My hard drive did not work when I connected power to it.
An IT technician friend opened up the external hard drive unit for me and discovered that part of it was burnt out. See attached image.
I searched for issues with this PCB and it seems a common problem, and most issues are resolved by by-passing the damaged circuitry with a wire solder. I have done basic soldering before, but have no circuit experience, especially concerning pcb's.
Could anyone tell me by looking at my damaged circuit board if I have any chance of salvaging. If so where would I need to solder?

Thanks for your time.

I kindly disagree to your comment that this is a common issue. This looks like a major one, not like the "common TVS issues" you read in this forum.

IMHO, your best bet is to replace entire PCB.

_________________
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Ransomware Reverse Engineering - NoMoreRansom! partners

I would just to for relacement of the dagamed components if you know about electronics and be able to measure them.

Else, I would follow up northwind advice.

And in the end, it might have damaged also pre-amp, that is internal.

It's a common issue. The 12V TVS diode has shorted as a consequence of an overvoltage on the +12V supply. You can remove it with flush cutters.

Then clean up the charred area with a toothbrush and isopropyl alcohol (tape/video head cleaner). Measure the resistance between each of the diode's pads and the +12V and ground pins at the SATA power connector.

http://pinouts.ru/Power/sata-power_pinout.shtml

If one of the damaged components is an open inductor, then we can replace it with a wire link. It may be easier to solder to the diode's pads, though.

Let us know what you find.

_________________
A backup a day keeps DR away.

OK let's see..

_________________
http://www.northwind.gr
SandForce SSD Recovery
Ransomware Reverse Engineering - NoMoreRansom! partners

I often encounter very similar damage at Seagate's forums. Plenty of end users have been able to repair their drives with a jumper wire. I've even shown one of your colleagues how to do it. ;-|

In fact it's trivial jobs like this that suggest to me that this forum is crying out for a simple Electronics 101 tutorial.

FYI, Seagate uses inductors in the supply line to each TVS diode, at least on some models. Unlike WD's zero-ohm resistors, these inductors are not fusible, so they burn up instead of going O/C gracefully. These inductors are usually on the +12V and +5V sides of the diode, but in the OP's case the charred components appear to be on the grounded side. That's why I asked for the resistance measurements.

_________________
A backup a day keeps DR away.

Thanks for the replies so far. I will clean up and try to get readings today.

I'm not going to rumble here about risks of such DIY, I've been through this a trillion times.



What you say makes sense, no doubt, but I still insist that chances of internal damage (preamp) is high for this kind of pcb damage, based on experience. Lets hope (for OP's sake) that I'm wrong.

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SandForce SSD Recovery
Ransomware Reverse Engineering - NoMoreRansom! partners

AISI, the overvoltage was limited to the +12V supply.

According to the L7250 (SMOOTH) datasheet, the preamp gets it positive supply from +5V. Its -5V supply is also derived from the +5V input, via an inverting buck converter. The +12V supply appears to drive the voice coil and spindle motor, whereas the +5V supply is used by the SMOOTH chip's digital logic.

Therefore ISTM that preamp damage would be unlikely, although not impossible.

_________________
A backup a day keeps DR away.

AISI, the overvoltage was limited to the +12V supply.

According to the L7250 (SMOOTH) datasheet, the preamp gets it positive supply from +5V. Its -5V supply is also derived from the +5V input, via an inverting buck converter. The +12V supply appears to drive the voice coil and spindle motor, whereas the +5V supply is used by the SMOOTH chip's digital logic.

Therefore ISTM that preamp damage would be unlikely, although not impossible.[/quote

Well,
I Have a question to ask you ,what do you do for a living ? .If you Cannot answer it here i will create a special thread for you in the other section .

_________________
Regards
Amarbir S Dhillon , Chandigarh Data Recovery Labs [India]
Logical,Semi Physical And Physical Data Recovery
Website-> http://www.chandigarhdatarecovery.com

It has taken a while but here is what happened since I last posted:
I calculated how much it would cost to buy the equipment, but realised it may be similar price to find someone with circuit knowledge and equipment to try for me.
I got in touch with someone last Friday and highlighted this thread to them.
They attempted to fix on Monday and they rang to tell me it looked promising. I picked up yesterday and I am really pleased to say that the hard drive is now working and I have been able to back up all the family photos and videos that I should have backed up originally.

I am extremelly grateful to fzabkar for his unoubted knowledge in this particular area of hdd/pcb issues, as well as my IT friend and the electronics repair services I used.

Thankyou again fzabkar, it has cost me a relatively small amount to repair, compared to the amount I would have likely been charged by a data recovery service company.