Oxidisation of Seagate & WDC PCBs
Franc Zabkar
http://maccentre.ru/board/viewtopic.php?t=70953&start=15
Here is Google's translator:
http://translate.google.com/translate_t?sl=ru&tl=en
The thread discusses oxidisation of contact pads in current Seagate
and Western Digital hard drives. The drives were used in typical
office and home environments, and are about a year old. The thread has
several detailed photos. All except the older tinned PCB appear to
show evidence of serious corrosion.
Is this the fallout from RoHS? Surely it's not the result of some cost
saving measure?
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Arno
> I came across a reference to this Russian forum thread in a WDC forum:
> http://maccentre.ru/board/viewtopic.php?t=70953&start=15
> Here is Google's translator:
> http://translate.google.com/translate_t?sl=ru&tl=en
> The thread discusses oxidisation of contact pads in current Seagate
> and Western Digital hard drives. The drives were used in typical
> office and home environments, and are about a year old. The thread has
> several detailed photos. All except the older tinned PCB appear to
> show evidence of serious corrosion.
> Is this the fallout from RoHS? Surely it's not the result of some cost
> saving measure?
The silver ones are not oxydized. Silver reacts with sulphur,
not oxygen. It is normal and cannot really prevented. It is
also not a problem in contacts that are not used, as the
process stops itselft after at thin coating is reached.
The golden ones look like the same thing to me. Maybe the
used a high silver content gold here. Sorry, I am noch a
chemist. But my parents used to deal in silver jewelery
and the look is characteristic.
I suspect air pollution as the root cause. As I said, it is
not a problem in this case, the sulphurisarion (?) process
will not eat through the traces. They are rather better
protected with this.
It would be a problem on the connectors though. But they will
have better and thicker gold anyways.
Arno
--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: ar...@wagner.name
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
whit3rd
> I came across a reference to this Russian forum thread in a WDC forum:http://maccentre.ru/board/viewtopic.php?t=70953&start=15
>
> Here is Google's translator:http://translate.google.com/translate_t?sl=ru&tl=en
>
> The thread discusses oxidisation of contact pads in current Seagate
> and Western Digital hard drives. The drives were used in typical
> office and home environments, and are about a year old. The thread has
> several detailed photos. All except the older tinned PCB appear to
> show evidence of serious corrosion.
>
> Is this the fallout from RoHS?
Maybe not. There are other known culprits, like the drywall (gypsum
board,
sheetrock... whatever it's called in your region) that outgasses
hydrogen
sulphide. Some US construction of a few years ago is so bad with
this
toxic and corrosive gas emission that demolition of nearly-new
construction
is called for.
Corrosion of nearby copper is one of the symptoms of the nasty
product.
William R. Walsh
> The thread discusses oxidisation of contact pads in current Seagate
> and Western Digital hard drives.
I've seen minor occurrences of it and wondered what it was, but only on the
"one use" contact pads on the bottom of the drive's PCB. (My guess is that
these are used to set the drive up for its first time use and do some basic
tests to assure the new drive is functional.)
Some drives had more of this apparent oxidation than others, but all of the
ones I've seen had it from the moment they were removed from the package. It
hasn't gotten any worse and these drives continue to operate properly. I
checked a few at random and did not find a similar effect on the contacts
going to the spindle motor or headstack.
William
larry moe 'n curly
Franc Zabkar wrote:
>
> I came across a reference to this Russian forum thread in a WDC forum:
> http://maccentre.ru/board/viewtopic.php?t=70953&start=15
>
> Here is Google's translator:
> http://translate.google.com/translate_t?sl=ru&tl=en
>
> The thread discusses oxidisation of contact pads in current Seagate
> and Western Digital hard drives. The drives were used in typical
> office and home environments, and are about a year old. The thread has
> several detailed photos. All except the older tinned PCB appear to
> show evidence of serious corrosion.
Does this mean we should apply contact protector, such as De-Oxit, to
the PCBs to prevent corrosion?
Arno
No need.
Franc Zabkar
put finger to keyboard and composed:
It's not just Russia that has this problem. The same issue comes up
frequently at the HDD Guru forums.
Franc Zabkar
<larrymo...@my-deja.com> put finger to keyboard and composed:
One of the sticky threads at the HDD Guru forums recommends that the
preamp contacts on WD drives be scrubbed clean with a soft white
pencil eraser whenever they come in for data recovery.
Sergey Kubushyn
> On Thu, 8 Apr 2010 14:03:39 -0700 (PDT), whit3rd <whi...@gmail.com>
> put finger to keyboard and composed:
>
>>On Apr 8, 12:11 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:
>
>>> Is this the fallout from RoHS?
>>
>>Maybe not. There are other known culprits, like the drywall (gypsum
>>board,
>>sheetrock... whatever it's called in your region) that outgasses
>>hydrogen
>>sulphide. Some US construction of a few years ago is so bad with
>>this
>>toxic and corrosive gas emission that demolition of nearly-new
>>construction
>>is called for.
>>
>>Corrosion of nearby copper is one of the symptoms of the nasty
>>product.
>
> It's not just Russia that has this problem. The same issue comes up
> frequently at the HDD Guru forums.
