Mackie DLM12 - Appendix A: Service Information; Troubleshooting

Owner’s Manual
19
Owner’s Manual
Appendix A: Service Information
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withtheother.
• Poorbassperformancemaybetheresultofbad
  ACpower.Seethesectiontitled‘ACPower’on
  thepreviouspageforfurtherdetails.
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.
Noise
• Whatisthepositionofthemic/lineswitch?
  ItshouldbeINwhenamicisconnectedand
  OUTwhenaline-levelsignalisconnectedto
  thechannel1input.
• Makesureallconnectionstotheactive 
  loudspeakersaregoodandsound.
• 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DLM8/12?Usean
  AClinelterorplugtheloudspeaker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
  DLMloudspeaker.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.
IfyouthinkyourMackieproducthasaproblem,
pleasecheckoutthefollowingtroubleshootingtipsand
doyourbesttoconrmtheproblem.VisittheSupport
sectionofourwebsite(www.mackie.com/support)
whereyouwillndlotsofusefulinformationsuchas
FAQsandotherdocumentation.Youmaynd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front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level
  controlsinthesystemareproperlyadjusted.
  Lookatthelevelmeter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output
  levelcontrolonthemixingconsoleisturnedup
  sufcientlytodrivetheinputsofthespeaker.
• Makesurethemixerdoesnothaveamuteonora
  processorloopengaged.Ifyoundsomethinglike
  this,makesurethelevelisturneddownbefore
  disengagingtheoffendingswitch.
• Hasitshutdown?Makesurethereisatleast
  sixinchesoffreespacebehindeachDLM 
  loudspeaker.