I have two Monster Powerbar 1100 strips and one seems to be working fine. The other seems fine except the blue "clean power" light is not lit. What could be malfunctioning to not allow this light to come on? All the rest of the lights are on. I've looked around some online and looked at the user manual and it barely mentions the light. I'm aware that there are more exotic conditioners out there but I've found these Monsters to be cost effective used. What should one of these have to do to make a person pass on one? Warning signs that indicate it's likely not working? Can one be malfunctioning and have all the lights indicating all is well?