IF THE HARD DISK EMITS UNUSUAL SOUNDS
(scratched metal, ringing) IT IS RECOMMENDED THAT YOU STOP USING IT AT ONCE !
These symptoms usually indicate a defect of the reading pins which could lead to the destruction of the data. When a hard drive has a mechanical defect you must take it out of use and come bring it in for service where a qualified technician will attempt to recover the data.
Usually the costs for data recovery in case of such defects can be very high and the recovery process can be very long.
DO NOT OPEN THE HARD DISK!! THIS WILL MOST CERTAINLY LEAD TO THE LOSS OF DATA. HARD DISKS CAN ONLY BE OPENED IN SPECIAL ROOMS (CLEAN ROOM CLASS 100) .
It is very often that persons who should take care of company data (network managers, IT technicians, electronics specialist) make the mistake of believing that they can solve a mechanical defect. In order to increase the chances of recovery in case of a mechanical defect, the following conditions must be met:
If you care for your data, do not perform experiments!
DO NOT ATTEMPT TO REPLACE THE ELECTRIC PLATE WITH ELECTRIC PLATES FROM OTHER HARD DRIVES RANDOMLY; THIS COULD LEAD TO DEFECTS OF THE READING PINS OR LOSS OF DATA.
If your hdd smells burnt after a power fluctuation and even more, if one of the chips on the back of the hdd is visibly deteriorated, you must address a specialised centre for a diagnosis. You can find details here.