i bought the 161 combo from humminbird and like it alot but 1 problem.if you change screen views to fast or get in real rough water it locks up and you cant even turn it of.you have to take it off the mount and then is hard to get it to re boot and come back on.its got good conection to the power cord and evry thing is hooked up right.it seems to do this more on the gps screen.has any one used this unit and if so did it do this to you.any help would be great.thanks.