Cox universal remote won't control samsung tv ln52a650 volume

This is a tough one, I can come up with possibly 2 solutions, 1 being that if the batteries are low you will sometimes lose partial control of some of the functions on the remote, and if that is not it, then I have another that this one happened to me once, The infrared on the TV was not picking up the volume button I was sitting at an angle, so everytime i sit in that chair everything works but the voulume control i have to point it right at it on direct line and not from the side...Hope this helps...Steve