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#51
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage Ant wrote:
In comp.sys.ibm.pc.hardware.storage nospam wrote: In article , Ant wrote: Fry right away or after a while? usually quickly, but it depends how much over 5v it is. chances are that unless you bought a noname charger, the usb host is within spec. Well, the USB ports are inside the computers. ;P Do they get hot in one computer but not another? -- __ __ #_ |\| | _# |
#52
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote:
In comp.sys.ibm.pc.hardware.storage Ant wrote: In comp.sys.ibm.pc.hardware.storage nospam wrote: In article , Ant wrote: Fry right away or after a while? usually quickly, but it depends how much over 5v it is. chances are that unless you bought a noname charger, the usb host is within spec. Well, the USB ports are inside the computers. ;P Do they get hot in one computer but not another? The memory sticks, that is. -- __ __ #_ |\| | _# |
#53
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote:
In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote: In comp.sys.ibm.pc.hardware.storage Ant wrote: In comp.sys.ibm.pc.hardware.storage nospam wrote: In article , Ant wrote: Fry right away or after a while? usually quickly, but it depends how much over 5v it is. chances are that unless you bought a noname charger, the usb host is within spec. Well, the USB ports are inside the computers. ;P Do they get hot in one computer but not another? The memory sticks, that is. Correct in memory sticks in all computers. -- Quote of the Week: "I really believe I've been a good person. Not perfect - forget about perfect - but just learning by what I was taught and living by my own values. I might have stepped on a few ants - and a few other things as well - but I've never hurt anybody." --Kiri Te Kanawa Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly. /\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site) / /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net | |o o| | \ _ / Please nuke ANT if replying by e-mail privately. If credit- ( ) ing, then please kindly use Ant nickname and AQFL URL/link. |
#54
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Is it me or are there many unreliable USB flash drives?
In article , Ant
wrote: In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote: In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote: In comp.sys.ibm.pc.hardware.storage Ant wrote: In comp.sys.ibm.pc.hardware.storage nospam wrote: In article , Ant wrote: Fry right away or after a while? usually quickly, but it depends how much over 5v it is. chances are that unless you bought a noname charger, the usb host is within spec. Well, the USB ports are inside the computers. ;P Do they get hot in one computer but not another? The memory sticks, that is. Correct in memory sticks in all computers. There's your problem ... "Memory Sticks" should only be used in Sony devices. ;-) |
#55
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Is it me or are there many unreliable USB flash drives?
Computer Nerd Kev wrote
nospam wrote Computer Nerd Kev wrote There are USB voltage meters sold cheaply on Ebay to show if the USB voltage from a computer is too high/low. If the USB voltage was far too high, the extra energy would cause excessive heating of the drive. if the voltage was too high, not only would it not be usb compliant, but it would likely fry anything plugged into it, which is expecting a regulated 5v. I don't mean by design (although anything's possible with Chinese knock-off stuff, if that's involved), I mean due to a failure of the computer hardware. Now the 5V at the USB ports being high would often only make sense if they were supplied by a separate line from the power supply. They are in desktops. That's the whole point of the +5V standby line. If the internal computer components and the USB ports were both subjected to a failure of the 5V voltage regulation, it would be very likely to destroy the computer without the user having any time to worry about their USB accessories. Depends on how much its out by. Certainly if its out by enough to see what normally stays at room temp get very hot when doing nothing with just the USB stick plugged in, doing nothing. Most desktop PCs have standard power supplies that provide the USB 5V from the same lines as everything else, That is just plain wrong. Its usually supplied by the +5V standby line, so you can wake the system by moving the mouse etc. so it is unlikely that an over-voltage situation would only affect the USB ports. You have that completely backwards. A laptop, however, may have a separate power supply circuit for the USB 5V. If this failed, and supplied too high a voltage, it may not sevierely affect the normal operation of the computer. In fact laptops are more likely to have a separate +5V line for the same reason. A power-boosted USB hub with a faulty or incorrectly specified mains adapter powering it could also be a culprit. the amount of current sourced is limited by what the device negotiates from the host. Current limiting only protects against an over-voltage situation if the device requires more than the minimum current limit (500mA) to be damaged. If an IC in the memory stick normally draws 20mA at 5V, it may draw 28mA at 7V (this based on rough calculations: 5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point), however the IC may only be rated to sustain 5.5V, so it may be damaged while only consuming 28mA. The rest of the components in the memory stick will also be drawing additional power, but you see that the total power draw is not increased enough to hit the 500mA maximum if the stick normally draws, say, 100mA? Another possibility, if you only ever use one USB port (or a group of similarly affected ones) for testing these memory sticks, is that a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector. Here, not only the heat, but also the coresponding reduced power to the memory stick, may induce irrecoverable write errors or other failures. unlikely. Such failures are known to occour due to strain on solder joints causing them to break, or joints that weren't correctly soldered in the first place. It is a less common failure, but it's also uncommon to consume large quantities of memory sticks. But doesn’t explain why all the sticks get hot. |
#56
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Is it me or are there many unreliable USB flash drives?
