Had 1 problemwith keeping a lock on bottom. This unit came on a boat I bought from a buddy of mine. I talked with Humminbird Greg on Bass Boat Central & he told me what to do & it has worked perfectly ever since.I'm going to buy a 581i to go in console for the gps & I will be moving the 525 to the trolling motor too. You can do some tweaking to the adjustments on the 525 & it's sure enough a pretty good cheap unit.