G,Day guys, I have a Volvo Diesel AD41P. The Tachometer has stopped operating, while the motor is running the tacho will occasionally creep up to 6000RPM (at idle) then go down to 0 rpm, it will do this abour every 30secs. Also the LCD hour meter which is part of the tacho shows some lines but will not show numbers, there is power to the tach. Any ideas?