Features

Disk looks like voice record plate but they have multiple layer. And each disk have round circle called tracks. Data could be stored electronically in the round circle.

Magnetic heads play the most important role of reading and writing data on the track.
At first magnetic storage device have changeable disk and computer users replace disk. But it might be polluted by dust and data could be easily destroyed by human error thus the hard disk have a sealed case which looks like recent hard disk drives. The origin of the word hard disk drive is as follows, At first people could only use floppy disk drives in personal computer, but as the quantity increase the floppy was substituted by relevant hard and concrete materials.

In case of not supplying electricity to a hard disk drive, a magnetic head would be parked in the landing zone and after electricities is on, it will start spinning. If a disk spins, it will make a wind, and the shape of magnetic heads would make the head flying to the upper part of platter like airplane fly in the sky. If magnetic head spins 3,600 to 7,200 times per minute, the magnetic head will make a constant flying height and read and write data according to signal.

Specification of Hard Disk Drive

Major Problems

• Spindle Motor
  

  Power Supplier Bad	PCBA power supplying pin and power supply cable connecting node might be bad. and PCBA power connector might be broken
  PCBA Bad	If PCBA chip is bad, we can change controller which handle spindle motor But the problems might be caused by other chips, it is strongly recommended to change good working PCBA
  Head Stiction	Magnetic head in head assembly unit and media might be sticked together, a little shock would the head to far away from media, but it would cause media to have scratches, thus a highly trained technician's work is required. Sudden rapid power supply is also possible to solving the above problem, but it is still dangerous.
  Hard Disk Service Area Data Corruption	Service area of hard disk drive contains very important information for hard disk operation, it is usually hard to access. In order to access into this area a special tools and a program of factory level is demanding, The corrupted data could be recovered
  Spindle Motor Bad	Defection in the motor itself could be repaired

• Spin-Down
  

  PCBA Bad	A defection in PCBA would caused this problem. the non working PCBA could be replaced by good working PCBA.
  Service Area Data Corruption	Which might be caused by service area data, this problem could be fixed by service area data
  Magnetic Head Bad	Defection in the head disk assembly would cause problem, it can be cured by replacing magnetic head.

• Not Ready
  If power reached to hard disk drive, a spindle motor would start spinning , it the spinning reached to a stage, the hard disk would start calibration, the terminology "Not Ready" means the hard disk do not performing any calibration work.
  

  PCBA Bad	Defection in the PCBA would cause problem, this problem could be cured by replacing good working PCBAs
  HDA Bad	This problem could by caused by errors in magnetic head and/or media, This could be cured by replacing good working HDA.
  Service Area Bad	If part of modules in service area is defective, the corruption could be cured by broken module

• Not Detect
  The calibration would work, but the hard disk drive could not be detected in a CMOS setup utility and/or system initialization.
  

  PCBA Bad	An error might be caused by defection in PCBA chip or data connector pins, these errors might be cured by replacing good working PCBAs
  Service Area Bad	If part of modules in service area is defective, the corruption could be cured by broken module.

• Hard Disk Fail
  In some case, during system initialization the model name would not appear, or the above error message would aprea and system might be freeze. For example the name of Maxtor would appear as family name of hard disk drive development like 'Athena', 'N40F' and 'Romulus' ,
  

  Service Area Bad	If part of modules in service area is defective, the corruption could be cured by broken module..
  HDA Bad	these errors might be caused by other parts, it might be cured by good working HDA

• Bad Sector
  Bad sectors would be divided into physical errors and logical errors, If one stoe many programs on hard disk drive and have been using it for a while, an error might be happened on searching the very data
  
  Physical bad sectors would happened by shock on scratches on the media, and the bad sectors cannot be removed by end users. A special devices and program would solve this problem and make the hard disk to a factory level.
  
  Even though a product is new, it might have some invisible bad sectors, but the manufacturer have hidden those bad sectors, in this case the end users would think the hard disk have no defection, After a physical level correction, a hard disk might have a quality of newly manufactured product. In case of severe scratches, the repairing process might be hard and even though a hard disk is repaired a long term use would cause problems
• All Bad Sector
  A hard disk drive might be recognized, but one cannot access into user data, the total hard disk would be appeared as bad sectors. This kind of phenomenon would appear corruption in service area data, a modification of service area module would cause one to access into service area.
• Password Lock
  If a user password is set on hard disk drive, one cannot access into user data. In this case the hard disk would appear as all bad sectors, we can repair these errors by special equipment and programs. A modification of PCBA chip would correct this problem, but a special facilities and software and analyzing skills are required

Quality of Repaired Product / Warranty

• Quality of Repaired Product
  Magnetic heads and condition of disk decide the quality of hard disk drive, since we replace heads and disk, the quality of repaired product will be that of new product. (The quality of repaired product is less than new one but you can use it as a new one.)
  
  Replacing new parts and burn in test of factory level would also decide the quality of repaired hard disk drive.
  
  Myung Information Technology provide warranty period of 6month to 1year, its because we have faith and assurance in quality.
• Warranty period of replace hard disk drive.
  

  Repaired script	Warranty duration
  sales of hard disk drive and equivalent products	1 year
  repairing of hard disk drive and equivalent products	6 months
  Computer system sales	1year
  sales of FDD/CDROM and equivalent products	6 months
  Repairing of FDD/CDROM and equivalent products	3 months

• Repaired product / Re-Repairing
  The first repairing cost would be deducted from repairing cost of same or upgraded products