Fried Smooth L7251 controller, possibly fried board WD 750GB

[SecretRaindrop]

my WD 750 GB died a couple of days ago.
A little information about the drive and PCB
Drive: S/N WCATR9199685, MDL WD750D2AAEX-00z3A0
PCB: (the sticker on the back) 2061-771640-303 ADB2 XC BN09 0MKX 3 0004080 2084
It could not be seen in bios and didnt spin up.
There had not been any power surges to my knowledge so in retrospect i think the chip had gone bad and the PSU was preventing any further damage by not powering it up.
I had no idea why it didnt work and connected it to a SATA to USB converter(bad idea)
Still nothing altho the underside of the pcb got a little hot, thats when the real damage happened.
Anyways, i brought it to work ( i work at a facillity producing cards for all types of companies) and removed the pcb and saw this:

I have ordered a new Smooth L7251 chip off of here:
http://www.aliexpress.com/snapshot/6396573792.html
When it arrives ill use a hot air blower to remove the chip and replace it with a new one.
In the mean time is there any way i can check if the rest of the pcb is alright?
I am planning to check it in our X-ray machine and do some measuremeants with a multimeter.
I can replace any part of the pcb other than the 3 big microprosessors as we have all thos parts in stock.

[jono-ats]

Often, when he SMOOTH IC cooks itself, it heats up and delaminates some of the PCB traces.

You have to be very delicate when removing the IC, or you will make a real mess of things and have to attach jumpers.

Quite often, there are additional bad parts in this failure scenario.

BY FAR the easiest approach would have been to move U12 to a similar board, and be done with it (unless the preamp is cooked, too).

Jono

[fzabkar]

IMO it would have been more expedient to purchase a compatible PCB and move the U12 chip from patient to donor.

That said, the damage to the SMOOTH chip is on the side that controls the Vcore and Vio supplies, plus the negative supply to the preamp inside the HDA. I suspect that the 5V TVS diode will also have been shorted, in which case there is a real possibility that the preamp has been damaged.

See http://www.users.on.net/~fzabkar/HDD/bi ... diodes.jpg

[SecretRaindrop]

is there any way to check if the U12 is fried?
Im not an electrical engineer, only a trainee atm, if you could tell me what specific components might be damaged i can replace them at work tomorrow.

Also how much does a new board cost? I dont have any super imortant stuff (some vacation pictures and videos i dont want too loose).

edit: forgot to mention that some of the pads and connectors look almost corroded, not sure if this could be caused by any smoke that haappened when the IC cooked (it actually burned the legs completely off o.O) or if it might indicate a powerfull electrical surge

[fzabkar]

If the onboard regulators are damaged, as they appear to be, then the MCU and SDRAM would have to be suspect. I would not bother trying to repair your board (I am an electrical engineer and I have extensive chip-level repair experience).

Some PCB suppliers will include a firmware transfer (U12) in the price (typically US$50).

A quick check of U12 would involve testing the resistance between pins 4 (Gnd) and 8 (Vcc). If your facility has a chip programmer, then try to read the contents of U12 (serial flash memory).

As for the discolouration ...

Oxidisation on Western Digital PCBs:
http://www.alexsoft.org/viewtopic.php?f=86&t=649

[SecretRaindrop]

this pcb is the closest i could find with a quick search
http://www.hddzone.com/wd-2060771640005-pcb-p-581.html
Would it match?

[SecretRaindrop]

I bought this board:
http://www.hddzone.com/wd-2060771640003-pcb-p-293.html
It has the exact same model number as the one i have right now
I will try to first swap the U12 and if that doesent work ill swap the main IC too.
sounds good?

[northwind]

If swapping the U12 doesn't work (and assuming that the transfer of the chip was done properly), then moving the main IC won't help you.

If you swap the U12 correctly and the procedure fails, then most likely the preamp is cooked too and the drive needs internal job (head swap).
Don't move the main IC, as it is a difficult process and it is absolutely needless.

[SecretRaindrop]

Oh i just read somewhere that there might drive specific data on the main OC too
i measured the 5v and 12v TVS diodes with a multimeter:
12V: 166 K ohm one way, 175 the other
5V: 0 Ohm's both ways

Is there any way to test the preamp to see if its ok without the new pcb?

[warnerr]

diode 5v is shorted. The board replacement with u12 swapped it the test: after that its heads as the preamp is mounted on them.

[SecretRaindrop]

Im going to check the preamp and the PCb in an xray machine.
i can upload some photos for you guys to take a closer look, maybe it can give some more info as to wether the preamp is damaged

[northwind]

Messing with the preamp will only result in you losing your data.
The test (for you) for the preamp is, as warnerr said, to swap pcb + U12 and see if the drive works.

[SecretRaindrop]

Here are the xrays, as you can see the Smooth controller is completely destroyed, but the U12 seems physically intact.
I didnt seem too find any pcb inside the hard drive itself unless its under the metal cover that the arm is connected too.
http://i.imgur.com/cNpea8K.jpg
Smooth controller:
http://i.imgur.com/tZJ6yDx.jpg
U12:
http://i.imgur.com/CoNHmcS.jpg
Main IC
http://i.imgur.com/hyoskoi.jpg
Hynix IC
http://i.imgur.com/vS8d5b8.jpg

[mr_spokk]

The preamp is located on a flexcable going from pcb connector to the HSA (head stack).
A new pcb with swap of the U12 should do it...if not, preamp is gone and a new head stack is needed.
Nice x-ray's btw

[SecretRaindrop]

Thanks, its a pretty nifty machine
The thing is i couldnt see any sign of a chip when zooming on the HSA, might just be the HDD enclosure that is causing to much interference tho...
As i have said, i have ordered a new PCB and will be moving the U12 when that arrives, crossing my fingers that everything will go flawlessly ^^

[mr_spokk]

Here is a picture from a Seagate taken by Artem.

Attachments

preamp.jpg (44.42 KiB) Viewed 28611 times

[SecretRaindrop]

oooh, if its that small i wont be able to see it in the xray with the enclosure...

[mr_spokk]

Nope, unless you know where it's located

[SecretRaindrop]

So apparatly i live too far from any city to get the board delivered with UPS or DHL...
Will post again in 7-14 days when the board arrives.
Thanks for all the help guys

[Haltec]

We will be here waiting.


Can you please post model of X-ray machine.



Thx



Haltec