Cable Box won't turn on

[WSB3]

After many years of use, the cable box on one of my 5 TVs is not turning on.  I checked the DC power, it's good.  The remote seems go as well.  I have done the on-line device restart and it "passed" without issue.  Is the box just dead?  How do I return it?

[BruceW]

What is the box model number? Some Scientific Atlanta and Cisco cable boxes won't fully power up if they don't detect a signal from Comcast on the coax cable input.

[AndyC2]

We have the same problem, suddenly. Other boxes all work. This Cisco RNG150N box suddenly has no power. I've tried unplugging etc; and pressing power button ten seconds; and switching the inputs to the TV. Should I just take it in and have it replaced?