7
Poor sound
• Is it loud and distorted? Make sure that you’re not
overdriving a stage in the signal chain. Verify that
all level controls are set properly.
• Is the input connector plugged completely into the
jack? Be sure all connections are secure. It’s a good
idea to periodically clean all electrical connections
with a non-lubricating electrical contact cleaner.
Noise
• Make sure all connections to the active loudspeak-
ers are good and sound.
• Make sure none of the signal cables are routed near
AC cables, power transformers, or other EMI-induc-
ing devices.
• Is there a light dimmer or other SCR-based device
on the same AC circuit as the SR151z? Use an AC
line filter or plug the SR151z into a different AC
circuit.
Hum
• Try disconnecting the cable connected to the MAIN
INPUT jack. If the noise disappears, it could be
a “ground loop,” rather than a problem with the
SR151z. Try some of the following troubleshooting
ideas:
◊
Use balanced connections throughout your
system for the best noise rejection.
◊
Whenever possible, plug all the audio equip-
ment’s linecords into outlets which share a common
ground. The distance between the outlets and the
common ground should be as short as possible.
SERVICE INFORMATION
If you think your Mackie product 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/support)
where you will find lots of useful information such as
FAQs, documentation, and user forums. You may find
the answer to the problem without having to send your
Mackie product 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.
• Is the POWER LED on the rear panel glowing
green? 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.
No sound
• Is the input level control for the input source
turned all the way down? Verify that all the volume
controls in the system are properly adjusted.
• Is the signal source working (and making union
scale)? Make sure the connecting cables are in good
repair and securely connected at both ends. Make
sure the output volume (gain) control on the mixing
console is turned up sufficiently to drive the inputs of
the speaker.
• Make sure the mixer does not have a Mute on or a
Processor loop engaged. If you find something like
this, make sure the volume/gain is turned down
before disengaging the offending switch.
• Is the THERMAL indicator lit red on the rear panel?
Make sure there is at least six inches of free space
behind the SR151z.
Poor bass performance
• Check the polarity of the connections between the
mixer and the loudspeakers. You may have your
positive and negative connections reversed at one
end of one cable, causing one loudspeaker to be
out-of-phase.
