference)
6–10
FM500 User's Manual
+12V
PAV
J2-4
C401
.01
R406
100K 1
Parts not loaded:
8
2
+5.00V
U2
1
J4-3
REM PADCV
1.00V = 10VDC
3
C403, 404
DZ401
R402, 403, 404
Q401, 402
U401
LB401
R401
1N4148
D406
R409
100
4
-12V
R410
100
5
(Jumper under board)
C406
.01
R405
2.49K 1
J402
12
13
R416
100K
R425
1M
U405F
74HC14
U3
3
50mv per degree C.
R422
75k
R420
100K 1
C407
.001
R424
100k
8
J4-6
REM PATEMP
2
14
R437
1M
+12V
/LOCK
J4-1
D403
R435
100K
D411
/+28V INH
D410
J2-1
INPUT LAMP
J3-16
6
U405C
74HC14
R439
100K
U404A
TL074
11
5
INPUT
J2-12
1
3
R436
24.9K
SEL A
SEL B
SEL C
RF LEVEL
+5.00V
PATEMP LAMP
PADC LAMP
INPUT LAMP
LOCK LAMP
SWR LAMP
LOCK LAMP
J3-18
4
3
C409
.001
U4
4
2
10mV/Deg. C
R419
24.9K
RECEPT 12X1
U405B
74HC14
R428
10K
-12V
2
4
6
8
10
12
14
16
18
20
1
3
5
7
9
11
13
15
17
19
(R435+R436)+R436
---------------- = ---(R435+R436)-R436
SWR LIMIT=
150K
R440
33K
R434
10K POT H
= 1.5:1
100K
POWER SET
9
D405
R441
1M
U4
R442
51K
D404
8
DC SUPPLY
J2-2
R445
R443
51K
C410
0.1
R451
100K 1
U4
6
U3
6
7
R444
200K
U403B
TL074
R452
10K 1
ALC
J4-2
5
U404B
TL074
J4
RECEPT 12X1
R448
100K 1
REM BATT
J4-7
5
C412
0.1
R447
1K
7
U404C
TL074
R454
100
FAULT SUM
REM BATT
REM PATEMP
REM RFWATTS
REM PADCA
REM PADCV
ALC
/LOCK
100K
10
12
11
10
9
8
7
6
5
4
3
2
1
GND
R446
10K
C411
0.1
J3
DPM REF
DPM IN
J404
+5.00V
-12V
+5.00V
HEADER 10X2
D412
R438
120K
RF LEVEL
J3-8
J2
HD403
D409
R492
10K
FAN
J2-7
U403D
TL074
PAV
PAI
DC SUPPLY
/+28V INH
PATEMP LAMP
J3-12
R431
120K
R430
100K
FAULT SUM
J4-8
12
11
10
9
8
7
6
5
4
3
2
1
+5V
R432
100K
C408
1.0UF
12
R427
240K
5.00V = 100 deg. C
C431
0.1
U3
13
R426
30.1K 1
10
U403C
TL074
10
U405A
74HC14
R429
220K
-12V
R423
240K
R421
100
11
U405E
74HC14
D402
U403A
TL074
11
-12V
U3
9
D408
R415
120K
1
INPUT
RF REV
RF FWD
RFV
VOLTMETER
FAN
TEMP OUT
PADC LAMP
J3-14
+12V
4
-12V
+12V
RECEPT 5X2
D401
1
C421
.001
TEMP OUT
J2-6
13
9
7
5
3
1
+5V
C405
.001
U4
U404D
TL074
2
-12V
+12V
SWR LAMP
J3-20
D407
R413
33K
12
R407
10.0K 1
10
8
6
4
2
U405D
74HC14
14
R408
1.1K 1
R418
1K
R414
2.2M
J4-4
REM PADCA
1.00V = 10.0A
U402B
TL072
J401
+5V
8
9
R412
10K POT H
7
PAI
J2-3
PAI LIMIT
U402A
TL072
6
R450
10K
U5
R411
15K
-12V
R449
11K 1
+5V
(1.999V reads "1999")
FULL SCALE
16
RF POWER (RFV SQUARED)
.001V per Watt
R453
RF POWER
SWR
ALC
PA DCV
PA DCI
PA TEMPERATURE
SUPPLY DC VOLTS
VOLTMETER
1.1K 1
10mV/Volt
100mV/Amp
1mV/Degree C
10mV/Volt
10mV/Volt
R455
100K 1
VOLTMETER
J2-8
C413
0.1
R456
1K 1
U406A
TL074
U6
1
3
D413
1N6263
(VFWD+VREFL)/40
R486
100K
13
100K
R487
R458
22K
R484
10K
D418
U406B
TL074
7
5
RF FWD
J2-10
Q403
2N5210
+5V
16
U6
13
14
15
12
1
5
2
4
(VFWD-VREFL)/4
U406D
TL074
1.00V
R491
2.49K 1
+5.00V
J3-9,10
J4-12
R464
1K
R463
100K
NUMBERS USED:
R1-91
(C2)
C1-29
R489
24.9K
D414
1N6263
C417
.001
C416
.01
U8
U408
74HC4051
INH
A
B
C
R490
10.0K 1
1K
R459
100K
14
U6
C422
0.1
R488
24.9K
12
6
DPM IN
J3-19
3
+5.00V
SWR CAL
R468
1K
-12V
R461
10K
X
X0
X1
X2
X3
X4
X5
X6
X7
8
R466
56K
R465
56K
R460
11 C415
.001
C414
.01
6
11
10
9
1K POTH
2
RF REV
J2-11
R467
+12V
4
R457
10K
13
14
15
12
1
5
2
4
1999 WATTS
19.99
19.99V
199.9V
19.99A
199.9 Deg. C
199.9V
199.9V
J3-2
J3-4
J3-6
+5.00V
6
11
10
9
SEL A
SEL B
SEL C
X0
X1
X2
X3
X4
X5
X6
X7
X
3
C423
0.1
DPM REF
J3-17
U9
U409
74HC4051
INH
A
B
C
8
D417
+5V
R462
22K
1
C1
8C
2
B2
7B
3
6E
E3
4
5
4
Q405
C420
.01
U407A
TL074
RFV
J2-9
R469
10K
+12V
4
2
1
3
11
C418
.01
D415
1N6263
LM394
1
8C
2 C1
7B
B
3 2
6E
E3
4
4
5
Q406
R472
10K POT H
R471
100K
C419
.001
R473
10K
6
5
-12V
U7
R481
39K
R483
1M
R476
49.9K
9
8
7
6
5
10
VDD
+12V
-12V
8
9
(2.5VDC at 100W)
(.135V)
R479
1.1K 1
R482
1K
R477
7.5K
R474
3.3K
R475
49.9K
R478
10.0K 1
13
12
-6.9V
C424
1.0UF
U7
14
R480
100
10
VR401
78L05
+12V
1
C425
1.0UF
U7
U407C
TL074
7
U407B
TL074
R470
22K
8
7
6
5
D416
POWER CAL
U7
R485
100K
LM394
IN
OUT
C
2
U6
(Clamp SWR reading below 5W.)
DZ402
LM329DZ
+5V
U8,9 pin 7
C426
1.0UF
C429
1.0UF
R417
3.3K
VSS
8
U406C
TL074
VCC
3
-12V
C427
1.0UF
C428
1.0UF
VEE
-12V
-6.9V
FM500
METERING
103204A
J4-5
REM RFWATTS
(1.00V at 100W)
U407D
TL074
METERING
Reference Drawings
6–11
6 - 12
FM30/FM100/FM250 User's Manual
DWG. NO.
1
2
3
4
REV.
1
201207-SCH
5
6
7
8
9
5
E . C . N.
