Autohelm Inboard Autopilots (ST6000 and ST7000 systems) Service ...

Autohelm1. DescriptionThe ST6000 course computer is SeaTalk compatible and consists of a single PCBcontaining both the course computer and power amplifier circuitry. It is built usingsurface mount technology and available for 12v operation only.Note: If the course computer or its PCB are replaced, calibration values previouslyaltered from the factory settings will require resetting. Also the Fluxgate Compass willrequire re-linearising (auto deviation correction). Both of these procedures areoutlined in the ST6000 system section.It is essential the cable used for the single DC supply is of adequate gauge otherwisethe 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 totalcable length from the main distribution panel to the course computer, plus the lengthfrom the course computer to the drive unit.Drive Unit and Power Supply Cable SizeCable length Cable type Copper area Cable gaugeup to 7m 50/0.25 2.5mm 2 12 awgup to 10m 56/0.3 4.0mm 2 10 awgup to 16m 54/0.3 6.0mm 2 8 awg2. Disassembly1. Unscrew and remove the 2 countersunk screws securing lid on terminal boxsection and lift off lid.2. Unscrew and remove the 2 thumb nuts securing extrusion assembly to terminalbox unit and pull extrusion assembly away from terminal box.3. Unscrew and remove the 8 pan head screws securing both the connector coverand extrusion end cap mouldings.4. Remove the two heatsink location screws (ensure associated nuts and washersare recovered).5. Carefully withdraw the PCB assembly.3. Re-assemblyIn all cases re-assembly is a reversal of the dismantling procedure but note thefollowing:-Apply a small amount of loctite 270 (or equivalent) to the threads of the two heatsinklocation screws after they have been installed.SeaTalk Service Manual 3