The circuit board on a hard disk is the ‘brain’ of the hard disk and a single component failure will render the drive useless. Recovering data from hard disk drives with electronics failures requires highly skilled electronics engineers who can to fix the drive temporarily in order to recover the data.

The electronics control the read/write mechanism and the motor that spins the platters. The electronics also assemble the magnetic domains on the drive into bytes (reading) and turn bytes into magnetic domains (writing). The electronics are all contained on a small board that detaches from the rest of the drive.

Hard disk electronic failure causes and symptoms

Cause 1: The drive is supplied with incorrect Voltages.
This is common with external hard disk drives and normally comes about when a similar looking power supply (often a laptop power supply) is plugged into the drive by mistake.  It can also occur when there is a fault with the Power Supply Unit or PSU.

Failure symptoms of the patient drives:

* A burning smell
* Fail to power up and unable to spin
* Data Inaccessible
* Not be recognised by the BIOS and will no show up at POST
* There can be noticeable scorching to the PCB or one of the components contained therein

Cause 2: Component failure

With this type of electronic failure the drive does not need to experience irregularity in the electricity supply, often the problem that leads to this nature of failure lies within the circuit board or component itself and no external influence is required.

Some components are more susceptible to failure or burning out, motor controller chips, particularly those manufactured by SMOOTH are prone to failing in this manner, when they do the problem is normally very easy to identify and commonly affects Seagate, Western Digital and Maxtor hard disks.

Failure symptoms of the patient drives:

* Your computer may not behave as expected, it may refuse to power on
* Your hard drive will not normally be recognised in the computer BIOS or at POST
* Again a burning smell may be noticed and physical damage may be observed to a chip, or chips on the PCB.

Cause 3: Motor Bearing Faults including Seizure

motor bearing seizure is a common fault affecting modern hard disks that can lead to problems with the electronics. More often than not, no damage is caused to the electronics, it’s not strictly an electronic failure but the symptoms are similiar.

Failure symptoms of the patient drives:

* The drive will not appear to spin up
* A quiet whining or whirring noise is often heard under close inspection
* There may be an almost musical noise coming from the drive or enclosure

Above  Statistics may be not complete and Data recovery Salon welcome your comments and share with your ideas and experience! Data recovery Salon, a professional free data recovery book for everyone who are interested in this field!