ST50 Speed Log Temperature Function

[Michael McCann]

Bill;A friend's ST50, and mine are approximately the same age (new in 1992/1993). His temperature reading is 28 degrees, while mine reads 51 degrees. Same day same water. Could this be in the transducer, or the instrument? Thank you for a great forum. There have been some great posts.Mike

 

[Bill Boudreau]

Temperature Test

There is no calibration adjustment for the Temperature in the ST50 Speed. To see if there is a fault with the transducer assembly, do following test;Disconnect the transducer cable from the display head and locate pins 1 and 2. You do this by facing the plug end of the instrument cable with the reference notch at six o'clock position, Pin 1 is at 7 o'clock and pin 2 is at 10 o'clock position. With the instrument powered on, place a 10Kohm resistor between Pin 1 and Pin 2. The display should give a reading of 25 degrees Centigrade.If this is the case then we can assume the instrument is functioning correctly and the temperature error is due to a faulty transducer or cabling.

 

[Don S]

Same Problem Same Year

I am having the same problem. My boat was bought new in 1993. I do have a very balky knot meter though. I need to clean the paddle wheel every week if I want to have a knot meter. Most times I just don't bother. When I clean the wheel, the temperature still reads 19 deg F

 

[Michael McCann]

Don S. (ST50 Temp)

Don;If the weather allows, I will do the test on mine this week end, and let you know. I didn't say, but the water temp is getting colder on mine (it is now reading 49 degrees F), however the water could be that cold at this time. I will not be able to check my friend's out, as his boat is in Seattle's Lake Union at this time.Mike

 

[Bradley Cavedo]

Mine doesn't work

It used to work great and give good water temps. Then there was a lightning strike about six boats over in the marina and the temp has been wrong ever since, by 20 degrees on average. The Raytheon people said the only fix is a new transducer/paddle wheel. Tooo expensive, particularly when the speed works fine.