I'm right here in the US and I had 3 of 3 WD 1TB drives failed at the same
time in RAID1 thus making the entire array dead. It is not that you can
simply buff that dark stuff off and you're good to go. Drive itself tries to
recover from failures by rewriting service info (remapping etc.) but
connection is unreliable and it trashes the entire disk beyound repair. Then
you have that infamous "click of death"... BTW, it is not just WD; others
are also that bad.
They had good old gold plated male/female headers on older drives and those
were reliable. Newer drives had, sorry for an expression, "gold plated" pads
and springy contacts from the drive heads. That would have them something
like $0.001 saving per drive wrt those headers and they took that road. Gold
plating was also of a cheapest variety possible, probably immersion so it
wouldn't last long. Newest drives from Seagate also have that construction
but pads look like tin plated, no gold. Don't know how long it would last.
What we are looking at is an example of a brilliant design with a touch of
genius--it DOES last long enough so they work past their warranty period and
at the same time it will NOT last enough to make it work very long past the
manucturer's warranty. I don't know if it is just greed/incompetence or a
deliberate design feature but if it is the latter my kudos to their
engineers for job well done :(
---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************
Arno
That sounds like BS to me. A soft pencil eraser cannot remove silver
sulfide, it is quite resilient. There are special silver cleaning
cloths that will do the trick.
Still, I doubt that this is a problem. It shoud not crawl between
working contacts, only unused ones.
Arno
> In sci.electronics.repair Franc Zabkar <fza...@iinternode.on.net> wrote:
>> On Thu, 8 Apr 2010 14:03:39 -0700 (PDT), whit3rd <whi...@gmail.com>
>> put finger to keyboard and composed:
>>
>>
>>>> Is this the fallout from RoHS?
>>>
>>>Maybe not. There are other known culprits, like the drywall (gypsum
>>>board,
>>>sheetrock... whatever it's called in your region) that outgasses
>>>hydrogen
>>>sulphide. Some US construction of a few years ago is so bad with
>>>this
>>>toxic and corrosive gas emission that demolition of nearly-new
>>>construction
>>>is called for.
>>>
>>>Corrosion of nearby copper is one of the symptoms of the nasty
>>>product.
>>
>> It's not just Russia that has this problem. The same issue comes up
>> frequently at the HDD Guru forums.
> I'm right here in the US and I had 3 of 3 WD 1TB drives failed at the same
> time in RAID1 thus making the entire array dead. It is not that you can
> simply buff that dark stuff off and you're good to go. Drive itself tries to
> recover from failures by rewriting service info (remapping etc.) but
> connection is unreliable and it trashes the entire disk beyound repair. Then
> you have that infamous "click of death"... BTW, it is not just WD; others
> are also that bad.
It is extremly unlikely for a slow chemical process to achive this
level of syncronicity. About as unlikely that it would be fair to call
it impossible
Your array died from a different cause that would affect all drives
simultaneously, such as a power spike.
> They had good old gold plated male/female headers on older drives and those
> were reliable. Newer drives had, sorry for an expression, "gold plated" pads
> and springy contacts from the drive heads. That would have them something
> like $0.001 saving per drive wrt those headers and they took that road. Gold
> plating was also of a cheapest variety possible, probably immersion so it
> wouldn't last long. Newest drives from Seagate also have that construction
> but pads look like tin plated, no gold. Don't know how long it would last.
Tin lasts pretty long, unless you unplug/replug connectors. That is its
primary weakness.
> What we are looking at is an example of a brilliant design with a touch of
> genius--it DOES last long enough so they work past their warranty period and
> at the same time it will NOT last enough to make it work very long past the
> manucturer's warranty. I don't know if it is just greed/incompetence or a
> deliberate design feature but if it is the latter my kudos to their
> engineers for job well done :(
I think you are on the wrong trail here. Contact mechanics and
chemistry is well understood and has been studied longer than modern
electronics. So has metal plating technology in general.
Arno
> ---
> ******************************************************************
> * KSI@home KOI8 Net < > The impossible we do immediately. *
> * Las Vegas NV, USA < > Miracles require 24-hour notice. *
> ******************************************************************
--
Jeff Liebermann
<fza...@iinternode.on.net> wrote:
>I came across a reference to this Russian forum thread in a WDC forum:
>http://maccentre.ru/board/viewtopic.php?t=70953&start=15
>
>Here is Google's translator:
>http://translate.google.com/translate_t?sl=ru&tl=en
A better way to do this is to drag the English translation tool to the
tool browser bar:
<http://translate.google.com/translate_tools>
The browser will automagically ask if you want to translate any
foreign language web page that you view.
>The thread discusses oxidisation of contact pads in current Seagate
>and Western Digital hard drives.
It's not oxidation. Oxides of both tin and lead are white in color.
My guess(tm) is lead sulphide (galena), as lead sulphate and tin
sulphate are usually white.
<http://en.wikipedia.org/wiki/Lead%28II%29_sulfide>
It's difficult to tell from the photos if the PCB contacts are gold or
tin-silver. It's also difficult to tell if there was a mix of contact
materials. Mixing gold and tin contacts usually results in black crud
and fretting:
<http://www.tycoelectronics.com/documentation/whitepapers/pdf/p316-90.pdf>
<http://www.tycoelectronics.com/documentation/whitepapers/pdf/p154-74.pdf>
(see Fig 3). Contact material galvanic mismatch is another
possibility.
