Where Can I Buy A Drive Controller For St305004fpb1e2-rk?

Not sure what you're looking for.

Did the hard drive itself die, or the case it's mounted in?

If it's the case you can mount the drive an any external case or inside any PC that supports SATA disks.

If it's the drive a new controller won't help.

You will more than likely not be able to buy a new circuit board to replace the one inside the case if thats what defective.

I recommend an entire new external case.  See this link: http://www.newegg.com/Store/SubCategory.aspx?SubCategory=92&name=External-Enclosures.  Look for a case that supports SATA disks.

---

Licenses & Certifications: Microsoft, Cisco, VMware, Novell, FCC RF & Amateur Radio licensed.

I had a similar issue. One cannot replace the controller with another as each one is unique to the drive. However if you have data which you need to recover then you can buy a new controller from a company in Canada. (Google replacement controller cards). They will sell you a new card but you have to send your old controller to them first to copy the drive information to the new PCB. They will return both to you and you fit the replacement and away you go. The cost wil be about the same as a new drive. But if its the data you want then it is worth it.