Marine Electronics Diagnostics · Part 1

Marine Electronics Diagnostics: Raymarine AIS, Wind and NMEA 2000 Fault Investigation

Marine electronics diagnostics starts before the engineer steps onboard. This case study follows the preparation for a Raymarine network fault where AIS and wind data may not be reaching the multifunction display.

The aim is simple: verify the power, verify the network, verify the data, then confirm what the Raymarine MFD can actually display.

Need help with Raymarine, AIS, SeaTalkNG or NMEA 2000 faults?
F&C Marine provides marine electronics diagnostics, fault finding and onboard service support for vessel communication, navigation and data systems.

This investigation forms part of our wider Marine Electronics Knowledge Base, where we document real-world marine electronics troubleshooting, service preparation and diagnostic methods.

Marine electronics diagnostics equipment prepared for a Raymarine AIS and wind data fault investigation — Preparing diagnostic equipment before attending a Raymarine, em-trak AIS and NMEA 2000 fault investigation.

The Reported Problem

The vessel owner has reported missing or unavailable NMEA 2000 data on a Raymarine multifunction display. The installation appears to involve an em-trak B923 AIS transceiver, a Raymarine iTC-5 instrument converter, wind instrumentation and a Raymarine display system.

Reported Symptom

AIS and wind information may not be appearing correctly on the Raymarine MFD.

Likely Networks

The installation may involve Raymarine SeaTalkNG, standard NMEA 2000, or both.

Diagnostic Goal

Find where the data stops: at the source, on the network, at the bridge, or at the MFD.

Manufacturer Documentation Reviewed During Preparation

Before attending the vessel, documentation and system information were reviewed for the relevant equipment families. The key manufacturers involved are Raymarine, em-trak and Actisense.

Raymarine iTC-5 instrument converter documentation.
Raymarine SeaTalkNG and MFD network information.
em-trak B900 series AIS documentation.
Actisense NGX-1 and Toolkit diagnostic workflow.

Reviewing the documentation helps define what data should be present before we connect to the vessel network.

Reviewing installation records before a marine electronics diagnostic service visit — Reviewing installation records helps identify known equipment before arriving onboard.

What We Know Before Attending

The Raymarine MFD is reportedly not showing expected network data.
The vessel has an em-trak B923 AIS transceiver.
The vessel appears to include a Raymarine iTC-5 and wind instrumentation.
The exact MFD model and onboard network layout still need to be confirmed.
The fault could be power, termination, network wiring, configuration or device-related.

Important: At this stage we do not assume equipment failure. Missing data can be caused by network power, terminators, cabling, data source selection, software configuration or a failed device.

Planning The Fault Paths

When more than one data source is missing, the fault may sit in the shared network path rather than in a single device. That is why the investigation must cover electrical health, device discovery, data output and display configuration.

Marine electronics fault path planning for Raymarine NMEA 2000 AIS and wind data diagnostics — Fault path planning helps avoid unnecessary equipment replacement.

Identifying Test Points And Data Verification Paths

The key diagnostic question is: where should the data be visible?

For this visit, the likely checkpoints are the Raymarine MFD, i70s display, iTC-5 converter, em-trak B923 AIS transceiver, SeaTalkNG backbone and NMEA 2000 network.

Raymarine and NMEA 2000 network test points for AIS wind and marine electronics diagnostics — Identifying test points before arrival allows the network to be checked logically.

Preparing Actisense Toolkit And Network Diagnostics

For this visit, an Actisense NGX-1 and Actisense Toolkit are being prepared to independently view the NMEA 2000 network. This lets us check whether devices are present and whether data is being transmitted, instead of relying only on the MFD screen.

Actisense Toolkit prepared for NMEA 2000 network diagnostics before a Raymarine service visit — Actisense Toolkit prepared before the service visit.

How We Connect To SeaTalkNG And NMEA 2000 For Live Diagnostics

The Raymarine A80675 SeaTalkNG to NMEA 2000 adapter allows diagnostic equipment to access the network where appropriate. Combined with the NGX-1, this gives a practical way to view live network traffic and device discovery.

Actisense NGX-1 and Raymarine A80675 connection method for SeaTalkNG and NMEA 2000 diagnostics — Connecting through an NGX-1 and A80675 allows live network diagnostics.