>The drives were used in typical
>office and home environments, and are about a year old.
Another possible culprit is a contaminated or poorly washed PC board.
The typical kitchen environment will also cause a problem. I see it
on machines and drives fairly often. If necessary, I just clean the
contacts with a pink pencil eraser, and reassemble. I've NEVER had a
drive failure that was directly attributed to such contact corrosion.
It's usually something else that kills the drive.
>The thread has
>several detailed photos. All except the older tinned PCB appear to
>show evidence of serious corrosion.
>
>Is this the fallout from RoHS? Surely it's not the result of some cost
>saving measure?
Nope. If the contacts were tin-silver, 5% lead, or one of the other
low lead alloys, the corrosion would probably be white or light gray
in color. The dark black suggests there's at least some lead involved
or possibly dissimilar contact material.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Arno
> On Thu, 08 Apr 2010 17:11:39 +1000, Franc Zabkar
> <fza...@iinternode.on.net> wrote:
> I've NEVER had a
> drive failure that was directly attributed to such contact corrosion.
> It's usually something else that kills the drive.
I think people are jumping to conclusion, because the discolorarion
is what they can see (and think they understand). There is a posting
in this thread with a person that has had a 3-way RAID1 fail and
attributes it to the contact discoloration. Now, whith a slow chemical
process, the required level of synchronicity is as unlikely that
calling it impossible is fair.
>>The thread has
>>several detailed photos. All except the older tinned PCB appear to
>>show evidence of serious corrosion.
>>
>>Is this the fallout from RoHS? Surely it's not the result of some cost
>>saving measure?
> Nope. If the contacts were tin-silver, 5% lead, or one of the other
> low lead alloys, the corrosion would probably be white or light gray
> in color. The dark black suggests there's at least some lead involved
> or possibly dissimilar contact material.
Actually pure silver also sulfidizes (?) in this way. The
look is very characteristic. I think this is silver plating
we see. It is typically not a problem on contacts that
are in use, it does not crawl between contact points.
I suspect in the observed instances, this is a purely
aestetic problem and has no impact on HDD performance
or reliability whatsoever.
Arno
Sergey Kubushyn
Yes, they did not die from contacts oxidation at that very same moment. I
can not even tell they all died the same month--that array might've been
running in degraded mode with one drive dead, then after some time second
drive died but it was still running on one remaining drive. And only when
the last one crossed the Styx the entire array went dead. I don't use
Windows so my machines are never turned off unless there is a real need for
this. And they are rarely updated once they are up and running so there is
no reboots. Typical uptime is more than a year.
I don't know though how I could miss a degradation alert if there was any.
All 3 drives in the array simply failed to start after reboot. There were
some media errors reported before reboot but all drives somehow worked. Then
the system got rebooted and all 3 drives failed with the same "click of
death."
The mechanism here is not that oxidation itself killed the drives. It never
happens that way. It was a main cause of a failure, but drives actually
performed suicide like body immune system kills that body when overreacting
to some kind of hemorrargic fever or so.
The probable sequence is something like this:
- Drives run for a long time with majority of the files never
accessed so it doesn't matter if that part of the disk where they
are stored is bad or not
- When the system is rebooted RAID array assembly is performed
- While this assembly is being performed a number of sectors on a
drive found to be defective and drive tries to remap them
- Such action involves rewriting service information
- Read/write operations are unreliable because of failing head
contacts so the service areas become filled with garbage
- Once the vital service information is damaged the drive is
essentially dead because its controller can not read vital data to
even start the disk
- The only hope for the controller to recover is to repeat the read
in hope that it might somehow get read. This is that infamous
"click of death" sound when drive tries to read the info again and
again. There is no way it can recover because that data are
trashed.
- Drives do NOT fail while they run, the failure happens on the next
reboot. The damage that would kill the drives on that reboot
happened way before that reboot though.
That suicide also can happen when some old file that was not accessed for
ages is read. That attempt triggers the suicide chain.
>
>> They had good old gold plated male/female headers on older drives and those
>> were reliable. Newer drives had, sorry for an expression, "gold plated" pads
>> and springy contacts from the drive heads. That would have them something
>> like $0.001 saving per drive wrt those headers and they took that road. Gold
>> plating was also of a cheapest variety possible, probably immersion so it
>> wouldn't last long. Newest drives from Seagate also have that construction
>> but pads look like tin plated, no gold. Don't know how long it would last.
>
> Tin lasts pretty long, unless you unplug/replug connectors. That is its
> primary weakness.
>
>> What we are looking at is an example of a brilliant design with a touch of
>> genius--it DOES last long enough so they work past their warranty period and
>> at the same time it will NOT last enough to make it work very long past the
>> manucturer's warranty. I don't know if it is just greed/incompetence or a
>> deliberate design feature but if it is the latter my kudos to their
>> engineers for job well done :(
>
> I think you are on the wrong trail here. Contact mechanics and
> chemistry is well understood and has been studied longer than modern
> electronics. So has metal plating technology in general.
---
Mike Tomlinson
writes
>That sounds like BS to me. A soft pencil eraser cannot remove silver
>sulfide, it is quite resilient.