In article , Computer Nerd Kev
wrote: There are USB voltage meters sold cheaply on Ebay to show if the USB voltage from a computer is too high/low. If the USB voltage was far too high, the extra energy would cause excessive heating of the drive. if the voltage was too high, not only would it not be usb compliant, but it would likely fry anything plugged into it, which is expecting a regulated 5v. I don't mean by design (although anything's possible with Chinese knock-off stuff, if that's involved), I mean due to a failure of the computer hardware. Now the 5V at the USB ports being high would often only make sense if they were supplied by a separate line from the power supply. If the internal computer components and the USB ports were both subjected to a failure of the 5V voltage regulation, it would be very likely to destroy the computer without the user having any time to worry about their USB accessories. if the internal power supply failed then computer wouldn't work, not just the ports. Most desktop PCs have standard power supplies that provide the USB 5V from the same lines as everything else, so it is unlikely that an over-voltage situation would only affect the USB ports. exactly the point. A laptop, however, may have a separate power supply circuit for the USB 5V. If this failed, and supplied too high a voltage, it may not sevierely affect the normal operation of the computer. no. A power-boosted USB hub with a faulty or incorrectly specified mains adapter powering it could also be a culprit. no hub was used. the amount of current sourced is limited by what the device negotiates from the host. Current limiting only protects against an over-voltage situation if the device requires more than the minimum current limit (500mA) to be damaged. If an IC in the memory stick normally draws 20mA at 5V, it may draw 28mA at 7V (this based on rough calculations: 5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point), however the IC may only be rated to sustain 5.5V, so it may be damaged while only consuming 28mA. The rest of the components in the memory stick will also be drawing additional power, but you see that the total power draw is not increased enough to hit the 500mA maximum if the stick normally draws, say, 100mA? usb devices don't work that way. Another possibility, if you only ever use one USB port (or a group of similarly affected ones) for testing these memory sticks, is that a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector. Here, not only the heat, but also the coresponding reduced power to the memory stick, may induce irrecoverable write errors or other failures. unlikely. Such failures are known to occour due to strain on solder joints causing them to break, or joints that weren't correctly soldered in the first place. broken joints don't get hot. they simply don't work. It is a less common failure, but it's also uncommon to consume large quantities of memory sticks. it's not uncommon at all. memory sticks are cheap enough to be considered disposable. sometimes they're even given away for free. |
#57
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage Rod Speed wrote:
Computer Nerd Kev wrote nospam wrote Computer Nerd Kev wrote There are USB voltage meters sold cheaply on Ebay to show if the USB voltage from a computer is too high/low. If the USB voltage was far too high, the extra energy would cause excessive heating of the drive. if the voltage was too high, not only would it not be usb compliant, but it would likely fry anything plugged into it, which is expecting a regulated 5v. I don't mean by design (although anything's possible with Chinese knock-off stuff, if that's involved), I mean due to a failure of the computer hardware. Now the 5V at the USB ports being high would often only make sense if they were supplied by a separate line from the power supply. They are in desktops. That's the whole point of the +5V standby line. No it isn't. The 5V Standby line is to enable the motherboard hardware to detect when the power switch is pressed, and on many motherboards it is used to power additional functions while the computer is off as well. The Standby line was only specified to 10mA before the ATX 2.2 spec. and 2A afterwards. That means that an ATX 2.2 PSU could only supply power for four USB 2 ports at 500mA maximum output, or two USB 3 ports as 900mA maximum output. Before ATX 2.2 no USB port could have been provided with remotely enough power from a PSU meeting the 10mA 5V standby minimum requirement. http://pinouts.ru/Power/atx_v2_pinout.shtml I know some PCs supply power