FYI - Inon strobes are designed to use S&S cables. I have found S&S cables to be reliable. It sounds like your strobes were not able to charge up the capacitors. The light comes on when they are charged. This could be due to a weak battery. Are your batteries OK? The circuitry responsible could be bad as well. I would do your tests with fully charged Eneloops. If you suspect the sync cable - test one strobe at a time with a singleton sync cable. Keep things as simple as possible to do a process of elimination.