ST290 GPS and NMEA issues

[Steve - Raymarine - Moderator]

Would be interested in the update diagram once you dive into the wiring.

After looking over the diagram, I have noticed a few things to point out, not necessarily specific to the issue, but can cause information transfer issues.

RayTech software is no longer supported on the Seatalk HS network. It should be removed and connected either to the NMEA 0183 port of the MFD or to the Seatalk/NMEA bridge.

The Seatalk bus and the amount of Seatalk to Seatalk NG converters are not correct. Each converter is designed for 5 Seatalk devices, this could affect power on the Seatalk bus which could cause information transfer.

The Seatalk Red wire should be removed on the S3 course computer and ST290 DPU, they provide power on the Seatalk bus and this is back feeding voltage into the Seatalk NG backbone (converter) the power should be supplied by the Seatalk NG backbone, and I am assuming that the Red unidentified connection on the converter is going to power. Once you add the additional Seatalk to Seatalk NG converters you want to make sure power is inserted into the center of the Seatalk NG backbone.