mm said:
That's not a decision *I* can make. My goal is to do a favor for my
friend. I can tell you that he doesn't think they are okay to lose.
How could your friend think his files were valuable when he took no
measures to keep backups of them? Only infants are unaware that
mechanical devices do fail. Now he wants you to do the recovery because
that would be cheap - and cheap is the value he has put on his files.
He should know (or you should've told him) that your recovery is risky,
will probably fail, and could make the situation even worse (by
corrupting the files so a later lab recovery is even less likely).
Make sure your friend has absolutely no intent to attempt a lab recovery
of his files if your attempt fails. It's your attempt or tossing the
drive in the trash. This friend should not expect to later send in the
drive to a lab if your attempt fails.
So is this a really old drive? If so, have you found another hard disk
for the SAME brand and model *and* which has the same version PCB on it?
Don't assume the same PCB is going to remain used throughout the sales
life of a particular hard drive. The drive assembly might stay the same
but they switch to a different version of the PCB sometime down the
road.
While it was mentioned the EPROM is soldered, I really doubt you have
the wave soldering equipment to remove and then solder back a
replacement chip. Have a look at this photo of the PCB for a hard
drive:
http://cobolhacker.com/images/content/gto_hard_drive.jpg
http://public.blu.livefilestore.com...stv4NigfudPJraWV-JXtKdgg6itRQXGg/P9060241.jpg
Look at the itty bitty pins on the chips and how close together they
are. Where are you going to find the equipment to desolder one of these
(without generating too much heat that damages the PCB or the chip).
Remember that you'll be heating the chip TWICE: once to desolder and
again to solder (onto the replacement PCB). There are some discrete
components, like resistors and diodes, that have just 2 solder points on
the tiny components and a micro-tip soldering iron will work if you are
very good at not using too much heat. Considering the size of the work,
you probably want to have an illuminated magnifying lamp so you can see
what you are doing - and a very steady hand. However, for the
hundred-pin chips that are also wave soldered onto the PCB, you really
think you can desolder a chip without damaging it and then apply heat
again without damage to solder it onto another PCB?
In the top pic, you can see a small square chip where a blue wire was
nearby soldered. That style chip can be, ahem, easily desoldered and
soldered. Presumably you have a solder sucker, solder wick, and a
micro-tip soldering iron and have the knack for soldering (e.g.,
remembering that solder flows toward the heat source and a very very
steady hand). There are some other components that are large enough for
hand [de]soldering, like the rectifier diode. Although really tiny, the
resistors and diodes can usually be [de]soldered by hand with proper
care. But as for those hundred-pin chips, well, good luck. Hope your
friend is willing to reimburse you for the proper equipment.
Yes, the chips are soldered. Yes, it's possible to desolder and
resolder the chips without damage and without shorting across the pins.
But is is DOABLE by *you*? You might get lucky if the EPROM isn't
soldered and instead is pushed into a carrier socket, like below:
http://blog.makezine.com/FD4RJI9BPXEXCFHR82.medium.jpg
I haven't seen this on a hard disk PCB but then I haven't seen every
hard disk. The lucky part is the EEPROM is an 8-pin chip, I think.
From the 2nd pic above, there are a couple of these package types at the
bottom left and right (e.g., just to the right of the EtronTech memory
chip is an 8-pin package). That's probably big enough and the style
that you can desolder and solder. I don't which does what because I
didn't bother to go look up their datasheets to see what they are. You
might want to read some forum posts by others doing similar low-level
hardware mods on hard drive PCBs, like:
http://forums.seagate.com/t5/Barrac...or-ST3500320AS-Firmware-SD35/m-p/45034#M18109
http://forum.hddguru.com/burnt-diode-resistor-capacitor-other-seagate-st380013as-t14919.html
The folks in those forums are way ahead of me. Personally, and since
this is not your files to recover, I'd back out of doing your friend a
favor and end up instead getting into hot water with that friend when
the attempt fails and the drive gets screwed up worse so now the lab
might not be able to recover anything. Let the friend think about it
for awhile and eventually the dead brick will just sit on their shelf
and those oh-so important files will be forgotten. Meanwhile, you
haven't rattled your friendship with a valiant but failed exercise.
