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USB stick leaking



 
 
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  #1  
Old April 20th 17, 06:13 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Linea Recta[_2_]
external usenet poster
 
Posts: 61
Default USB stick leaking

I used a Lexar USB stick yesterday to boot a computer. I haven't used the
stick intensively, but now I noticed that it is leaking sticky stuff from
the seam on the sides. Any idea what the stuff is? Is it toxic? Can I keep
using the stick normally?



--


|\ /|
| \/ [email protected]
\../
\/os

  #2  
Old April 20th 17, 06:45 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,149
Default USB stick leaking

Linea Recta wrote:

I used a Lexar USB stick yesterday to boot a computer.


Yep, sure, Lexar has only one model of USB drive. See:
http://www.lexar.com/products/usb-flash-drives.html

I haven't used the stick intensively, but now I noticed that it is
leaking sticky stuff from the seam on the sides. Any idea what the
stuff is? Is it toxic? Can I keep using the stick normally?


Inside a legit USB drive, there is a PCB, chips, connector, and some
solder. None of that leaks. Some use silicon to seal them. Maybe this
is the goo that overheated and is leaking out.

http://blog.premiumusb.com/2011/02/w...drive-get-hot/

They all heat up with use. A plastic shell versus a metal shell only
changes the thermal transfer rate; i.e., a metal shelled USB drive may
feel hotter than a plastic one - but they both generate heat during use.
Defective ones get hot. USB ports can go bad and supply too much
current. Some users plug into charging-capable USB ports designed for
smartphones, not USB flash drives. Test plugging if another USB device
into the same port (and not a charging USB port) also heats up too much.
Condensation inside the shell can cause shorts (that cause heating up)
or corrode contacts (causing heat due to increased resistance).

Yours overheated. Return it under warranty.
  #3  
Old April 20th 17, 08:04 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Paul[_26_]
external usenet poster
 
Posts: 357
Default USB stick leaking

Linea Recta wrote:
I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky stuff
from the seam on the sides. Any idea what the stuff is? Is it toxic? Can
I keep using the stick normally?


All the Lexars I have here (three of them) have the same
mechanical design. I've taken two of them apart, because
they failed and no longer function.

There is the bottom tub, the PCB and connector which slide
back and forth, and a white top cover. The top cover has
four prongs that snap into place. There are no liquids inside.

__P__________P__
/ \
| |
\________________/
P P

You can release the top cover and get it out.
That's the white part in this picture.

https://www.amazon.com/Lexar-JumpDri.../dp/B007B6YPNY

*******

Lexar makes many many different drives, and not all use
the same packaging.

*******

Ordinary USB flash drives, do not have thermal control.
Any heat dissipated, could flow through the metal connector
barrel (except for those cheap-ass Lexars with the plastic
barrel, which I recommend you avoid).

In terms of hardware design, if you want thermal control, you need:

1) Thermally conductive cover. Some SSDs use a metal sled for this.
2) Sil Pad or thermal paste. If something in a drive gets really hot,
you can use a Sil Pad as an intermediary, to conduct heat into the
cover.

Since USB flash drives, a lot of them have plastic covers, using
Sil Pads or thermal paste would be a waste of materials.

For a metal-jacketed product, the metal itself may be good
enough to encourage a lower internal temperature.

If a component becomes really hot, using a Sil Pad to
conduct from the chip to the cover might work. It depends
on dimensional analysis, whether a Sil Pad will work,
or curable silicon rubber is needed. Generally, thermal control
materials are too expensive for throwaway items like USB
sticks. The roll of Sil Pads we had at work, cost $500.00
per roll.

The color and consistency of the material may suggest what
it is. If the stuff is a bright white color, that could be
Zinc Oxide in silicone oil. The ones I've used, the oil
quickly separates and leaves the area. Leaving a spotty
Zinc Oxide residue to support cooling.

http://www.mgchemicals.com/products/...r-compound-860

Real thermal pastes, are made from a more viscous substrate.
Some are so thick, they resemble "crumbly cookie dough" and
they're hard to spread into place. Those should not leak a
liquid. There are thinner ones, like a graphite-like material
in a less viscous oil substrate.

