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I regret that my information source seems to have been wrong about that reset procedure.
Did you purchase the NP-30 in Australia, or from some other country? this determines what national branch of Yamaha you could contact about the matter.
Also you will need to know where nearest Yamaha-authorized repairer of this line of instruments is located. Please tell me your region - as indicated by post code or postal code, or by town/city and province/region. Thanks.