Lectrosonics CR175 User manual

CR175
COMPACT RECEIVER
OPERATING INSTRUCTIONS
and trouble-shooting guide
LECTROSONICS, INC.
Rio Rancho, NM
U.S. Patent Number: 5,414,776 and 5,402,500

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Compact Receiver
INTRODUCTION
Thank you for selecting the Lectrosonics Professional Series wireless microphone
system. This system represents well over 10 years of manufacturing experience in
wireless microphones, and almost 70 years of design experience.
The CR175 receiver design is the result of surveying the needs of professional video
producers, ENG cameramen and many others in the broadcast and pro video
industry. Hundreds of conversations with dealers and end-users developed the final
parameters for the design.
The CR175 receiver is a fixed frequency design that eliminates the need to “tune” or
adjust the receiver every time it is used. This is the preferred design for a number of
reasons, among them simplicity of operation, no adjustments in “high pressure”
situations, and interference rejection by design rather than by trying to “tune” it out.
The CR175 miniature receiver was designed by professionals for outstanding
performance and flexibility, while preserving ease of operation. It is compatible with
all Lectrosonics VHF narrow-band transmitters. The CR175 receiver represents one
of the best values in wireless receivers, regardless of price.
TABLE OF CONTENTS
INTRODUCTION .................................................................................................. 3
CONTROLS AND FUNCTIONS - FRONT PANEL.............................................. 4
CONTROLS AND FUNCTIONS - REAR PANEL ................................................ 6
BATTERY REPLACEMENT ................................................................................. 6
ANTENNA USE AND PLACEMENT ................................................................... 7
OPERATING INSTRUCTIONS ............................................................................ 8
INDICATOR QUICK REFERENCE ...................................................................... 8
TROUBLESHOOTING ......................................................................................... 9
CR175 REPLACEMENT PARTS AND ACCESSORIES ..................................... 9
SPECIFICATIONS .............................................................................................. 10
SERVICE AND REPAIR ..................................................................................... 11
RETURNING UNITS FOR REPAIR ................................................................... 11
WARRANTY ......................................................................................... Back cover
The CR175 is type acccepted by the Federal Communications Commission
FCC ID: DBZCR175
Rio Rancho, NM – USA
3

CONTROLS AND FUNCTIONS - FRONT PANEL
MODULATION LEDs
Indicate the modulation (audio level) of the incoming signal, and can be used for proper adjustment of the
transmitter’s “MIC LEVEL” or “GAIN”. The -20 LED glows when the transmitter modulation is at a high enough level to
produce a good audio signal-to-noise ratio. It will normally flicker, or stay lit as you speak into the microphone. The
0dB lamp indicates a “peak,” showing that the transmitter modulation is at maximum. Constant lighting may indicate
that the audio gain in the transmitter may be set too high. It is normal and desirable that you see an occasional flicker
of the 0dB lamp in typical use.
OUTPUT CONTROL
Attenuates the audio output level of the receiver to match the input requirements of the equipment with which it is
used. The XLR output jack on the rear panel provides an audio output at microphone level for low impedance,
balanced inputs. At the extreme counter-clockwise position of the control knob, the output level of this XLR jack will
be 50dB at full modulation. In the fully clockwise position, the output level will be -20dB at full modulation. Intermedi-
ate settings are sometimes necessary due to the variations in different input compressors and ALC (automatic level
control) circuits on various VCR’s and audio inputs. The markings around the control knob are provided simply as
“memory markers;” they are not calibrated with reference to a specific output level.
OFF/ON POWER SWITCH
Turns the receiver power off and on.
POWER LED
Glows when the power switch is in the proper position and the battery is good, or when external 12 Volt DC power is
properly supplied. If this LED is very dim or does not light up when the switch is turned on, replace the battery or
check the connections from the external power source. The LED glows brightly to indicate a good battery and dims
as the battery voltage decreases.
The POWER LED is connected to a precision battery test circuit that continuously monitors battery voltage. The LED
is at full brightness with a new 9 volt alkaline battery. As the battery voltage drops during use, the LED brightness will
also decrease. After 4 to 5 hours, the battery voltage will be about 7 volts. The LED will be completely extinguished.
IMPORTANT!
When the battery voltage drops below 6 Volts, the power LED will remain off, but the other
3 LEDs will light up and a loud rush of audio noise will be heard as the squelch opens.
This condition is normal, and is easily remedied by replacing the battery.
4

