Troubleshooting Tips
NO POWER
Check the connections between the mixer and the power supply and the external AC power supply. Examine the
Check the wall outlet.
NO SOUND
•Make sure the MIC/Line switch is in the proper position. (This is the most likely cause.)
•Make sure both the master and channel input controls are turned up.
•Check that the source signal cable(s) is properly connected and undamaged.
•Adjust Input Gain/Trim Control potentiometer(s) to increase gain.
•If there is still no sound, try changing input source(s) to different channel(s).
DISTORTED SOUND
•Turn down the master volume control. If distortion persists, input channel(s) gain is the likely cause.
•Check position of all line/MIC switches.
•Determine the distorting input channel(s) by checking them one at a time.
•Decrease gain of input channel(s) causing distortion by turning the screw on the rear panel.
EXCESSIVE HISS or HUM
Hiss: Make sure the volume control knobs for all the unused channels are turned all the way off (i.e., at the 7 o’clock position).
•Make sure that all unused input channels have the MIC/Line switch in the Line position.
•Make sure the MIC/Line switch is in the correct position for both the inputs and the main output.
Hum: MIC lines can easily cause hum. Make sure to locate them away from vibration and magnetic field sources (motors, power supplies and lines, and data lines).
Check MIC lines, especially the shield, for damage.
Another common source of hum is a ground loop, which can result from connecting two or more powered devices together.
Turn both the Main and Auxiliary volume controls down. If the hum is still present, the ground loop or other cause is not in the mixer, but in the devices after it in the audio path or in the connection between the mixer and following equipment. (If the hum disappears, then the cause is either in the mixer or in one of the inputs to the mixer. Turn each of the volume controls [both the individual input channels and the two buses] down independently, to deter- mine which one is the source of the hum.)
Check for unbalanced connections; use balanced connections, if possible. For all unbalanced connections, try disconnecting the signal line ground to eliminate multiple ground paths.
Page 24 of 32