[CA] [CA11] Equipment issues

[optionsailor]

I have the following Raymarine products installed on my 40' Beneteau sailboat:
ST50 Speed; ST60+ Depth; ST60+ Wind (w/ST60 short arm vane xducer);ST60 Multi;
C80 MFD (repaired by Raymarine in 2013);
ST6000+ Autopilot; ST600R; 300 Course Computer; Fluxgate Compass; Rotary Rudder Reference; Reversing Hydraulic Pump Type 2 12V; RS150 GPS Antenna (w/Seatalk1 to Seatalkng converter kit);
RD218 Radome;
Ray218 DSC VHF; Raymic;
AIS500 (w/R62241 GPS Coax Antenna);
Gyroplus2 SHS.

I am having the following issues after having been off of the boat since this past July:

(1) The C80 displays "no AIS". The Ray218 DSC VHF shows no GPS; AIS500 status indicator is green. C80 System diagnostics shows no NMEA sentences received. NMEA sentences are being transmitted. I disconnected the AIS500 and reconnected the NMEA directly to the Ray218 DSC VHF and changed the C80 settings to NMEA 4800. GPS coordinates appear on the Ray 218. C80 System diagnostics shows no NMEA sentences received. NMEA sentences are being transmitted.

(2) The compass heading on the ST6000+ Autopilot and ST600R is ~90° off. I tested the fluxgate per the process described on the Forum and all tests were within 2 ohms. The Forum states that if all tests pass, the problem is with the 300 Course Computer.

Could these problems be related? Would you recommend replacement of the C80 and/or the 300 Course Computer ?

Thank you.