I recently removed my hdd from my old laptop and installed it on my desktop. While doing so, I removed a silver sheet which was attached to the bottom of the hdd(logic board). What is the use of that sheet? will it pose a problem in future because of removing it? ... right now the hdd is sitting with the logic board facing down and touching the surface of another hdd. Will leaving the logic board exposed harm it?
As Joe C said, it's an emi shield. It could also be Mu metal, designed for magnetic shielding. The EM fields produced by the drive motor can cause problems in a laptop because of the close proximity of the motor to the MoBo. It's more than likely a non-issue on the desktop. If it fits on the drive and the drive still fits in the enclosure, then put it back. If not, then leave it off. No harm done.
I don't know much about it. I think it is also a banner for the whole thing surrounding the warrantee.
electric motors use iron and and coiled wire wrapped around it, when an electric current is applied to the iron core, it turns into a magnet and this magnetism is what causes the motor to spin. This magnetism created in the motor from the electric coils of wire and iron can interfere with the close proximity of the motherboard so they put a metal shield in between to prevent that from happening. It's a little more complicated than that because they have names like a rotor and stator, but thats about the very basic operation of it
On that note, keep in mind that the spindle motor is a stepper motor. That means square waves driving it.
EMI shouldn't be an issue with a desktop pc because the hard drive is far enough away from the motherboard. MJ, you link refers to A/C power and everything operating inside of computers is usually D/C
I have a few of those foil wrappers that came on laptop hdd's. I removed them so I could fit an SSD in the bay
the hilarious thing is, on every laptop ive taken apart, this shielding in on the bottom of the hard disk - when the motherboard is either beside/around^ the drive or above it ^ many motherboards have a hard-disk-sized hole in the pcb with the sata and power connectors surface-mounted - without the casing around it, it would look like the hard disk is in the motherboard