Harman JBL Professional VL8A, Руководство пользователя, Страница: 26 / 40

26
TROUBLESHOOTER
Symptom Probable cause What to do
There is no sound. The amplifier is not connected to
electrical power. Check if there is a damaged cord or if the amplifiers are
connected to the mains.
The power is not turned on. Turn on the power and check that the power LED is on.
No sound, the amplifier is
connected to electrical
power, but does not turn
on. The power cord of the amplifier is
faulty or improperly connected. Check the power cord at both ends.
Replace with a good quality power cord.
The amplifier turns on but
there is no sound. Signal source (Mixer, processor,
...) is not sending signal. Check the amplifier if the signal LED is on.
The mixer device or another
source is overloaded. Check the Owner's Manual of your mixer device and
adjust the controls as necessary.
Once this is done, review the Quick Start Guide
instructions in this manual.
The sound is distorted
and too loud, the clip LED
is lit most of the time. Excessive input signal, trying to
exceed the capacity of the
speakers. Reduce the output level of the source.
Decrease the volume control of the amplifier.
Use more additional VL8 boxes.
Sound is distorted even
at moderate volume and
the clip LED is not lit. The mixer or other signal source is
saturated. Check the owner's manual of your mixer device and adjust
the controls as necessary.
•
Input sensitivity;
•
Channel Faders;
•
Main Faders.
Noises or whistles are
heard at the exit. Noise source device. Disconnect the devices that are connected to your system
one at a time.
If the noise disappears, the problem is at the source or the
connecting cable.
Noise and humming that
increase or decrease
when the level controls of
the mixing device are
moved. Inappropriate AC ground or faulty
equipment connected to the output
of the mixer. Disconnect or mute the channels one at a time, isolating
the problem. Refer to the user manual of the faulty device
for troubleshooting or help.
A defective cable between the
equipment source and the mixer. Replace defective cable with good quality one.
Noise or buzzing Inappropriate AC grounding,
ground loops.
•
"Raise" the audio using an XLR/F to XLR/M adapter
at one end.
Re-route audio cables away from power and light cables.
The size of the unbalanced cable
is too long.
•
Use the balanced output (if available) on your mixer
or source of your VL system.
Optimize the structure of the
system gain. Reduce the level of the INPUT controls and increase the
output level of your source device.