Microtune, a digital tuner company, says Digital TV converters now available for sale may not pick up some local channel signals. The converter box, which enables analog TVs to display digital signals, is crucial to the success of next year's scheduled transition to Digital TV. Full-power local stations must begin broadcasting in digital on February 17, 2009 and an estimated 15-20 million people will likely need the converters to continue watching television at that time. But Microtune says it tested 14 Digital TV converters now available at retail and found that five failed to receive the signals of some local digital channels. The National Telecommunications and Information Administration, which is overseeing the transition, says it will review Microtune's findings.