I have an old Magellan Sportrak Map that I used reliably for years and then was put away for about 4 years. recently, I inserted new batteries and reset the unit and now it is very inaccurate. After marking a waypoint, walking around the block, back to that waypoint, it is sometimes off by 100 feet. I have tried this numerous times and, when returning to the waypoint the bearing is fairly close but the distance is always way off. There are always lots of satellites connected. Does anyone have any idea why this could be and what i could do about it? Thanks in advance.