It's a technique that has been used on edge connectors for many years.
--
Mike Tomlinson
JW
wrote in Message id: <iEygm6AA...@none.invalid>:
Yup, and it works. I learned the technique when servicing Multibus I
systems, and still use it to this day.
Jeff Liebermann
<k...@koi8.net> wrote:
>I'm right here in the US and I had 3 of 3 WD 1TB drives failed at the same
>time in RAID1 thus making the entire array dead.
That's the real problem with RAID using identical drives. When one
drive dies, the others are highly likely to follow. I had that
experience in about 2003 with a Compaq something Unix server running
SCSI RAID 1+0 (4 drives). One drive failed, and I replacing it with a
backup drive, which worked. The drive failure was repeated a week
later when a 2nd drive failed. When I realized what was happening, I
ran a complete tape backup, replaced ALL the drives, and restored from
the the backup. That was just in time as both remaining drives were
dead when I tested them a few weeks later. I've experienced similar
failures since then, and have always recommended replacing all the
drives, if possible (which is impractical for large arrays).
Arno
Ah, I see. I did misunderstand that. May still be something
else but the contacts are a possible explanation with that.
> I don't use Windows so my machines are never turned off unless there
> is a real need for this. And they are rarely updated once they are
> up and running so there is no reboots. Typical uptime is more than a
> year.
So your disks worked and then refused to restart? Or you are running
a RAID1 without monitoring?
> I don't know though how I could miss a degradation alert if there was any.
Well, if it is Linux with mdadm, it only sends one email per
degradation event in the default settings.
> All 3 drives in the array simply failed to start after reboot. There were
> some media errors reported before reboot but all drives somehow worked. Then
> the system got rebooted and all 3 drives failed with the same "click of
> death."
> The mechanism here is not that oxidation itself killed the drives. It never
> happens that way. It was a main cause of a failure, but drives actually
> performed suicide like body immune system kills that body when overreacting
> to some kind of hemorrargic fever or so.
> The probable sequence is something like this:
> - Drives run for a long time with majority of the files never
> accessed so it doesn't matter if that part of the disk where they
> are stored is bad or not
I run long smart selftest on all my drives (RAID or no) every
14 days to prevent that. Works well.
> - When the system is rebooted RAID array assembly is performed
> - While this assembly is being performed a number of sectors on a
> drive found to be defective and drive tries to remap them
> - Such action involves rewriting service information
> - Read/write operations are unreliable because of failing head
> contacts so the service areas become filled with garbage
> - Once the vital service information is damaged the drive is
> essentially dead because its controller can not read vital data to
> even start the disk
> - The only hope for the controller to recover is to repeat the read
> in hope that it might somehow get read. This is that infamous
> "click of death" sound when drive tries to read the info again and
> again. There is no way it can recover because that data are
> trashed.
> - Drives do NOT fail while they run, the failure happens on the next
> reboot. The damage that would kill the drives on that reboot
> happened way before that reboot though.
> That suicide also can happen when some old file that was not accessed for
> ages is read. That attempt triggers the suicide chain.
Yes, that makes sense. However you should do surface scans on
RAIDed disks regularly, e.g. by long SMART selftests. This will
catch weak sectors early and other degradation as well.
Arno
Arno
> <k...@koi8.net> wrote:
>>I'm right here in the US and I had 3 of 3 WD 1TB drives failed at the same
>>time in RAID1 thus making the entire array dead.
> That's the real problem with RAID using identical drives. When one
> drive dies, the others are highly likely to follow. I had that
> experience in about 2003 with a Compaq something Unix server running
> SCSI RAID 1+0 (4 drives). One drive failed, and I replacing it with a
> backup drive, which worked. The drive failure was repeated a week
> later when a 2nd drive failed. When I realized what was happening, I
> ran a complete tape backup, replaced ALL the drives, and restored from
> the the backup. That was just in time as both remaining drives were
> dead when I tested them a few weeks later. I've experienced similar
> failures since then, and have always recommended replacing all the
> drives, if possible (which is impractical for large arrays).
For high reliability requirements it is also a good idea to use
different brand drives, to get a better distributed times between
failures. Some people have reported the effect you see.
A second thing that can cause this effect is when the disks are not
regularly surface scanned. I run a long SMART selftest on all disks,
also the RAIDed ones for this every 14 days. The remaining disks are
under more stress during array rebuild, especially if the have weak
sectors. This additional load can cause the remaining drives to
fail a lot faster, in the wort case during array rebuild.
Arno
It works with a harder eraser and it works for tin contacts with
a soft one. But it does not work for silver contacts, you need
to have at least some sand in th eraser for that.
Sergey Kubushyn
I don't think it is something else but everything is possible...
>> I don't use Windows so my machines are never turned off unless there
>> is a real need for this. And they are rarely updated once they are
>> up and running so there is no reboots. Typical uptime is more than a
>> year.
>
> So your disks worked and then refused to restart? Or you are running
> a RAID1 without monitoring?
They failed during weekly full backup. One of the files read failed and they
entered that infinite loop of restarting themself and retrying. Root
filesystem was also on that RAID1 array so there was no other choice than
to reboot. And on that reboot all 3 drives failed to start with the same
"click of death" syndrome.
>> I don't know though how I could miss a degradation alert if there was any.
