Guys i Have a lowrance 520c gps sonar unit and i have got problems with it. When i first got it, it worked fine and was great.. Now it wont load the maps up when u get on the lake ... its like stuck in between the navionics and the base map, but sometimes when you take the card out it will load the creek names of the lake up and then sometimes it will show everything that should be on the card. What im trying to say is im having trouble getting it to work with the navionics card in it. Its not wanting to load anything up. Im thinking it has something to do with the card reader in the unit, could the card go bad??? Need some help from you guys cause LOWRANCE CUSTOMER SERVICE IS BAD! Can not get them to pick up the phone, Always on hold.