• Home / Head faults in hard disk drives

Head faults in hard disk drives

One of the most common failures of a modern hard disk that always requires expert data recovery help is a failure of the read write assembly. Often identifiable by a clicking, ticking or knocking noise, read write head failures have affectionately been referred to as the Click of Death, amongst other things. There are a number of components that make up the head assembly of a hard disk drive and one or more of these can fail in any one case:

The Head SlidersHead sliders can become 'dirty', over time deposits of platter lubricant can build up on the surface of the ceramic slider mechanism. This issue can occur as a result of a fault, where there is contact of the head and platter in cases of sudden power loss or can be caused by uneven deposition of the lubricant over the platter surface.

Pre-Amplifier Chip Failure

The minute analog signal that is received by the read/write elements at the tip of the head slider have to be amplified in order to be processed into a digital signal by a component known as a pre-amplifier. The pre-amplifier is normally located on the head assembly itself. When this component fails, the hard drive electronics are no longer able to receive data from the platter surface making the data absolutely irretrievable until either the fault is repaired or the entire head assembly is replaced.

Shock Damaged Heads

There is a third common type of failure associated with hard disk read write heads, physical damage caused by impacts, shock or other external influence - this can cause the delicate suspension arm, the arm that supports the head slider and read / write elements to bend - this can seriously damage the platter surface if the problem goes unnoticed.

Damage caused to a Samsung hard drive read write head after an impact

Head Jamming and Stiction

The final common fault with hard disk drive heads is caused by them becoming stuck, either to the platter surface or underneath the head parking area that exists in some 3.5" drives and all 2.5" drives currently produced. Heads can become stuck to the platter surface following jolts, knocks and other physical shock, whilst rarely terminal the heads do become, due to the lack of friction between the incredibly smooth surfaces of the head slider and platter, bonded to the platter surface. This is known within the industry as Stiction and leads to the heads preventing the drive from spinning up or becoming ready. Stiction is often mistaken for an electronic issue as the drive does not spin up and makes little or no noise, occasionally a feint ticking noise will be heard.

As mentioned above heads can also become jammed in the parking mechanism, this normally occurs when power to the drive is lost. The heads will automatically revert to a parked position, even when no power is present, however, if the drive platters lose too much momentum the air cushion that maintains the flying height of the head is lost. If the heads are not far enough above the platter they cannot park properly and become trapped, this occasionally destroys the heads requiring a full hard drive rebuild. It has been observed in a number of cases that mechanical shock has lead to the platter and motor bearing assembly dropping, a scenario that can cause contact between the platter and the parking area, such a case can lead to a similar mis-parking of the heads.

notebook hard drive suffering from stiction

Data Recovery

Any mechanical noise coming from a hard disk drive is a sign of something being seriously wrong, if your hard disk starts to make unusual noises the best policy is to power it down and contact a professional data recovery company. Hard disk drive rebuilds can only be carried out in a Class 5 clean room environment or better with full ESD precautions being observed, you can read about our data recovery lab here.

If you would like a competitive quote for recovery of lost data due to a mechanical fault with the hard drive call now on 0845 2002 845 or use our contact form.

free no obligation consultation 0207 1297 097 Email