HD7 FAN
FAN+12V
ALC / METERING
HEADER 2 .156
H
RF EXCITER
U2
2
3
J2
J1
HD42
1
2
3
4
5
6
7
8
9
10
11
12
HEADER 12
+5.00V
1K
HD31
HEADER 5 x 2
+12V
DATE
DWN
02-05-05
DW
PE
DW
Vin
NC
GND
7
2
6
3
TRM
TL072
1
U3A
-12V
+5.00V
Z9
R43
OPEN
100
C51
5
H
C52
.01
C50
1.0
+12V
8
C54
1.0
1.0
26 HEADER
J5
MCX
J6
MCX
TL072
7
U3B
6
NC
ALC
-12V
R29 1K
/LOCK
FSK IN
NC
+12V
TEMP
FAN
V-METER
RFV
RF FWD
RF REV
INPUT
/LOCK FAULT
DC SUPPLY
PAI
PAV
/LOCK
ALC
METER PAV
METER PAI
METER RFW
METER PATEMP
METER BATT
FAULT SUM
.01
1
2
3
4
5
6
7
8
9
10
NC
5
C10
HD4
HD41
HEADER 12
FOR PROTOTYPE
REF02
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
HD44
R26
J1
NC
TEMP Vout
4
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
J4
1
2
3
4
5
6
7
8
9
10
R25
Q1
OPEN
IRF541
1
2
3
4
5
6
7
8
9
10
.01
1
2
3
4
5
6
7
8
9
10
11
12
C27
.01
1
2
3
4
5
6
7
8
9
10
11
12
C26
1
2
3
4
5
6
7
8
9
10
11
12
1.0
TP1
VOLTMETER
G
1
C54
.01
REV
APPROVALS
CHK
CM
+12V
1
2
3
4
5
6
C25
REVISION HISTORY
DESCRIPTION
R42
4.7K
HD2
HEADER 6X1 .156
12
11
6
1
AUDIO PROCESSOR SHUNT
+12V
1
2
10
Z31
OPEN
R28 1K
G
-12V
ADD FOR M2HD-S
MOTHERBOARD ONLY
R27 1K
AUDIO PROCESSOR
RFX OUT
/LOCK
ALC
HEADER 5 x 2
HD12
COMP OUT
+12V
NC
HD5
C41
.001
1
2
3
FSK IN
NC
RIGHT
C42
.001
HEADER 3X1
NC
F
FAULT SUM
METER BATT
METER PATEMP
METER RFW
METER PAI
ALC
METER PAV
INPUT
R IN1
TEMP
R IN2
HD3
LPIN L
NC
NC
LPOUT L
LPIN R
LPOUT R
NC
Z30
JUMPER
NC
NC
C17
.01
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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
NC
+12V
HD61
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
J3
J1
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
F
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
+12V
-12V
/+6DB
/+12DB
L VU
R VU
+5.00V
PROC A
PROC B
PROC C
BR GR
HEADER 10 x 2
HI GR
NC
Z32
Z33
OPEN
OPEN
HEADER 13 x 2
HEADER 10 x 2
E
-12V
INSTALLED WHEN USING
AUDIO PROC. SHUNT CKT.
C18
JUMPER .01
COMP METER
COMP METER
Z28
NC
ALC
JUMPER
C19
.01
STEREO/MON
+12V
Z27
C40
OPEN
C39
OPEN
C38
OPEN
C36
.01
C35
.01
C34
.01
C33
.01
C32
.01
C30
.01
C31
.01
C29
.001
C28
.001
JUMPER
C20
.01
TP2
+12V
Z26
JUMPER
C21
.01
STEREO GENERATOR
Z25
Z24
JUMPER
C23
.01
Z23
JUMPER
+5.00V
HD22
MON L
MON R
C24
.01
NC
LPIN L
LPOUT L
LPIN R
LPOUT R
38KHZ
38KHZ
COMP METER
COMP METER
/EXT ENABLE
/EXT ENABLE
1
2
3
4
5
6
7
8
9
10
11
12
+12V
1
2
3
4
5
6
7
8
9
10
11
12
+12V
HD23
STEREO/MON
RIGHT
LEFT
Z22
OPEN
J3
1
2
3
4
5
6
7
8
9
10
11
12
_/CARRIER OFF
4
_FSK IN
R16 220
11
_ALC
R15 100
3
_COMPOSITE OUT
R14 390
10
_38 KHZ OUT
R13 390
_/EXT ENABLE
R12 1K
R IN2
1K
L IN2
1K
C5
220pF
C4
220pF
C6
220pF
FSK IN
C2
220pF
Z5
JMP2 OPEN
R11 220
/EXT ENABLE
C11
.01
C12
OPEN
C13
.001
C14
.001
C15
C16
.01
.01
OPEN
Z3
C3
220pF
Z2
JUMPER
Z1
JUMPER
JMP1 OPEN
DB15
R4
1K
COMP METER
C7
220pF
R1A
R3A
300
300
R4A
300
300
1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL.
2. ALL CAPACITORS ARE IN MICROFARADS.
Z13
R9
1K
Z7
R8
1K
R5
1K
R6
1K
1
Reference Drawings
2
3
50 KOHM
600 OHM
Z1, Z2 ON
Z3, Z5, Z7, Z8 OFF
Z4, Z6 OFF
Z1, Z2 ON
Z3, Z5, Z7, Z8 ON
Z4, Z6 OFF
4
OMNIA BOARD AES/EBU INPUT
3
1
Z1, Z2 OFF
Z3, Z5, Z7, Z8 OFF
Z4, Z6 ON
OPEN
Z11
EXT RTN
240
OPEN
EXT IN
1
2
3
4
5
HD6
OPEN
OPEN
R33
R34 24.9K 1%
24.9K
1%
2
R35
C48
1.0
TL072
1
U1A
HI
LO
GND
REF. FOR
XLR CON.
3
24.9K
1%
-12V
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.
6
7
8
D3
R32
1K
C49
1.0
R38
4.02K
1%
+12V
R36
24.9K
1%
ANALOG LEFT/RIGHT
LEFT IN 1
LEFT IN 2
5
R41 1K
SCA IN
R10
B
100
OPEN
Z8
1
2
3
3
2
1
2
NON-OMNIA BOARD INPUT IMPEDENCE
A
R39
Z14
OPEN
J2
OPEN
INPUT CONFIGURATION CHART
R40
100
OPEN
R7
1K
Z10
J1
XLR
STEREO GENERATOR SHUNT
OPEN
Z12
C1
220pF
R2A
OPEN
UNLESS OTHERWISE SPECIFIED:
C8
220pF
OPEN
R2
2
1
L IN2
1K
Z4
NOTES:
HEADER 12
C9
220pF
R3
R IN1
C
J1
1N4148
12
TP5
GND
-12V
1
2
3
4
5
6
7
8
9
10
11
12
D2
_/AUTO CAR. OFF
1
2
3
4
5
6
7
8
9
10
COMP METER
5
OPEN
R1
COMP OUT
_FAULT SUM
SCA IN
13
Z6
EXT RTN
_METER BATT
EXT IN
_METER PA TEMP
6
MON_R
MON_L
EXT_IN
EXT_RTN
SCA
_METER RFW
14
R IN1
L IN1
_METER PAI
7
1
2
3
4
5
6
7
8
9
10
HEADER 5 x 2
R17 220
OPEN
Z21
R19 220
R18 220
OPEN
Z20
R20 220
OPEN
OPEN
OPEN
Z19
R21 220
Z18
Z17
R23 220
R22 220
OPEN
OPEN
Z16
Z15
R24 220
ALC
_METER PAV
15
TP4
+12V
J2
HD21
J4
8
D
+5.00V
HEADER 12
C
9
TP3
-12V
C22
.01
COMP OUT
JUMPER
D1
1N4148
B
+5.00V
HD13
Z29
HEADER 10 x 2
D
J2
HD11
L IN1
L IN2
E
1
2
3
4
5
6
7
8
9
10
HEADER 5 x 2
C43
.001
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
1N4148
V+
TEMP
GND
LEFT
R37
6
3.9K
5
IREC
TL072
7
U1B
APPROVALS
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.