>
> Well, if it is Linux with mdadm, it only sends one email per
> degradation event in the default settings.
Yep, I probably missed it when shoveling through mountains of spam.
I know but I simply didn't think all 3 drives can fail... I thought I have
enough redundancy because I put not 2 but 3 drives in that RAID1... And I
did have something like a test with regular weekly full backup that reads
all the files (not the entire disk media but at least all the files on it)
and that was that backup that triggered disk suicide.
Anyway lesson learned and I'm taking additional measures now. It was not a
very good experience loosing some of my work...
BTW, I took a look at brand new WDC WD5000YS-01MPB1 drives, right out of the
sealed bags with silica gel and all 4 of those had their contacts already
oxidized with a lot of black stuff. That makes me very suspicious that
conspiracy theory might be not all that crazy--that oxidation seems to be
pre-applied by the manufacturer.
Rod Speed
MUCH more likely that someone fucked up in the factory.
Arno
>>> That suicide also can happen when some old file that was not accessed for
>>> ages is read. That attempt triggers the suicide chain.
>>
>> Yes, that makes sense. However you should do surface scans on
>> RAIDed disks regularly, e.g. by long SMART selftests. This will
>> catch weak sectors early and other degradation as well.
> I know but I simply didn't think all 3 drives can fail... I thought I have
> enough redundancy because I put not 2 but 3 drives in that RAID1... And I
> did have something like a test with regular weekly full backup that reads
> all the files (not the entire disk media but at least all the files on it)
> and that was that backup that triggered disk suicide.
> Anyway lesson learned and I'm taking additional measures now. It was not a
> very good experience loosing some of my work...
Yes, I can imagine. I have my critical stuff also on a 3 way RAID1,
but with long SMART selftests every 2 weeks and 3 different drives,
two from WD and one from Samsung. One additional advantage of the
long SMART selftest is that with smartd you will get a warning
email on every failing test, i.e. one every two weeks. For additional
warning you can also run a daily short test, e.g..
> BTW, I took a look at brand new WDC WD5000YS-01MPB1 drives, right out of the
> sealed bags with silica gel and all 4 of those had their contacts already
> oxidized with a lot of black stuff. That makes me very suspicious that
> conspiracy theory might be not all that crazy--that oxidation seems to be
> pre-applied by the manufacturer.
Urgh. These bags are airtight. No way the problem happened on your
side then. My two weeks old WD5000AADS-00S9B0 looks fine on the top
of the PCB. I think I will have a look underneath later.
Sergey Kubushyn
> [...]
>>>> That suicide also can happen when some old file that was not accessed for
>>>> ages is read. That attempt triggers the suicide chain.
>>>
>>> Yes, that makes sense. However you should do surface scans on
>>> RAIDed disks regularly, e.g. by long SMART selftests. This will
>>> catch weak sectors early and other degradation as well.
>
>> I know but I simply didn't think all 3 drives can fail... I thought I have
>> enough redundancy because I put not 2 but 3 drives in that RAID1... And I
>> did have something like a test with regular weekly full backup that reads
>> all the files (not the entire disk media but at least all the files on it)
>> and that was that backup that triggered disk suicide.
>
>> Anyway lesson learned and I'm taking additional measures now. It was not a
>> very good experience loosing some of my work...
>
> Yes, I can imagine. I have my critical stuff also on a 3 way RAID1,
> but with long SMART selftests every 2 weeks and 3 different drives,
> two from WD and one from Samsung. One additional advantage of the
> long SMART selftest is that with smartd you will get a warning
> email on every failing test, i.e. one every two weeks. For additional
> warning you can also run a daily short test, e.g..
No matter what you do you can not prevent an occasional disaster :( One
MUST remember that "backup" in not a noun but a verb in imperative.
>> BTW, I took a look at brand new WDC WD5000YS-01MPB1 drives, right out of the
>> sealed bags with silica gel and all 4 of those had their contacts already
>> oxidized with a lot of black stuff. That makes me very suspicious that
>> conspiracy theory might be not all that crazy--that oxidation seems to be
>> pre-applied by the manufacturer.
>
> Urgh. These bags are airtight. No way the problem happened on your
> side then. My two weeks old WD5000AADS-00S9B0 looks fine on the top
> of the PCB. I think I will have a look underneath later.
Those 4 were fine on the top of PCB. Black stuff was underneath, on those
pads contacting with springy heads pins.
Arno
> In sci.electronics.repair Arno <m...@privacy.net> wrote:
>> In comp.sys.ibm.pc.hardware.storage Sergey Kubushyn <k...@koi8.net> wrote:
>> [...]
>>>>> That suicide also can happen when some old file that was not accessed for
>>>>> ages is read. That attempt triggers the suicide chain.
>>>>
>>>> Yes, that makes sense. However you should do surface scans on
>>>> RAIDed disks regularly, e.g. by long SMART selftests. This will
>>>> catch weak sectors early and other degradation as well.
>>
>>> I know but I simply didn't think all 3 drives can fail... I thought I have
>>> enough redundancy because I put not 2 but 3 drives in that RAID1... And I
>>> did have something like a test with regular weekly full backup that reads
>>> all the files (not the entire disk media but at least all the files on it)
>>> and that was that backup that triggered disk suicide.
