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#1
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usb flash drive
I magnetized usb flash drive with the center of a metal candle holder
which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. If I could see the drive, I could copy the files on it. |
#2
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usb flash drive
Joel727 wrote:
I magnetized usb flash drive with the center of a metal candle holder which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. If I could see the drive, I could copy the files on it. The flash chip is not affected by the state of the adjoining magnetic fields. You did not disrupt its operation when you held a magnet near it. Flash is sensitive to very high electrical fields, radiation, or perhaps UV light (only if the top of the chip was removed so light could strike it). Years ago, the ability of light to erase flashable memory, was a feature. These devices had a "window" on top, so you could erase the contents by shining a UV light on the device for 20 minutes or so. Now, flash can be erased electrically, so they no longer put a window on them like this. I used to erase trays of these under UV light in the lab. http://www.antronics.co.uk/portfolio...ram/eproms.jpg ******* If you use a degaussing coil to remove the residual magnetism, that could induce an AC voltage on some of the conductors. I don't see a particularly good reason to be using a degaussing coil on it. So that would be a needless risk. A degaussing coil will not revive the flash. Flash memory can be damaged by static electricity. Maybe that is what broke it. Or, perhaps one of the four conductors leading to the USB connector, is cracked. And that electrical connection failure is what is preventing it from working. Many flash sticks are poorly designed, such that if any force is applied to the metal connector on the end, it can cause a connection to crack and fail. The flash is usually separated into at least two chips. The design looks like this. Small capacity devices have one Flash chip, while higher capacity ones can hold two. USB ------------- Controller ----- Raw Flash connector Chip Memory (1 or 2 chips) There is a picture of that, here, showing room for two flash chips. http://en.wikipedia.org/wiki/File:Usbkey_internals.jpg At a data recovery firm, they can probe the flash memory chip directly, to bypass a failed controller chip. That is about the only opportunity for data recovery on a USB flash. If it is the Raw Flash chip which has failed, then your data is gone. Paul |
#3
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usb flash drive
On Nov 24, 7:11*pm, Paul wrote:
Joel727 wrote: I magnetized usb flash drive with the center of a metal candle holder which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. *If I could see the drive, I could copy the files on it. The flash chip is not affected by the state of the adjoining magnetic fields. You did not disrupt its operation when you held a magnet near it. Flash is sensitive to very high electrical fields, radiation, or perhaps UV light (only if the top of the chip was removed so light could strike it). Years ago, the ability of light to erase flashable memory, was a feature. These devices had a "window" on top, so you could erase the contents by shining a UV light on the device for 20 minutes or so. Now, flash can be erased electrically, so they no longer put a window on them like this. I used to erase trays of these under UV light in the lab. http://www.antronics.co.uk/portfolio...ram/eproms.jpg ******* If you use a degaussing coil to remove the residual magnetism, that could induce an AC voltage on some of the conductors. I don't see a particularly good reason to be using a degaussing coil on it. So that would be a needless risk. A degaussing coil will not revive the flash. Flash memory can be damaged by static electricity. Maybe that is what broke it. Or, perhaps one of the four conductors leading to the USB connector, is cracked. And that electrical connection failure is what is preventing it from working. Many flash sticks are poorly designed, such that if any force is applied to the metal connector on the end, it can cause a connection to crack and fail. The flash is usually separated into at least two chips. The design looks like this. Small capacity devices have one Flash chip, while higher capacity ones can hold two. * * *USB ------------- Controller ----- Raw Flash * * *connector * * * * Chip * * * * * * Memory (1 or 2 chips) There is a picture of that, here, showing room for two flash chips. http://en.wikipedia.org/wiki/File:Usbkey_internals.jpg At a data recovery firm, they can probe the flash memory chip directly, to bypass a failed controller chip. That is about the only opportunity for data recovery on a USB flash. If it is the Raw Flash chip which has failed, then your data is gone. * * Paul Thank you It is the data on the device, not the cost of the device. The USB drive is a 64Mb Lexar jump drive. I am going use a compass to check the strength of the magnetic field from the drive. I am thinking of using my tape head de-magnetizer device that I used to use for my the reel to reel tape recorder, this is the smaller probe device, not the large device for erasing entire reels. The files on it are important, particularly the MS Excel file with all my passwords. I will be doing a better job of backing up copies from now on. |
#4
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usb flash drive
On Nov 24, 7:11*pm, Paul wrote:
