make sure your tv and cable box are turned on at the same time. If you are using the "ALL ON" button to normally turn on your tv and cable box, press the CABLE button and then power to turn on your cable box. If your tv is off, press the TV button and then press power. If your tv is already on, skip this step. Now make sure you press the CABLE button again after turning on the tv. If you can see the back of the cable box and tv, if will be helpful to locate your input. From the wall to the cable box will be a screw on cable wire. From the cable box to the tv there are several different types of connections. If the connection from the cable box is the same as the one from the wall to the cable box, your input should be either channel 3 or channel 4. Not 3.1, 3-1 or anything like that. If there isn't a channel 3, but a channel 3.0, use that one. If the connection is a 3 wired cable, YELLOW, RED and WHITE, your input is either Video or Composite. If you look where the cable are connected to the tv it will tell you the number if there is more than one. If the connection is a 5 wired cable, RED, BLUE, GREEN, red and white, that is a component connection. The input will say COMPONENT or Yp,Br,Pb or something like that. Also make sure to check the input number. If the connection is a single flat connection like USB, that is the HDMI connection. The input will be HDMI. Also, check the number on the back I hope this helps. Please message me back if you need further assistance.
The only effect your cable box has on "no signal" is if it is turned off or the hdmi cable is loose. You did the right thing by checking all inputs. Many HD TVs also must have the physical TV on channel CA 03. Cable channel 3. Worth giving it a try.
Try to power cycke the cable box. Make sure all connections are in on the backnof the box and the back of the tv. Make sure canke box is on. Verify the input # on the back of the tv that comes from the cable box. Try turning tvnon and off. Let me know! If any of that helps. Worse case call 1800 comcast and have a refresh sent and if still not working you may need a texh to come out
I have been with Comcast for 8 years. I work in the Field as a Comm Tech 4
I primarily work on advance services and Commercial Installs and service calls