The point of the inquiry was the possibility of recovering data that was recoverable. Not saving the hard drive. The data where the scratch is would not be read, but the rest would be recoverable. This is not a theoretical suggestion. It is something I have done. I have also, using my in circuit capacitor meter *, which measures the ESR of the cap, replaced caps and got hard drives working long enough to be able to get data that others gave up on. With the surface mount technology, it is often almost impossible to fix these things, but sometimes, before you throw the thing out, there are some things you could try. Of course, if you back up your data, you won't have this problem. That's 20/20 though,and offers no solution.
This is what I use. Nasa uses it on the Space Shuttle. The same unit. You do not have to unsolder the cap to use it. I also have a leak tracer. Fixing electronics to component level is a pain in the butt, but not too bad if you have the tools. I pass on what I have learned freely, as I have learned much from here.
By the way, Subaru owners, if your Mass Airflow Sensor goes bad, re-solder the (4)pins on the circuit board, they often crack. This can save you hundreds of dollars.