9
10
DWN
CHK
DW
11-23-04
CM
DW
11-23-04
INTERNATIONAL RADIO AND ELECTRONICS CORP.
25166 LEER DRIVE ELKHART, IN. 46514
WWW.IREC1.COM
Error
: logo3A.jpg file not found.
574-262-8900
DISTRIBUTION
K
FILENAME:
A
TITLE:
PE
SIZE
SCH, FM/IBOC MOTHER BOARD
REV
DWG . NO .
201207-SCH
D
SCALE :
NONE
11
1
PROJ NO.
SHEET
1 OF 1
12
6 - 13
Jumper FMA "E"
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
Z12
Z13
Z14
Z15
Z16
Z17
Z18
Z19
Z20
Z21
Z22
Z23
Z24
Z25
Z26
Z27
Z28
Z29
Z30
Z31
Z32
Z33
JMP1
JMP2
Short
Short
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Short
Short
Open
Open
FMA "T"
50K input
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMA"T"
600 input
Short
Short
Short
Open
Short
Open
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMA "R"
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMA "Omnia"
Analog input
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMA "Omnia"
AES input
Open
Open
Open
Short
Open
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMX "E" FMX "T"
50K input
Short
Short
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Open
Short
Open
Short
Open
Short
Open
Short
Open
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Short
Open
Short
Open
Open
Open
Open
Open
FMX "T"
600 input
Short
Short
Short
Open
Short
Open
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMX "R" FMX "Omnia"
Analog input
Short
Short
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
FMX "Omnia"
AES input
Open
Open
Open
Short
Open
Short
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
FMX
RMS
Short
Short
Short
Short
Short
Open
Open
Open
Open
Open
Open
Open
Open
Short
Short
Short
Open
Open
Motherboard Configuration Chart
6-14
FM30/FM100/FM250 User's Manual
R27
D 8167-5
Illustration 6–10 Display Board
(Add 600 to component designators for schematic reference)
6–14
FM500 User's Manual
U602
LM3915
JP601
+12V
+12V
R601
68K
L VU
R602
100K
8
R604
1.2K
D601
1N4148
8
2
3
4
U601A
TL072
7
6
5.00V
R603
1K
1
C601
1.0UF
9
5
C602
1.0UF
D602
1N4148
4
3
+12V
2
-12V
1
MODE
DL601-610
+5V
RADJ
L9
ROUT
L8
DHI
L7
IN
L6
DLO
L5
V+
L4
V-
L3
L1
10
L10
11
YEL
12
G
G
DL621-625
16
1
8
GRN
18
L
1
C603
1.0UF
R VU
R607
68K
D603
1N4148
6
7
7
6
5.00V
R609
1K
5
U601B
TL072
9
8
R610
1.2K
5
C604
1.0UF
D604
1N4148
4
3
+12V
2
1
MODE
L
6
1
3
1
2
1
1
D
L
O
2
3
I
N
4
L
9
L
1
0
D
H
I
R
O
U
T
R
A
D
J
M
O
D
E
COMPOSITE
HI GR
+12V
+12V
ROUT
L8
DHI
L7
IN
L6
V-
L3
L1
L2
Y
Y
G
G
G
G
Y
1
8
R615
33K
50mA
L
2
GRN
15
L
3
GRN
18
1
5
L
4
L
5
U605
GRN
17
1
6
1
4
L
6
1
3
1
2
R624
1M
L
7
L
8
L
9
L
1
R616
33K
+5V
V
1
D
L
O
V
+
2
3
D
H
I
I
N
4
7
6
5
R612
M
O
D
E
C608
.001
8
L4
V-
L3
L1
L2
C634
1.0UF
R633
33K
ST/MON
R657
1K BECKMAN
RF LEVEL
INPUT
6
SW602
DITHER
10V P-P DITHER
12
PA TEMP
DECIMAL POINT
13
R619
510
R620
220K
PATEMP LAMP
U606B
TL072
R632
620
C609
1.0UF
DL659
RED
+5V
DP100
R656
220
2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
DL636-643
Pin 1, upper left from front of unit.
F.S.
RF POWER
+12V
C631
1.0UF
OUT
C
2
SWR
19.99
ALC
19.99
PA DC VOLTS
199.9
VDD
VCC
+5V
3
C624
1.0UF
C629
1.0UF
GRN
GRN
16
14
U10
U11
U9
GRN
7
PA DC AMPS
-12V
2 1 1 1 1 1 1 1 1 1 1
0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1
U612
C622
1.0UF
C630
1.0UF
R638
100K
C618
0.1
DPM REF
SUPPLY DC VOLTS
199.9
VOLTMETER
199.9
GRN
UP
SW605
R651
2.2K
R628
1K
1
C617
0.1
R637
470K
U609C
74HC14
5
C619
100PF
U609D
74HC14
9
11
Reference Drawings
8
DOWN
SW606
R654
1K
R640
100K
2
X
R641
10K
15
1
10
9
C621
.01
3
4
5
4
11
14
R642
10K
A
B
C
D
QA
QB
QC
QD
UP
DN
LOAD
CLR
CO
BO
U609E
74HC14
10
1
3
5
7
9
11
13
15
17
19
+12V
-12V
/+12DB
/+6DB
5.00V
+12V
-12V
COMPOSITE
MON/ST
HEADER 10X2
3
R630
150
INH
A
B
C
J602
SEL A
SEL B
SEL C
RF LEVEL
5.00V
PATEMP LAMP
PADC LAMP
INPUT
LOCK LAMP
SWR LAMP
U610
74HC193
U609B
74HC14
C633
.001
X0
X1
X2
X3
X4
X5
X6
X7
2
4
6
8
10
12
14
16
18
20
1
3
5
7
9
11
13
15
17
19
5.00V
DPM REF
DPM IN
HEADER 10X2
SEL A
SEL B
SEL C
3
2
6
7
12
13
SCM, FM DISPLAY
+5V
NOTES :
C614
0.1
C615
0.1
6
C632
.001
R639
100K
+5V
DZ601
6.2V
13
14
15
12
1
5
2
4
6
11
10
9
U609A
74HC14
C620
.01
-12V
R636
100K
199.9
GRN
C627
1.0UF
R635
100K
PA TEMPERATURE
ICL7107
2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
C616
0.1 POLY
GRN
VEE
VSS
2
4
6
8
10
12
14
16
18
20
GND
U611
74HC4051
19.99
8
-12V
+5V
+12V
-12V
L VU
R VU
5.00V
PROC A
PROC B
PROC C
BR GR
HI GR
1999
GRN
VR601
7805
DPM IN
J601
GRN
+12V
/+12DB
U609F
74HC14
DL647
RED
D617
D616
/+6DB
INPUT
DP10
C623
1.0UF
STEREO
+5V
PA DC
5
U606A
TL072
IN
GRN
SW601
DL646
RED
7
1
GRN
18
GRN
DL645
RED
R650
100K
BECKMAN
PROC B
R634
5.1K
DP10
DP100
GRN
17
LOCK
UNITS
+5V
GRN
16
MONO
SWR LAMP
5.00V
R631
5.6K
-12V
TENS
V+
GRN
15
SWR
9
3
100's
L5
R629
680
5.00V
PADC LAMP
1000
DLO
GRN
14
C625
0.1
DL644-647, 659
C613
.01
1
DL101
DISPLAY
L6
LOCK LAMP
+12V
4
IN
GRN
13
SW603
PROC C
2 1 1 1 1 1 1 1 1 1 1
0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1
L7
DITHER
R655
4.7K
+5V
2
DHI
YEL
12
PROC A
R617
1K
Q602
MPS-A56
L8
"PILOT"
R649
10K POT H
MOD. CAL.
