Ive not heard of this problem before but it definetely sounds like it needs repairing. Call or email Nintendo, they will give you a repair order number and directions for sending it to them.
As long as its still under warranty they will pay for postage and repair it for free. All you have to provide is a box to send it off in. It usually takes under 2 weeks, i just sent mine off last week and they emailed me to say that it would be back by next saturday.