1. Check if using Menu button you are able to access the Menu.
2. Check if the decoder is in standby (press power button if LED is red).
3. Check if the Smart Card is correctly inserted (if on a scrambled channel).
4. Switch the STB off and on (using the remote or unplugging power cable).
5. Make sure that all cables are connected properly and firmly secured and then hand–tighten, if necessary
6. Reconnect all cables.
7. Try to change channel.