Last night we had a a power cut for 30 mins and when the power came back the clock was making a continual beep/whine noise. I reset the time / alarm / sunrise. Whilst doing this the noise it makes to demonstarte the alarm still sounded normal but the beep/whine was in the background. This noise continued all night and did keep me a awake. The alarm went off ok and made the usual noise. I have tried unplugging and resetting the clock seveeral times. but still the noise is there. What can I do to solve this?