Infinity MSW-II, Service Manual

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Modulus MSW-II TEST PROCEDURE
The operation of the Modulus MSW-II subwoofer, and the proper settings for the Room Adaptive Bass Optimization System,
or R.A.B.O.S., is thoroughly covered in the Owner’s guide, part# 406-000-00921.
For service purposes, the R.A.B.O.S. system is canceled when all three front panel controls (F) (L) (W) are turned fully CW
(Clockwise), or if the R.A.B.O.S. On/Off switch is OFF. The only other control of concern is the Main Level Control on the
front panel, which operates like a traditional potentiometer.
Equipment needed:
x
Function/signal generator/sweep generator
x
Integrated Amplifier
x Multimeter
x RCA cables; Speaker cables
General Unit Function (UUT = Unit Under Test)
Switch/Controls:
MAIN LEVEL control full clockwise (0)
LOW PASS FILTER switch OFF
R.A.B.O.S. On/Off switch OFF
PHASE button - either position
(3) R.A.B.O.S. controls – do not matter
1) From the signal generator, connect one line level (RCA) cable to the Input jacks (L/R) on the UUT. Use a Y-
cable from a mono source if necessary to connect to both inputs.
2) Turn on generator; adjust to 150mV, 50 Hz .
3) Plug AC power cord in UUT, turn power switch ON.
4) Red LED should ON (in the Level wheel at the front of the UUT). Turn up LEVEL control to full
counterclockwise (10).
5) Green LED should ON; Bass response should be heard and felt from port tube opening.
6) Turn LEVEL control full clockwise (0). Turn power switch OFF.
Sweep Function
1) Follow steps 1-3 above, using a sweep generator as a signal source – adjust the generator to 100mV, 50 Hz .
2) Sweep generator from 20Hz to 300Hz. Listen for any rattles, clicks, buzzes or any other noises. If any unusual
noises are heard, test woofer according to the instructions below.
Driver Function
1) Remove woofer from the enclosure; (see exploded view on page 8).
2) Check DC resistance of woofer; it should be
3.5
:
±10%,
3) Connect a pair of speaker cables to woofer 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 6.0V.
4) Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
MSW-II
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