The cable box is good. The cable box remote works perfectly when aimed directly in front of the cable box. (i.e., changing channels, guides, menus, etc.)

The cable box is a different model (motorola dcx3400) but the remote still works properly when directly in front of it.

I did your LCD/IR interference test and the channels still do not change so I assume the LCD light isnt the problem.

Would an RF remote interfere with other cable boxes that are inside the same entertainment cabinet? The other cable box is not connected to the IR repeater and is different model than the cable box we are discussing. The box we are discussing was an upgraded version from my cable provider I received when exchanging boxes. The remote is the same as the cable provider told me I didnt need to exchange it.