Thank you for posting your question on Just Answer! I will be happy to help you with this problem.
please run the channel search in the menu setting
before buying a main board try your dvd or vcr player to the input you use as cable if a no go then
The main board is the unit that has the inputs for all of your external toys DVD,VCR so forth, you will have to open unit and read the name on the board, so we know who makes it and get the part number also.
These are some part stores, CALL THEM IF POSSIBLE always check with manufacturer , And you may need the name of the part and its part number off the part itself
But if you hook the dvd player to the same input it works???
And you have tried reprograming using air and digital