If you deal with a non-responsive Samsung Momentus hard disk drive, then more than likely the HDD sustained multiple failures. For this particular customer, the drive sustained a mechanical failure as the primary failure, stiction, then the typical firmware and bad sectors issues.
In order to perform a successful hard drive repair, the drive had to be opened in a Class 100 clean room environment and re-position the read-write mechanism to its normal position. Here is a photo of the Samsung HDD during the data recovery service and its donor HDD:
The next step in the hard drive recovery process involved testing the integrity of the hdd firmware, including the critical terminal output. In many cases, just like in this particular case, hard disk repair is not possible without advanced modification to eliminate the disk's internal firmware from engaging its own hard disk repair algorithms to scan and reallocate sectors with errors. This type of firmware alteration requires deep data recovery firmware related knowledge, along with sophisticated expensive tools that only data recovery company specialists possess.
Once the mechanical and firmware components were stabilized, the final step in the hard drive recovery process was using an advanced hardware imager, like Data Extractor, to maintain the HDD stable, while imaging and recovering the critical files requested by the customer. The reason a harware based imager was necessary was due to the fact that Linux software based utilities like dd and ddrescue were not able to successfully mount the drive and deal with with the bad sectors.
Here is a video of the hard drive recovery while imaging:
Hard drive repair and recovery with mechanical, firmware and bad sectors problems requires expertise and advanced tools that a regular home users and computer shops lack. To maximize the chances of a successful hard drive data recovery outcome, it is highly recommended to consult with a data recovery pro.