Flooded SD Card

> Saltwater is a virtual death sentence for anything electronic. I have
> actually resurrected some electronics that were immersed in freshwater.

True, but is the card electronic or magnetic? If the latter, it may be
possible to recover the data.

> My only suggestion would be to soak the card in fresh water (distilled
> water would probably be better) for a couple of hours.

Yes

> Take the card out and put it in some 91% rubbing alcohol for another
> couple of hours. Take it out and let it air dry. If it does
> not work, it is totalled. You are no worse off than when you started.

Alcohol dissolves some plastics. I'd think two or three times before
submerging a SD card in alcohol.

Lee

On Mon, 04 Sep 2006 17:39:09 +0100, Triple Jumper
<no_email_thanks@gmail.com> wrote:

>Hi
>
>I have a Transcend 4Gb 150x SD card which has just spent half an hour
>having its first swim in the Caribbean Sea at some 30m / 100ft.
>
>Unsurprisingly it is no longer readable (and of course the camera is
>completely dead).
>
>Can anyone explain technically what has made it unreadable, e.g. how did
>the salt water affect the device?
>
>Is there any chance that a specialist data recovery firm could retrieve
>its contents?
>
>Thanks
>TJ

I am an electronics engineer. Powered-up electronic devices in salt
water undergo electrolysis that corrodes contacts and any exposed
metal parts, (like circuit boards) and the hydrogen and oxygen
produced in the process also combine with the metals and other
compounds in the water forming the salts you see. If the power was
killed soon enough, the SD card may only be externally damaged on the
exposed contacts and if the seals around the contacts were good enough
to resist the pressure at depth the card and data inside may be
recoverable. Powered down, the card still undergoes the usual
electrolytic action of the dissimilar metals inside and the seawater
surrounding them but the process is slower.

I am looking at one I have that has a write protect tab on it. There
is no pretense at making it water resistant. If yours is like that,
chances are it is probably toast. Good news is, it's rated for some
humidity:

Operation: 25°C / 95% rel. humidity
Storage: 40°C / 93% rel. hum./500h
Salt Water Spray: 3% NaCl/35C; 24h acc. MIL STD Method 1009

Of course it's "spray", just tell them you sprayed it at depth.

The cases of SD cards are molded around the substrate supporting the
chips inside. If that substrate was passivated to prevent oxidation
there is a chance someone with the right equipment could recover that
data but it would take a lab, some microprobes and some patience.

If recovery of the images is important to you, seek professional help.

"Geoff" <geoff@invalid.invalid> wrote in message
news:741qf2tbkp96gf71n2c9cu0j62l0ona4pm@4ax.com...
> On Mon, 04 Sep 2006 17:39:09 +0100, Triple Jumper
> <no_email_thanks@gmail.com> wrote:
>
>
> I am an electronics engineer.

So am I.

>
> I am looking at one I have that has a write protect tab on it. There
> is no pretense at making it water resistant. If yours is like that,
> chances are it is probably toast.

The write protect tab is purely a bit of plastic and there is no interface
to the cards electronics. However I've just looked at a card under a
microscope and I could see edge of the printed circuit through the hole for
the write protect tab. I could also see the edges of copper tracks through
that hole. I'm not sure how SD cards are moulded but from looking at the
one I've got I'm not convinced the moulding will offer waterproofing to the
printed circuit. I reckon the electronics will be protected well enough but
salt deposits on the printed circuit may well stop it working.

Previous advice on cleaning it seems sensible enough to me but you need to
pay attention to the hole for the write protect tab. If that fails you
could try a more destructive approach to get at the PCB.

I've just noticed that Amazon sell a waterproof SD card. Presumably that
means they also sell non-waterproof cards.

Stephen

Stephen wrote:

> I've just noticed that Amazon sell a waterproof SD card. Presumably that
> means they also sell non-waterproof cards.

Or they just add more of a markup to some to allow for replacements
under warranty.

Lee Bell wrote:
>>Saltwater is a virtual death sentence for anything electronic. I have
>>actually resurrected some electronics that were immersed in freshwater.
>
>
> True, but is the card electronic or magnetic? If the latter, it may be
> possible to recover the data.
>
>

It has a memory chip in it as opposed to a ferrous oxide surface such as
on a 3.5" floppy or an audio tape.

>>My only suggestion would be to soak the card in fresh water (distilled
>>water would probably be better) for a couple of hours.
>
>
> Yes
>
>
>>Take the card out and put it in some 91% rubbing alcohol for another
>>couple of hours. Take it out and let it air dry. If it does
>>not work, it is totalled. You are no worse off than when you started.
>
>
> Alcohol dissolves some plastics. I'd think two or three times before
> submerging a SD card in alcohol.

I have resurrected several devices using this method including a cell
phone that had been through a complete wash cycle in a washing machine.
If the alcohol dissolves the plastic, he is still back where he started
from...an unusable SD card. If recovery of the images are so critical
he cannot risk that procedure then he needs some high $$$ professional help.

Thanks for the replies folks.
I'll check out the waterproof SD card for my replacement!

cheers
TJ

Stephen wrote:
> "Geoff" <geoff@invalid.invalid> wrote in message
> news:741qf2tbkp96gf71n2c9cu0j62l0ona4pm@4ax.com...
>> On Mon, 04 Sep 2006 17:39:09 +0100, Triple Jumper
>> <no_email_thanks@gmail.com> wrote:
>>
>>
>> I am an electronics engineer.
>
> So am I.
>
>> I am looking at one I have that has a write protect tab on it. There
>> is no pretense at making it water resistant. If yours is like that,
>> chances are it is probably toast.
>
> The write protect tab is purely a bit of plastic and there is no interface
> to the cards electronics. However I've just looked at a card under a
> microscope and I could see edge of the printed circuit through the hole for
> the write protect tab. I could also see the edges of copper tracks through
> that hole. I'm not sure how SD cards are moulded but from looking at the
> one I've got I'm not convinced the moulding will offer waterproofing to the
> printed circuit. I reckon the electronics will be protected well enough but
> salt deposits on the printed circuit may well stop it working.
>
> Previous advice on cleaning it seems sensible enough to me but you need to
> pay attention to the hole for the write protect tab. If that fails you
> could try a more destructive approach to get at the PCB.
>
> I've just noticed that Amazon sell a waterproof SD card. Presumably that
> means they also sell non-waterproof cards.
>
> Stephen
>
>

On Mon, 04 Sep 2006 22:50:02 GMT, ajtessier <ajtessier@worldnet.att.net> wrote:
> The alcohol is a good idea but do that after you clean it with lemon juice
> and water.
I would not put it in lemon juice. Lemon juice could damage the card.

As someone says down further, it could cause elctrolytic effect (charges are small, but)

No, lemon juice would be bad.



>

Willy Eckerslyke wrote:
> Stephen wrote:
>
>> I've just noticed that Amazon sell a waterproof SD card. Presumably
>> that means they also sell non-waterproof cards.
>
> Or they just add more of a markup to some to allow for replacements
> under warranty.

If the warranty only covers replacement (as is typical, I suppose) and not
any contingent losses then the purchaser stands to lose a lot more than the
seller!

Mike.
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