Hard drive repair and data recovery information
Printed Circuit Board Failure (PCB)

These range from spindle IC failure such as overheating and even a physical burn out of components
This could even be the aftermath of more serious problems such as the bearings locking up of the spindle motor that rotates the internal platters at variable speeds

Spindle Motor Jam

As mentioned above this can cause all sorts of problems... you might even think there is no power getting to the drive and yet every time you try something new in the hopes of retrieving data... all you accomplish is more damage to critical components

Head Crash Related

This can be caused by several different scenarios from rotational speed enabling the read write heads to make contact with the platters, which would normally cause a ring or scratch around the platters surface.
Head Slap or violent knocking of the armature causing the heads to become misaligned.
Unsuccessful park from an improper shut down normally from a sudden power loss.

System Area Corruption

This also can be caused by several different scenarios from improper computer shut downs to sudden power loss.
This when possible changes are made to the system area of the drive while the drive is in operation. eg slow reads of sectors might be moved or marked in a defect list while in use. although this happens. without your knowledge these changes have a great impact on the drives operation and if these changes fail to complete or the drive losses power half way through these changes you will have corruption in that particular system area module and the drive will no longer be recognized, seen as a different model, serial number is no longer visible or seen as hieroglyphics in the computer's BIOS

Hard drive repair processes and equipment
The most important tool you MUST have if data is irreplaceable
These are the terms associated with the common faults of a failed hard drive
What can & will go wrong with a hard drive due to age, voltage or impact

Remember if data is important please consider the experts!

First step in do it yourself hard drive repair
Common hard drive faults