It would not be in the best interest of the company, to
use a liquid toxic substance in the construction. But,
you never know. There have been assemblies built in
electronics which are very dangerous (beryllia substrate).

https://en.wikipedia.org/wiki/Beryllium_oxide

"BeO is carcinogenic and may cause chronic beryllium disease.
Once fired into solid form, it is safe to handle if not
subjected to machining that generates dust."

Some older products, there would be a warning sticker saying
"not to grind" the item the warning sticker was adhered to. Because
it was made of beryllia. That's the nastiest example I can think of.

Paul
  #4  
Old April 20th 17, 08:40 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Linea Recta[_2_]
external usenet poster
 
Posts: 61
Default USB stick leaking

"Linea Recta" schreef in bericht
news
I used a Lexar USB stick yesterday to boot a computer. I haven't used the
stick intensively, but now I noticed that it is leaking sticky stuff from
the seam on the sides. Any idea what the stuff is? Is it toxic? Can I keep
using the stick normally?



--


|\ /|
| \/ [email protected]
\../
\/os



The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4


but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China




--


|\ /|
| \/ [email protected]
\../
\/os

  #5  
Old April 20th 17, 09:03 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Linea Recta[_2_]
external usenet poster
 
Posts: 61
Default USB stick leaking

"Paul" schreef in bericht
news
Linea Recta wrote:
I used a Lexar USB stick yesterday to boot a computer. I haven't used the
stick intensively, but now I noticed that it is leaking sticky stuff from
the seam on the sides. Any idea what the stuff is? Is it toxic? Can I
keep using the stick normally?


All the Lexars I have here (three of them) have the same
mechanical design. I've taken two of them apart, because
they failed and no longer function.

There is the bottom tub, the PCB and connector which slide
back and forth, and a white top cover. The top cover has
four prongs that snap into place. There are no liquids inside.

__P__________P__
/ \
| |
\________________/
P P

You can release the top cover and get it out.
That's the white part in this picture.

https://www.amazon.com/Lexar-JumpDri.../dp/B007B6YPNY

*******

Lexar makes many many different drives, and not all use
the same packaging.

*******

Ordinary USB flash drives, do not have thermal control.
Any heat dissipated, could flow through the metal connector
barrel (except for those cheap-ass Lexars with the plastic
barrel, which I recommend you avoid).

In terms of hardware design, if you want thermal control, you need:

1) Thermally conductive cover. Some SSDs use a metal sled for this.
2) Sil Pad or thermal paste. If something in a drive gets really hot,
you can use a Sil Pad as an intermediary, to conduct heat into the
cover.

Since USB flash drives, a lot of them have plastic covers, using
Sil Pads or thermal paste would be a waste of materials.

For a metal-jacketed product, the metal itself may be good
enough to encourage a lower internal temperature.

If a component becomes really hot, using a Sil Pad to
conduct from the chip to the cover might work. It depends
on dimensional analysis, whether a Sil Pad will work,
or curable silicon rubber is needed. Generally, thermal control
materials are too expensive for throwaway items like USB
sticks. The roll of Sil Pads we had at work, cost $500.00
per roll.

The color and consistency of the material may suggest what
it is. If the stuff is a bright white color, that could be
Zinc Oxide in silicone oil. The ones I've used, the oil
quickly separates and leaves the area. Leaving a spotty
Zinc Oxide residue to support cooling.

http://www.mgchemicals.com/products/...r-compound-860

Real thermal pastes, are made from a more viscous substrate.
Some are so thick, they resemble "crumbly cookie dough" and
they're hard to spread into place. Those should not leak a
liquid. There are thinner ones, like a graphite-like material
in a less viscous oil substrate.

It would not be in the best interest of the company, to
use a liquid toxic substance in the construction. But,
you never know. There have been assemblies built in
electronics which are very dangerous (beryllia substrate).

https://en.wikipedia.org/wiki/Beryllium_oxide

"BeO is carcinogenic and may cause chronic beryllium disease.
Once fired into solid form, it is safe to handle if not
subjected to machining that generates dust."

