Garmin GPS 100 Service Manual

The Garmin GPS 100 is a compact, rugged marine GPS receiver designed for navigation. This manual provides comprehensive service information including technical specifications, disassembly procedures, troubleshooting, calibration, and maintenance guidelines for authorized service personnel. Below are key sections covering features, installation, operation, diagnostics, and repair procedures.

Features and Specifications

Key components: Water-resistant case, high-sensitivity GPS receiver, backlit LCD display, NMEA 0183 output, external antenna capability, and marine mounting hardware.

Installation and Mounting

Unpack and inspect contents. Select suitable mounting location with clear view of sky.

1. Mounting bracket installation: Use provided screws to secure bracket to flat surface.
2. Unit attachment: Slide GPS 100 onto bracket and secure with locking knob.
3. Power connection: Connect red wire to positive DC source, black wire to negative/ground.
4. Antenna connection: For external antenna, connect to rear port and secure with weather cap.
5. Data connections: Connect NMEA output wires to compatible chartplotter or autopilot.

WARNING! Ensure all connections are waterproofed using marine-grade sealant. Route cables away from high-temperature areas and sharp edges.

Initial Setup and Configuration

Power on unit; follow initialization procedure.

1. First-time satellite acquisition: Place unit in open area with clear sky view. Allow 5-15 minutes for initial fix.
2. Configure system settings: Press MENU, navigate to System Setup to set units (nautical/statute), time format, and datum.
3. Calibrate compass: If equipped, follow on-screen calibration procedure.
4. Set NMEA output: Configure baud rate (4800 default) and sentences in Interface menu.
5. Configure alarms: Set anchor drag, arrival, and off-course alarms as needed.

CAUTION! Do not attempt calibration while vessel is in motion. Ensure stable platform during setup procedures.

Technical Specifications

• Dimensions: 5.2" W × 3.1" H × 2.4" D (132 × 79 × 61 mm).
• Weight: 12 oz (340 g).
• Display: 2.7" diagonal, 160 × 240 pixels, FSTN LCD with LED backlight.
• GPS Accuracy: Position: <10 meters RMS, Velocity: 0.1 knot RMS.
• Update Rate: 1 Hz standard.
• Operating Voltage: 10-40 VDC.
• Current Draw: 120 mA @ 12 VDC.
• Operating Temperature: -15°C to 70°C (5°F to 158°F).
• Storage Temperature: -40°C to 85°C (-40°F to 185°F).
• Waterproof Standard: IEC 60529 IPX7.

Controls and Interface

Front panel controls: POWER button, PAGE/ESC rocker, ENTER/MARK button, UP/DOWN arrow keys.

Display Pages: Satellite Status, Position, Compass, Highway, Map, Active Route, Menu.

Menu Structure: Main categories include Waypoints, Routes, Tracks, System Setup, Interface, Alarms, Calibration, Diagnostic.

Button Functions: POWER - Turns unit on/off; PAGE - Cycles through display pages; ENTER - Confirms selection; MARK - Creates waypoint at current position; UP/DOWN - Scrolls through lists and options.

System Connections

Rear panel connections: Power input (2-pin), Data port (6-pin), External antenna (MCX connector).

1. Power connection: Red wire to positive (10-40 VDC), Black wire to negative/ground.
2. NMEA 0183 output: Connect TX+ (yellow) and TX- (green) to compatible device's NMEA input.
3. NMEA 0183 input: Connect RX+ (blue) and RX- (brown) to receive data from other instruments.
4. External antenna: Connect active antenna to MCX connector, ensure weather cap is sealed when not in use.

Tip: Use marine-grade heat-shrink tubing on all wire connections. Apply dielectric grease to connectors to prevent corrosion.

Operation and Navigation

Basic navigation functions and waypoint management.

1. Creating waypoints: Press MARK at desired location, edit name and symbol if needed.
2. Navigating to waypoint: Select Go To from menu, choose waypoint, press ENTER to begin navigation.
3. Creating routes: Select Routes from menu, create new route, add waypoints in sequence.
4. Following routes: Select route, choose Navigate, follow on-screen guidance.
5. Track recording: Enable track log in Tracks menu to record vessel's path.
6. Man Overboard (MOB): Press and hold MARK for 3 seconds to mark MOB position and begin navigation back.
7. Sunrise/Sunset times: Access from Almanac page in Menu.

WARNING! GPS is an aid to navigation only. Always maintain proper watch and use all available navigation resources.

Diagnostic Modes

Access diagnostic functions for testing and troubleshooting.

To enter diagnostic mode: Power off unit. Press and hold PAGE + ENTER while powering on. Release when diagnostic menu appears.

Diagnostic tests include: LCD test (all pixels on/off), button test, memory test, GPS receiver test, NMEA output test, power supply test.

Satellite information page: Shows SNR (signal-to-noise ratio) for each satellite, position accuracy (EPE), and satellite constellation.

Maintenance and Cleaning

Regular maintenance ensures optimal performance and longevity.

1. Exterior cleaning: Use fresh water and mild soap. Rinse thoroughly. Do not use high-pressure spray.
2. Display cleaning: Use soft, lint-free cloth slightly dampened with fresh water. Do not use chemicals or abrasives.
3. Connector maintenance: Inspect regularly for corrosion. Clean with electrical contact cleaner if needed.
4. Battery backup: Internal lithium battery maintains memory and real-time clock. Typical life: 5 years.

CAUTION! Do not open unit unless qualified for service. Internal components are sensitive to ESD. Use anti-static precautions.

Regulatory and Compliance

FCC Part 15: Class B digital device compliant. CE marked. RoHS compliant. Meets IEC 60945 for marine navigation equipment. Contains GPS receiver which is subject to United States export controls. Copyright © Garmin Ltd. or its subsidiaries. For technical support, contact Garmin Product Support at 1-800-800-1020 or visit www.garmin.com.

Troubleshooting and Repair

Factory Reset: Menu > System > Reset > Factory Defaults (Note: Erases all user data).

Service Centers: Authorized Garmin service centers only. Do not attempt internal repairs without proper training and equipment.

Support: 1-800-800-1020; www.garmin.com/support