>>
>>> Anyway lesson learned and I'm taking additional measures now. It was not a
>>> very good experience loosing some of my work...
>>
>> Yes, I can imagine. I have my critical stuff also on a 3 way RAID1,
>> but with long SMART selftests every 2 weeks and 3 different drives,
>> two from WD and one from Samsung. One additional advantage of the
>> long SMART selftest is that with smartd you will get a warning
>> email on every failing test, i.e. one every two weeks. For additional
>> warning you can also run a daily short test, e.g..
> No matter what you do you can not prevent an occasional disaster :( One
> MUST remember that "backup" in not a noun but a verb in imperative.
Indeed.
>>> BTW, I took a look at brand new WDC WD5000YS-01MPB1 drives, right out of the
>>> sealed bags with silica gel and all 4 of those had their contacts already
>>> oxidized with a lot of black stuff. That makes me very suspicious that
>>> conspiracy theory might be not all that crazy--that oxidation seems to be
>>> pre-applied by the manufacturer.
>>
>> Urgh. These bags are airtight. No way the problem happened on your
>> side then. My two weeks old WD5000AADS-00S9B0 looks fine on the top
>> of the PCB. I think I will have a look underneath later.
> Those 4 were fine on the top of PCB. Black stuff was underneath, on those
> pads contacting with springy heads pins.
Mine is fine on both sides. However there is a quite a bit of contact
area that looks and feels silver-plated to me, most notably areound
the screws and on the bottom the contacts to the head assembly.
Sergey Kubushyn
That makes me wonder why are they silver-plated. It is definitely not the
best material longevitywise, especially for such low-level signals. It makes
me even more suspicious and adds to the conspiracy theory.
Arno
> In sci.electronics.repair Arno <m...@privacy.net> wrote:
>>> Those 4 were fine on the top of PCB. Black stuff was underneath, on those
>>> pads contacting with springy heads pins.
>>
>> Mine is fine on both sides. However there is a quite a bit of contact
>> area that looks and feels silver-plated to me, most notably areound
>> the screws and on the bottom the contacts to the head assembly.
> That makes me wonder why are they silver-plated. It is definitely
> not the best material longevitywise, especially for such low-level
> signals. It makes me even more suspicious and adds to the conspiracy
> theory.
Well, maybe. However I tend to think that "never attribute to
malice what can be adequately explained by stupidity" may apply.
These contacts should be gold plated with high quality gold. It is
also possible that the HDD vibration (always present with a running
HDD) and thermal variation allows the process to creep between the
contacts and kill them. Maybe a young, inexperienced engineer was
hired to replace an older, experienced (but more expensive one)
and that person made a pretty bad judgement call due to
inexperience, wanting to save a few cents on the design.
I have to say that the last time I saw silver plating as contact
protection was in vaccuum tube equipment. Modern electronics
typically uses Gold, or Tin for low insertion cycle contacts.
I also found a statement on Wikipaedia that silver plated
copper, once the copper is exposed in a place, will rapidly
corrode all over because of some electro-chemical process.
No idea whether this is true or not.
Rod Speed
Likely just some fool's reaction to the price of gold.
> It makes me even more suspicious and adds to the conspiracy theory.
Nope.
Sjouke Burry
You know of course that the black silver layer is still conductive
for low level signals??
Arno
> Sergey Kubushyn wrote:
>> In sci.electronics.repair Arno <m...@privacy.net> wrote:
>>> Mine is fine on both sides. However there is a quite a bit of contact
>>> area that looks and feels silver-plated to me, most notably areound
>>> the screws and on the bottom the contacts to the head assembly.
>>
>> That makes me wonder why are they silver-plated. It is definitely not the
>> best material longevitywise, especially for such low-level signals. It makes
>> me even more suspicious and adds to the conspiracy theory.
> You know of course that the black silver layer is still conductive
> for low level signals??
Silver Silfide is a (bad) conductor? That will help for the
R/W signal. However the lines for the moving coil go through
the same connector and they need a low resistance path.
Sergey Kubushyn
> In comp.sys.ibm.pc.hardware.storage Sergey Kubushyn <k...@koi8.net> wrote:
>> In sci.electronics.repair Arno <m...@privacy.net> wrote:
> [...]
>>>> Those 4 were fine on the top of PCB. Black stuff was underneath, on those
>>>> pads contacting with springy heads pins.
>>>
>>> Mine is fine on both sides. However there is a quite a bit of contact
>>> area that looks and feels silver-plated to me, most notably areound
>>> the screws and on the bottom the contacts to the head assembly.
>
>> That makes me wonder why are they silver-plated. It is definitely
>> not the best material longevitywise, especially for such low-level
>> signals. It makes me even more suspicious and adds to the conspiracy
>> theory.
>
> Well, maybe. However I tend to think that "never attribute to
> malice what can be adequately explained by stupidity" may apply.
I agree but it looks like there is a pattern here...
> These contacts should be gold plated with high quality gold. It is
> also possible that the HDD vibration (always present with a running
> HDD) and thermal variation allows the process to creep between the
> contacts and kill them. Maybe a young, inexperienced engineer was
> hired to replace an older, experienced (but more expensive one)
> and that person made a pretty bad judgement call due to
> inexperience, wanting to save a few cents on the design.
