After performing a platter swap (hard drive repair) it seems like the issue isn't with the PCB or head or mechanics but with the platter itself?

Question

This question isn't mainly about recovering the data. I just don't understand how to interpret my observations.

Initial situation:

So I have this old 320 GB 2.5" hard drive which wouldn't get recognized by my laptop anymore. The data on it isn't super important so it's definitely not worth hiring a professional data recovery service.

However, incidentally, I own another one of this exact same hard drive model. So I thought, why not try to do a platter swap myself? (The hard drive only has one platter, so not even as complicated as this platter swap for example.) At the very least, it would be a fun project and - like I said - I didn't care much for the data. I went into this, expecting the operation to render the hard drive completely broken in the process.

Observation after platter swap:

• The only thing I swapped is the platter. Nothing else.
• The donor drive (the one which worked fine before) now has the platter from the defective hard drive. It doesn't work any more.
• However, the formerly defective hard drive (which now has the platter from the donor drive) now works?

Obviously, this won't help with recovering the data, but how is this even possible? The defective part is the platter itself?!

Answer 1

Your question is vague at best, but it you appear to be asking if the platter itself can be defective. To that question, the answer is yes. The platter is what holds the magnetic material in which the data is stored. The surface of the platter could be incorrectly made, scratched by dust, or the head itself, affected by outside magnetic fields, etc.

Its no different than say a CD/DVD/Blu-Ray drive. All the mechanical and electrical components may work, but if the disc itself is bad, it wont work.

Answer 2

First it should be said that a platter swap is among the most difficult and expensive options available to a data recovery professional. As such it is done only when other options are considered impractical or unlikely to be successful. Of course other options would be thoroughly investigated before proceeding. This is where experience comes into play.

A hard drive can only be safely opened in a special Cleanroom. The air in such a room will be at least 1000 times cleaner than that found in a normaly clean room. This is important. During operation the disk heads float on a cushion of air above the platter at a height less than the size of normal dust particles. This is even less than the size of some bacteria. Collision of the disk head with one of these dust particles is likely to damage the head, platter, or both.

You would need a qualifying donor drive. A drive that is the exact same model number may not be good enough. Such a drive may have actually come from a factory in a different country and have significant internal differences. Specific numbers on the drive must match. Which ones they are depend on the drive make and model.

Removal of the platter and drive heads is complex. The heads are very delicate and easily damaged. This damage probably won't be visible. Typically special tools and procedures are needed. This is particularly difficult with multi platter drives. Alignment of the platters must be maintained. Once lost there is virtually no possibility of data recovery.

After the platter has been installed in the donor drive along with the drive heads you are not yet done. Typically one of the chips on the original drive will contain drove specific data which must be transferred over. Which chip depends on the drive make and model.

If you have done everything correctly and damaged nothing the data should be accessible. But that is a very big if. There is much you can do wrong that is far from obvious.

Just an example of how difficult this is: I read of a case where someone had on attempted a platter swap on 3 separate occasions. He had done his research and had done everything that could be expected from a well informed amateur. All 3 attempts failed with no recovered data.

Note that I have done none of this myself. I know better than to try. I have just done a lot of reading.