Compact Receiver
OUTPUT
OFF
POWER RF
ON
LECTROSONICS
CR175
-20 0dB
MODULATION
Since the internal circuits are all tightly regulated the receiver will continue to operate to a battery voltage of 6.5 volts.
From 6.5 volts to 6 volts, the receiver will still operate, but with degraded performance. Below 6 volts, the regulated
and temperature compensated squelch circuit will cease to be regulated. The result is that the squelch circuit will
remain “open”. This will allow considerable noise to pass through the audio circuits if the associated transmitter is off,
or if other circuits of the CR175 stop operating because of the low voltage condition. In addition, three out of the four
LEDs on the front panel will light (the exception being the POWER LED). Please note that a weak battery will some-
times light the POWER LED immediately after turn on, but soon will discharge to the point where the LED will extin-
guish. Regular installation of fresh batteries will insure optimum operation.
RF LED
Lights when the transmitter is turned on and the receiver has a good signal. When the carrier signal from the trans-
mitter is too weak to produce a clean audio signal, the lamp will go out.
MINI PHONE JACK
Provides a monitor, separate from the rear panel XLR audio output. The output level from this jack is controlled by the
recessed trim-pot on the side panel.
The output at this mini connector is designed for a medium impedance earphone. An earphone with an impedance
between 30 and 300 Ohms will usually provide adequate volume. The sound from a low impedance ear phone (ie. 8
Ohms) will not be very loud and may be distorted at higher listening levels.
ANT TERMINAL
Connects to any 50 ohm antenna with a BNC type connector (a telescoping whip antenna is supplied). The A-185
Coax remote type antenna may also be used.
Rio Rancho, NM – USA
5

CONTROLS AND FUNCTIONS - REAR PANEL
12 VDC INPUT
Connects to the supplied CH-12 AC adapter for powering the receiver from a 110/120V AC source. The receiver may
also be powered from external 12 volt DC sources using the correct plug (Switchcraft S-760 power plug). The center
pin is positive (+). The receiver has built in polarity protection which protects the receiver from damage in case of
reversed polarity.
AUDIO OUTPUT
Supplies a balanced, low impedance output at microphone level. The audio signal is output on pins 2 and 3, while pin
1 is ground. The output level of this jack is controlled by the OUTPUT control on the front panel of the receiver. The
connector is a standard XLR type.
BATTERY REPLACEMENT
The CR175 is powered by a standard alkaline 9 volt battery. It is important that you use ONLY an ALKALINE battery
for longest life. Standard zinc-carbon batteries marked “heavy duty”or “long-lasting”are not adequate. They will
provide only about one hour of operation. Similarly, nicad rechargeable batteries give less than 2 hours of operation,
and will also run down quite abruptly. Alkaline batteries provide about 5 hours of operation.
To open the battery compartment, press outward on the cover door in the direction of the arrow as shown in the
drawing. Only slight, sliding pressure is needed to open and close the battery door.
Swing the door open and take note of the polarity marked inside showing the location of the positive (+) and negative
(-) terminals. Insert the battery and close the cover by pressing in and across, reversing the opening procedure
outlined above. Note that the battery door will NOT close if the battery is inserted incorrectly, since the terminals will
hit a protective polarity barrier. Do not force the battery in.
TO OPEN
AUDIO OUTPUT 12 VOLT DC INPUT
Center Pin Positive
(
+
)
6

