DIY and FIXES
My depth - speed(log) - temperature instrument - Raymarine tridata A22013 stoped working. I checked the hall input from the sensor (blue wire) and it worked perfectly (voltage changes from 12v to 0v and back ). It turned out, there was a faulty thermistor (part of the transducer for temperature measurement). Raymarine firmware checks the temp sensor, and if it is faulty, it won't show anything. Guess why... force the customer too buy a new transducer!
If you don't need water temperature data, just place a 10K resistor between white and brown wire, or even better, connect 10K thermistor to the brown/white wire and epoxy it to the hull of the boat and with minor calibration you will have fully functional instrument.
I have placed a variable resistor between input pins on TRIDATA instrument and it is clear, the curve follows the 10K NTC characteristics.
Original Volvo penta panel has been broken at the holes in the edges and cheap plastic looks bad after only ten years. New one is too expensive, so i decided to laser - cut it on my own.
Tha plans as attached as followsČ
On my sailboat, when i got it, the tacho and hours meter LCD instrument was dead. It is marked VDO Model N02070009 or Volvo number 873660.