Bought a boat mid Sept, and it had a dead Piranha on it. Bought a new 170 and plugged into old power and transducer, worked OK. Thursday I kept seeing bunches of fish 10 ft off bottom, thought I found the mother load. Then I noticed flashing in the bottom left corner"simulation".....? I turned it off & on, changed depth, sensitivity, and about everything else but no better. I got a message about transducer not connected and unplugged/plugged in but no change. When I pulled the boat out I looked at the foot. Everything looked OK, no torn wires. What's up??? Temp reading looked OK all day. It never read depth above about 7 mph. This thing is driving me nuts! Who knows this unit?