Joel727 wrote: I magnetized usb flash drive with the center of a metal candle holder which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. *If I could see the drive, I could copy the files on it. The flash chip is not affected by the state of the adjoining magnetic fields. You did not disrupt its operation when you held a magnet near it. Flash is sensitive to very high electrical fields, radiation, or perhaps UV light (only if the top of the chip was removed so light could strike it). Years ago, the ability of light to erase flashable memory, was a feature. These devices had a "window" on top, so you could erase the contents by shining a UV light on the device for 20 minutes or so. Now, flash can be erased electrically, so they no longer put a window on them like this. I used to erase trays of these under UV light in the lab. http://www.antronics.co.uk/portfolio...ram/eproms.jpg ******* If you use a degaussing coil to remove the residual magnetism, that could induce an AC voltage on some of the conductors. I don't see a particularly good reason to be using a degaussing coil on it. So that would be a needless risk. A degaussing coil will not revive the flash. Flash memory can be damaged by static electricity. Maybe that is what broke it. Or, perhaps one of the four conductors leading to the USB connector, is cracked. And that electrical connection failure is what is preventing it from working. Many flash sticks are poorly designed, such that if any force is applied to the metal connector on the end, it can cause a connection to crack and fail. The flash is usually separated into at least two chips. The design looks like this. Small capacity devices have one Flash chip, while higher capacity ones can hold two. * * *USB ------------- Controller ----- Raw Flash * * *connector * * * * Chip * * * * * * Memory (1 or 2 chips) There is a picture of that, here, showing room for two flash chips. http://en.wikipedia.org/wiki/File:Usbkey_internals.jpg At a data recovery firm, they can probe the flash memory chip directly, to bypass a failed controller chip. That is about the only opportunity for data recovery on a USB flash. If it is the Raw Flash chip which has failed, then your data is gone. * * Paul I will check for cracks and breaks on the connectors on the Lexar 64mb jump drive, one data recovery company thought they could recover the data with a cost of $250-$400. I can not justify spending that much, making backup copies is now in order. |
#5
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usb flash drive
Joel727 wrote:
On Nov 24, 7:11 pm, Paul wrote: Joel727 wrote: I magnetized usb flash drive with the center of a metal candle holder which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. If I could see the drive, I could copy the files on it. The flash chip is not affected by the state of the adjoining magnetic fields. You did not disrupt its operation when you held a magnet near it. Flash is sensitive to very high electrical fields, radiation, or perhaps UV light (only if the top of the chip was removed so light could strike it). Years ago, the ability of light to erase flashable memory, was a feature. These devices had a "window" on top, so you could erase the contents by shining a UV light on the device for 20 minutes or so. Now, flash can be erased electrically, so they no longer put a window on them like this. I used to erase trays of these under UV light in the lab. http://www.antronics.co.uk/portfolio...ram/eproms.jpg ******* If you use a degaussing coil to remove the residual magnetism, that could induce an AC voltage on some of the conductors. I don't see a particularly good reason to be using a degaussing coil on it. So that would be a needless risk. A degaussing coil will not revive the flash. Flash memory can be damaged by static electricity. Maybe that is what broke it. Or, perhaps one of the four conductors leading to the USB connector, is cracked. And that electrical connection failure is what is preventing it from working. Many flash sticks are poorly designed, such that if any force is applied to the metal connector on the end, it can cause a connection to crack and fail. The flash is usually separated into at least two chips. The design looks like this. Small capacity devices have one Flash chip, while higher capacity ones can hold two. USB ------------- Controller ----- Raw Flash connector Chip Memory (1 or 2 chips) There is a picture of that, here, showing room for two flash chips. http://en.wikipedia.org/wiki/File:Usbkey_internals.jpg At a data recovery firm, they can probe the flash memory chip directly, to bypass a failed controller chip. That is about the only opportunity for data recovery on a USB flash. If it is the Raw Flash chip which has failed, then your data is gone. Paul I will check for cracks and breaks on the connectors on the Lexar 64mb jump drive, one data recovery company thought they could recover the data with a cost of $250-$400. I can not justify spending that much, making backup copies is now in order. Well, all I can tell you is, the magnetism didn't do it. One of the other failure modes must be responsible. If it is the purchase price of the Lexar that is the concern, does Lexar have a warranty at all ? Do you still have the purchase receipt ? In the article here, the "Floating Gate" section describes how your data is stored. http://en.wikipedia.org/wiki/Flash_memory "Because the FG [floating gate] is electrically isolated by its insulating layer, any electrons placed on it are trapped there and, under normal conditions, will not discharge for many years." So the information is an electrical charge, which has no way to escape from the gate electrode, on each memory bit. That is how the info is stored. Waving a magnet around, still doesn't provide a way for the electrons to leave the floating gate. Paul |
#6
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usb flash drive
On Nov 25, 12:33*pm, Paul wrote:
Joel727 wrote: On Nov 24, 7:11 pm, Paul wrote: Joel727 wrote: I magnetized usb flash drive with the center of a metal candle holder which was magnetic. How do I un-magnetize my usb flash drive? This action was an error on my part, forgetting that the center of dish was magnetic. The drive can not be seen by any of the 5 computers I tried it on, this means not lights are on, in the usb jump drive. *If I could see the drive, I could copy the files on it. The flash chip is not affected by the state of the adjoining magnetic fields. You did not disrupt its operation when you held a magnet near it. Flash is sensitive to very high electrical fields, radiation, or perhaps UV light (only if the top of the chip was removed so light could strike it). Years ago, the ability of light to erase flashable memory, was a feature. These devices had a "window" on top, so you could erase the contents by shining a UV light on the device for 20 minutes or