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SERVICE AND REPAIR 

If your system malfunctions, you should attempt to correct or isolate the trouble before concluding that the 
equipment  needs  repair.  Make  sure  you  have  followed  the  setup  procedure  and  operating  instructions. 
Check out the inter-connecting cords and then go through the TROUBLE SHOOTING section in the manual 

We strongly recommend that you 

do not 

try to repair the equipment yourself and 

do not 

have the local 

repair shop attempt anything other than the simplest repair.  If the repair is more complicated than a broken 
wire or loose connection, send the unit to the factory for repair and service.  Don’t attempt to adjust any 
controls inside the units.  Once set at the factory, the various controls and trimmers do not drift with age 
or  vibration  and  never  require  readjustment. 

There  are  no  adjustments  inside  that  will  make  a 

malfunctioning unit start working

LECTROSONICS service department is equipped and staffed to quickly repair your equipment.  In-warranty 
repairs are made at no charge in accordance with the terms of the warranty.  Out of warranty repairs are 
charged at a modest flat rate plus parts and shipping.  Since it takes almost as much time and effort to 
determine what is wrong as it does to make the repair, there is a charge for an exact quotation.  We will 
be happy to quote approximate charges by phone for out of warranty repairs. 

RETURNING UNITS FOR REPAIR 

You will save yourself time and trouble if you will follow the steps below: 

A.   DO NOT return equipment to the factory for repair without first contacting us by letter or by phone.  We 

need to know the nature of the problem, the model number and the serial number of the equipment. 
We also need a phone number where you can be reached 8 am to 4 pm (Mountain Standard Time). 

B.   After receiving your request, we will issue you a return authorization number (R.A.).  This number will 

help speed your repair through our receiving and repair departments.  The return authorization number 
must be clearly shown on the outside of the shipping container. 

C.   Pack the equipment carefully and ship to us, shipping costs prepaid.  If necessary, we can provide you 

with the proper packing materials.  UPS is usually the best way to ship the units.  Heavy units should 
be "double-boxed" for safe transport. 

D.   We also strongly recommend that you insure the equipment, since we cannot be responsible for loss 

of or damage to equipment that you ship.  Of course,  we insure the equipment when we ship it back 
to you. 

Mailing address: 

Shipping address:  

Telephones: 

Lectrosonics, Inc. 

Lectrosonics, Inc.  

(505) 892-4501 

PO Box 15900 

581 Laser Rd.  

(800) 821-1121 

Rio Rancho, NM  87174 

Rio Rancho, NM  87124  

FAX: (505) 892-6243 

USA  

USA 

World Wide Web: 

http://www.lectrosonics.com  

email: 

[email protected] 

16 

Summary of Contents for FM-AV4

Page 1: ...FM AV4 PORTABLE WIRELESS SOUND SYSTEM OPERATING INSTRUCTIONS and trouble shooting guide LECTROSONICS INC Rio Rancho NM ...

Page 2: ...wer supply and the high quality of the audio output set this system apart from any other portable PA system on the market This manual covers the FM875 RECEIVER optional microphones and transmitters TABLE OF CONTENTS INTRODUCTION 2 GENERAL TECHNICAL DESCRIPTION 4 RECHARGEABLE BATTERIES 4 CONTROLS AND FUNCTIONS 5 TRANSMITTERS 7 SYSTEM SETUP 9 OPERATING TIPS 10 OPERATING INSTRUCTIONS 11 MICROPHONE CH...

Page 3: ...ound system all at the same time The FM875 is powered by built in rechargeable batteries and will easily operate for over 12 hours after an overnight charge The sound output will cover an audience of several hundred people RECHARGEABLE BATTERIES It is very important to recharge the battery pack immediately after the unit is used The battery pack is charged by plugging the CH 40 charger into the ja...

Page 4: ...ll go out when the batteries are discharged CHARGE LED Lights when the unit is being charged This green led will go out when the batteries are fully charged OMNI BUS IN OUT An RCA phono jack that functions both as a line level input and line level output This omnibus jack is primarily used for interconnecting several FM875s together for simultaneous operation This jack can also be used with a tape...

Page 5: ...of the MIC OR AUX IN and the AUX IN inputs MIC OR AUX IN This jack is a standard 1 4 phone jack and will accept a dynamic microphone WIRELESS MIC VOLUME This control adjusts the volume of the built in wireless microphone system knob does not affect the MODULATION LEDs located near it This MODULATION LEDs The 20 and LIMIT Leds continuously indicate the modulation level audio level of the received s...

