The power light on my DTV converter box goes on and off. What could be the problem?

When I press the On button on the DTV converter box remote, the power light comes on, and then it goes off again. I'm not able to get the light to stay on so I can scan through the channels or do anything. Can someone please tell me what is going on and how I can solve this problem? The dtv converter box I use is Magnavox TB100MW9. Thanks.