to USB devices when off (I find this a pain), but it's not the case in many designs, and the required use of the 5V standby line by the motherboard's circuitry means that damaging voltage on this line will affect the computer at the same time as the USB devices, leaving the user with more to worry about than just their memory sticks dying. If the internal computer components and the USB ports were both subjected to a failure of the 5V voltage regulation, it would be very likely to destroy the computer without the user having any time to worry about their USB accessories. Depends on how much its out by. Certainly if its out by enough to see what normally stays at room temp get very hot when doing nothing with just the USB stick plugged in, doing nothing. The maximum voltage ratings would probably only be known by the memory stick IC manufacturers and their clients, however 5.5V is a common design maximum. 5.25V is the maximum PSU output under the ATX specification. Most desktop PCs have standard power supplies that provide the USB 5V from the same lines as everything else, That is just plain wrong. Its usually supplied by the +5V standby line, so you can wake the system by moving the mouse etc. so it is unlikely that an over-voltage situation would only affect the USB ports. You have that completely backwards. A laptop, however, may have a separate power supply circuit for the USB 5V. If this failed, and supplied too high a voltage, it may not sevierely affect the normal operation of the computer. In fact laptops are more likely to have a separate +5V line for the same reason. A power-boosted USB hub with a faulty or incorrectly specified mains adapter powering it could also be a culprit. the amount of current sourced is limited by what the device negotiates from the host. Current limiting only protects against an over-voltage situation if the device requires more than the minimum current limit (500mA) to be damaged. If an IC in the memory stick normally draws 20mA at 5V, it may draw 28mA at 7V (this based on rough calculations: 5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point), however the IC may only be rated to sustain 5.5V, so it may be damaged while only consuming 28mA. The rest of the components in the memory stick will also be drawing additional power, but you see that the total power draw is not increased enough to hit the 500mA maximum if the stick normally draws, say, 100mA? Another possibility, if you only ever use one USB port (or a group of similarly affected ones) for testing these memory sticks, is that a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector. Here, not only the heat, but also the coresponding reduced power to the memory stick, may induce irrecoverable write errors or other failures. unlikely. Such failures are known to occour due to strain on solder joints causing them to break, or joints that weren't correctly soldered in the first place. It is a less common failure, but it's also uncommon to consume large quantities of memory sticks. But doesn?t explain why all the sticks get hot. "a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector." The socket is the bit in the computer. If the same socket/s are used, all the USB memory sticks drawing the same, or similar, currents will get hotter than normal. They will also receive less voltage than otherwise due to the voltage drop over the resistance of the failed solder joint - which is waht causes the heat. -- __ __ #_ |\| | _# |
#58
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage Ant wrote:
In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote: In comp.sys.ibm.pc.hardware.storage Computer Nerd Kev wrote: In comp.sys.ibm.pc.hardware.storage Ant wrote: In comp.sys.ibm.pc.hardware.storage nospam wrote: In article , Ant wrote: Fry right away or after a while? usually quickly, but it depends how much over 5v it is. chances are that unless you bought a noname charger, the usb host is within spec. Well, the USB ports are inside the computers. ;P Do they get hot in one computer but not another? The memory sticks, that is. Correct in memory sticks in all computers. If the USB insert preferred term sticks get hot in different computers then the failure isn't in the computer after all. unless the stress under the 5V high voltage has causes parts of them to short and now they're heating up at normal voltage, but it's unlikely that different models would all fail in that way. -- __ __ #_ |\| | _# |
#59
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Is it me or are there many unreliable USB flash drives?