Page 6: ...ch should be left in the off position when the transmitter is not in use When the switch is in the on position the battery will be drained even though the transmitter is not being used The BATTERY INDICATOR LAMP will light when the transmitter is turned on and will stay lit as long as the battery is good As the battery voltage drops the lamp will grow dim and finally go out The MIC LEVEL is a rece...

Page 7: ...time remaining When the battery voltage is too low for proper transmitter operation the sound from the wireless system may be distorted intermittent or totally absent When the transmitter is first turned on the lamp may light for a short while even with a bad battery It is good practice to check the brightness of the lamp after the transmitter has been on for several minutes and to note the bright...

Page 8: ...th the direct signal If the direct and reflected signals are out of phase with each other as depicted in the figure below a partial or complete cancellation of the received signal will occur The result will be a drop out A drop out sounds like either a hum or hiss or in severe cases may result in a complete loss of the sound when the transmitter is positioned in certain locations in the room Movin...

Page 9: ...e FM875 Feedback is generally more of a problem when using lavalier lapel type microphones than with hand held or headset type microphones because the microphone is farther from the mouth See below for more details on feedback 8 The standard FM AV4 system includes an M140 cardioid lavalier microphone This directional microphone will minimize background noise and provide resistance to feedback when...

Page 10: ...on in the same location it will be in during actual operation The microphone should ideally be within 6 to 10 inches from the mouth to minimize feedback 9 A small screwdriver is supplied with the transmitter The screwdriver is used to adjust the audio gain of the transmitter to match the microphone with your voice The adjustment is made while observing the MODULATION lamps on the FM875 control pan...

Page 11: ...k connect the AUX IN on the unit with the AUDIO OUT line level on the tape recorder Set the AUX VOLUME at about 6 then adjust the volume control on your tape player to get the desired volume Not all tape recorders will work with the FM AV4 Low cost tape recorders may not have line level inputs and outputs required for quality recording and playback CONNECTING INTO HOUSE SOUND SYSTEMS 1 Connect MIC...

Page 12: ...75 using a standard microphone cord MM 16 or MC 16C The M121S is available as an accessory item HM142V This single band headset microphone is normally worn on the head but can also be worn around the neck for hands free operation It provides maximum gain before feedback since the microphone is very close to the user s mouth The built in volume control helps control feedback in difficult environmen...

Page 13: ...ransmitter gain control set much too low 4 Transmitter audio muted Check to see that the audio is not muted on your transmitter if this feature is available on your model transmitter NO SOUND BUT RECEIVER MOD LEVEL LEDs ARE ON 1 WIRELESS or AUX VOLUME control turned completely down 2 Sound system or recorder input is turned down 3 Defective speaker DISTORTED SOUND 1 Transmitter gain audio level is...

Page 14: ...Wind Screen RK 119 Wind Screen RK 142 Wind Screen USE Replacement With locking micro plug With locking micro plug For hand held use plugged into the AUX MIC INPUT jack of the FM875 cord not supplied 16 ft coiled cord 1 4 male to male for M121S Straight cord 1 4 male to male for M121S 36 RCA male to male for interconnecting HI LEVEL IN and OUT jacks with other equipment For M121S microphone For M14...

Page 15: ...n Below the noise at all input levels Spurious image rejection Greater than 100dB M175 SERIES TRANSMITTERS Operating frequencies 169 to 186 MHz RF Power Output 50 mW Deviation 15kHz Spurious Radiation 50dB below carrier Frequency Stability 0 005 Equivalent Input Noise 123dB Input Sensitivity 8mV to 1 6V for full modulation Input Compressor Soft Compressor 12dB range Electret Bias 5 Volt DC positiv...

Page 16: ...n exact quotation We will be happy to quote approximate charges by phone for out of warranty repairs RETURNING UNITS FOR REPAIR You will save yourself time and trouble if you will follow the steps below A DO NOT return equipment to the factory for repair without first contacting us by letter or by phone We need to know the nature of the problem the model number and the serial number of the equipme...

Page 17: ......

Page 18: ...evelop we will at our option repair or replace any defective parts without charge for either parts or labor If we cannot correct the defect in your equipment we will replace it at no charge with a similar new item We will pay for the cost of returning your merchandise to you This warranty applies only to items returned to us shipping costs prepaid within one year from the date of purchase This war...

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