C-80 stopped displaying Data

[PatTormey]

I have an old C-80 which seems to be installed using a Seatalk conversion kit powered from the AutoPilot
The Tridata and ST60+ work and the AutoPilot display seems to be OK.
BUT None of the telemetry from and sensors (GPS, Wind, Depth) are being shown in the C-80 display. I've replaced the battery in the GPS antenna and remade all connections.

I'd like a technique to test the 3 wire (Seatalk 1??) at the C-80 connection or ANY other idea to help solve this problem.

Please see the attached file for some pictures of the equipment.
Thanks
Pat
Blue Skies
Portsmouth NH & Newport RI

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Pat,

Should the SeaTalk cable be unplugged from the MFD's SeaTalk port, an analog meter may be used to test for data transmission. Should the meter's leads be connected to the cable's plug to test voltage across its data (yellow) and ground (shield) leads, the meter's needle should pulse between +9 & +11VDC.

C-Series Classic MFDs are not designed to support SeaTalkng communications. Should a system feature devices having a SeaTalkng communications interface and devices having a SeaTalk communications interface, then the SeaTalkng backbone must include a SeaTalk to SeaTalkng Converter to support integrating the SeaTalk devices to the SeaTalkng system. Should the problem not be identified, then please add system diagram (a photo of a hand rendered diagram will suffice) to your response to this thread.