B&G net Quad problem

[Iason]

Hi, just joined the forum and need help with this.
The Quad transmitter is used with an AirMar speed and temperature sensor, 01-0596. The temperature reading is ok but we get no speed value. These are old units, as they were purchased in 1996, many years before I got the boat. On the 6 pin connector of the transmitter I am getting 5 Volts on pins 1 and 2 (Ground and +ve voltage), on pins 1 and 3 (Ground and Speed signal). The pin numbers I have figured out from a different sensor on the AirMar site, as I could not find mine.

Does anyone know if that's how it should be, i.e. the sensors need 5Volts to run, and the output with the paddle wheel not turning is also 5 Volts.
I have yet to find a way to measure the voltage across the pins with the sensor connected.

Thanks
Iason