BR GR
330
R611
1K
ROUT
RED
11
R625
10K
R618
1.2K
+12V
L9
"110"
GRN
DL644
RED
C607
0.1
1
RADJ
R652
5.6K
10
L10
R626
33K
1
0
8
2
MODE
C628
1.0UF
-12V
GRN
RED
R647
1K
L
1
0
R
A
D
J
3
+12V
4
D607
LM3914
R
O
U
T
1
C610
0.1
C612
.001
4
1K
8
RED
1
1
DITHER
GRN
16
1
7
2
3
DL626-635
GRN
14
Q603
2N5210
5
GRN
13
R648
D618
4
G
G
6
5
+12V
U607B
TL072
7
3
+5V
YEL
12
L4
C606
0.1
RED
R653
1K
1
-12V
11
L5
8
2
U607A
TL072
D606
1N6263
6
5.00V
U613A
TL072
8
7
R643
3.3M
R623
10.0K
5.00V
C605
.001
2.7K
1N6263
R622
10.0K
1.2K
R627
-12V
R614
R613
1K
U608
LM3914
9
9
8
7
6
5
JP603
JUMPER
FOR BAR
R646
10M
D605
L
8
LM3914
V
+
5
1
0
L
7
330
10
L10
L9
V+
1
4
L
5
DL11-20
RADJ
DLO
V
1
1
5
L
4
U604
Q601
MPS-A56
+12V
1
6
L
3
+5V
GRN
RED
1
7
L
2
+5V
+12V
7
R644
33K
GRN
17
C611
0.1
DL648-658
C626
1.0UF
GRN
R605
1K
R608
100K
+12V
GRN
15
6
Q604
2N5087
R645
100
Y
50mA
14
U603
LM3915
G
GRN
R606
JP602
G
GRN
13
L2
U613B
TL072
RED
1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED.
2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED.
103206
DISPLAY
6–15
Reference Drawings
6 - 17
CARR SW
R701
4.7K
U703C
R702
10K
/CARRIER OFF
5
6
ELKHART, IN. 46517
R723
1K
D701
1N4148
U703A
R704
10K
/AUTO CARRIER
1
3
2
+6V
+12V
R705
91K
4
D703
1N6263
2
1
1
1
C701
.01
11
R716
10K
7
12
5
U701B
TL074
R715
2.2K
R714
220
-12V
R710
75K
1
13
R711
100K
14
DL701
GREEN
DL702
RED
C704
.001
R712
1M
7
5
4
6
14
13
15
1
2
3
Q4
Q5
Q6
RST
Q7
Q8
Q9
Q10
Q12
Q13
Q14
R721
24.9K
1
VDD
C705
1.0
POLY
FILENAME:
TIME-OUT
SELECT
2
4
6
8
10
1
3
5
7
9
APPROVED BY :
SUPERSEDES
NONE
EE
E.C.
MLOWCMO
PE
DWG. NO.
10.SCM
9
8
2. ALL CAPACITORS ARE IN
MICROFARADS UNLESS OTHERWISE SPECIFIED.
74HC14
INPUT FAULT
HEADER 5X2
C706
1.0
POLY
Modifications for use
with 12.5V RF driver.
Remove:
PROGRAM DETECT
(C707)
(R726)
(R708)
(R749)
9
8
10
U706
L704
R745
R744
C724
D713
R720
10K
R724
100
+UNREG
1
2
3
4
C711
.01
C709
2200PF
POLY
R725
100K
1
2
3
4
C715
0.1
R735
51
R736
2K
11
12
U703F
74HC14
Q701
IRF540
R737
4.3K
R738A
1.0
0.5W
LM3578
U1
C723
330
100V
U2
1 -IN
V+
2 +IN
CS 7
R732 100K to 49.9K
D714 1N5822 to MUR110
DZ703 1.5KE36A to ICTE-12
C721, C722 3300UF to 220UF/50V
Add:
1UF/100V between L701 and L703 under board.
7912 regulator, using "L704" pads.
Jumper "U706" pads 1 and 2.
DZ705
8
IR2125
1 VCC
VB
2 IN
8
7
OUT
3 OSC
C 6
3 ERR
CS 6
4 GND
E 5
4 ESS
VS
5
R738A
1.0
0.5W
Q704
MJE15028
L701
380UH
C718
220
63V
D711
MUR110
10
Change:
(+13.5V)
R728
68K
C710
56PF
NPO
OPEN
C713
100PF
8
7
6
5
1
2
3
4
8
7
6
5
C714
0.1
R748
10K
13
C707
.001
8
7
6
5
R730
2.2K
D709
VDD
1
2
3
4
U705
IR2125
8
7
6
5
DZ702
1N9661B
16V
D710
1N4148
C712
1.0
U704
LM3578
P701
R734
10K
Q705
MPSA06
R749
1.5K
R739
510
DZ703
ICTE-12
R740
10
C719
1000
35V
DRVR V+
C725
220
63V
R741
1K
R729
4.12K
1
U706
LM2576–ADJ
Q702
MPSA06
1 2 3 4 5
-12V
+12V
METER UNREG
R750
100
R742
1K
R744
1.1K 1%
R745
10K 1%
+UNREG
+12V
L702
960UH
INPUT FAULT
+12V
SYNC
-12V
DRVR V+
PAV
PAI
ALC
HD701
/LOCK FAULT
R751
JUMPER
D715
1N4004
R743
220
C717
1UF
R732
82.5K
1
R727
620
R726
100K
6 5 4 3 2 1
(+12.5V)
Q703
MPSA56
U703E
74HC14
C708
220 Pf
CARR SW
DRVR V+
A
THESE DRAWINGS AND SPECIFICATIONS ARE THE
PROPERTY OF CROWN INTERNATIONAL, INC. AND
SHALL NOT BE REPRODUCED, COPIED, OR USED
AS THE BASIS FOR THE MANUFACTURE OR SALE
OF APPARATUS OR DEVICES WITHOUT PERMISSION.
1. ALL RESISTORS ARE IN OHMS,
1/4W, 5% UNLESS OTHERWISE SPECIFIED.
28V ENABLE
REV
103207
NEXT ASM:
R719
10K
U701C
TL074
DO NOT SCALE PRINT
ME
NOTES :
_______
_______
U703D
D708
1N4148
JP701
MINUTES
0.5
2
4
8
9
10
PO
PO
R718
100K
12
U701D
TL074
R722
100K
PI
R717
10K
D704
1N6263
SCALE
VSS
U702
74HC4060
D706
1N4148
U701A
TL074
8-25-97
JFL
CHECKED
PROJ #
6
R708
100K
3
C703
.001
R706
5.1K
R713
100K
R709
1K
DRAWN
VCC
DZ701
1N4735
6.2V
+12V
D707
1N4148
R707
180K
VDD
4
74HC14
Fo=5KHZ BPF; Q=3
C702
.001
FM VOLTAGE REGULATOR
D702
1N4148
U703B
74HC14
VDD
PHONE (219) 294-8000
74HC14
VDD
R703
4.7K
AUDIO or COMPOSITE
COMP2
CROWN INTERNATIONAL, INC.
+12V
1718 WEST MISHAWAKA ROAD
R733
4.7K
+12V
6
5
4
3
2
1
HD704
1 1 1 1 1 2
2 4 6 8 0 2 4 6 8 0
1 2 3
c 8667-5
COMP2
38KHZ
/CARRIER OFF
/AUTO CARRIER
FAN
A10124-22
HD703
DZ704
ICTE-12
D713
1N5822
Inductor Data
HEADER 6
(TO POWER REG. BOARD)
L701
L702-703
L
380uH
960uH
Wire
#22
#26
1 3 5 7 9 1 1 1 1 1
1 3 5 7 9
HD702
C720
220UF
50V
Turns
80
Micrometals T90 core
165
C724
47
20V
D714
1N5822
-12V
L704
960UH
-12V
L703
960UH
C721
3300UF
16V
C722
3300UF
16V
VOLTAGE REGULATOR
Reference Drawings
6–17
Illustration 6–12 Power Regulator Board
6–18
FM500 User's Manual
1
2
3
4
5
6
REVISION HISTORY
DESCRIPTION
ON CHASSIS
E . C . N.
