I have a Pulsar 940 IR illuminator (79076) which will be used on a Yukon Photon XT 6.5x50 Digital Night Vision Sight (26348). My problem is it does not seem to be illuminating. Are they compatable with each other? The red light is coming on when the illuminator is switched on. The light is invisible to the human eye. It was purchased new about 4 years ago and has never been used,