Ttellabs 9791 Loudspeaker

practice section 829791
©Tellabs, Inc., 1 December 1983
all rights reserved, printed in USA
Ttellabs
technical manual
76-829791
rev A
9791 Loudspeaker
contents
page 1
section 1
general description
page 1
section 2
application
page 1
section 3
installation
page 2
section 4
specifications
page 3
section 5
tunctional wiring diagram
page 4
section 6
testing and troubleshooting
1.
general description
1.01
The Tellabs 9791 Loudspeaker (figure 1) is a
0.5 watt amplifier unit with an integral5-inch speaker.
The 9791 features automatic gain control circuitry
and is equivalent to the industry-standard Type
1066 Loudspeaker.
1.02
The 9791 is enclosed in an attractive, neutralgreen metal enclosure with a brushed aluminum
front screen and bezel. Four rubber feet (removable)
are provided on the 9791 for desktop applications.
1.03
Input impedances of 2400,600 or 1.5 ohms
(wire optional) are provided on the 9791 Loudspeaker.
The 2400 and 600 ohm impedance inputs are capacitiveiy coupled, while the 1.5-ohm input features
direct coupling.
1.04
Three controls for amplifier gain are incorporated into the 9791 Loudspeaker. One is externally adjustable; the other two may only be accessed
internally. One of the internal controls, the output
level control, sets a maximum speaker output level
(even in overload conditions). The other, the chassis
gain control, sets the minimum and maximum volume
level ranges through which the front-panel volume
control can be adjusted. The front-panel volume control may be optionally disabled, allowing adjustment
from an external control.
Figure 1. 9791 Loudspeaker
2.02
The internal speaker of the 9791 may be optionally disabled and the amplifier's output (3.2 ohm
impedance) used to drive an external device.
3.
installation
inspection
3.01
The 9791 Loudspeaker should be visually inspected upon arrival in order to find possible damage
incurred during shipment. If damage is noted, a claim
should immediately be filed with the carrier. If stored,
the unit should be visually inspected again prior to
installation.
1.05
Incorporated into the front-panel volume
control is an on/off switch that allows the unit to be
turned on and off at the user's convenience. This on/
off control may be optionally disabled to provide continuous operation, or it may be optionally replaced
with an external control. Also located on the front
panel is a pilot lamp that lights when the unit is
active.
desk mounting
3.02
The Loudspeaker is equipped with four rubber feet for desktop use. Select a location that is free
from excessive noise. lithe Loudspeaker is used on a
telephone line, allow a minimum separation of 3 feet
between the unit and the telephone set to minimize
feedback.
1.06
The 9791 Loudspeaker will operate on ±20
to 56Vdc, 200mA input power source.
cover removal
3.03
In order to make the installer connections to
the 9791, the rear cover must be removed. Loosen
the two screws on the rear olthe unit and remove the
cover. An access hole is provided through the cover
for cable entry. Make sure that the external leads to
the 9791 Loudspeaker pass through this opening.
3.04
All connections (except power) are made to
2.
application
2.01
The 9791 Loudspeaker may be used to provide amplification and voice broadcasting in a wide
variety of applications. It is commonly used with the
Tellabs 265A Voice Signaling System as the loudspeaker for a voice paging network. In this "hoo!'n'holler" system, any telephone in the system going
off-hook seizes the network and broadcasts a mes-
screws located on the back of the 9791. Make the in-
sage through loudspeakers at all other locations. For
more detailed information, refer to the Tellabs 265A
Voice Signlaing System Practice.
staller connections in accordance with the functional
wiring diagram (section 5) and the option instructions
in paragraphs 3.05 through 3.11.
page 1
"
practice section 829791
3.05
The 9791 Loudspeaker is factory optioned
with the front-panel off!on/Volume control functional
and the integral speaker strapped in. If the Loudspeaker is to be used in this standard arrangement,
only two option selections plus input power connections need be made.
