When we are dealing with a damaged hard drive in most cases its because customer drop their external, unplug/plug in the wrong power supply to the external caddy.
So it happens the drive starts to make clicking sound, and buzzing sound, in this scenario we would recommend to stop powering the and contact a data recovery professional you're just making the matter worst.
Your hard drive has failed due to the chock and if its kept powering this will lead to further damages resulting in total data lost.
Some of the customer's try and opened their hard drives and they cause all of sort of problems, messing the platters leaving with finger prints. Even after the physical work to repair the drive sometimes its difficult to repair it, because further degradation has been done to the drive and the data itself can become corrupt.
Drop Laptop, Water damaged can physically cause damages to your hard drive, even though its inside it still fails, therefore it should still be possible for the data to be recovered.
Mechanical fault the data recovery professional has to acquire parts and perform physical work in order to make the drive work again and using expecial equiment to retrieve the data.
This occurs to hard drive still working however you can not acess the data on anywhere such PC, Laptop, and iMac which all seem to fail to boot, crashes all the time, get a reading error basically you lost acess to evertyhing.
Logical faults we are looking at all kind of problems with drive and sometimes it can be easily fixed such as (firmware) in this caseof the times you will need professional help in case you have to sent your media to a data recovery company.
Usually customers try first on the PC shops without success they eventually have to contact professionals, major companies will charge a high for the service and also they will not tell the exact price/quote until you sent in your media.
This happens when you plug incorrect power to your external caddy and it does damages the Electronic Circuit Board, and some times they even further damages.
We deal with so many tipes of hard drive brand and individuals alike when they have damaged electronic circuit boad, they choose to search for a exact match, depend on the type of hard drive sometimes it does work, but most of the times it will not, so they have already wasted money in buying parts that is not compatible and not knowing it does require certain process to fix and make the drive work again.
The price of having a technology from Smartphone, Tablet, iPad, Computers, SD, Memory Stick, and Except SSD which are more realiable, but they will eventually fail one day either by accident or due to ware and tear with time.
So to take precations one must always have backup, I would recommend using Cloud Storage instead of any other physical media, some of them provide with storage space up to certain limit. We definitely think the Cloud Storage will be the future.
So our final advice to anyone has an important data to recover from your damaged media seek help and stop wasting your time/money without sucess which will lead to total data lost.
Some of the videos on YouTube showing you how to do data recovery using various tools do not believe in most scenarios it would probably will not help you recovering your hard drive.