Very common for all headphones, and as mentioned Grados in particular. It's actually pretty rare to have things actually go wrong with headphones from the electronics perspective. Usually its the headband/pads wearing out. I would put headphones breaking in this order.
1. Plug(s) at the end(s) of the cable or headphone-side female connector
2. The cable itself.
3. Flux residue that was not cleaned up properly around solder joints becoming conductive and creating short(s).
4. Voice coil leads going to their respective solder joints on the pcb on the back of each driver.
That is, unless you're really driving them past listenable points.
Fixed it for you.
Edited by Mad Max - 4/27/14 at 9:34am