Data recovery from a failed PCB.
This is probably the simplest type of fault to have to explain how and why failure has happened. In most cases of a failure of the printed circuit board (PCB) it is a result of a power surge. This is more common in 3.5″ desktop hard disk drives (HDD) than 2.5″ laptop HDDs. Desktop HDDs have a 12 volt and a 5 volt input rather than just a 5v input as in the 2.5″ drives. The surges usually relate to voltages higher than 12v causing damage to the circuit board. Faulty PSUs, AC adapters and use of the incorrect AC adapter are typical reasons for incorrect voltage which will damage the HDD’s PCB.
Necessary donor parts are frequently required to recover data from a failed HDD. At Cheadle Data Recovery we keep a large stock of complete HDDs and PCBs. It is usually necessary to have a very close match donor PCB for recovery to be successful. If we do not have donor parts in stock then we contact our suppliers in and around Manchester and the North West of England, followed by the remainder of the UK. If donor parts cannot be sourced from within the UK then we will look to Europe, North America and finally Asia.
Can you just swap the PCB?
Now, in nearly all cases the answer is, “no”. The reason for this is because most HDD PCBs have unique information stored on them called ‘adaptive data’. The function of this varies slightly from manufacturer to manufacturer. For example, in the IBM/Hitachi NVRAM it relates to detailing where the start of the service area is on the platter surface. The service area is the part of the platter where the firmware is stored. This can vary from HDD to HDD. As such it is very important information and can not easily be recreated. Performing actions such as a ‘hot-swap’ with a donor on IBM/Hitachi HDDs can result in the associated NVRAM/firmware areas being adjusted leading to (nearly) unrecoverable data. It should not be done under any circumstances. On Western Digital hard disk drives (from 2007 onwards) there is data on the PCB which relates to the ATA command set revision, which is again critical to the normal operating of the hard disk drive.
In old Seagate HDDs it used to be possible to exchange the failed PCB with a matching working one and the HDD would power on normally and the data would be recoverable. There used to be a possibility for a DIY fix if you could get hold of matching donor parts. However, in all modern Seagate hard disk drives there is now unique data stored on the PCB which is critical for the recovery of data from the hard disk drive.
In some HDDs (particularly those made by Toshiba) the PCB is particularly important for the purposes of data recovery. Toshiba HDDs have most of the firmware modules on the PCB. Often these are contained in a BGA chip made by Marvell. Removal and refitting of a BGA chip is extremely challenging work, and one which many data recovery companies will not attempt. Fortunately CDR can successfully remove and replace BGA chips on occasions when it is necessary.
What does this mean for you?
A PCB failure might seem like something that is very straight forward to resolve in order to recover data. Sometimes it can be, frequently it is not. You are best not to spend money on donor parts to attempt a DIY fix. Firstly it is unlikely that you will find an appropriate match PCB, and secondly, as outlined above, the failed PCB has unique data on it and consequently the donor PCB will not work on your failed patient HDD. When we have received HDDs where customers have purchased a donor HDD (at some expense) we have examined it and have had to tell them that actually it is not nearly a close enough match for the purposes of a donor part. We have also received in HDDs where the original PCB had been disposed of by the customer, which has resulted in unrecoverable data.
There is also the significant danger that matters can be made worse by a botched DIY attempt when repairing the PCB or replacing it. This can make life much more challenging for the data recovery company, or make recovery impossible.
Finally, when there is a power surge it can also cause secondary faults with the hard disk drive. Including a failure of the pre-amplifier (a component of the head-assembly) and more commonly, the drive is found to have bad sectors. It is certainly not possible to ‘DIY’ these faults.