Synergistic Research Cable w/mpc / tuning bullets not lighting up

I re cabled my whole system with Synergistic Research Element series cables about 7 or 8 years ago through a local dealer here in Atlanta.  I'm discovering that some of the tuning bullets on two interconnects are no longer lighting up.  I've tried switching mpc's and other tuning bullets but I have a pair of XLR copper series that won't light up at all and another set that one side doesn't light up anymore.  Anyone else experienced this?