Off/On/volume control option
3.06
The front-panel volume control is factory wired
so that the integral speaker is cut-all at minimum
volume setting. If it is desired thatthespeaker beaudible at minimum volume settings, remove the white
wire from terminal D and connect it to terminal C.
3.07
The 9791 Loudspeaker will operate from within a positive or negative grounded 20 t056Vdc power
supply. If a negative grounded supply is used, connect the negative side of the power supply to the terminal, and the positive side of the supply to the
+V1 terminal. Remove one end of the green jumper
from the chassis ground screw and connect it to the
-V terminal. If the power supply is positive grounded,
remove one end of the green jumper wire from the
chassis ground screw and connect it at the +V1
terminal.
3.08
If the on/all function of the front panel on/off!
volume control is to be removed from the circuit, connect the positive side of the power supply to the
+V2 terminal.
Note: If one end of the green jumper wire from the
chassis ground is connected to the +Vl terminal,
remove it, and connect it to the +V2 terminal. To disable the votume controt function of the on/off/volume
control remove the white wire from terminal 0 and connect it to terminal B.
remote volume control
3.09
If the volume control function of the front
panel on/oll/Volume control was disabled (paragraph
3.08) and because a remote volume control is required,
connect the remote volume control as follows: remove
and tape the red, blue and white leads from terminals
A Band D, respectively, and connect. the external
volume control to the appropriate terminals.
input impedance options
3.10
The 9791 Loudspeaker can be wire-optioned
for 2400, 600 or 1.5 ohm input impedance. If 2400
ohm input impedance is required connect the input
leads to screw terminals com and 2400. For600-ohm
input, connect the leads to screw terminals com and
600; and for 1.5·ohm input impedance, connect the
leads to screw terminals com and 1.5.
speaker options
3.11
The 9791 is factory optioned to use the integral speaker. If an external speaker or other device
is to be used, remove and tape the wires can nected to
the LS1 terminals, and connect external speaker to
the LS1 terminals.
3.12
Two signal level adjustments are required for
proper Loudspeaker operation. The chassis gain
control (located near the top of the pc board) sets the
minimum and maximum volume level range through
which the Loudspeaker may be adjusted. The output
level control, which is also located near the top of the
pc board, prevents output signals from exceeding a
predetermined level, even for input overload conditions. To adjust the level controls of the 9791 Loudspeaker, proceed as follows:
A. Initiate a call to make the 9791 operational.
B. Turn chassis gain potentiometer 5 turns from
maximum clockwise position.
Note: Chassis gain control is a 20-turn potentiometer.
C. Turn front panel on/off/Volume control to maximum clockwise position.
D. Turn output level potentiometer 5 turns from
maximum counterclockwise position.
Note: Output level control is also a 20-turn potentiometer.
E. Have called party talk. Turn chassis gain potentiometer to a point just before crosstalk or noise
is present.
F. Turn output level potentiometer to desired loudness.
G. When all installer connections and level adjustments are completed, the rear cover may be
replaced.
4.
specifications
power requirements
input power: ±20 to 56Vdc
input current (quiescent): 200mA
input impedance
2400, 600 or 1.5 ohms
acoustic power output
97.5dBAat18 inches
acoustic response (amplifier and speaker)
±5dB, 350 to 5000Hz
frequency response (amplifier)
±3dB 200 to 5000Hz
input sensitivity (600 ohms)
minimum required for full output: -60dBm
maximum allowable for less than 5% distortion:
-5dBm at 1000Hz
operating environment
32- to 120-F (0' to 49-C), humidity to 95%
(no condensation)
dimensions
5.5 inches (14.0cm) wide
6.20 inches (15.7cm) hi9h
4.75 inches (11.7cm) deep
weight
5.5 pounds (2.5kg)
mounting
desktop
page 2
practice section 829791
2400
600
LINE
INPUT
TERMINALS
COM
1.5
M~
CHASSIS
GAIN CONTROL
A
B
STRAP
PANEL
VOLUME
CONTROL
Cer1
MINIMUM
VOLUME LIMIT
Der-1
NOMINIMIM
VOLUME LIMIT
E
AUTOMATIC
GAIN CONTROL
F
OUTPUT LEVEL
CONTROL
WHITE
BLUE
LOUDSPEAKER
LS1
PANEL ON-OFF
SWITCH
+V1
FILTERED
DC SUPPLY
INPUT
TERMINALS
+V2
-V0
0-1
l
CHASSIS
GROUND
figure 5. Functional wiring diagram
page 3
POWER
SUPPLY
practice section 829791
6.
