Most of the time when the cable comes into your house it is split off so service is still working at your home it must be the box. I would unplug the Box and leave it for 5 minutes then plug it back on and let it reboot.
It also maybe the setting on the television make sure it's on the correct input or source
I actually have replaced the TV with another one and it still says "no signal" could it b the cable box itself?
No signal is almost always an issue with the input(source) the tv is on. Check the cable from the back of your television to the box(if you look at the spot the cable is plugged into it will tell you the correct input), also of course make sure your cable box is powered on.
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