BATTERY
~
-
DC INPUT
+
C1001
0.015F
110V
~
D804
BYV72EW-150
P802
FASTON TAB
PRODUCTION RELEASE
8
DATE
DWN
10-31-03
DW
APPROVALS
CHK
CM
PE
DW
DP
274
B
CORRECTED Z3 AND Z6 UNIT STATUS FOR M2 AND FM100
01-29-04
DW
DW
DP
323
C
SWAPPED Z1, Z2 TO MATCH PWB
08-10-04
DW
DW
DP
2
F
REV
A
3
1
P801
FASTON TAB
7
P806
FASTON TAB
F
P803
FASTON TAB
CIRCUIT BREAKER
L801
P804 + UNREG IN
FASTON TAB
P805
FASTON TAB
P807
FASTON TAB
HD1
DZ801
U801
1
2
+IN
CS
OSC
C
GND
E
8
U2
7
6
1
5
2
LM3578AN
R806A
330K
2
* Z7
1
2
R807
2.2K
C805
100PF
4
VB
IN
OUT
ERR
CS
ESS
VS
C809
.1
8
R809
51.0
7
R811
6
C808
5
.0027
IR2125
R810
2.0K
D803
BYV72EW-150
1N966B 16V
3
* Z8
B
REF DES
L802
R811
R827
R828
DZ806
DZ807
R805B
200K
D805
1N4148
6 - 20
1
R818B
2.0K
2W
C813
.01UF
R817B 1
2K
2W
* Z5
TP2
R815
100.0
R816
1.0K 1%
R813
1.0K
UNIT CONFIGURATION
FM250
FM500
EURO
OPEN
SHORT
SHORT
SHORT
OPEN
SHORT
SHORT
OPEN
OPEN
H43608-1
3.3K
OPEN
OPEN
OPEN
OPEN
OPEN
SHORT
SHORT
SHORT
OPEN
SHORT
SHORT
OPEN
OPEN
H43395-5
3.3K
OPEN
OPEN
OPEN
OPEN
OPEN
SHORT
SHORT
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
H43533-1
3.3K
OPEN
OPEN
OPEN
OPEN
OPEN
SHORT
SHORT
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
H43533-1
3.3K
OPEN
OPEN
OPEN
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
OPEN
OPEN
SHORT
SHORT
H43533-1
3.3K
OPEN
OPEN
OPEN
OPEN
OPEN
SHORT
SHORT
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
H43533-1
5.11K 1%
OPEN
OPEN
OPEN
OPEN
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.
2
* Z4
2
2
P808
PA-DC OUT
FASTON TAB
R818A
2.0K
2W
C820
0.01UF DISK
TP1
C819
.01UF
U803
OP-27GNB
2
3
DZ802
1N966B 16V
NOTES:
HARRIS M1
OPEN
SHORT
OPEN
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
H43533-1
3.3K
INSTALLED
INSTALLED
INSTALLED
INSTALLED
HARRIS M2
UNLESS OTHERWISE
SPECIFIED:
SHORT
OPEN
C818
.1UF
R822
22.0K
Q802
MPSA56
R814
22.0K
1. ALL RESISTORS ARE IN OHMS,
1/4W, 5% TOL.
OPEN
SHORT
OPEN
OPEN
SHORT
SHORT
H43533-1
3.3K
INSTALLED
INSTALLED
INSTALLED
INSTALLED
INTERNATIONAL RADIO AND ELECTRONICS CORP.
25166 LEER DRIVE ELKHART, IN. 46514
574-262-8900
Error
: logo3A.jpg file not found.
WWW.IREC1.COM
APPROVALS
5
DWN
CHK
CM
PE
DW
09-30-03
DW
09-30-03
DP
09-30-03
DISTRIBUTION
FILENAME:
TITLE:
SIZE
SCH, FM POWER REGULATOR
REV.
DWG . NO .
200915-SCH
B
200915-SCH
6
B
IREC
2. ALL CAPACITORS ARE IN
MICROFARADS.
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.
4
C
Q803
2N5087
6
3
FM100
C10582-2 PWB_100969-1
B_L_SHT1_A.DOT REV. A
+
OPEN
FM30
PWB_REV.G
C811
C810
330/100V
+
*
R819
.04 OHM 15W 3%
4.7UF/63V
R820
100K
FM1
A
DZ803
1N4735 6.2V
L803
30UH
7
2
*
Z1
Z2
Z3
Z8
Z7
Z6
Z4
Z5
Z9
R812B
0.1
5W
C806
R804
10.0K 1%
JUMPER
R812A
0.1
5W
L802
* DZ807
R806B
R805A
330K
2
* Z9
*
R817A
100
1
+
1
C
Q804
MPSA06
200K
* Z6
1
R821
10.0K
Q801
IRF540
8
1
C814
1/50V
VCC
C 7527-2_6 HDR
* R828
30K
4
1
56PF
V+
3
82K
2
4
3
D
C804
.01
C803
R803
C801
220PF C802
2200PF POLY
1
3
-IN
1.0K
D802
1N4148
C812
1/50V
REV.
1.0K
330/100V
*DZ806
* Z1
1
2
3
4
5
6
R808
C
* R827
2
1
1
2
2
1N4735 6.2V
R802
10K
PA VOLTAGE SET
C817
330/100V
* Z3
1
1N966B 16V
24.9K
+
DWG. NO. 200915-SCH
1
* Z2
R801B
+
E
R801A
27.4K 2
E
30UH
C816
330/100V
+
C815
330/100V
SCALE : NONE
7
PROJ NO. 533
A
C
SHEET
1 OF 1
8
FM30/FM100/FM250 User's Manual
R19
R20
Illustration 6–13 Power Amplifier
(Add 1100 to component designators for schematic reference)
6–20
FM500 User's Manual
C909
L904
L903
23.2uH
U900
10.4uH
R900
MRF 137
680PF
C908
27PF
C907
5PF
C910
36PF
THESE DRAWINGS AND SPECIFICATIONS ARE THE
PROPERTY OF CROWN INTERNATIONAL, INC. AND
SHALL NOT BE REPRODUCED, COPIED, OR USED
AS THE BASIS FOR THE MANUFACTURE OR SALE
OF APPARATUS OR DEVICES WITHOUT PERMISSION.
C906
36PF
C905
10PF
9
C903
0.01
8
CA2832
7
5
3
2
CROWN INTERNATIONAL, INC.
1718 WEST MISHAWAKA ROAD
J2
R900
51
DRAWN
JFL
C900
RF DRIVER BD
SCALE
R901
51
0.01
SUPERSEDES
NONE
EE
E.C.
R103
PE
FILENAME:
1001771A.SCM
REV
100177
NEXT ASM:
A
R904
51
D900
1N753A
6.2V
0.01
ME
DWG. NO.
PROJ #
L900
33uH
C902
DO NOT SCALE PRINT
APPROVED BY :
7-12-96
CHECKED
R903
4.7K
PHONE (219) 294-8000
FM500 P.A.
1
T900
L902
ELKHART, IN. 46517
R902
2.7
5W
R905 10K
C904
C901
NOTES :
_______
_______
0.01
0.01
1. ALL RESISTORS ARE IN OHMS,
1/4W, 5% UNLESS OTHERWISE
SPECIFIED.
