Test Procedure - JBL SUB500 Service Manual

SUB500 (SCS500.5 Subwoofer)
SUB500 TEST PROCEDURE
SYSTEM AURAL SWEEP TEST
Equipment needed:
• Function/signal generator/sweep generator
• Integrated Amplifier
• Multimeter
• Speaker cables
General Unit Function (UUT = Unit Under Test)
Auto-On switch – either position
1) From the signal generator, Connect both right and left line level inputs (RCA) to signal generator and UUT.
Use Y-cable if necessary from mono source. Do not use the LFE jack.
2) On the front of the unit, turn the LEVEL control full counterclockwise (MIN).
3) Turn on generator, adjust to 100mV, 50 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 port tube opening.
6) Turn off generator, turn LEVEL control fully counterclockwise (MIN), disconnect RCA cable.
7) Connect one pair of speaker cables to one pair Speaker Level input terminals on UUT. Cables should be
connected to an integrated amplifier fed by the signal generator.
8) Turn on generator and adjust so that speaker level input at the amplifier is 2.0V, 50 Hz.
9) Turn LEVEL control full clockwise (MAX)
10) 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 1kHz. 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; detach + 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.
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