WD3200AAJS PCB fried due to high Voltage

dshopping221 · August 16, 2019, 8:59pm

I have a WD SATA disk. Model - WD3200AAJS which was working fine till yesterday. I had to backup some data so i connected to an External Casing. Soon after 15 seconds, i smelt some wire burning. I turned it off quickly. Now the HDD wont start. I need to start this HDD just once so i could take a backup of my data. I have taken a pic of the PCB and uploaded it here

It would be gerat help if i could find a way to fix this PCB

I researched on ebay and found that i am getting the exact same model of this PCB. There are few things that i need to know. Will the PCB switchover work with this drive? Does this PCB has a rom chip in it and will i need to switch that too?

fzabkar · October 15, 2015, 2:50am

The 5V TVS diode has been damaged. If resistor R67 is open circuit, then there is a high likelihood that the preamp on the headstack will be damaged as well.

As for the “ROM”, there is no discrete serial flash memory IC on your board. Instead the ROM code is embedded within the Marvell 88i8845C MCU. You will need a tool such as WDR to rebuild the ROM from firmware modules in the System Area (SA) on the platters.

Realistically I think your chances are very slim.

dshopping221 · October 15, 2015, 2:50am

I had some of my imporatant project files on this disk. Is there any way out. Assuming the headstacks preamp is not damaged. Can i just take out the D3 diode and try connecting the hdd. What would you suggest in this case?

fzabkar · October 15, 2015, 2:50am

What is the resistance of R67?

dshopping221 · October 15, 2015, 2:50am

R67 is showing 00.8 (I assume its normal)

I used 200 ohms setting

fzabkar · October 15, 2015, 2:50am

That’s good news. Now just snip the shorted diode and you should be OK.

Best of luck.

dshopping221 · October 15, 2015, 2:50am

I Sent the PCB to a HDD repair workshop and they changed the damaged diode.

Now when i connected the hdd, it is totally dead. It doesn’t spin nor gives any clicks

fzabkar · October 15, 2015, 2:50am

That’s very disappointing.

There are some voltage checks you could do while the PCB is disconnected from the drive.

Measure the voltages at transistor Q1 near the SATA power connector. It should be producing +3.3V.

Measure the voltages at inductors L2 and L1 between the SMOOTH chip and the Marvell MCU. These will be the Vcore (~ +1.2V) and possibly a second Vio voltage (+2.5V ???).

Measure the voltage at the anode (non-striped end) of diode D2 located above L3 to the left of L1. This will be the negative supply for the preamp, possibly -5V.

Use a screw hole as your ground reference.