Compact Receiver
ANTENNA USE AND PLACEMENT
Connect the antenna to the front panel jack. Position the antenna so that it is not within 3 or 4 feet of large metal
surfaces. If this is not possible, try to position the antenna so that it is as far away from the metal surface as is
practical. It is also good to position the receiver so that there is a direct “line of sight”between the transmitter and the
receiver antenna. In situations where the operating range is less than about 50 feet, the antenna positioning is much
less critical.
A wireless transmitter sends a radio signal out in all directions. This signal will often bounce off nearby walls, ceilings,
etc. and a strong reflection can arrive at the receiver antenna along with the direct signal. If the direct and reflected
signals are out of phase with each other a cancellation may occur. The result would be a “drop out.” A drop out
sounds like either audible noise (hiss), or in severe cases, may result in a complete loss of the carrier and the sound.
Moving the transmitter even a few inches may eliminate it. A dropout situation may be either better or worse as the
crowd fills and/or leaves the room, or when the transmitter or receiver is operated in a different location.
Dropouts can be avoided by careful placement of the receiver. If you are mounting the receiver on a video camera or
camcorder, experiment with the location prior to going into the field. By placing the antenna above the body of the
camera, you will increase your operating range. If the antenna is laid next to the camera, as shown in the illustration
below, the body of the camera will serve as a shield and reduce range. This position may work but be certain at least
part of the antenna extends above the camera. Alternate locations can include the back of the camera, the top of the
camera or mounted vertically on the side.
If dropouts occur in the field, moving the transmitter or receiver slightly in any direction will usually eliminate the
problem.
Example mounting locations
for single or multiple receiver(s).
Rio Rancho, NM – USA
7

OPERATING INSTRUCTIONS
1) Connect the power cord or install the battery.
2) Attach and extend the antenna.
3) Connect the audio cable.
4) Set the front panel switch to either “EXT”or “INT”, depending upon the power source. Check to see that the red
POWER LED lights up.
5) THIS IS PERHAPS THE MOST IMPORTANT STEP IN THE SET UP PROCEDURE. Adjust the transmitter
“gain”. See your transmitter manual (Operating Instructions section) for specific directions on the proper gain
adjustment of your particular transmitter.
6) Adjust the output control according to the type of input on your equipment. The input levels on different VCR’s
and PA equipment vary, which may require that you set the OUTPUT control in an intermediate position. Try
different settings and listen to the results. If the output of the receiver is too high, you may hear distortion or a
loss of the natural dynamics of the audio signal. If the output is too low, you may hear steady noise (hiss) along
with the audio. The CR175 output was designed to drive microphone level inputs. The output signal level ranges
from -50dBV with the output control fully counter clockwise to -20dBV with the output control fully clockwise.
INDICATOR QUICK REFERENCE
(Refer to Controls and Functions section for more detailed descriptions)
RF - This LED lights up when the transmitter is turned on. This indicates that the receiver is getting an adequate RF
signal (carrier) from the transmitter.
POWER - This LED lights up when the receiver is properly connected to a power supply and switched on. It indicates
proper battery voltage when the receiver is using a battery.
MODULATION - The “-20”LED lights up when an audio signal is present at an adequate level to produce a good
signal to noise ratio. The “0dB”LED lights up when the audio level is high and the signal is being compressed in the
transmitter. An extremely high audio level may cause distortion.
REVIEW THE TRANSMITTER INSTRUCTION MANUAL FOR
PROPER ADJUSTMENT AND SETUP OF THE TRANSMITTER
MIC LEVEL OR GAIN.
8

