Saberstaff electronics stopped working

[Gryphawoo]

I have a friend who has a saberstaff with obsidian lite sound and suddenly both sides stopped working. I'm pretty sure it's a Phantasm v3. He tried replacing the batteries and that didn't help and it's weird that both stopped working simultaneously. Neither the lights or sound works on them now. He says they worked fine one day then when he tried turning them on after them not being used overnight they suddenly broke. He tried contacting US a few weeks ago and has heard absolutely nothing from them since. Does anyone know what we should be looking for in order to repair them ourselves? Thanks!