Try changing channel: the selected channel may be off-air.
Check that the CM-7500/DVR+ is plugged in, switched on, and has had sufficient time to power-up.
Make sure the DVR+ is not in standby mode (you can bring the box out of standby by pressing the standby button on the front of the box). Ensure the HDMI® cable is firmly connected to the box and to the TV, that the antenna cables are firmly connected to the box and are not faulty. Finally make sure that the TV is not set up to receive an input from a different device such as a DVD Player. We would also recommend checking that the TV brightness level is set correctly.
CM-7500TB1 CM-7500GB16 CM7500GB16 CM7500TB1 CM-7500 CM7500