Some older products, there would be a warning sticker saying
"not to grind" the item the warning sticker was adhered to. Because
it was made of beryllia. That's the nastiest example I can think of.

Paul




Thanks for the info.
Mine is quite old indeed, but as said: not intensively used. I have several
other sticks of different make and indeed... with metal case.
BTW I had no idea that a USB stick is regarded as "throwaway item".

(For details see my second message in the thread.)



--


|\ /|
| \/ [email protected]
\../
\/os

  #6  
Old April 20th 17, 10:32 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,149
Default USB stick leaking

Linea Recta wrote:

"Linea Recta" ...

I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky
stuff from the seam on the sides. Any idea what the stuff is? Is it
toxic? Can I keep using the stick normally?


The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4

but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China


http://www.lexar.com/products/usb-fl...ash-Drive.html

Those are not listed as waterproof/resistant so there should be no
silicone filling to ooze out (but shouldn't anyway since, when it set,
silicone is not going to ooze but burn from an overheated chip).

Is what oozed out soft or hard? Is it like paste that you can smoosh
between your fingers, like toothpaste? Is it rubbery, like silicone
caulking? It is hard, like the plastic shell itself?
  #7  
Old April 20th 17, 10:36 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Paul[_26_]
external usenet poster
 
Posts: 357
Default USB stick leaking

Linea Recta wrote:
"Linea Recta" schreef in bericht
news
I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky
stuff from the seam on the sides. Any idea what the stuff is? Is it
toxic? Can I keep using the stick normally?



--


|\ /|
| \/ [email protected]
\../
\/os



The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4



but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China


LJDTT4GBASBNA

The Amazon reviews say average write is 3.2MB/sec, average read
is 18.2MB/sec. It's an old style single channel flash, and should
not run hot, and should not need any liquids or pastes inside.
There are the usual reports of failures, but none involving
liquids or sticky substances.

I would have the hack saw out by now, and cut it in half...

For thermal paste, they recommend soap and water for cleanup,
or maybe a bit of GooGone (monoterpene limonene a.k.a orange oil).
Thermal paste doesn't go that well on crackers, even though it
looks like a good spread for canapés.

Sil Pads contain their contents pretty well, and only
extreme pressure on them, might cause the carrier to ooze out.
The item just doesn't look like it needs that kind of thing.

Paul
  #8  
Old April 21st 17, 12:47 AM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Ken Blake[_3_]
external usenet poster
 
Posts: 19
Default USB stick leaking

On Thu, 20 Apr 2017 17:36:38 -0400, Paul
wrote:

Linea Recta wrote:
"Linea Recta" schreef in bericht
news
I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky
stuff from the seam on the sides. Any idea what the stuff is? Is it
toxic? Can I keep using the stick normally?



--


|\ /|
| \/ [email protected]
\../
\/os



The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4



but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China


LJDTT4GBASBNA

The Amazon reviews say average write is 3.2MB/sec, average read
is 18.2MB/sec. It's an old style single channel flash, and should
not run hot, and should not need any liquids or pastes inside.
There are the usual reports of failures, but none involving
liquids or sticky substances.

I would have the hack saw out by now, and cut it in half...




Then each half world only be 2GB--not enough to be really useful.
vbg
  #9  
Old April 21st 17, 05:12 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Linea Recta[_2_]
external usenet poster
 
Posts: 61
Default USB stick leaking

"VanguardLH" schreef in bericht
...
Linea Recta wrote:

"Linea Recta" ...

I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky
stuff from the seam on the sides. Any idea what the stuff is? Is it
toxic? Can I keep using the stick normally?


The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4

but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China


http://www.lexar.com/products/usb-fl...ash-Drive.html

Those are not listed as waterproof/resistant so there should be no
silicone filling to ooze out (but shouldn't anyway since, when it set,
silicone is not going to ooze but burn from an overheated chip).

Is what oozed out soft or hard? Is it like paste that you can smoosh
between your fingers, like toothpaste? Is it rubbery, like silicone
caulking? It is hard, like the plastic shell itself?




