Where to start???

[Chuck - Raymarine - Moderator]

Darren,

Q1a. on the autopilot side... I know I have the controller head, the hydraulic drive unit is the pump with the hydraulic lines going to it?
A1a. the autopilot's hydraulic pump would indeed have hydraulic lines connected to it. It would also have a set of motor leads leading from the pump to the corresponding Motor A/B terminals of the autopilot course computer.

Q1b. The Fluxgate heading sensor is a tennis ball size looking round thingy on a square base?
A1b. Sounds like the M81190 Fluxgate Compass and its leads would also be connected to the corresponding Compass terminals of the autopilot course computer.

Q1c. I'm not sure what (or where to look) for the rudder position sensor?
A1c. Autopilots of this vintage required a rudder reference transducer which would be connected to the rudder arm. Linear rudder reference transducers were also produced for outboard powered vessels.

Q1d. I am also guessing none of this matters if the 'course computer' is missing???
A1d. I suggest that you trace the fluxgate compass leads or hydraulic pump leads to see where they terminate.

Q2. Is there a way to identify the top mounted GPS sensor, mine is missing the cover?
A2. Perhaps, if a photo of the GPS sensor is attached to the thread, then it may be possible to identify the model of GPS sensor. However, should its cover be missing, then the system will quite possibly be in need of a new GPS sensor.

Q3. I did try to go to the manual section, but got lost in all the sub-menus. I sort of expected to just download 3 manuals, but found it very difficult to navigate.
A3. The generation of displays that you own were known as hsb Pathfinder Series Displays.
- RL70 Manual: https://raymarine.app.box.com/s/eri3w81z...74180851/1
- RC520 Manual: https://raymarine.app.box.com/s/eri3w81z...74191583/1