i just got a new boat and put my fishhawk on it, i never had a problem with it on my old boat. i took it out the other day and tried it for the first time on the new boat. i turned the display on and it reads the surface temp for 30 seconds then it makes me calibrate it, so i just press the set button through all the calibrations. Then it wll read surface temp again for 30 seconds and shut off. the display shows a backwards c in the lower right hand corner. i tried putting the probe in the water but the batteries were dead.... so my question is, will the display act like this when there is no probe. when i used it before the display would stay on and it would just read surface temp.