J3
J5
2. ALL CAPACITORS ARE IN
MICROFARADS UNLESS
OTHERWISE SPECIFIED.
C1126
0.1
J1
L1121
50NH
R1101
15K
DZ1110
1N4735
6.2V
R1110
10K
C1121
0.01
DISC
C1110
R1120
2.7K
0.01
C1122
0.01
DISC
TEMP SENSE
LM35DZ
1 2 3
R1111
10K
POT V
C1132
0.1
L1122
50NH
C1111
0.01
R1112
5.6
R1113
5.6
2W
2W
Q1101
BLF278
C1127
0.1
R1116
10K
C1112
0.01
T1111P
R1119
200
3W
C1134
0.1
C1133
0.1
C1135
0.1
C1136
0.1
C1138
0.068
T11S
C1114
0.01
C1137
0.1
C1125
60PF
R1117
24
3W
C1116
27PF
C1128
0.1
C1113
0.01
C1123
0.01
C1124
0.01
T1121
C1115
0.01
R1114
5.6
2W
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
R1115
5.6
2W
PA INPUT BD
PA OUTPUT BD
L1125A
L1124A
C1129
L1123
L1126
0.1
L1124B
L1121
50NH
R1101
15K
DZ1110
1N4735
R1110
10K
L1125B
C1121
0.01
DISC
C1110
0.01
R1120
2.7K
6.2V
ZENER
C1122
0.01
DISC
J2
R1111
10K
POT V
R1112
5.6
2W
5.6
2W
27PF
C1138
0.068
T11S
C1114
0.01
R1114
5.6
2W
_
B1
_
B2
_
B3
C1125
60PF
R1117
24
3W
C1116
PA INPUT BD
Q1101
BLF278
C1113
0.01
C1112
0.01
T1111P
C1130
0.1
R1113
R1116
10K
R1119
200
3W
C1131
0.1
L1122
50NH
C1111
0.01
C1123
0.01
C1115
0.01
C1124
0.01
+
+
T1121
+
R1115
5.6
2W
PA OUTPUT BD
FM500 POWER AMPLIFIER
Reference Drawings
6–21
P10421-9
Illustration 6–14 RF Output Filter
(Add 1200 to component designators for schematic reference)
6–22
FM500 User's Manual
(455MHz)
(195MHz)
(176MHz)
(252MHz)
C1202
1.35PF
C1204
7.1PF
C1206
9.3PF
C1208
5.13PF
C1211
47PF NP0
R1202
* 75
R1203
10
RF OUT
RF IN
L1202
90.5NH
L1201
250NH
C1201
15.4PF
C1201A
10PF
L1203
94.1NH
C1203
40.9PF
C1217
3.5PF
C1205
38.9PF
C1209
14.1PF
C1207
37.7PF
C1209A
2PF
R1201
100
D1202
1N6263
C1212
47PF NP0
D1201
1N6263
Approx. 7V RMS
with 200W RF in.
R1209
1K
R1206
1K
RF MONITOR
C1213
.001
INDUCTORS
I.D.
TURNS
L1201
0.25"
0.7"
#17
L1202
0.5"
3
0.6"
#12
L1203
0.5"
3
0.5"
#12
L1204
0.5"
3
0.7"
#12
L1205
0.4375"
3
0.6"
#12
14
EXACT COIL LENGTHS ARE FACTORY-SET.
* IF NECESSARY, SELECT R1202 FOR
SWR READING OF 1.1 OR BETTER WITH
50-OHM LOAD. R1205 = R1202
R1202,R1203,C1211,D1202,C1216
ON UNDERSIDE OF CIRCUIT BOARD.
R1205
* 75
R1204
10
C1219
47PF SM
HD1201
1
2
3
C1218
47PF SM
L1205
77.9NH
L1204
87.5NH
LENGTH
GUAGE
C1214
.01
R1207
100K
C1215
.01
R
E
F
L
C1216
.001
R1208
20K
F
W
D
R1210
10K
RFV
D1203
1N6263
R1211
100K
C1220
.01
1 2 3 4 5
HD1202
HEADER 5
NOTES :
_______
_______
1. ALL RESISTORS ARE IN OHMS,
1/4W, 5% UNLESS OTHERWISE
SPECIFIED.
2. ALL CAPACITORS ARE IN
MICROFARADS UNLESS
OTHERWISE SPECIFIED.
3. C1201-1209A,1217 are circuit board pads.
103209
RF OUTPUT FILTER & REFLECTOMETER
Reference Drawings
6–23
Reference Drawings
6 - 25
1
2
3
4
5
E . C . N.
REV
264
M
279
316
361
ADDED TO PWB (200922-PWB-D IN LOCATION
SHOWN, AND DEPICTED ON COMPONENT MAP.
F
C23
6
C24
7
REVISION HISTORY
DESCRIPTION
8
APPROVALS
CHK
CM
DATE
DWN
PRODUCTION RELEASE
12-10-03
DW
DW
DP
PE
N
XU1 WAS 200479-TERM-10
01-29-04
DW
DW
MH
O
PWB CHG'D TO REV. C
06-14-04
DW
DW
DP
P
PWB CHG'D TO REV. D
03-22-05
DW
DW
DP
F
.01
.01
R5
OPEN
XU1
MHW6342T
C4
OPEN
R18
C8
OPEN
R7
OPEN
0
IN
GND
GND
N/C
VCC
N/C
GND
GND
OUT
3
C1
2
1
.01
1
R2
2
R1
OPEN
T1
R6
OPEN
C3
.01
R17
51
VR1
OPEN
1
Vout
GND
Vin
E
L2
OPEN
L1
33uH
3 +5V
C10
10pF
L3
C11
36pF
C12
36pF
C13
5pF
C14
27pF
C6
0.01
C22
OPEN
C21
OPEN
C9
OPEN
FOR FM30:
20VDC INPUT APPLIED HERE.
FOR FM100 AND FM250: 18V
C18
OPEN
FOR FM500: 20V
R16
OPEN
2
D
D
G
3
OPEN
R3
OPEN
C2
OPEN
C5
22
S
R4
OPEN
Q1
BLF245
1
2
3
4
5
6
7
8
9
D2
OPEN
J2
RF OUT
P
E
D1
OPEN
C15
680pF
L5
23.2uH
REV.
J1
RF IN
L4
10.4uH
DWG. NO. Q43310-4
L6
OPEN
C7
0.01
R8
*
FOR FM30: FEED POINT FROM PWR. REGULATOR PWB.
+24VDC
J3
1
L7
OPEN
R11
4.7K
R12
R9
51
1/2W
C
D3
1N753A
6.2V
C20
OPEN
RT1
T
2.7K NTC
OPEN
C17
0.01
R13
OPEN
C
8
C16
0.01
OPEN
R10
10K
J4
U2A
3
1
U2B
5
1
2
OPEN
OPEN
NOTE:
4
C19
OPEN
7
6
UNLESS OTHERWISE SPECIFIED:
B
FM30
OPEN
OPEN
FM100
FM250
2. ALL CAPACITORS ARE IN MICROFARADS.
FM500
3 OHM 5W 3 OHM 5W 2.7 OHM 5W
R15
OPEN
INTERNATIONAL RADIO AND ELECTRONICS CORP.
25166 LEER DRIVE ELKHART, IN. 46514
574-262-8900
WWW.IREC1.COM
APPROVALS
J5
1
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.
A
B_L_SHT1_A.DOT REV. A
6 - 26
1
2
3
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.
4
5
DWN
CHK
CM
PE
DW
08-28-03
DW
10-30-03
DP
10-30-03
DISTRIBUTION
TITLE:
SIZE
FM RF DRIVER
REV.
DWG . NO .
