sounds strange, PASSTHATSHIT is right, ive had problems and thought somthing had blown, but my kit does require a "cool down" period before you can fire it up again.

i dont mean to sound like an ass, but have you checked your plug fuses? does the ballast have an internal fuse?

what exactly is a hydrofarm 400, a full kit, a ballast, what?

most ballasts are fairly rugged, they shouldnt just break.