Light does not get "on" signal

[DrG]

I have been using an x-10 system for many years. I use Active Home (V1.42) with a CM11A. I also have a X-10 Pro  XPCR phase coupler/repeater. In the past few months my back light has not been going on as scheduled most nights . Other times some of the lights do not shut off.  However, I  can turn them all off and on with my remote and from my computer, including the back door light. I checked the coupler/repeater  and when I send a signal  from my remote I do not see the green light blink. The red light is not on. When I push the test button it works perfectly(blinking and turning off and on the selected device). I am confused. I have had to replace the coupler/repeater once  before after a power surge- but that one acted quite differently. The telltale sign was this same back light not going on. I think this circuit is the furthest in the box.  If I can't see the green light blink but the signal is getting through is it possible the XPCR is  really  not working properly? Does anyone have any ideas?
DrG