Q43310-4
B
FILENAME:
SCALE : NONE
6
B
IREC
1. ALL RESISTORS ARE IN OHMS, 1/4 WATT +/- 5% TOL.
R8 POWER LEVEL CONFIGURATION
R14
7
A
P
PROJ NO. 533
SHEET
1 OF 1
8
FM30/FM100/FM250 User's Manual
Mother Board
J 403
6 5 4 3 2 1
HD561
Ribbon
V+
Temp
Gnd
HD 502
HD701
HD503
3 2 1
FM500 Chassis Wiring
C.Donner
2-23-98
CROWN BROADCAST
Ribbon Cable
6 5 4 3 2 1
HD702
Ribbon
J 602
FM500 CHASSIS WIRING
6
5
4
3
2
1
HD505
Metering
Board
HD504
P1
Unreg
Voltage Regulator
Board
J 601
Display Board
Reflectometer Feed-Thru
HD1202
1 2 3 4 5 6
BNC
Temp Sensor
8
9
44
45
46
47
DC
DC Bus
31
32
33
67
68
69
35
36
71
72
10
9
8
7
6
5
4
3
2
1
1 2 3 4 5 6
P804
P806
P801
28
29
Socket
10
9
8
7
6
5
4
3
2
1
Bus
52
53
54
55
56
57
62
63
64
65
P3
Header
P802
BNC
20 VAC
P3
Left Power
Regulator Board
P803
P2
40
41
42
P807
WHT / BLK
PA RF Output
+
4
5
6
22
23
24
25
57 VAC
Bridge
Rectifier
37
38
17
18
19
20
PA 2 DC Input
BLU / WHT
RED
WHT
Driver DC Input
Outer Fans
Power Transformer
1
2
12
13
14
15
PA 1 DC Input
Inner Fan
Ribbon Cable
J1
Back view
Driver input
P1
120 VAC
P805
P808
Power Amp Interconnect
Board
RED / WHT
P804
P801
P807
RF Output
Filter & Reflectometer Board
P806
P802
RF In
P803
RF Out
P805
P808
Right Power
Regulator Board
57 VAC
100 VAC
BLK
BLU
On
BRN / WHT
12.5 VAC
Carrier
Switch
BRN
Off
A
Gnd
B
C
P5
A
*
P4
Wht
Brn
Red/Wht
S1A
S1B
On
Brn/Wht
Blk/Wht
120V
240V
*
100V
220V
P1
Fan
Red
Blk
Gnd
D
P7
AC Input, Fuse, & Filter
Blk
Red
D
*
P6
AC
Power
Switch
Off
AC Distribution Board
*Jumpered for 120VAC
CHASSIS WIRING
6–26
FM500 User's Manual
Illustration 6–16 Receiver Board
Reference Drawings
6–27
Receiver
6–28
FM500 User's Manual
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 Service at the following number.
(866) 262-8917
You may also write to the following address:
International Radio & Electronics Corporation
25166 Leer Drive
Elkhart, Indiana, U.S.A. 46514-5425
7-2
FM600 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
Revised August 2001
Service and Support
7–3
Notes:
7–4
FM500 User's Manual
Factory Service Instructions
To obtain factory service, complete the bottom half of this page, include it with the unit, and ship to:
International Radio & Electronics Corporation
25166 Leer Drive
Elkhart, Indiana, U.S.A. 46514-5425
For units in warranty (within 5 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 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:
Telephone: (866) 262-8917 or (866) 262-8972
Fax: (866) 262-8909
Company:
Name:
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
Please Quote before servicing
Card Number:
Exp. Date:
Return Shipment Preference if other than UPS Ground:
Mastercard
Signature:
Expedite Shipment
Other
ENCLOSE WITH UNIT—DO NOT MAIL SEPARATELY
Service and Support
7-5
Appendix
Transmitter Output Efficiency
FM500 User's Manual
Appendix–1
Transmitter efficiency output
RF Power Output Efficiency-FM500
PADC Volts
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
65%
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
A B C
Glossary
The following pages define terms and abbreviations used
throughout this manual.
Glossary
G–1
A B C
AF
Audio Frequency; the frequencies between 20 Hz
and 20 kHz in the electromagnetic spectrum.
ALC
Automatic Level Control
AM
Amplitude Modulation; the process of impressing
information on a radio-frequency signal by
varying its amplitude.
bandwidth
The range of frequencies available for signalling.
BCD
Binary-Coded Decimal; a digital system that uses
binary codes to represent decimal digits.
BFO
Beat Frequency Oscillator
BNC
A bayonet locking connector for miniature coax;
said to be short for Bayonet-Neill-Concelman.
broadband
As used in the FM transmitter, refers to the entire
audio spectrum as opposed to the spectrum
influenced by the pre-emphasis; also called
"Wideband."
carrier
A continuous signal which is modulated with a
second, information-carrying signal.
crosstalk
In FM broadcasting, this term generally refers to
the interaction between the main (L+R) and the
subcarrier (L–R) signals as opposed to "separation" which generally refers to leakage between
left (L) and right (R) channels.
density (program)
A high average of modulation over time.
deviation
The amount by which the carrier frequency
changes either side of the center frequency.
DIP
Dual In-line Pins; term used to describe a pin
arrangement.
distortion
The unwanted changes in signal wave shape that
occur during transmission between two points.
DPM
Digital Panel Meter
EPROM
Erasable Programmable Read Only Memory
ESD
Electrostatic Discharge; a discharge that is
potentially destructive to sensitive electronic
components.
G–2
FM500 User's Manual
exciter
FET
(1) A circuit that supplies the initial oscillator
used in the driver stage. (2) A transmitter configuration 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 conjunction with frequency dividers and multipliers.
FM
Frequency Modulation; the process of impressing
information on a radio signal by varying its
frequency.
FSK
Frequency Shift Keying; an FM technique for
shifting the frequency of the main carrier at a
Morse code rate. Used in the on-air identification of frequencies.
gain reduction
The process of reducing the gain of a given
amplifier.
harmonics
Undesirable energy at integral multiples of a
desired, fundamental frequency.
HF
Hight Frequency; Frequencies in the 3.0 to 30.0
MHz range.
Highband
Frequencies affected by the pre-emphasis.
I/O
Input/Output
LED
Light-Emitting Diode
modulation
The process by which a carrier is varied to
represent an information-carrying signal.
MOSFET
Metal Oxide Semiconductor Field Effect Transistor; a voltage-controlled device with high input
impedance due to its electrically isolated gate.
nearcast
A transmission within a localized geographic area
(ranging from a single room to a several kilometers).
PA
Power Amplifier
Glossary
G–3
A B C
PAI
Power Amplifier Current
PAV
Power Amplifier Voltage
pilot
A 19–kHz signal used for stereo transmissions.
pre-emphasis
The deliberate accentuation of the higher audio
frequencies; made possible by a high-pass filter.
processing
The procedure and/or circuits used to modify
incoming audio to make it suitable for transmission.
receiver
An option which adds incoming RF capability to
an existing transmitter. See also "Translator."
RF
Radio Frequency; (1) A specific portion of the
electromagnetic spectrum between audiofrequency and the infrared portion. (2) A frequency useful for radio transmission (roughly 10
kHz and 100,000 MHz).
SCA
Subsidiary Communications Authorization; see
"subcarrier."
S/N
Signal to Noise
spurious products
Unintended signals present on the transmission
output terminal.
stability
A tolerance or measure of how well a component,
circuit, or system maintains constant operating
conditions over a period of time.
stereo pilot
See "pilot."
stereo separation
The amount of left-channel information that
bleeds into the right channel (or vice versa).
subcarrier
A carrier signal which operates at a lower frequency 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
SWR
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.
THD
Total Harmonic Distortion
translator
A transmitter designed to internally change an
FM signal from one frequency to another for
retransmission. Used in conjunction with terrestrial-fed networks.
satellator
A transmitter equipped with an FSK ID option for
rebroadcasting a satellite-fed signal.
