Attempts to repair mechanical failures by anyone other than a qualified data recovery shop or the manufacturer, will void the warranty.

Swap at your own risk!

There is a certain amount of agreement, between several of the data recovery service companies, that replacing the PCB, on newer hard disk drives, is a bad idea. In fact, swapping the PCB may actually damage the drive further. They make a good case, have cited examples, and some have gone to great lengths to document their information.

Selecting a data recovery service company is perhaps one of the most stressful things a person or company can endure when all other restoration options have been attempted. It's the nature of business to highlight the positives and down-play the negatives particularly in a service oriented business. Virtually no one wants to say... "We can't do this or we can't do that." Virtually all will tell you how wonderful and better they are than the "other guy". This makes selection difficult to say the least. Here are some things to consider when selecting a data recovery service company...

Fiction:
The belief that media can be removed from a multiple platter drive and data can be
successfully recovered using a Universal Media Reader.

Fact:
A Universal Hard Drive Media Reader does not exist. The operative term here is
Universal. If such a thing existed, the company that owned it could, and would have
by now, put all the others out of business.

The full article in PDF format...

All file systems use the first sector of a hard drive as a partition block. This sector contains the total number of sectors in the drive (a.k.a. Disk Capacity), size of the primary partition, defines the file system on the primary partition, the location of the next partition and the location of the boot block. The partition combined with the boot block is also referred to as the Master Boot Record or Boot Strap. In a Hex Viewer or Editor using Absolute Sector mode this will be sector 1(one). In LBA mode it is sector 0(zero).

A partition is one sector or 512 bytes in length and defines the size of the partition and indicates the beginning sector of the boot block(s). All partitions have a signature located in the last 2 bytes of the sector which is 55AA (hex, of course). The use of "overlay" programs such as Disk Manager in some cases installs additional sectors, which will need to be considered, that changes the location of partitions and boot sectors. If you've used one of these programs, you're pretty much on your own to figure-out how to fix or replace a partition. Of course, you could send your media to a data recovery service company. If your data is mission-critical, that would not be a bad idea. If you're hardcore, poor or just plain stubborn you can try the following;