What seems to be going on is this: Your box has two things in it called "tuners" that send TV channels to each of your TVs. For some reason, signal is getting to one of your tuners and not the other. When this happens, it's almost never a problem with the signal strength itself, because that would mean BOTH TV's wouldn't be working.
"No Signal" is NOT a message that Dish network receivers give. However, a lot of TV's will show that message if they aren't set to the right input. If all you're seeing is a blue or black screen with "No Signal" on it, then the problem is not with Dish's equipment. As Mary Catherine said, the problem could be fixed by changing the input on the television to make sure that it's looking for signal in the right place. For example, if you have your receiver connected to the TV with a piece of coaxial cable, but the TV is trying to find a picture over the component input, then it could show a "No Signal" error. The thing to do would be to cycle through your TV's input options until you find the appropriate picture again.
If you can provide me with a phone number, I'd be happy to call you today and try to work this out over the phone with you. I'm not sure what time zone you're in, but I'm available any time after 12:00 noon, eastern time. My number is 301-418-1935
Unplugged box for close to one hour then reconnected. Picture came on for 5 minutes then off again. We've noticed a whirring noise, sometimes for long time (over one minute). Went through the the cycle of imputs which didn't seem to help. Might note - HOT here, today 105-112 degrees. Know this can not be good on electronics. Been making notes on what is going on. I can be reached at 620-622-4470 anytime this afternoon. (Central time zone). Jeanie Beeley
If the Main TV is the only one not showing a picture and it say just "No Signal". Make sure the green light lights up on the front of the receiver box. Then check the input or channel that the TV is set to. If you can cycle the inputs and be sure to pause a momenmt or 2 at each setting (Video1, component, HDMi, etc).
I would reset the receiver box, unplug from the power for 10 seconds and then plug back in. See if it reboots if not then you will need to do more advance troubleshooting. If you have additional questions, please feel free to contact me at firstname.lastname@example.org! Thank you!