In comp.sys.ibm.pc.hardware.storage nospam wrote:
In article , Computer Nerd Kev wrote: There are USB voltage meters sold cheaply on Ebay to show if the USB voltage from a computer is too high/low. If the USB voltage was far too high, the extra energy would cause excessive heating of the drive. if the voltage was too high, not only would it not be usb compliant, but it would likely fry anything plugged into it, which is expecting a regulated 5v. I don't mean by design (although anything's possible with Chinese knock-off stuff, if that's involved), I mean due to a failure of the computer hardware. Now the 5V at the USB ports being high would often only make sense if they were supplied by a separate line from the power supply. If the internal computer components and the USB ports were both subjected to a failure of the 5V voltage regulation, it would be very likely to destroy the computer without the user having any time to worry about their USB accessories. if the internal power supply failed then computer wouldn't work, not just the ports. Most desktop PCs have standard power supplies that provide the USB 5V from the same lines as everything else, so it is unlikely that an over-voltage situation would only affect the USB ports. exactly the point. A laptop, however, may have a separate power supply circuit for the USB 5V. If this failed, and supplied too high a voltage, it may not sevierely affect the normal operation of the computer. no. Yes. If the 5V supply circuit was built separately for use by the relatively high current USB devices, it's failure (in this way) would not stop the computer operating. In some cases it might (I won't spend the time spelling it out), but if no USB devices are connected, it won't. A power-boosted USB hub with a faulty or incorrectly specified mains adapter powering it could also be a culprit. no hub was used. Known now, yes. the amount of current sourced is limited by what the device negotiates from the host. Current limiting only protects against an over-voltage situation if the device requires more than the minimum current limit (500mA) to be damaged. If an IC in the memory stick normally draws 20mA at 5V, it may draw 28mA at 7V (this based on rough calculations: 5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point), however the IC may only be rated to sustain 5.5V, so it may be damaged while only consuming 28mA. The rest of the components in the memory stick will also be drawing additional power, but you see that the total power draw is not increased enough to hit the 500mA maximum if the stick normally draws, say, 100mA? usb devices don't work that way. OK, so the device can specify roughly the current it needs via the USB protocol, which if you're lucky will be respected by the computer hardware. The current specification isn't accurate enough to prevent damage though, for the reason shown above. The current increase as voltage is increased isn't great enough to trip the limiting. Another possibility, if you only ever use one USB port (or a group of similarly affected ones) for testing these memory sticks, is that a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector. Here, not only the heat, but also the coresponding reduced power to the memory stick, may induce irrecoverable write errors or other failures. unlikely. Such failures are known to occour due to strain on solder joints causing them to break, or joints that weren't correctly soldered in the first place. broken joints don't get hot. they simply don't work. Sometimes they simply form a high resistance. Look it up - dry joints. It is a less common failure, but it's also uncommon to consume large quantities of memory sticks. it's not uncommon at all. memory sticks are cheap enough to be considered disposable. sometimes they're even given away for free. As I remember it, OP figures that he's bought good ones - hence his confusion about the cause of the failure rate. -- __ __ #_ |\| | _# |
#60
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Is it me or are there many unreliable USB flash drives?
In article , Computer Nerd Kev
wrote: A laptop, however, may have a separate power supply circuit for the USB 5V. If this failed, and supplied too high a voltage, it may not sevierely affect the normal operation of the computer. no. Yes. If the 5V supply circuit was built separately for use by the relatively high current USB devices, it's failure (in this way) would not stop the computer operating. In some cases it might (I won't spend the time spelling it out), but if no USB devices are connected, it won't. usb devices are not 'relatively high current'. usb originally specified a maximum of 500ma. the usb charging spec can go to about 2a, and at 5v, is just 10w. A power-boosted USB hub with a faulty or incorrectly specified mains adapter powering it could also be a culprit. no hub was used. Known now, yes. it was known before. the amount of current sourced is limited by what the device negotiates from the host. Current limiting only protects against an over-voltage situation if the device requires more than the minimum current limit (500mA) to be damaged. If an IC in the memory stick normally draws 20mA at 5V, it may draw 28mA at 7V (this based on rough calculations: 5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point), however the IC may only be rated to sustain 5.5V, so it may be damaged while only consuming 28mA. The rest of the components in the memory stick will also be drawing additional power, but you see that the total power draw is not increased enough to hit the 500mA maximum if the stick normally draws, say, 100mA? usb devices don't work that way. OK, so the device can specify roughly the current it needs via the USB protocol, which if you're lucky will be respected by the computer hardware. luck has absolutely *nothing* to do with it. the usb spec *requires* that a usb peripheral device use *up* *to* 100ma and then negotiate higher current requirements, which the usb host can deny. anything else is not compliant with the usb spec. The current specification isn't accurate enough to prevent damage though, for the reason shown above. The current increase as voltage is increased isn't great enough to trip the limiting. no. Another possibility, if you only ever use one USB port (or a group of similarly affected ones) for testing these memory sticks, is that a high resistance in the computer's USB socket is causing the _socket_ to heat up, and the heat is being transferred to the drives themselves via the USB connector. Here, not only the heat, but also the coresponding reduced power to the memory stick, may induce irrecoverable write errors or other failures. unlikely. Such failures are known to occour due to strain on solder joints causing them to break, or joints that weren't correctly soldered in the first place. broken joints don't get hot. they simply don't work. Sometimes they simply form a high resistance. Look it up - dry joints. they're commonly called cold solder joints, and will cause a device to fail not get hot. It is a less common failure, but it's also uncommon to consume large quantities of memory sticks. it's not uncommon at all. memory sticks are cheap enough to be considered disposable. sometimes they're even given away for free. As I remember it, OP figures that he's bought good ones - hence his confusion about the cause of the failure rate. it wasn't due to heat. |
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