I understand that not everyone understands how a hard drive works, and what goes wrong. I made two video’s to show the internals. The basic operation of a hard drive is similar to how a record player operates (an old analogy I know). The read arm should be parked off the platters when the hard drive has no power. When the hard drive receives power and the platters spin up to full speed, the read arm should extend over the platters to read the data from the hard drive.
In this first video, the read arm is permanently stuck over the platters, and you can see has even come in contact with them. You can also hear it grinding on the platter.
In this second video the read arm is parked like normal, and the drive spins up like normal, but still the drive isn’t functioning properly. The read arm fails to actuate properly.