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Eject Button Touch this button to eject a disc. If the disc is not removed for about 10 seconds after eject, the disc is reinserted automatically. Reset Button Press it with a thin, sharp object. The unit will then be reset to factory default settings.
Please make sure your scale is on a stable horizontal surface, free of vibration. My scale's display reads "Out2", what does this mean? Out2 is displayed when too much force (i.e. overload) has affected, and potentially damaged the load cell.
NO manual online. Try pressing and holding buttons. They removing the battery, wait 10 minutes and replace. Perhaps the battery is 'Out 2 Voltage Spec'.
You can use Garmin Express™ software to download and install the latest map ... large, and this process may take a long time on slower Internet connections.
Only from the maker, or a somewhere like here
https://www.sparesmarine.co.uk/webshop/electronics/globalmap-3500c/lowrance-globalmap-3500c-spares-accessories/?brandFilter=Lowrance%20GPS%20Chartplotter