Infinity ENTRA, Service Manual

Page: 11 / 25

Entra Subwoofer
11
SYSTEM AURAL SWEEP TEST
Equipment needed:
• Function/signal generator/sweep generator
• Integrated Amplifier
• Multimeter
• Speaker cables
General Unit Function (UUT = Unit Under Test)
Switches/knobs on the amplifier faceplate:
Crossover Frequency adjust full CW (150Hz)
Phase switch – either position
1. From the signal generator, Connect single line level input (RCA) cable to “Line Level Input” jack on UUT.
2. Turn the LEVEL control full counterclockwise (Min).
3. Turn on generator, adjust to
400mV, 30 Hz .
4. Plug in UUT; turn the power switch ON. Turn LEVEL control full clockwise (Max)
5. LED should now be Green; immediate bass response should be heard and felt from rear port tube
opening.
6. Turn off generator, turn LEVEL control fully counterclockwise (Min), disconnect RCA cable.
7. Connect two pairs of speaker cables to Speaker Level input terminal on UUT. Cables should be connected
to an integrated amplifier fed by the signal generator. Observe polarity.
8. Turn on generator and adjust so that speaker level input at the amplifier is 6.0V, 30 Hz. Turn LEVEL
control full clockwise (Max)
9. Green LED should light, immediate bass response should be heard and felt from the port tube opening.
Sweep Function
1. Follow steps 7-10 above, using a sweep generator as a signal source.
2. Sweep generator from 20Hz to 20kHz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or
any other noises. If any unusual noises are heard, remove woofer and test.
Driver Function (Woofer)
1. Remove woofer from cabinet; and - wire clips. See page 9 for removal instructions.
2. Check DC resistance of woofer; it should be
3.3 ohms ±10%.
3. Connect a pair of speaker cables to driver terminals. Cables should be connected to an integrated
amplifier fed by a signal generator. Turn on generator and adjust so that speaker level output is 5.0 V.
4. Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
Test Setup and Procedure
SIGNAL
GENERATOR
AMPLIFIER
AC VOLT
METER (10V)
ENTRA SUB
UNDER TEST
OUTPUT FROM
GENERATOR/AMPLIFIER
AMPLIFIER MADE IN CHINA
INFINITY SYSTEMS INC. NORTHRIDGE, CA, USA
R
WARNING: SHOCK HAZARD-DO NOT OPEN
NO USER SERVICEABLE PARTS INSIDE
AVIS: RISQUE DE CHOC ÉLECTRIQUE-
NE PAS OUVRIR
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO
NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
ATTENTION: POUR ÉVITER TOUT RISQUE DE FEU OU CHOC
ÉLECTRIQUE, NE PAS EXPOSER CET APPAREIL À LA PLUIE OU À
L'HUMIDITÉ.
SERIAL NO.
OFF ON
120V ~ 60Hz 3A
POWER
R
+
_
+
_
L
OUTPUT INPUT
DIRECT INPUT BYPASSES FILTER
LEVEL
00473
R
DIRECT
+
_
M IN
+
INPUT
LINE
LEVEL
_
L
120
CROSSOVER
80
60
180°
M AX
0°
50 150
PHASE
FREQUENCY
R
SPEAKER LEVEL