Wow, serious. How about: Tuesday May, 12 1998 - Kevin & Kell? (sorry)
Seriously: Apparently-dead L5 seems to suggest that you need charged battery. I have similar experience, but I’m not sure if it was same, and in that case managed to boot using my spare battery (and got life from other after using separate battery charger). Why a charged battery worked and not the cable, I have no idea. That would be one more thing to try, if you have one of those type of chargers that have been shown here too?