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#1
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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? -- |\ /| | \/ |@rk \../ \/os |
#2
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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
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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
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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? -- |\ /| | \/ |@rk \../ \/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 -- |\ /| | \/ |@rk \../ \/os |
#5
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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.) -- |\ /| | \/ |@rk \../ \/os |
#6
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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
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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? -- |\ /| | \/ |@rk \../ \/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
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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? -- |\ /| | \/ |@rk \../ \/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
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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. -- |\ /| | \/ |@rk \../ \/os |
#10
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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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