Erratic operation of Autohelm ST50 Tridata paddlewheel speed log

Do yourself a favor an take it to a qualified repair shop . You need a factory scan tool to see these code's
DTC C0040 00 : Right Front Wheel Speed Sensor Circuit No Additional Information
DTC C0040 0F : Right Front Wheel Speed Sensor Circuit Erratic Signal
DTC C0040 18 : Right Front Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum

DTC C0899: Device Voltage Low
Circuit/System Description
The electronic brake control module (EBCM) monitors the battery voltage level available for system operation. A low voltage condition prevents the system from operating properly.

Circuit/System Testing
Measure the voltage at the battery terminals.
With scan tool, read the battery voltage in the EBCM data list.
? If less than 10 volts, test the ground circuit of the EBCM for high resistance. If the circuit test normal, test or replace the EBCM.
Go to Battery Inspection/Test and Charging System Test .

You need to grease the speedometer cable

I assume you have an ST-50 or ST60 windvane setup. These are the calibration instructions from the unit manual for the ST-50. They are the same for the ST-60 and ST-60+ units.

Hope it helps you.

Initial Calibration Windvane Alignment
Before the unit is used for navigational purposes the masthead transducer must be accurately aligned to the vessel. Before this procedure is carried out the windvane should be linearised as follows.

1 . Powerup lhe ST50 Plus Wind instrument.

2. Tum the vessel through two complete circles, making sure that the windvane remains in line with the wind -the instrument will automatically linearise the windvane.

Alignment
1. Press and hold CAL for 2 seconds until CO is displayed by the LCD.

2. Press < > to move the pointer to the correct wind angle.- WIND
- Press < > once to move the pointer by 1 degree.
- Press < > for 1 second to move the pointer by 10 degrees/second.
The LCD will now display the applied correction.

3. Press and hold CAL for 2 seconds to exit and store windvane alignment.

Windspeed Unit Selection

1 . Press and hold CAL until Ul (Knots) or U2 (Meters/second is displayed.

2. Press CALwithin 8 seconds to change the windspeed units selection.

3. After 8 seconds the wind instrument returns to normal operation.

Erratic signals come from the speed sensors(all that I found). At the sensors by the tires/CV axles. When I tear them apart (the bearings) they have fine metal around them. The causes the erratic signals. As you said, they seem normal at most points. But you have to watch and see where(the signal) they jump. Could be 2 MPH or 20 MPH. Replace that wheel bearing.

Go to Raymarine.com to find the usermanual for these units. They should be helpful.

The part number for the lower pod is Q002. I am willing to bet that Raymarine will not have any more of these. The new ST60+ version will read faster than what the wind is actually.

I had one. Don't think you calibrate it. Reading is relative to it's mounting base. To change the direction reading, you would need to rotate the base.

It is unlikely the problem is in the A65 screen.....most likely it is an issue with the paddlewheel itself, its circuit in the depth/speed transducer, or least likely, in the DSM25 sounder module.

Both the log and the trip functiions are read from the paddle-wheel sensor of the connected DSM25 sounder module and transducer.

1. Make sure you have a DSM25 sounder module and transducer with a paddle wheel (the A65 is available without the DSM25 option.)

Double check the connections between the DSM25 and the A65, as well as the transducer connection to the A65. There is an indicator light on the DSM25 to confirm it is on.

2. Make sure the paddle wheel turns freely. They tend to get fouled easily with debris and growth.

3. Make sure the A65 is giving to a reading for SPEED when underway or when having a buddy spin the paddlewheel by hand. Do not confuse SPEED with SOG. SPEED is from the paddlewheel.....SOG (Speed over ground) comes from your GPS sensor and is not used by A65 for log or trip purposes.

If you get npo speed reading at all the paddle wheel may be defective or the depth/speed transducer may be defective. See your dealer about a replacement.

Depth: Could be for a number of reasons, too deep for the sounder - check the manual for it's max depth. Dirty water, sounder unable to penetrate through to the bottom. Weed or other debris covering the transducer. Transducer on a swing mount & being pushed out of alignment then dropping back in once stopped.

Speed: Is the speed readout controlled by a GPS or paddlewheel? If it's GPS, check the power connection of the sounder, may be loose which would also cause the depth to 'drop out'. If it's paddlewheel, you're down to bad connections or faulty unit.