They did not save anything on that design. Gold plating is a common
procedure, it is everywhere, most of card-edge connectors (e.g. PCI) are
gold and they even called "gold fingers" by chinese PCB manufacturers.
Silver, on the other hand, is almost unheard of and I'm pretty sure PCB
makers would charge extra for this if they agree to do it at all. And it is
NOT that the entire board is silver-plated; there are gold-plated parts on
that same board that makes it have at least 2 different platings so it will
be more expensive than simple gold all over.
> I have to say that the last time I saw silver plating as contact
> protection was in vaccuum tube equipment. Modern electronics
> typically uses Gold, or Tin for low insertion cycle contacts.
Yep. Silver plating was usually used in microwave equipment, HF coils etc.
where skin effect was so profound that current only ran through that silver
(that was quite thick, btw.) Silver is also used for HIGH CURRENT relay
contacts where the corrosion is removed by mechanical action of closing
contacts and burned through with high current.
If you look at low current signal relays with stated minimal current
capacity _NONE_ of them have silver contacts. It is usually gold, platinum,
rhodium, or a mix thereof.
I am all pro Occam's Razor but all this looks like deliberate effort to make
it fail after some time. It is NOT easier or cheaper to put silver there
because it is an _ADDITIONAL_ step and not so common one.
Sergey Kubushyn
It is not. Look at low level signal relays with stated _MINIMAL_ current
capacity and think why none of them has silver contacts.
Sjouke Burry
> In sci.electronics.repair Sjouke Burry <burrynu...@ppllaanneett.nnll> wrote:
>> Sergey Kubushyn wrote:
>>>> area that looks and feels silver-plated to me, most notably areound
>>>> the screws and on the bottom the contacts to the head assembly.
>>> That makes me wonder why are they silver-plated. It is definitely not the
>>> best material longevitywise, especially for such low-level signals. It makes
>>> me even more suspicious and adds to the conspiracy theory.
>>>
>>> ---
>>> ******************************************************************
>>> * KSI@home KOI8 Net < > The impossible we do immediately. *
>>> * Las Vegas NV, USA < > Miracles require 24-hour notice. *
>>> ******************************************************************
>> You know of course that the black silver layer is still conductive
>> for low level signals??
>
> It is not. Look at low level signal relays with stated _MINIMAL_ current
> capacity and think why none of them has silver contacts.
I have done brain wave registration, eye movement detection and
skin resistance measurement with silver-chloride electrodes,
and they conducted nicely.
Sergey Kubushyn
That is totally different application. Yes, silver sulfide is not a perfect
dielectric but it is not a good conductor either. And modern HDD heads are
magnetoRESISTIVE.
454
> In comp.sys.ibm.pc.hardware.storage Sjouke Burry
> <burrynu...@ppllaanneett.nnll> wrote:
>> Sergey Kubushyn wrote:
>>> In sci.electronics.repair Arno <m...@privacy.net> wrote:
> [...]
>>>> Mine is fine on both sides. However there is a quite a bit of
>>>> contact area that looks and feels silver-plated to me, most
>>>> notably areound the screws and on the bottom the contacts to the
>>>> head assembly.
>>>
>>> That makes me wonder why are they silver-plated. It is definitely
>>> not the best material longevitywise, especially for such low-level
>>> signals. It makes me even more suspicious and adds to the
>>> conspiracy theory.
>
>> You know of course that the black silver layer is still conductive
>> for low level signals??
> Silver Silfide is a (bad) conductor?
Nope.
> That will help for the R/W signal. However the lines for the moving coil
> go through the same connector and they need a low resistance path.
The black silver layer conducts that fine.
Arno
Good points. An exotic process would be more expensive than a
common one and two processes instead of one as well. I also happen
to know that putting gold directly on silcer is problematic, but
putting it directly on copper is fine. At least that is for galvanics
on jewelery and if I remember this correctly.
>> I have to say that the last time I saw silver plating as contact
>> protection was in vaccuum tube equipment. Modern electronics
>> typically uses Gold, or Tin for low insertion cycle contacts.
> Yep. Silver plating was usually used in microwave equipment, HF coils etc.
> where skin effect was so profound that current only ran through that silver
> (that was quite thick, btw.) Silver is also used for HIGH CURRENT relay
> contacts where the corrosion is removed by mechanical action of closing
> contacts and burned through with high current.
That explains it. I have indeed seen it in power relais as well.
> If you look at low current signal relays with stated minimal current
> capacity _NONE_ of them have silver contacts. It is usually gold,
> platinum, rhodium, or a mix thereof.
> I am all pro Occam's Razor but all this looks like deliberate effort
> to make it fail after some time. It is NOT easier or cheaper to
> put silver there because it is an _ADDITIONAL_ step and not so
> common one.
Well, it only makes the required level of stupidity larger,
because (if we have this right) they also need to mess up the
economic angle. If we assume they are competent, then indeed this
looks very much like a deliberate and rather bad design error.
Arno
Silver cloride and silver sulfide are two different things.
Ok, finally looked it up:
Silver Sulfide (Ag2S) is black and forms when silver is
exposed to the atmosphere by a reaction with hydrogen sulfide.
