Failed Head Rack Assembly

Head rack assembly, as the name suggests, refers to a system which facilitates the read/ write heads to move over the disk surface. It comprises of a voice coil attached to its end. Voice coil is placed between two ferrite magnets. A hard drive head usually has one set of read write head for each platter surface. The head is attached with the spring to facilitate its movement over the platter. The platter is sandwiched by head from both upper and lower side. When the disk is at rest the heads are in direct contact with the platter. As soon as the disk starts moving speedily, air pressure gets developed over the head and lifts them off up to few micro inches. This gap further shortens to support higher densities to work upon and will subsequently result into direct contact between them.

As the voice coil rotates between the ferrite magnets it gets energized by electromagnetic induction. This energized voice coil will further drive the head on to the location of the media where task of reading/ writing is performed. Failure of head rack assembly will eventually lead to ill performance of the system.

Factors leading to failure of Head Rack Assembly

There are several reasons behind failure of head rack assembly. A HRA may stop working due to technical maladjustments. As it is a highly sensitive component extra care should be taken in handling devices containing them. HRA failure is generally detected by clicking sound from the system. Some of the common reasons of HRA failure are as follows:

• Due to prolonged use of heads the spring attached to it loses its elasticity. This hampers the movement of head over the platters and thereby its functioning gets deteriorated.
• When the heads fail to keep away from the disk or the mounting air pressure isn’t sufficient enough to maintain required distance from heads, the heads get in contact with the disk. This contact alters the head movement over the platter and once the heads lose their pace, their efficiency gets diminished periodically.
• The continuous landing of head on a platter makes the head defunct. The head should be landed on a place where no data is stored otherwise the informative sector will get damaged.