The receiver should not have any effect on your tv/cable box turn-off problem. Same thing with System Control 1, since you said you had programmed a key on the cable box screen., so back to the original problem.

I”ll repeat this advice from my previous reply: When you learn the command from the cable box remote, are you holding the button down until the 3000 beeps? If the cable box remote turns both tv and cable box off with a single key press, then this key should be able to be learned on the 3000, evein if it is composed of two different commands.

Just removing the batteries will not make you start over unless you forget the 20 second rule, and that is not always a cause of losing settings, and I wouldn’t bother to do a reset because that is not your problem.