so. Now, flash can be erased electrically, so they no longer put a window on them like this. I used to erase trays of these under UV light in the lab. http://www.antronics.co.uk/portfolio...ram/eproms.jpg ******* If you use a degaussing coil to remove the residual magnetism, that could induce an AC voltage on some of the conductors. I don't see a particularly good reason to be using a degaussing coil on it. So that would be a needless risk. A degaussing coil will not revive the flash. Flash memory can be damaged by static electricity. Maybe that is what broke it. Or, perhaps one of the four conductors leading to the USB connector, is cracked. And that electrical connection failure is what is preventing it from working. Many flash sticks are poorly designed, such that if any force is applied to the metal connector on the end, it can cause a connection to crack and fail. The flash is usually separated into at least two chips. The design looks like this. Small capacity devices have one Flash chip, while higher capacity ones can hold two. * * *USB ------------- Controller ----- Raw Flash * * *connector * * * * Chip * * * * * * Memory (1 or 2 chips) There is a picture of that, here, showing room for two flash chips. http://en.wikipedia.org/wiki/File:Usbkey_internals.jpg At a data recovery firm, they can probe the flash memory chip directly, to bypass a failed controller chip. That is about the only opportunity for data recovery on a USB flash. If it is the Raw Flash chip which has failed, then your data is gone. * * Paul I will check for cracks and breaks on the connectors on the Lexar 64mb jump drive, one data recovery company thought they could recover the data with a cost of $250-$400. *I can not justify spending that much, making backup copies is now in order. Well, all I can tell you is, the magnetism didn't do it. One of the other failure modes must be responsible. If it is the purchase price of the Lexar that is the concern, does Lexar have a warranty at all ? Do you still have the purchase receipt ? In the article here, the "Floating Gate" section describes how your data is stored. http://en.wikipedia.org/wiki/Flash_memory * * "Because the FG [floating gate] is electrically isolated by its * * *insulating layer, any electrons placed on it are trapped there and, * * *under normal conditions, will not discharge for many years." So the information is an electrical charge, which has no way to escape from the gate electrode, on each memory bit. That is how the info is stored. Waving a magnet around, still doesn't provide a way for the electrons to leave the floating gate. * * Paul thanks again I just checked, no magnetic field - the compass needle does not move. I checked the four conductors for cracks after cutting the metal cover off the top half of the end of the device. No cracks, I just place clear tape over the four conductors for the same effect as a worn credit card, no go. I then placed a 2nd piece of clear tape, still no light on in the usb drive, I also opened my computer window and refreshed several times. I will connect a USB cable. This drive is too old no warranty, I did talk to Lexar once, maybe I should call them again for a different opinion that the first person. thanks again |
#7
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usb flash drive
On Wed, 25 Nov 2009 10:52:57 -0800 (PST), Joel727
wrote: thanks again I just checked, no magnetic field - the compass needle does not move. I checked the four conductors for cracks after cutting the metal cover off the top half of the end of the device. No cracks, I just place clear tape over the four conductors for the same If you place clear tape over the USB connector contacts, you're insulating them. This definitely will prevent the flash drive from working. effect as a worn credit card, no go. I then placed a 2nd piece of clear tape, still no light on in the usb drive, I also opened my computer window and refreshed several times. I will connect a USB cable. This drive is too old no warranty, I did talk to Lexar once, maybe I should call them again for a different opinion that the first person. thanks again |
#8
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usb flash drive
On Nov 25, 4:37*pm, Andy wrote:
On Wed, 25 Nov 2009 10:52:57 -0800 (PST), Joel727 wrote: thanks again * * *I just checked, no magnetic field - the compass needle does not move. *I checked the four conductors for cracks after cutting the metal cover off the top half of the end of the device. *No cracks, I just place clear tape over the four conductors for the same If you place clear tape over the USB connector contacts, you're insulating them. This definitely will prevent the flash drive from working. effect as a worn credit card, no go. I then placed a 2nd piece of clear tape, still no light on in the usb drive, I also opened my computer window and refreshed several times. I will connect a USB cable. *This drive is too old no warranty, I did talk to Lexar once, maybe I should call them again for a different opinion that the first person. * * thanks again Okay I will remove the tape |
#9
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usb flash drive
On Nov 29, 10:32*am, Joel727 wrote:
On Nov 25, 4:37*pm, Andy wrote: On Wed, 25 Nov 2009 10:52:57 -0800 (PST), Joel727 wrote: thanks again * * *I just checked, no magnetic field - the compass needle does not move. *I checked the four conductors for cracks after cutting the metal cover off the top half of the end of the device. *No cracks, I just place clear tape over the four conductors for the same If you place clear tape over the USB connector contacts, you're insulating them. This definitely will prevent the flash drive from working. effect as a worn credit card, no go. I then placed a 2nd piece of clear tape, still no light on in the usb drive, I also opened my computer window and refreshed several times. I will connect a USB cable. *This drive is too old no warranty, I did talk to Lexar once, maybe I should call them again for a different opinion that the first person. * * thanks again Okay I will remove the tape I did remove the clear tape, looks like the usb drive is not going to work. |
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