are available). If the situation is not critical, follow the
testing and troubleshooting
6.01
The testing guide checktist in this section
may be used to assist in the installation, testing, or
troubleshooting of the 9791 Loudspeaker. The
checklist is intended as an aid in the localization of
trouble to the Loudspeaker. If a Loudspeaker is
suspected of being defective, a new one should be
substituted and the test conducted again. If the
substitute Loudspeaker operates correctly, the
original Loudspeaker should be considered defective and returned to Tellabs for repair or replacement as directed below. We strongly recommend
that non internal (component-level) testing or
repairs be attempted on the Loudspeaker. Unauthorized testing or repairs may void the Loudspeaker's warranty. Also, if the Loudspeaker is part
of a registered system, unauthorized repairs will
result in noncompliance with Part 68 of the FCC
Rules and Regulations.
6.02
If a situation arises that is not covered in
the checklist, contact Tellabs Customer Service as
follows (telephone numbers are given below):
USA customers: Contact Tellabs Customer Service
at your Tellabs Regional Office.
Canadian customers: Contact Tellabs Customer
Service at our Canadian
headquarters in Mississauga,
Ontario.
International customers: Contact your Tellabs
distributor.
US central region: (312) 969-8800
US northeast region: (412) 787-7860
US southeast region: (305) 645-5888
US western region: (702) 827-3400
Canada: (416) 624-0052
6.03
If a Loudspeaker is diagnosed as defective,
follow the reptacement procedure in paragraph
6.04 when a critical circuit is down and no spares
repair and return procedure in paragraph 6.05.
replacement
6.04 To obtain a replacement Loudspeaker, notify
Tellabs via letter or telephone (see addresses and
numbers below) or via TWX (910-695-3530 in the
USA, 610-492-4387 in Canada). Be sure to provide
all relevant information, including the 8X9791 part
number that indicates the issue of the Loudspeaker
in question. Upon notification, we shall ship a
replacement Loudspeaker to you. If the Loudspeaker in question is in warranty, the replacement
will be shipped at no charge. Pack the defective
Loudspeaker in the replacement Loudspeaker's
carton, sign the packing slip included with the
replacement, and enclose it with the defective
Loudspeaker (this is your return authorization).
Affix the preaddressed label provided with the
replacement Loudspeaker to the carton being
returned, and ship the Loudspeaker prepaid to
Tellabs.
repair and return
6.05
Return the defective Loudspeaker, shipment prepaid, to Tellabs (attn: repair and return).
in the USA: Tellabs, Inc.
4951 Indiana Avenue
Lilse, Illinois 60532
telephone (312) 969-8800
in Canada: Tellabs Communications Canada, Ltd.
1200 Aerowood Drive, Unit 39
Mississauga, Ontario, Canada L4W 2S7
telephone (416) 624-0052
Enclose an explanation of the Loudspeaker's malfunction. Follow your company's standard procedure with regard to administrative paperwork
Tellabs will repair the Loudspeaker and ship it back
to you. If the Loudspeaker is in warranty, no invoice
will be issued.
testing guide checklist
trouble condition
probable cause (in order of likelihood)
unit dead
1) Power connection faulty and/or on/off switch wiring incorrect. Verify
presence of input power by measuring voltage between terminals +V1 and
-V (if front panel on/off switch used) or +V2 (if front panel on/off switch
bypassed) D.
no output from speaker
1) Incorrect input wiring D.
2) Volume control wiring incorrect D.
page 4
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