Pr
oFX
v3 P
rofes
sional E
ffects Mix
er with USB
ProFXv3 Professional Effects Mixer with USB
22
If you think your mixer has a problem, please check
out the following troubleshooting tips and do your best
to confirm the problem. Visit the Support section of our
website (www.mackie.com) where you will find lots of
useful information such as FAQs, documentation and
any updated PC drivers etc. You may find the answer to
the problem without having to send your mixer away.
Troubleshooting
No Power
• Our favorite question: Is it plugged in?
Make sure the AC outlet is live [check
with a tester or lamp].
• Our next favorite question: Is the power
switch on? If not, try turning it on.
• Make sure the line cord is securely seated
in the line cord socket and plugged all
the way into the AC outlet.
• Is the power LED on the top panel
illuminated? If not, make sure the AC outlet
is live. If so, refer to “No sound” below.
• The internal AC line fuse may be blown.
This is not a user serviceable part.
If you suspect the AC line fuse is blown,
please see the “Repair” section next.
Hum
• Try disconnecting the cable connected
to the input jack. If the noise disappears,
it could be a “ground loop,” rather than
a problem with the mixer.
Try some of the following troubleshooting ideas:
• Use balanced connections throughout your
system for the best noise rejection.
• Whenever possible, plug all the audio
equipment’s line cords into outlets which
share a common ground. The distance
between the outlets and the common
ground should be as short as possible.
Bad Channel
• Try the same source signal in another
channel, set up exactly like the suspect
channel.
• Is phantom power required for your
microphone?
No sound
• Is the level knob for the input source turned
all the way down? Verify that all the volume
controls in the system are properly
adjusted. Look at the level set LEDs
and meters to ensure that the mixer
is receiving a signal.
• Is the signal source working? Make sure
the connecting cables are in good repair
and securely connected at both ends.
Make sure the master volume level
is turned up sufficiently to drive the inputs
of the speaker.
• Make sure the input source is not muted
or has a processor loop engaged. If you find
something like this, make sure the level
is turned down before disengaging
the offending switch.
• Is the main level turned up?
• Are the EQs set to reasonable levels?
• Are any aux returns maxed out?
• Unplug anything from the other line-level
outputs, such as monitor out, just in case
one of the external pieces has a problem.
• Make sure that you are not overdriving
the amplifiers. Check the loudspeaker
average load impedance is not less than
the minimum the amplifier can handle.
Check the speaker wiring.
Noise
• Turn the channel gains down, one by one.
If the sound disappears, it’s either that
channel or whatever is plugged into it,
so unplug whatever that is. If the noise
disappears, it’s from your whatever.
• Make sure none of the signal cables are
routed near AC cables, power transformers,
or other EMI-inducing devices.
• Is there a light dimmer or other SCR-based
device on the same AC circuit as the mixer?
Use an AC line filter or plug it into
a different AC circuit.
Appendix A: Service Information
