Scratchy and grinding noise at damaged hard disc drive
Scratching or grinding noises of a damaged hard disc drive have to be taken very seriously. Usually thease sounds are based on a physical contact of the read / write unit and the rotating magnetic platters inside of the hdd.
Ferro-Magnetic disc drives always do work free from any physical contact to the platters, because the head is floating on an air bearing above the rotating platters, with just a few nano-meters over them. The platters itself do rotate with 4.200 rpm, 5.400 rpm and upto 10.000 rpm, depending on the age and model of the drive.
Once there is a contact of headkit and rotating platter, very small pieces are broken out of the layer covering the platter itself. Now thease micro-particles can also get inbetween the head and the rotating platter again and again, generating more and more particles. In data recovery business this is called a "domino-effect". More or less this is the main cause for scratching or grinding noise of a broken hard disc drive. So the best thing to do in case of thease noises is to switch off everything, don´t run the hdd again and call a professional. If your data is important to you somehow, try to avoid -under all circumstances- to connect the hdd again.
Which factors can be the main cause for grinding or scratching noises ?
Thease symptoms can be broken down to two common scenarios:
1. Headcrash of hdd caused by a shock
Scratchy and grinding noises can often be heard from hard drives which have been a victim of a falling damage. Usually the mechanical parts of the hdd are damaged heavily and the head or parts of the head do lie physically on the platters surface. So once they did lay on the surface and the drive is getting powered not only the scratchy sound can be heard, it´s pretty logical if something which touchs a surface which is turning at least at 7.200 rpm will get worm or will generate some sort of frictional heat.
2. Wearing of mechanical parts inside of an hdd - damage to mechanical parts
Nothing will last forever - This is also valid for every aspect in case of hard drive mechanics. If a hard disc drive is operating fine for years, a mechanical failure to the drive can happen anytime, the risk is getting higher the older the drive itself is getting.
In case of damages with scratchy or grinding noises, a professional data recovery service with a clean room environment will be needed, especially in case of high capacity hdds higher 1 TB. Because of the higher data density of modern hard disks, it is getting more challenging for recovery engineers acomplishing 100% success rate. So whenever you see a marketing slogan like "99% success rate" by a data recovery lab, forget about it, as it is a pure marketing slogan, but that is a different story.
With a higher data density rate per magnetic platter, the challenges processing data recovery the right way is getting really important. After the drive has been opened in a clean room environment the scratching noise will be also visible in form of an concentric scratch on the surface. This scratch does mean that the substrate or the upper layer of the platter has been harmed by the head laying on them. The data or informations within this scratch are usually not recoverable by anybody, because the damage in that area has changed the magnetic characteristics of the area itself in a physical way. Because of this, there is no chance reading or even re-calculating something.
It can happen that a grinding or scratchy noise can be heard which necessarly doesn´t have to be connected to damages on the magnetic platters. There are also scenarios where firmware problems can be responsible for such sort of noises.