Raymarine Autohelm ST6000, Service Manual

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SeaTalk Service Manual 3
1. Description
The ST6000 course computer is SeaTalk compatible and consists of a single PCB
containing both the course computer and power amplifier circuitry. It is built using
surface mount technology and available for 12v operation only.
Note: If the course computer or its PCB are replaced, calibration values previously
altered from the factory settings will require resetting. Also the Fluxgate Compass will
require re-linearising (auto deviation correction). Both of these procedures are
outlined in the ST6000 system section.
It is essential the cable used for the single DC supply is of adequate gauge otherwise
the system may reset back to standby mode when the drive motor operates.
The table below gives a guide to cable size required. The length quoted is the total
cable length from the main distribution panel to the course computer, plus the length
from the course computer to the drive unit.
Drive Unit and Power Supply Cable Size
Cable length Cable type Copper area Cable gauge
up to 7m 50/0.25 2.5mm
2
12 awg
up to 10m 56/0.3 4.0mm
2
10 awg
up to 16m 54/0.3 6.0mm
2
8 awg
2. Disassembly
1. Unscrew and remove the 2 countersunk screws securing lid on terminal box
section and lift off lid.
2. Unscrew and remove the 2 thumb nuts securing extrusion assembly to terminal
box unit and pull extrusion assembly away from terminal box.
3. Unscrew and remove the 8 pan head screws securing both the connector cover
and extrusion end cap mouldings.
4. Remove the two heatsink location screws (ensure associated nuts and washers
are recovered).
5. Carefully withdraw the PCB assembly.
3. Re-assembly
In all cases re-assembly is a reversal of the dismantling procedure but note the
following:-
Apply a small amount of loctite 270 (or equivalent) to the threads of the two heatsink
location screws after they have been installed.