It possibly has an open circuit mains transformer or cracked joint on the circuit board. Since you have checked the fuse, it probably needs to go to a dealer to be diagnosed. It is very rare for them to be totally dead, so it is probably a component failure.
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If anyone is looking for a Samsung cash register manual, try here:
http://the-checkout-tech.com/manuals/cashregisters/samsung1.php
Registerman
July 2010