PCB Replacement

WD Internal Drives Desktop & Mobile Drives
1

HELP!!!

I connected my WD6400AAKS Caviar Blue to a USB adapter, a smoke started coming out, it got extremely hot at the power connector. Looks like The PCB has a short. If I buy a replacement board, what are the requirements? Does it have to have the same exact model, DCM, LBA, etc? Please advise. Your response will be greatly appreciated. Many THX.
Eugene

2

The drive’s PCB has a TVS diode on each of the +5V and +12V inputs near the SATA power connector. If you are lucky, the diode will have sacrified itself to protect the rest of the drive. If so, then you can simply remove it with flush cutters. The drive will work without it, but it will no longer have any overvoltage protection on the affected supply rail.

Can you upload a detailed photo of the component side to a file sharing service?

You can just see the two diodes and two zero ohm resistors in this photo:
http://news.sosol.com.cn/news/html/shtml/NewsImage/20080711/20080711084511991.jpg

Usually the diode goes short circuit and the resistor goes open. In the latter case you need to replace the resistor with a wire link.

3

The board got so hot that one of the TVS diods came off. Here is a picture.

http://cid-0f040896ddc1c8de.office.live.com/self.aspx/.Public/IMG%5E_0057.JPG

4

D3 is the 5V TVS diode. You can leave it out, or replace it with an SMAJ5.0A from Farnell, Mouser, Digikey.

R67 is the associated resistor. If R67 measures open on the 200 ohms range of a multimeter, then replace it with a wire link.

However, I fear that the damage may not have been contained by the diode. If not, then you will need to engage professional data recovery. The Marvell MCU (big “M”) contains adaptive data which need to be transferred from patient to donor, so a straight PCB swap will probably not work.