Humminbird 987C SI COMBO Finding the Cause of Noise, Other electronic devices, Noise re-appears

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FINDING THE CAUSE OF NOISE

Electrical noise usually affects the display with many black dots at high speeds, and high sensitivity readings. One or more of the following sources can cause noise or interference:

Possible Source of Noise	Isolation
Other electronic devices	Turn off any nearby electronic devices to see if the problem goes away, then turn them on one at a time to see if the
	noise re-appears.
The boat’s engine	To determine whether the boat’s engine is the source of the noise, increase the RPMs while the boat is in neutral and
	stationary to see if the noise increases proportionately; if noise appears when you rev the engine, the problem could
	be the spark plugs, alternator, or tachometer wiring. Replace the spark plugs with resistor plugs, install an alternator
	filter, or route the control head power and transducer cables away from the engine wiring.
Cavitation from the boat’s propeller	Turbulence created by the propeller can cause noise; make sure the transducer is mounted at least 15” (38 cm) from the
	propeller, and that the water flows smoothly over the face of the transducer at all times.

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Contents Page Thank You Table of Contents Side Imaging X-Press Menu Menu System Start-Up Options MenuSonar X-Press Menu Sonar Menu TabAlarms Menu Tab Setup Menu TabViews Menu Tab Accessories Menu Tab Troubleshooting Contact HumminbirdSide Imaging Sonar Series IntroductionHOW the 900 Series Works Dualbeam Plus SonarMULTI-MEDIA Card MMC/SD Slot Multi-Media Card MMC/SD SlotAccessory BUS Installation OverviewControl Head Installation 900 Series has a wide variety of configurationsAccessory Bus Gimbal Mounting the Control Head Mounting Screws Washer Cables Routed Near Mounting Bracket Speed Communications Transducer Cable Collector InsertIN-DASH Mounting the Control Head Parts and tools specific to In-dash mounting areBack of Control Head Expansion ports use for future accessories Connecting the Control Head Power Cable to the Boat Beginning of this procedureTransducer Installation Transom Transducer Trolling Motor TransducerMotor Position Transom Transducer Installation Stepped HullWithout deadrise adjustment Not a hull, motor, or other transducer, etcBe fully tightened until all adjustments are made Headed pin can be inserted from either side of the bracketCompletely tighten Force is necessary to pivot the assembly Normal CavitationTrolling Motor Transducer Installation Test and Finish the Transducer Installation Hand-tighten onlyFollow these steps to stem mount the GPS receiver To the cable as shownAccess Under Mounting Location No Access Under Mounting LocationAccess Under Mounting Location Speed Accessory Installation Finish Routing the Cable and Check GPS Receiver OperationInstall the Speed accessory Hand tighten onlyTesting the System Installation Rotating Retaining Axial Clip to Remove PaddlewheelPowering UP the Control Head Series 987c SI Combo Title ScreenWHAT’S on the Sonar Display TriplogUnderstanding Sonar History Real Time Sonar RTS WindowSonar Bottom Presentation KHz provides highest resolution with 160 total beam width Understanding Side ImagingKHz provides maximum coverage with 180 total beam width WHAT’S on the Side Imaging Display Topography Changes Bottom Return TriplogSide Imaging Technology HOW IT Works Side Imaging on the Water InterpretationSide Imaging Representation Submerged Ravine with Timber Submerged Standing and Fallen Timber, Plus Bait Fish Submerged Swimming PoolView KEY POWER/LIGHT KEYKEY Functions Menu KEYExit KEY View Preset KeysWAY Cursor Control KEY Info KEYViews available on your 900 Series are ViewsMARK/GOTO KEY Sonar viewsViews and Readouts Sonar ViewSonar View Sonar Zoom View Sonar Zoom ViewSplit Sonar View Split Sonar ViewSide Imaging View Side Imaging ViewSIDE/SONAR Combo View Side/Sonar Combo ViewChart/Bird’s Eye Combo View Bird’s Eye ViewChart View with Active Cursor Chart/Sonar ViewCHART/SIDE Combo View Chart/Side Combo ViewChart View with Cursor Present NavigationWAYPOINTS, Routes and Tracks Waypoints, Routes and TracksNavigate to a Waypoint or Position Chart View with Target Chart View with GridADD a Waypoint Target or Trolling Grid SAVE, Edit or Delete a Route Menu System Press MenuNormal Simulator System Status Sonar Tab, Normal Mode Sonar Tab, Advanced ModeSTART-UP Options Menu Start-Up Options MenuSimulator Self Test Accessory Test GPS Diagnostic ViewNormal Operation System StatusAccessory Test Accessory Test ScreenGPS Diagnostic View Active Side To Adjust Split Screen PositionSonar X-PRESS Menu Split PositionSensitivity To adjust the SensitivityTo adjust the Upper Range Upper RangeChart Speed Lower RangeZoom Level Bottom Lock Bottom RangeSonar Colors Highlight Split Position on the Side Imaging X-Press Menu Side Imaging Views onlySide Imaging X-Press Menu SI Side SI SensitivitySI Range To change the SI Colors SI ColorsNavigation X-PRESS Menu Highlight SI Colors on the Side Imaging X-PressmenuTo Save Current Track Save Current TrackClear Current Track To Clear Current TrackSkip Next Waypoint Cancel NavigationSave Current Route Remove TargetTo Remove a Grid Remove GridSonar Menu TAB Only if a Grid is activeBeam Select Side View FrequencyFish ID+ To turn Fish ID+ on or off To change the Fish ID Sensitivity settingFish ID Sensitivity Highlight Fish ID Sensitivity on the Sonar main menuBottom View To change the RTS Window settingTo adjust the Bottom View Zoom WidthSurface Clutter KHZ SensitivityDepth Lines Noise FilterMAX Depth Water TypeColor BAR Sonar View only, with Temperature input Temperature GraphTo change the display of the Temperature Graph Navigation Menu TABTracks WaypointsRoutes Trolling Grid Rotation Chart OrientationNorth Reference Trackpoint IntervalExport ALL NAV Data Track MIN DistanceMAP Datum Delete ALL NAV DataTo change the Chart Detail Level setting Chart Menu TABChart Detail Level MAP BordersShaded Depth LAT/LON GridSpot Soundings SET Simulation PositionSET MAP Offset Alarms Menu TABTo change the Map Offset setting Clear MAP OffsetLOW Battery Alarm Depth AlarmFish ID Alarm Temp AlarmOFF Course Alarm Arrival AlarmDrift Alarm To change the Alarm Tone setting Alarm ToneSetup Menu TAB Highlight Alarm Tone on the Alarms main menuUnits Distance Units DepthUnits Temp Units SpeedRestore Defaults User ModeTriplog Reset LanguageDefault Sonar View Select ReadoutsDepth Offset To change the Depth Offset settingTo change the Temp Offset setting Temp OffsetDaylight Saving Time Speed CalibrationLocal Time Zone Position FormatTime Format Date FormatNmea Output Following views are available Views Menu TABTo turn Sonar on or off To Change the View Status of Any ViewSeries Doesn’t Power Up Accessories Menu TABTroubleshooting Series Defaults to Simulator with a Transducer AttachedDisplay Problems Control head loses power at high speedsNoise re-appears Finding the Cause of NoiseOther electronic devices Boat’s engineYear Limited Warranty Humminbird Service PolicyReturning Your Unit for Service Series AccessoriesFor IN-WARRANTY service, complete the following steps Specifications Area of CoverageAppendix a Transducer Mounting Template XHS-9-SI-160-TContact Humminbird