Compact Receiver
TROUBLESHOOTING
Before going through the following chart, be sure that you have a good battery in the receiver (or a properly con-
nected AC adapter). The POWER LED should glow brightly.
SYMPTOM POSSIBLE CAUSE
NO POWER LED 1) Receiver switch in “OFF”position
2) Dead or weak battery
3) External 12 Volt power disconnected
4) CH-12 AC adapter disconnected
5) Receiver switch in wrong position for the power
source used
NO RF LED 1) Transmitter not turned on
2) Transmitter battery dead
3) No microphone on transmitter (the microphone serves
as the antenna
4) Receiver antenna not connected
RF LED ON BUT NO SOUND 1) Transmitter switch in “MUTE”
AND NO MODULATION LEDS position
2) Transmitter microphone not connected
3) Microphone switch in “OFF”position
4) Possible malfunction in the audio section of the
transmitter See transmitter manual
5) Check transmitter modulation LEDs for possible
transmitter problem
MODULATION LED’s ON 1) Receiver LEVEL control turned
BUT NO SOUND down.
2) Audio cable disconnected
3) Recorder or sound system off, or not properly adjusted.
CR175 REPLACEMENT PARTS AND ACCESSORIES
Part No. Description
CH-12 110 Volt AC adapter for CR175 receiver
A-185 Coax Remote, folded-dipole antenna with coaxial cable
35753 System pouch
A-195RA Helical, flexible (“rubber duckie”)antenna with a 9inch
whip and a right angle BNC connector
A195S Ruber Duckie Antenna
Rio Rancho, NM – USA
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SPECIFICATIONS
Operating Frequencies:
RF Sensitivity:
IF Selectivity:
Squelch Quieting:
AM Rejection:
Modulation Acceptance:
Third Order Intercept:
Distortion:
Signal/Noise Ratio:
Audio Outputs:
Antenna Input:
Controls:
Indicators:
Power Requirements:
Power Consumption:
Weight:
Dimensions:
169 to 186 MHz, crystal controlled
–110 dBm for 20 dB Sinad (0.7 uV)
•150 kHz interference bandwidth
• –30 dB @ ±200 kHz
–109 dB
below the noise at all input levels
±15 kHz
+5 dBM
0.5% @ 1 kHz, 12 kHz deviation (system)
–90 dB (system)
XLR: 200 Ohms bal; 100 mV max.
Front Panel Monitor: “Off”to –20 dBm
BNC; 50 Ohms impedance
•Front panel attennuator controls XLR output
•Recessed trim-pot controls headphone
•3 position power/function switch
•Red LED for power ON
•2 LEDs for mod level
•RF LED for transmitter ON
•12 Volts DC external (either polarity)
•110 Volts AC via CH-12 AC adapter
•Single 9 Volt alkaline battery
70 mA @ 12 kHz deviation, 61 mA @ idle
11 ounces including battery
1.1 x 2.75 x 5.2 inches
Specifications subject to change without notice
10

Compact Receiver
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 intercon-
necting 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 connec-
tion, 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:
Lectrosonics, Inc.
PO Box 15900
Rio Rancho, NM 87174
USA
Shipping address:
Lectrosonics, Inc.
581 Laser Rd.
Rio Rancho, NM 87124
USA
Telephones:
Regular: [phone]
Toll Free [phone]
FAX: [phone]
World Wide Web: http://www.lectrosonics.com Email: [e-mail]
Rio Rancho, NM – USA
11

LIMITED ONE YEAR WARRANTY
The equipment is warranted for one year from date of purchase against defects in
materials or workmanship provided it was purchased from an authorized dealer. This
warranty does not cover equipment which has been abused or damaged by careless
handling or shipping. This warranty does not apply to used or demonstrator equipment.
Should any defect develop, Lectrosonics, Inc. will, at our option, repair or replace any
defective parts without charge for either parts or labor. If Lectrosonics, Inc. cannot
correct the defect in your equipment, it will be replaced at no charge with a similar new
item. Lectrosonics, Inc. will pay for the cost of returning your equipment to you.
This warranty applies only to items returned to Lectrosonics, Inc. or an authorized
dealer, shipping costs prepaid, within one year from the date of purchase.
This Limited Warranty is governed by the laws of the State of New Mexico. It states the
entire liablility of Lectrosonics Inc. and the entire remedy of the purchaser for any
breach of warranty as outlined above. NEITHER LECTROSONICS, INC. NOR
ANYONE INVOLVED IN THE PRODUCTION OR DELIVERY OF THE EQUIPMENT
SHALL BE LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, CONSEQUENTIAL,
OR INCIDENTAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THIS EQUIPMENT EVEN IF LECTROSONICS, INC. HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES. IN NO EVENT SHALL THE LIABILITY OF
LECTROSONICS, INC. EXCEED THE PURCHASE PRICE OF ANY DEFECTIVE
EQUIPMENT.
This warranty gives you specific legal rights. You may have additional legal rights which
vary from state to state.
LIMITED ONE YEAR WARRANTY
LECTROSONICS, INC.
581 LASER ROAD
RIO RANCHO, NM 87124 USA
November 1, 2001