Section 9: Trouble Shooting - JBL EO210P User Manual

Section 9: Trouble Shooting

Symptom
No sound
Sound is distorted
Sound is thin
Sound is too boomy or dark
Hum or Buzz that increases
or decreases when the mixer
level controls are moved
Hum or Buzz
20
Likely Cause
No Power
Volume's are turned down
Mechanical connections
are loose
Bad Cables
Phantom Power is off
Input overload
System is overloading
Too much treble
Not enough bass
Speakers not
connected properly
Effects levels may be too high
Not enough treble
Too much bass
Improper A/C ground or faulty
equipment connected to
mixer input
Faulty cable between source
equipment and mixer
Improper A/C grounding,
ground loops
Excessively long unbalanced
cable run
Improper system gain structure
What to do
Make sure that the AC cord is properly seated into the AC receptacle
both at the wall outlet and on the mixer. Make sure the AC switch is in
the "ON" position. If you are using an "AC Strip" check to see that it
is working properly.
Make sure both the mixer's channel volume and master volume are
turned up. Double check to see if the source volume is turned up.
Check to see if the input to the mixer is properly seated.
Check the speaker connections to see if they plugged in all of
the way.
Your speaker cables may have been damaged. Inspect for any cuts
or crimps and if found, replace the cables.
If you are using a "Condenser" type microphone you will need to
activate the "Phantom Power" switch for the microphone to work.
If the "Peak LED Indicator" is flashing red or on constantly you may
be overloading the input. On channels 1-4 turn the channel volume
down and press the MIC/LINE switch. Slowly bring the volume up. If
the distortion is gone but you don't have enough volume, turn up the
master volume.
If you are using an external device like a personal music player or
electronic instrument try lowering the volume on that device.
Check the "SYSTEM LEVEL INDICATOR" LED's and if the "LIMIT"
or red light at the top of the ladder is on constantly you may be
overdriving the system. Turn down the MASTER VOLUME.
Check the channel's "TREBLE" control and turn it to the "0" position.
Check the channel's "BASS" control and turn it to the "0" position.
Check the speaker connections to see if they plugged in all of the
way.
Try turning down the MASTER EFFECTS RETURN.
Check the channel's "TREBLE" control and turn it to the "0" position.
Check the channel's "BASS" control and turn it to the "0" position.
Disconnect or mute channels one at a time to isolate the
problem. Refer to the owner's manual of the faulty equipment for
troubleshooting help.
Substitute a known-good cable for the suspected faulty cable.
Try using a ground lift adaptor. Connect all power cords to the
same power strip.
Try a shorter cable if possible, otherwise use a DI box to
convert the unbalanced signal to a balanced signal and use
the appropriate cabling.
Reduce the INPUT level controls and increase the output level of
your source devices.