It is sticky and quite soft. Colour: transparent yellowish.
I tried to clean it, but it seems the red colour of the case comes off
now...
BTW I'm not aware the stick ran hot.




--


|\ /|
| \/ [email protected]
\../
\/os

  #10  
Old April 21st 17, 11:04 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,149
Default USB stick leaking

Linea Recta wrote:

"VanguardLH" schreef in bericht
...
Linea Recta wrote:

"Linea Recta" ...

I used a Lexar USB stick yesterday to boot a computer. I haven't used
the stick intensively, but now I noticed that it is leaking sticky
stuff from the seam on the sides. Any idea what the stuff is? Is it
toxic? Can I keep using the stick normally?

The stick looks like this one:

https://www.amazon.com/Lexar-JumpDri.../dp/B0021AFWL4

but I took a magnifying glass to read what's exactly on mine:

lexar LJDTT4GB-000-1001AC
333074GBGA
N12610

product of China


http://www.lexar.com/products/usb-fl...ash-Drive.html

Those are not listed as waterproof/resistant so there should be no
silicone filling to ooze out (but shouldn't anyway since, when it set,
silicone is not going to ooze but burn from an overheated chip).

Is what oozed out soft or hard? Is it like paste that you can smoosh
between your fingers, like toothpaste? Is it rubbery, like silicone
caulking? It is hard, like the plastic shell itself?


It is sticky and quite soft. Colour: transparent yellowish.
I tried to clean it, but it seems the red colour of the case comes off
now...
BTW I'm not aware the stick ran hot.


"transparent yellowish" had me first think it was solder rosin (aka
resin aka flux); however, the chips, connector, and other components are
wave soldered onto the PCB. If rosin were oozing out, I'd suspect
someone refurbished the device by, for example, replacing the memory
chip and they had to use a rework station that employed rosin to assist
in removing the chip, dewicking the solder off the chip, and later when
soldering the new chip onto the pads on the PCB. When using rosin, and
in a rework lab, there is usually a bath where the parts are dipped or
sprayed to remove the excess rosin. Another possibility is excessive
application of rosin during original manufacturer.

https://www.youtube.com/watch?v=CalydGKwEy8

That shows a guy removing a memory chip and noticed there was excessive
rosin left behind. Rosin doesn't flow at room temperature. That's why
it stays in the core of solder thread that incorporates solder inside of
it. It does flow when heated. Just because it doesn't feel hot to you
does not mean the chip(s) was not hot. All USB flash drives generate
heat. A plastic case has a slower transfer rate than metal. That means
a plastic cased USB flash drive will dissipate heat more slowly and it
also means you won't feel as much heat. A metal cased drive will feel
hotter to the touch than with the same PCB and components on it inside
of a plastic case.

The shell is typically 2 halves made of plastic that are snapped
together. Maybe the soft stuff was a sealant. I'm guessing rosin.
Original manufacture would leave almost no rosin behind. Little, if
any, would be used during original manufacture and if any were used then
the PCB goes through a bath to remove the rosin. Maybe you got a
remanufactured device. Refurbished usually means just testing and
passing the device on if testing is successful. Most times, refurbish
has nothing physically done to the device. Remanufacture means
rebuilding some of it.

I don't have any of those so I cannot pop one apart to look inside.
Haven't found a Youtube video about USB drive disassembly that looks at
that specific brand and model. The above video is for a Lexar JumpDrive
but a different model. The video author noticed excess rosin on the
memory chip at timemark 5:50. He uses a hot air desoldering station
which does not apply any flux. What he noted on the memory chip was
already there. The flux was on the underside of the chip (between chip
and PCB). So the manufacture process used flux (rosin) but did not do a
good job at washing it off. It is a tight fit between chip and board
but the flux was all over the bottomside of the chip. Seems Lexar's
manufacture process is sloppy with rosin since it only needs to be
applied for soldering the pins on the chip and nowhere as much on the
pins as what is shown sticking to the bottomside of this chip in this
video. Sloppy manufacture.
 




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