Are you having problems with accessing pages? Having to reset your knob list, °C/°F, winds, and other display settings? The displays internal clock battery is likely discharged. Replacing this battery will get you back to normal.
We have found that the internal clock battery lasts from 6 to 10 year in a display. It is important to use a BR chemistry battery over the CR type due to their improved performance in high temperature environments and stable voltage over battery life. CR batteries will need replacement more often - their usage is discouraged.