I have an Eagle 320c which I modified to use an Airmar 7 pin plug transducer.
The depth sounding works fine.
The temperature reads 20* too low.
the original transducer, the temperature resistor had failed, reads about a million ohms and Eagle 320c was saying it was minus 10*F.
With the Airmar 7 pin transducer, the Eagle 320c reports a 77* true temperature as 55*.
So my theory is the lower the ohms, the higher the temperature readout on the display.
I measured the Airmar 7 pin transducer temp wires and they read about 8300ohms at 77* true water temp.
So my idea is place a resistor in parallel with the temp sensor in the transducer, that will lower the ohms and bring up the reading.
Question is how big ohms resistor to use?
Preferably, an adjustable one would be ideal. What range should I look at getting?
I was thinking 0 to 100,000 ohms range pot, if that exists.
here is the link to schematic for the Airmar 7 pin
http://www.airmartechnology.com/uploads/wiringdiagrams/91_386.pdf
here is my mod, I paralleled the wires inside the 320c to use the plugs for a 7 pin setup.
So I can either use the original slightly broken transducer, or the Airmar 7 pin transducer.
The depth sounding works fine.
The temperature reads 20* too low.
the original transducer, the temperature resistor had failed, reads about a million ohms and Eagle 320c was saying it was minus 10*F.
With the Airmar 7 pin transducer, the Eagle 320c reports a 77* true temperature as 55*.
So my theory is the lower the ohms, the higher the temperature readout on the display.
I measured the Airmar 7 pin transducer temp wires and they read about 8300ohms at 77* true water temp.
So my idea is place a resistor in parallel with the temp sensor in the transducer, that will lower the ohms and bring up the reading.
Question is how big ohms resistor to use?
Preferably, an adjustable one would be ideal. What range should I look at getting?
I was thinking 0 to 100,000 ohms range pot, if that exists.
here is the link to schematic for the Airmar 7 pin
http://www.airmartechnology.com/uploads/wiringdiagrams/91_386.pdf
here is my mod, I paralleled the wires inside the 320c to use the plugs for a 7 pin setup.
So I can either use the original slightly broken transducer, or the Airmar 7 pin transducer.