NMEA 0183

I have just changed out my old Northstar GPS monitor for the Raymarine a98 MFD. The Northstar sent GPS coordinates to a Simrad Autopilot AP11 via a Robertson J300X terminal. It also sent GPS coordinates to the VHS radio.

I have connected the aSeries to the SeaTalk and the SeaTalk to an Actisense NGW-1 NWEA converter 0813 to 2000. The lights are flashing on the NGW-1. However the Autopilot and radio both say "no signal" for the GPS coordinates.

Are there any settings that I need to do on the a98 series? What can I check to see if the GPS signal is coming over to the Robertson junction box and the radio?

Thanks