5
TROUBLESHOOTING A SYSTEM
Thekeytofindingtheprobleminatroubledsoundsystemistoisolatepartsofthatsysteminalogicalfashiontotrackdownthe
fault.
ThediagnosticsystemwillnotshutdowntheMBC1ortheamplifier(s),althoughtheamplifier(s)ownprotectioncircuitrymayshut
the amplifier(s) down should a fault status occur.At which time you will need to consult the owners manual for that particular
amplifier.
Lowoutputpower
1-Checkthatlevelcontrolshavebeensetupproperly.
2 - Make sure that the battery voltage, as measured at the amplifier(s) and MBC1 +12 volt and ground terminals, is 11 volts or
more.
3-Checkall+12voltandgroundconnections.
Fusesblowing
1-Insurethatthevoltagetotheunitdoesnotexceed15volts.
2-A shortonthemain+12voltcablefromthebatterytothevehiclechassiswillcausethemainfusetoblow.
3-IftheMBC1 isblowingfusescontinuallywithonly+12volt,groundandremoteleadsconnected,theunitmaybefaulty.
Systemdoesnotturnon
1-Checkallfuses.
2-Checkallconnections.
3-Measurethe+12voltandremoteturnonvoltagesattheamplifier(s)andMBC1terminals.Ifthesearenonexistentorlow,take
voltagemeasurementsatfuseholders,distributionblocks,theheadunit’s+12voltandremoteleadstolocalizetheproblem.
Noiseproblems
Systemnoisecanbedividedintotwocategories,hiss,andelectricalinterference.
Hiss,orwhitenoise
1 - High levels of white noise usually occur when level controls are turned up too high - reduce the levels until the noise is no
longerpresent.
2-Anothermajorproblemthatcancauseexcessivehiss,isanoisyheadunit-unplugtheMBC1InputRCA’s,andifthehisslevel
reduces,thesourceunitisatfault.
Electricalinterference
The inside of an automobile is a very hostile electrical environment. The multitude of electrical systems, such as the ignition
system,alternator,fuelpumps,airconditioners,tomentionjustafew,createradiatedelectricalfields,aswellasnoiseonthe+12
voltsupplyandground.Totryandeliminatethisnoise,runawirefromtheradiogroundwiretothegroundinputontheMBC1.
A tickingorwhinethatchangeswithengineRPM:
1-ThisproblemcouldbecausedbyradiationpickupofRCAcablesthataretooclosetoafuelpumporadistributor.
2-Checkthattheheadunitgroundisconnectedstraighttothevehiclechassis,anddoesnotusefactorywiringforground.
3-Try tosupplytheheadunitwitha clean+12voltsupplydirectlyfromthe battery+,insteadofusingasupply fromtheindash
wiring/fusebox.
Aconstant whine:
This type of noise can bemore difficult to pinpoint,but is usually caused by somekind of instability, causing oscillations in the
system.
1-Checkallconnections,especiallyforgoodgrounds.
2-Makesurethatnospeakerleadsareshortingtoexposedmetalonthevehiclechassis.
3-RCAcablesarenotoriousfortheirproblematicnature,socheckthatthesearegood,inparticulartheshieldconnections.
