Digital TV Converter keeps shutting off

I recently bought the RCA DTA800 Digital Converter from WalMart. I have it installed and working. However, the it turns off (not standby) after only a few minutes. It does not turn back on with the remote or the button on the unit. I had to unplug it and plug it back in before it would turn on again. Then it did the same thing again. I gave up on it and left it alone. After a few minutes it turned back on by itself. I checked the setting that turns it off after a certain time limit, but that doesn't seem to be the problem. Is this something fixable, or do I need to exchange it?