VSWR
Voltage Standing-Wave Ratio; see "SWR."
Wideband
See "broadband."
VCO
Voltage-Controlled Oscillator
Glossary
G–5
Index
Symbols
19–kHz
level adjustment 5–3
phase adjustment 5–3
A
AC. See power: input
ALC 3–3, 3–8, 4–8
altitude
operating range 1–8
amperes
PA DC 3–3, 3–8
amplifier
reference drawings 20
RF 4–13
bias set 5–6
antenna 2–9
mismatch 3–3
applications 1–3
audio
broadband 3–5
distortion 5–9
frequency 5–9
high 3–5
input connectors 4–3
input level 3–5
monitor connections 2–12, 4–5
performance 5–7
pre-emphasized 3–5
processing 3–5, 4–9
wide 3–5
audio processor 3–6
adjustments 5–2
board location 4–3
bypass 2–11, 2–12, 4–9
circuit description 4–3
indicators 3–5
input 3–5
reference drawings 6–4
B
backup
transmitter use 1–4
bandwidth
RF 5–8
battery. See power: input
Bessel nulls 5–9
bias set 5–6
booster
transmitter use 1–4
broadband. See audio: broadband
bypass
audio processor 2–12, 4–9
C
cables
audio input 2–10
carrier 4–9, 5–8
automatic turnoff 2–13, 3–8, 5–6, 5–
10
frequency 5–8, 5–10
carrier switch 3–4, 5–5
Channel. See frequency
channel. See frequency
main 5–10
main into sub 5–10
sub into main 5–10
chassis
circuit 4–13
circuit boards
audio processor 4–3, 6–4
display 14
metering 10
motherboard 12
power regulator 18
RF exciter 8
stereo generator 4–5, 6
voltage regulator 16
circuits
chassis 4–13
display 4–10
metering 4–8
motherboard 4–9
part numbering 4–2
power regulator 4–12
RF exciter 4–6
stereo generator 4–4
voltage regulator 4–11
components
numbering 4–2
composite
input 2–11
input connection 2–11
output
Index–1
adjustment 5–3
connectors
audio input 2–10
audio monitoring 2–12
composite in 2–11
remote I/O 2–11, 2–13
RF input 2–9
RF output 2–9
RF output monitoring 2–9
SCA In 2–11
XLR 2–11, 4–3
cooling fan 3–2
control 4–9
coverage area 1–4
crosstalk 1–7
measurements 5–9
current limit
PA 5–5
D
DC. See power: input
de-emphasis 2–12, 5–2, 5–7
jumpers 2–12
delay
program failure to carrier turnoff 2–
13, 5–6
dimensions 1–8
DIP
socket 2–10, 4–9
display
circuit description 4–10
front panel 3–2, 3–5, 3–7
modulation calibration 5–6
display board
reference drawings 14
distortion 1–7
audio 5–9
harmonic 4–5
E
emissions 5–8
exciter. See RF exciter
configuration 1–4
F
fan
control 4–9
fault
indicators 4–10
input 3–8
lock 3–8
power 3–8
servicing 3–8
SWR 3–8
Index–2
temperature 3–8
FCC guidelines 1–8, 5–8, 5–10
filter
RF output 22
frequency
carrier 5–8, 5–10
measurement 5–4
pilot 5–8
receiver 2–7
response 5–9
selection 2–5, 5–4
receiver 2–7
samples 2–6
synthesizer 5–10
frequency synthesizer. See RF exciter
adjustments 5–4
front panel
display modulation calibration 5–6
FSK 1–5, 1–6
measurement 5–4
G
gain control 3–5
gain reduction 4–4
gain switches
input 3–6
H
harmonic distortion 4–5
harmonics 5–8
heatsink 3–8
highband 3–5
processing 4–4
humidity
operating range 1–8
I
I/O connector 1–2, 2–13
pinout 2–13
indicators
audio processor 3–5
fault 3–8, 4–10
highband 3–5
LED 3–5, 3–7, 4–10
pilot 3–5
wideband 3–5, 5–6
input
audio connections 2–10
composite 2–11
fault 3–8
gain switches 3–5
program
fault 2–13
SCA connection 2–11
FM500 User's Manual
L
labels 1–10
LEDs 3–5, 4–10
line voltage 2–3
lock
status 4–7
lock fault 3–8
M
metering 1–2
circuit description 4–8
metering board
adjustments 5–5
location 4–8, 4–15
reference drawings 10
modulation 2–11, 3–5, 5–3, 5–7, 5–8
calibration 5–6
compensator 2–6
display 3–5
percentage 3–5, 5–9
monitor
audio 2–12, 4–5
mono
operation 2–11, 3–6
motherboard
circuit description 4–9
reference drawings 12
multimeter 3–7
front panel 3–3
N
networks
satellite-fed 1–6
terrestrial-fed 1–5
noise 1–7, 3–8
measurements 5–9
O
operating environment 1–8, 2–2
options 1–3, 1–4, 1–6
output
power 1–7, 3–7
display 3–7
output filter 4–14
P
pilot indicator 3–5
power
AC supply 4–13
AC voltage selection 2–3
amplifier
reference drawings 20
fault 3–8
input 1–8, 2–3
FCC guidelines 5–10
output 1–3, 1–7, 5–8
display 3–7
output filter 4–14
regulator
circuit description 4–12
RF 3–3, 3–7
RF amplifier 4–13
transformer 4–13
power regulator board
reference drawings 18
power switch 3–4
pre-emphasis 1–7, 4–4, 5–2, 5–7
curve 2–12
networks 4–3
processing
audio 2–12, 3–5
control 3–6
control setting 3–2
highband 3–5, 4–4
processor
audio
bypass 2–12
program failure 2–13, 5–10
program source 2–10, 3–6
R
receiver
frequency selection 2–7
option 1–5
specifications 1–9
reflectometer 4–14, 22
regulatory approvals 1–8
remote control 1–2
remote I/O
connector 2–13
pinout 2–13
remote operation 2–13
repair
warranty 7–3
part numbering 4–2
parts
spares 7–2
performance
checklist 5–7
tests 5–10
pilot frequency 5–8
Index–3
R (continued)
RF
amplifier 4–13
bias set 5–6
bandwidth 1–8, 5–8
exciter 2–5, 2–11
board location 2–5, 4–6
circuit description 4–6
reference drawings 8
input 1–5, 2–9
output 1–2, 1–5, 1–7, 3–3, 3–7
impedance 1–7
output filter 4–14, 22
tuning 2–7
S
safety 1–10
satellator
transmitter use 1–6
SCA 1–5
input connection 2–11
sensitivity
monaural 1–9
stereo 1–9
separation
stereo 1–7
stereo generator 5–3
service
warranty 7–3
Service Instructions 7–5
specifications
receiver 1–9
transmitter 1–7
stand-alone
transmitter use 1–4
stereo
separation 1–7, 5–9
stereo generator 1–2, 2–12
adjustments 5–3
board location 4–5
bypassing 2–11
circuit description 4–4
reference drawings 6
subcarrier 5–10
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
SWR 3–7
calibrate 5–5
fault 3–8
SWR fault 4–9
synchronization 4–11
synthesizer. See RF exciter
T
temperature
fault 3–8, 4–9
operating range 1–8, 5–10
PA 3–3, 3–8
test point
voltage 3–8
tests
performance 5–7, 5–10
time-out
program input failure 2–13
transformer 4–13
translator
transmitter use 1–5
V
VCO 4–6
voltage
AC selection 2–3
voltage regulator 3–8
adjustments 5–6
circuit description 4–11
reference drawings 16
voltage selection 2–3
voltmeter
display 3–8
volts
PA DC 3–3, 3–8
VSWR 1–2, 2–9
W
Warranty 7–3
weight 1–8
wideband 3–5, 5–6
X
XLR connectors 2–10
FM500 User's Manual
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