Since you got your data off that drive, there is no way to make it worse. So sure, go ahead and open it up and learn something. But I think you're underestimating the flimsiness of the mechanics inside. It's like nanometers clearance between the read heads and the surface of the platters. You won't get it right without expensive equipment. And changing the PCBs is probably not going to change anything if it's a mechanical failure.