Infinity IL50 L, Service Manual

Page: 25 / 47

Test Set Up and Procedure
SYSTEM AURAL SWEEP TEST
Equipment needed:
• Function/signal generator/sweep generator
• Integrated Amplifier
• Multimeter
• Speaker cables
General Unit Function (UUT = Unit Under Test)
1. Remove the loudspeaker grille.
2. Switches on the amplifier faceplate:
Sub Input to "Line Level"
Low Pass Filter to OFF
Bass Optimization system to OFF
3. From the signal generator, connect one line level (RCA) cable to the Subwoofer Line Level Input jack
on the UUT.
4. On the front of the unit, turn the LEVEL control full counterclockwise (1).
5. Turn on generator, adjust to 50mV, 50 Hz.
6. Plug in UUT; turn the power switch ON. LED should be Red. Turn LEVEL control full clockwise (10)
7. LED should now be Green; immediate bass response should be heard and felt from port tube opening.
8. Turn off generator, turn VOLUME control fully counterclockwise, disconnect RCA cable.
9. Connect one pair of speaker cables to Speaker Level input terminal on UUT. Cables should be
connected to an integrated amplifier fed by the signal generator.
10. Switch Sub Input on the amplifier faceplate to "Speaker".
11. Turn on generator and adjust so that speaker level input at the amplifier is 1.5V, 50 Hz. Turn LEVEL
control full clockwise.
12. Green LED should light, immediate bass response should be heard and felt from the port tube opening.
Sweep Function
1. Follow steps 10-12 above, using a sweep generator as a signal source.
2. Sweep generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or
any other noises. If any unusual noises are heard, remove woofers and test.
Driver Function
1. Remove woofer from cabinet; and - wire clips.
2. Check DC resistance of woofer; it should be 3.4 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 5.0V.
4. Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
IL50
25