Garmin GPSMAP 78sc Manual

The Garmin GPSMAP 78sc is a rugged, waterproof marine handheld GPS with a high-sensitivity receiver, built-in worldwide basemap, 1.7 MB internal memory, microSD™ card slot, and a 2.6-inch color TFT display. It features a 3-axis tilt-compensated electronic compass, barometric altimeter, and supports BlueChart® g2 and LakeVü™ g3 mapping. 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 GPS Navigation 8. Accessibility Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Waterproof case (IPX7), High-sensitivity GPS receiver, 2.6" color TFT display, Electronic compass, Barometric altimeter, microSD card slot, USB port.

Feature	Description
Waterproof rating	IPX7 standard (submersible to 1 meter for 30 minutes)
Display	2.6-inch, 160 x 240 pixels, color TFT
Internal memory	1.7 MB
External memory	microSD card slot (supports up to 32 GB)
GPS receiver	High-sensitivity, WAAS-enabled
Compass	3-axis tilt-compensated electronic compass
Altimeter	Barometric altimeter with automatic calibration
Battery	2 AA batteries (NiMH or alkaline) or external power
Connectivity	USB 2.0 for data transfer and power
Marine features	Supports BlueChart g2 and LakeVü g3 mapping

Installation

Unpack and inspect contents. Install batteries and optional accessories.

Install batteries: Open battery compartment, insert 2 AA batteries observing polarity.
Install microSD card (optional): Insert card into slot until it clicks.
Attach wrist strap: Thread through loop on device.
Charge via USB (optional): Connect to computer or compatible charger.

WARNING! Use only recommended batteries. Ensure battery compartment is sealed for waterproofing.

First-Time Setup

Power on device; follow on-screen prompts.

Acquire satellite signal: Go outdoors with clear sky view; wait for GPS fix.
Set language: In SETUP menu, select preferred language.
Calibrate compass: Follow on-screen instructions; rotate device slowly.
Set units: Configure distance, speed, elevation, and depth units.
Load maps: Install BlueChart or LakeVü maps via microSD card or Garmin Express.

CAUTION! Calibrate compass away from magnetic interference (metal, electronics).

Specifications

Dimensions: 2.4" x 6.3" x 1.4" (6.1 x 16.0 x 3.6 cm).
Weight: 7.6 oz (215 g) with batteries.
Display: 2.6-inch diagonal, 160 x 240 pixels, color TFT.
Waterproof: IPX7 (1 meter for 30 minutes).
Battery life: Up to 20 hours (varies with settings and use).
GPS: High-sensitivity, WAAS/EGNOS/MSAS support.
Compass: 3-axis tilt-compensated electronic compass.
Altimeter: Barometric altimeter with pressure trend.
Interface: USB 2.0, NMEA 0183 compatible.
Operating temp: -4° to 140°F (-20° to 60°C).

Controls and Settings

Access menus via PAGE and MENU buttons. Front Panel: POWER, PAGE, MENU, ROCKER (up/down/left/right/ENTER), QUIT.

Side buttons: ZOOM IN/OUT, MARK, FIND.

Main Menu: Map, Compass, Active Route, Waypoint Manager, Tracks, Setup. Setup: System (language, display, units), Navigation (routing, alarms), Marine (tides, currents), Sensors (compass, altimeter calibration).

Connecting Devices

USB: For data transfer and power. NMEA 0183: For connecting to marine instruments (requires optional cable).

Turn off device before connecting cables.
Connect USB cable to computer for file transfer or charging.
For NMEA 0183, connect to compatible device using specified wiring diagram.
Configure NMEA settings in Interface menu if needed.

Tip: Use Garmin Express software to update software and install maps.

Using GPS Navigation

Supports waypoints, routes, tracks, and marine navigation.

Create waypoint: Press MARK at location; edit name/symbol if desired.
Navigate to waypoint: Press FIND, select waypoint, choose Go To.
Create route: Main Menu > Routes > Create Route, add waypoints.
Follow route: Select route, choose Navigate.
Record track: Tracks > Track Log > Record.
View map: Press PAGE to cycle to Map page; zoom with ZOOM buttons.
Use marine features: Access tide tables, marine services, and navigation aids.
View trip data: Compass page shows speed, heading, distance to destination.

WARNING! GPS accuracy can be affected by environment; always use with caution for navigation.

Accessibility Features

Display settings: Adjust backlight, contrast, and color themes for visibility. Audio alerts: Enable tones for waypoint arrival, off-course, etc.

Care & Cleaning

Rinse with fresh water after saltwater use. Wipe with soft, damp cloth; dry thoroughly.

CAUTION! Do not use harsh chemicals, solvents, or high-pressure water. Ensure seals are clean and intact.

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. Copyright © Garmin Ltd. or its subsidiaries. For support, visit www.garmin.com/support or contact Garmin Product Support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Dead batteries	Replace with fresh AA batteries; check polarity.
Poor GPS reception	Obstructions	Move to open area; ensure clear view of sky.
Compass inaccurate	Need calibration/interference	Recalibrate compass; move away from metal/electronics.
Device not connecting to computer	USB cable/driver	Use provided cable; install Garmin USB drivers if prompted.
Display difficult to read	Backlight/contrast settings	Adjust backlight and contrast in Display settings.

Reset: Hold POWER + PAGE + MENU for 10 seconds to perform master reset (erases user data).

Service: Contact Garmin Product Support or visit www.garmin.com.