First hard drive recovery

[Gumby]

Hi all, I am thinking of attempting my first hard drive data recovery. I just want to make sure I am proceeding correctly. There is a long story behind this drive but I'll try to keep it as short as possible. A local PC repair shop had coppied data from a failing disk to a used disk they had laying around. When the client took the used disk home and plugged it in the sata power connector started to melt. It turns out the plastic tab that makes sure the power is plugged in properly (SATA) had been cut away or broken off somehow. So when the client plugged the disk in at home they created a short which melted some of the plastic at the pins of the power connection. The disk is an older one that also has the older 4 pin power connector on it. I tried powering it up with a spare PSU using the 4 pin connector but I get nothing, no disk spinup, no noise at all, no vibration coming from the HDD when power is supplied so I assume the PCB is dead or (from what I have read online) the diodes that act as fuses are blown. I also tried scraping the melted plastic off of the contacts and plugging in power on the SATA side of the disk and still nothing. The main sticker on the front of the HDD has also been removed so I used the sticker on the back of the disk on the PCB to identify the drive.

From sticker on PCB
0A53047
BA2178_
Md8742
42RB

On the PCB itself is printed
F 0A29531 01

Google tells me this HDD is a Hitachi 500GB HDT725050VLA360.

So, how to proceed....

After reading awhile it seems like replacing the PCB will be the best option. I have found what I believe is a matching PCB on Ebay

http://www.ebay.com/itm/Hitachi-500GB-H ... 2a314e0645

And also have read how to replace the ROM chip found at component "U5" on the PCB by desoldering/resoldering it using a heat gun and some flux.

My main question is, does this seem like the most logical and best option for recovering the data on the HDD or are there better/alternate options?

Thanks for your help

[HaQue]

for power issues that could have blown something, search on forum for fuses and TVS diode solutions. Fzabkar has posted a good number of posts helping people so you should be able to find out how to proceed.

If you are unsure, post good quality pics of both sides of the board and you may be able to be guided through more steps. This is often easier than replacing the board.

cheers

[fzabkar]

Measure the resistances of D3, D4, and R5 near the power connector.

[Gumby]

Measure the resistances of D3, D4, and R5 near the power connector.

Thanks for your responses fzabkar haque and sorry for the slow reply.

@Haque - I will search more of fzabkar posts as soon as I finish responding to fzabkar

@fzakbar - The readings are as follows

D3 - I'm getting readings from 97.5 to 98.1 ohms
D4 - Shows between 80 and 155 ohms quickly and then goes back to 1 (open circuit?)
R5 - Similar results to D4

Attachments

PCB Back

PCB Front

[mr_spokk]

You should replace ROM, this Pcb has burned connectors.
So check your PSU / Cables as well.

Bosse

[Gumby]

You should replace ROM, this Pcb has burned connectors.
So check your PSU / Cables as well.

Bosse

thanks mr_spokk.

I figured as much but thought it would be best to ask here first.

[mr_spokk]

I figured as much but thought it would be best to ask here first.

Now when I read the whole question I saw that you were aware of it...shame on me
Replace ROM and you should be ready to go...

[Gumby]

I figured as much but thought it would be best to ask here first.

Now when I read the whole question I saw that you were aware of it...shame on me
Replace ROM and you should be ready to go...

Do you mean just the ROM or the whole board and swap ROMs from the old board to a new board. Sorry for my ignorance, I am just learning how to do all of this.

[mr_spokk]

Replace ROM from your old Pcb to the new matching Pcb.

[Gumby]

Replace ROM from your old Pcb to the new matching Pcb.

Ok perfect thanks! I haven't purchased the new PCB yet so this will be the first step

[mr_spokk]

Yep, first two lines on Pcb should match

[fzabkar]

D3 - I'm getting readings from 97.5 to 98.1 ohms
D4 - Shows between 80 and 155 ohms quickly and then goes back to 1 (open circuit?)
R5 - Similar results to D4

R5 should measure 0.47 ohms. Your measurements suggest that it is open circuit.

R5 is in series with the +5V supply to the preamp. Therefore I suspect that the preamp may be dead. Before installing your replacement PCB, I would first measure the resistance between ground and the HDA side of R5, with the original PCB installed on the drive.

Attachments

preamp_5V_pos.jpg (100.07 KiB) Viewed 13665 times

5V_TVS_R5.JPG (97.13 KiB) Viewed 13665 times

[fzabkar]

@Gumby, I would measure the following voltages with the PCB removed from the drive. Note that you could power your drive from the Molex connector.

Attachments

VR1.jpg (53.73 KiB) Viewed 13659 times

Q3.jpg (94.71 KiB) Viewed 13659 times

Q1.jpg (60.17 KiB) Viewed 13659 times

[Gumby]

Note that you could power your drive from the Molex connector.

I'm afraid I moved to quickly. I've already removed the ROM from the board and in doing so pulled up one of the traces (well, I pulled almost all 8 up but one I appear to have pulled right off of the board). I wanted to get a head start on this board so that when the new one arrived I knew what I was doing or at least it would not be my first time. With the ROM off of the board is this testing still possible?

[fzabkar]

With the ROM off of the board is this testing still possible?

Yes, and probably safer, too.

[Gumby]

from the single contact side facing down to the top left contact = 1.73
from the single contact side facing down to the top right contact = 1.06

download/file.php?id=7844
from the single contact side facing right to the left top contact = 1.02
from the single contact side facing right to the left bottomt contact = 1.70

download/file.php?id=7843
from the single contact side facing left to the right top contact = 1.70
from the single contact side facing left to the right bottomt contact = 1.00

download/file.php?id=7842&t=1
Measures 0

[Gumby]

I think my last message is awaiting moderator approval because I used links to the images you posted fzabkar. So instead I'll post my results without the images (fingers crossed any further messages aren't moderated also)

VR1
from the single contact side facing down to the top left contact = 1.73
from the single contact side facing down to the top right contact = 1.06

Q3
from the single contact side facing right to the left top contact = 1.02
from the single contact side facing right to the left bottomt contact = 1.70

Q1
from the single contact side facing left to the right top contact = 1.70
from the single contact side facing left to the right bottomt contact = 1.00

Cuk Converter - I'm not sure I am measuring this one correctly. I just tested using the two holes. I'm completely ignorant if I am supposed to be using a contact point somewhere else.
Measures 0

[Gumby]

Um, check out C25.... Surely that can't be normal and I did not remove it.

Attachments

[mr_spokk]

Ooops, someone did remove that capacitor

[fzabkar]

Capacitors C25 and C24 appear to be the filter capacitors for the +12V supply. C25 (the smaller capacitor) filters the high frequencies while C24 (the larger, missing) capacitor filters the low frequencies. The absence of C24 should not affect the functioning of the HDD, unless the +12V supply is extremely noisy. In any case it is not responsible for the current symptoms.

As for the voltage measurements, each pin should be measured with respect to ground. That is, place your black probe on the screw hole or Molex ground pins.

For example, the voltages at VR1 should be +3.3V, +5.0V, and +4.0V, IIRC.

Also measure the resistance between ground and each side of R5, with and without the original PCB installed on the drive. This will determine whether the preamp is shorted.