As to conducticity, it seems this really messes up contact
characteristics, including formiong diode-like effects and the
like. I found an abstract of a IEEE article from 1970 online:
"Electrical Characteristics of Contacts Contaminated
with Silver Sulfide Film"
So it seems it does concuct, but not well, uniformly or even
in an ohmic fashion. Very bad. THis would explain the HDD
failures, I think. If such a noise source is found in the
signal path from/to the heads and the moving coil, I think
this can cause all sorts of problems.
Silver Chloride (AgCl)is a white crystal used as referecne
electrode, becasue it has very stable characteristics, giving
you 230mV +/-10mV against a standard hydrogen electrode. I
conclude from this that Silver Cloride conducts reasonably
well and mostly in an ohmic fashion.
Sorry, but your observation does not aplly to the discussion
at hand.
454
Or some fool has focussed on the price of gold metal and has
lost sight of the fact that more complex pcb manufacturing
process negates any advantage by using the cheaper metal.
MUCH more likely than any conspiracy to shaft the user.
Sergey Kubushyn
Just took a brand spanking new WD5000AAKS drive out of sealed bag with
silica gel and all that stuff. The PCB is all _SILVER_ plated, no gold. And
that silver is almost totally black right out of the bag.
Arno
> In sci.electronics.repair Sergey Kubushyn <k...@koi8.net> wrote:
> Just took a brand spanking new WD5000AAKS drive out of sealed bag with
> silica gel and all that stuff. The PCB is all _SILVER_ plated, no gold. And
> that silver is almost totally black right out of the bag.
Not good. Silver really is unsuitable for modern, low voltage,
electronics. The last WD disk I bought (a WD5000AADS, 500GB
Caviar Green) had mixed gold and silver plating and the
silver plating was completely fine, on both sides of the
PCB.
Something is fishy here.
Arno
--
Jeff Liebermann
>In comp.sys.ibm.pc.hardware.storage Sergey Kubushyn <k...@koi8.net> wrote:
>> In sci.electronics.repair Sergey Kubushyn <k...@koi8.net> wrote:
>
>> Just took a brand spanking new WD5000AAKS drive out of sealed bag with
>> silica gel and all that stuff. The PCB is all _SILVER_ plated, no gold. And
>> that silver is almost totally black right out of the bag.
>
>Not good. Silver really is unsuitable for modern, low voltage,
>electronics. The last WD disk I bought (a WD5000AADS, 500GB
>Caviar Green) had mixed gold and silver plating and the
>silver plating was completely fine, on both sides of the
>PCB.
I just removed the PCB from a WD200EB-75CSF0 20GB drive. Tin plating
on both the PCB contacts and the mating pin array going into the HDA
assembly. No gold or silver.
However, there's one extra item that hasn't entered the discussion.
There was a sheet of foam something between the PCB and the HDA. In
this case, it was quite clean and dry, but it wouldn't take much for
most any liquid to get absorbed by the foam and rot out the board.
There was a cut-out hole around the connector area, so there was no
common points of contact, but it was close enough that any volatiles
would certainly enter the connector area.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS
Sergey Kubushyn
> On 30 Apr 2010 23:57:32 GMT, Arno <m...@privacy.net> wrote:
>
>>In comp.sys.ibm.pc.hardware.storage Sergey Kubushyn <k...@koi8.net> wrote:
>>> In sci.electronics.repair Sergey Kubushyn <k...@koi8.net> wrote:
>>
>>> Just took a brand spanking new WD5000AAKS drive out of sealed bag with
>>> silica gel and all that stuff. The PCB is all _SILVER_ plated, no gold. And
>>> that silver is almost totally black right out of the bag.
>>
>>Not good. Silver really is unsuitable for modern, low voltage,
>>electronics. The last WD disk I bought (a WD5000AADS, 500GB
>>Caviar Green) had mixed gold and silver plating and the
>>silver plating was completely fine, on both sides of the
>>PCB.
>
> I just removed the PCB from a WD200EB-75CSF0 20GB drive. Tin plating
> on both the PCB contacts and the mating pin array going into the HDA
> assembly. No gold or silver.
>
> However, there's one extra item that hasn't entered the discussion.
> There was a sheet of foam something between the PCB and the HDA. In
> this case, it was quite clean and dry, but it wouldn't take much for
> most any liquid to get absorbed by the foam and rot out the board.
> There was a cut-out hole around the connector area, so there was no
> common points of contact, but it was close enough that any volatiles
> would certainly enter the connector area.
20Gb sounds like an old drive. Those were made before this "invention."
My brand spanking new drive was purchased from Amazon 4 days ago and the
manufacturing date is something like a month back. I bought it for a router
I'm building for my recently acquired /28 CIDR IP block on Intel D510MO
Athom board and Intel dual gigabit ethernet adapter (BTW, I highly recommend
that motherboard--it is a small miracle in a huge heap of manure selling
these days.) That means it is _ABSOLUTELY_ the "latest and greatest," not
something dug out of old junk heap. And it is retail.
That means it definitely comes like this right from the manufacturer. I have
serious doubts that it got that tarnished by a mere negligence. They
supposed to have clean rooms there and those drives are packed in airtight
bags. I have a lot of silver plated parts at home in usual zip lock bags and
even without any bags and they don't get this black in years less for a mere
month...