Some interesting links for would be HDD surgeons.
This link has some really nice photographs of drives including the Seagate Barracuda 7200.7 drive
My failed drive was a Seagate Barracuda 7200.8 and I went down the path of buying another identical drive to swap the driver boards. Heat and power supply disruption can cripple hard drive controllers, the spindle motor control chip normally taking the brunt and dying.
Do you need a clean room?
There are instructions here and a great diagram to show how big dust particles are compared with the gap between the heads and the platter (yes, the heads have an aerofoil design and float above the platter at running speeds for a frictionless drive. I have personally had drives open and used permanent markers on them (while running!) to show the partition and the action of the FAT. Here is an unfinished basic drive training video I made in 2007 (Videopro10). I used to teach high end computer servicing and always opened a running drive pair to demonstrate how the drive lettering worked with partitions.
Video was unfinished because most students lost interest and had little or no intention of working with drives at this level. But someone needs to be able to resurrect data on a dead drive, right? I have plans to make a new video now in 2016 of a Seagate Barradude 7200.8 drive strip down and rebuild. 200GB of data is a lot to lose for anybody and there is some serious money in drive repair.