Electrical Checks Before Replacing Marine Electronics Components

A network interface can show data, but it does not prove that the network is electrically healthy. A digital multimeter is used to check power, voltage drop, device supply and backbone resistance.

With network power switched off, a correctly terminated CAN backbone will normally measure approximately 60 ohms between CAN-H and CAN-L. A very different reading can indicate a missing terminator, extra terminator or wiring fault.

SeaTalkNG and NMEA 2000 electrical checks using a multimeter before replacing marine electronics — Electrical verification checks network power, resistance, terminators and device supply voltage.

Understanding The Raymarine iTC-5

The Raymarine iTC-5 is central to the wind side of this investigation. It converts compatible analogue instrument transducer data onto the Raymarine SeaTalkNG network. If wind data is missing, the iTC-5, its connected transducer wiring and its network output all need to be verified.

Raymarine iTC-5 SeaTalkNG and NMEA 2000 network diagnostics overview — The iTC-5 is the expected gateway for analogue wind and instrument data.

Verifying iTC-5 Data

The most important checks are whether the iTC-5 is visible on the network and whether apparent wind angle and apparent wind speed are present and updating. Where fitted, depth, speed, temperature, heading and rudder data may also need to be checked.

Raymarine iTC-5 expected data and verification guide for wind depth speed heading and rudder diagnostics — Expected iTC-5 data checks include wind, depth, speed, temperature, heading and rudder data where fitted.

Understanding The em-trak B923 AIS Transceiver

The em-trak B923 is a key checkpoint because it should place AIS and position-related data onto the NMEA 2000 network. If the B923 is visible in diagnostics but not on the MFD, the fault may sit in display configuration or data source selection. If it is not visible at all, the fault may be power, cabling, network or AIS related.

For background reading, see What Is AIS and How Does It Work on a Boat? and Common Marine AIS Installation Faults.

em-trak B923 AIS transceiver NMEA 2000 diagnostics and troubleshooting guide — The B923 is a key AIS checkpoint in the network investigation.

Verifying AIS Data From The B923

The B923 should be checked for power, status indication, network visibility, valid position data and AIS output. If the AIS is transmitting and the network is healthy, the Raymarine MFD should be able to use that data when configured correctly.

em-trak B923 AIS NMEA 2000 data verification and diagnostics guide — Expected AIS checks include device discovery, GPS position data, AIS reports and MFD verification.

Using The Raymarine MFD As The End-Point Check

The MFD is where the customer sees the fault, so it is also where the repair must be verified. The MFD checks will include device visibility, data source selection, AIS target display, wind display and network status.

Exact menus can vary by Raymarine model and LightHouse software version, so the first onboard step is to identify the display model and software before relying on a fixed menu path.

Raymarine MFD SeaTalkNG and NMEA 2000 network troubleshooting guide — The MFD is the end-point where AIS, wind and network data must be confirmed.

What The MFD Should Help Confirm

Device Discovery

Can the display see the iTC-5, B923, i70s and other expected network devices?

Data Sources

Are wind, AIS, GPS and heading data assigned to the correct sources?

Live Data

Are AIS targets and wind values visible, stable and updating?

Raymarine MFD expected data and verification guide for AIS wind and NMEA 2000 diagnostics — MFD verification confirms whether the network data is actually reaching the display.

The Complete Marine Electronics Diagnostics Workflow

This investigation combines three layers of testing:

Electrical health: voltage, resistance, terminators and device power.
Data health: device discovery and network traffic using NGX-1 and Toolkit.
Display verification: confirming the Raymarine MFD sees and displays the correct data.

Complete marine electronics diagnostics workflow for Raymarine SeaTalkNG and NMEA 2000 systems — Electrical checks, network diagnostics and display verification are used together.

Related F&C Marine Guides

Related Equipment

Preparation Complete – The Next Step Is Onboard Diagnostics

The preparation stage is now complete. The next step is to board the vessel, identify the actual network layout, connect diagnostic equipment and compare the expected data path against the real readings found onboard.

After the visit, the follow-up case study will document the confirmed fault cause, test results, corrective action and final verification on the Raymarine MFD.

Marine electronics investigation preparation complete before onboard Raymarine AIS and wind diagnostics — Preparation complete. The next stage is live onboard diagnostics.

To be continued: live vessel diagnostics, actual network findings and confirmed fault cause.

Marine Electronics Diagnostics: Raymarine AIS, Wind and NMEA 2000 Fault Investigation (Part 1)