Troubleshooting - Harman JBL VL18-SUB Guia Del Usuario

Symptom
No sound.
No sound, the amplifier is
connected to electrical
power but does not turn
on.
No sound, power on.
The sound is distorted
and too loud, the clip
LED is lit most of the
time.
Sound is distorted even
at moderate volume, the
clip LED is not lit.
Noises or whistles are
heard at the sound
output.
Noise and humming that
increase or decrease when
the level controls of the
mixer are moved.
Noise or buzzing
Likely Cause
The amplifier is not plugged into
the power outlet.
The power supply is not on.
The power cord of the amplifier is
faulty or improperly connected.
Signal source (Mixer, processor, ...)
is not sending signal.
The mixer or other source is
overloaded.
Excess of input signal,
attempting to exceed the
loudspeakers capacities.
The mixer or other source is
overloaded.
Device or cable as source of
noise.
Inappropriate AC ground or faulty
equipment
connected to the output of the
mixer.
A faulty cable between the power
supply
of the equipment and mixing
equipment.
Inappropriate AC grounding,
ground loops.
The size of the unbalanced cable
is too long.
Poor regulation of earnings.

TROUBLESHOOTING

Review if there is a damaged cable or if the
amplifiers are disconnected to the power outlet.
Turn on the power and check if the power LED is lit.
Check the power cord at both ends. Replace with a good
power cord.
Check if the signal LED of the amplifier is on.
Check the Owner's Manual of your mixer and adjust the
controls as required. Once this is done, review the
instructions in the quick start guide
of this manual.
Reduce the source output level.
Decrease the volume control of the amplifier.
Use additional VL18-SUB speakers.
Check the Owner's Manual of your mixer and adjust
the controls as required.

Input Sensitivity;

Channel faders:

Main Faders;
Disconnect the devices that are connected to your mixer
one at a time.
If the noise goes away, the problem is with the source
or the connecting cable.
Disconnect or mute the channels one at a time, isolating
the problem. Please, refer to the user's guide of the
faulty equipment to solve the problem or help.
Replace defective cable with a good quality one.

"Raise the GND" of the audio signal using an XLR /
F to XLR / M adapter at one end.
Re-route audio cables away from power and light cables.

Use the balanced output, (if available) on your
mixer or source of your VL system.
Reduce the level of the INPUT controls and increase the
output level of your source device.
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What to Do