Garmin GPSMAP 840xs Combo Manual

The Garmin GPSMAP 840xs Combo is a high-performance marine chartplotter and fishfinder featuring an 8-inch sunlight-readable display, built-in CHIRP traditional sonar and CHIRP ClearVü scanning sonar, preloaded BlueChart g3 coastal charts, support for NMEA 2000 and NMEA 0183 networks, Wi-Fi connectivity for updates and ActiveCaptain app integration, and rugged, waterproof construction (IPX7). Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Using Sonar Features 8. Chartplotter Navigation 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: 8-inch WVGA display, Power/data cable, Transducer, Mounting hardware, Protective cover.

FeatureDescription
Display8-inch sunlight-readable, capacitive touch, WVGA (800 x 480 pixels)
SonarBuilt-in CHIRP traditional sonar and CHIRP ClearVü scanning sonar
ChartsPreloaded BlueChart g3 coastal charts
ConnectivityWi-Fi, NMEA 2000, NMEA 0183, Ethernet (network expansion)
Power Input10–32 V DC
Waterproof RatingIPX7 (submersible to 1 meter for 30 minutes)
MountingFlush mount, bracket mount, or RAM® ball compatible
TransducerGT56UHD-TM included for traditional and scanning sonar
ActiveCaptainWireless updates and app integration via Wi-Fi
Internal Storage16 GB for charts and data

Installation

Unpack and inspect contents. Plan mounting location for clear view and access.

  1. Mount the display: Choose flush or bracket mount; secure using provided hardware.
  2. Install transducer: Mount on transom, trolling motor, or through-hull as appropriate.
  3. Connect power/data cable: Route cable to power source (10–32 V DC) and connect to display.
  4. Connect transducer: Attach transducer cable to power/data cable connector.
  5. Connect NMEA networks: Attach NMEA 2000 drop cable or NMEA 0183 wires if used.

WARNING! Ensure all connections are waterproofed. Disconnect power before making connections.

First-Time Setup

Power on unit; follow on-screen prompts.

  1. Select language: Choose from available options (default ENGLISH).
  2. Configure settings: Set units (nautical, statute), time zone, and date format.
  3. Connect to Wi-Fi: Go to Settings > Wi-Fi to connect for updates and ActiveCaptain.
  4. Calibrate sensors: Follow prompts to calibrate compass and water speed if applicable.
  5. Update software: Check for updates via Wi-Fi or Garmin Express.

CAUTION! Ensure secure mounting before operation on moving vessel.

Specifications

Controls and Settings

Primary control via capacitive touchscreen. Physical buttons: Power, Volume, Back.

Home Screen: Access Sonar, Chart, Radar, Music, Settings.

Settings Categories: System (language, units, Wi-Fi), Sonar (frequency, range, sensitivity), Chart (overlays, detail), Alarms (anchor drag, shallow water), Communications (NMEA, network), Display (brightness, color scheme).

Connecting Devices

NMEA 2000: Connect via drop cable to network for engine data, instruments. NMEA 0183: Connect to compatible devices via serial wires. Ethernet: Connect to compatible Garmin devices for network expansion. Wi-Fi: Connect to smartphone/tablet for ActiveCaptain.

  1. Ensure power is off before connecting devices.
  2. Use appropriate cables and connectors.
  3. Configure device interfaces in Settings > Communications.

Tip: Label cables during installation for easier identification.

Using Sonar Features

Access via Sonar icon. Modes: Traditional, ClearVü, SideVü (with compatible transducer).

  1. Select sonar view: Choose Traditional for depth/fish; ClearVü for detailed bottom imaging.
  2. Adjust settings: Frequency, range, sensitivity, color scheme for conditions.
  3. Use A-Scope: Real-time water column data.
  4. Set alarms: Depth, fish, temperature.
  5. Record sonar logs: For later review.

WARNING! Ensure transducer is properly mounted and free of obstructions.

Chartplotter Navigation

Access via Chart icon. Use preloaded BlueChart g3 or optional maps.

  1. View chart: Pan, zoom with touch gestures.
  2. Create waypoints: Touch and hold location, select “Create Waypoint.”
  3. Plan route: Select points to create route; edit as needed.
  4. Navigate: Select Go To for waypoint or route; follow course line.
  5. Use data overlays: Depth, tide, currents, marine services.

Note: Always verify chart data with official sources for navigation.

Care & Cleaning

Turn off and disconnect power before cleaning. Use soft, damp cloth with mild soap; avoid solvents.

CAUTION! Do not use abrasive cleaners; ensure seals are intact for waterproofing.

Regulatory Information

FCC Compliance: This device complies with part 15 of the FCC Rules. Operation is subject to conditions: (1) device may not cause harmful interference, (2) device must accept any interference received. IC Compliance: Complies with Industry Canada license-exempt RSS standard(s). Copyright © Garmin Ltd. or its subsidiaries. For support, visit support.garmin.com or contact your local dealer.

Troubleshooting

SymptomPossible CauseCorrective Action
No powerPower connectionCheck fuse (3 A); verify 10–32 V DC at power cable; ensure connections are secure.
No sonar displayTransducer connectionVerify transducer cable is connected; check for damage; ensure proper mounting.
Poor GPS signalAntenna obstructionEnsure clear view of sky; check antenna connection if external; allow time for acquisition.
Touchscreen unresponsiveScreen contaminationClean screen; restart unit; ensure no screen protector interference.
Wi-Fi not connectingSettings/distanceVerify Wi-Fi is enabled; check password; move closer to router.

Reset: Settings > System > Reset to default if needed.

Service: Contact Garmin Product Support or authorized dealer.

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