What exactly broke?
I've had a cable crap out on me, the original one that came with the HE500 when it was first released. Some where up near the right channel cable, either the wire was pinched and snapped, or the little connector that hifiman uses might have moved and lost some connection with the cable (which really, why in the world did they go with that crap? Horrible idea; love their headphones, but damn I hate their connectors). I've gotten two cables since then. Picked up an HE400 cable for basically nothing (like $20?) which works just fine. And of course I had a custom cable made by Brian over at BTG Audio that is awesome (braided, sheathed, terminates balanced, with adapters for speaker taps and normal 3.5/6.3mm).
Very best,