Need USB card with enough power for external hard drive
in [Laptops]
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From: mike on 23 May 2010 15:05 Carl wrote: > On May 23, 12:37 pm, Roger Mills <watt.ty...(a)gmail.com> wrote: >> On 23/05/2010 16:58, Carl wrote: >> >> >> >>> I have an HT-Link Cardbus/PCMCIA USB 2.0 2-port card (NEC / 32-bit). >>> My external hard drive w/USB adapter won't work with it, and it will >>> work plugged directly into a USB port on a different laptop. (My USB >>> ports got fried.) I got the card off E-Bay. My MP3 player works >>> plugged into that card. The drivers for the card say "Known >>> limitations: High Speed Isochronus, USB Composite Devices." (No other >>> details provided.) I don't know if the hard drive adapter is >>> "isochronous" or "composite." I've read there are problems with too >>> little power being supplied to the drive. The cable to the drive has >>> two USB plugs on one end, and it doesn't make any difference if I plug >>> both of them into the Cardbus card. >>> What card should I get? I see many different brands on E-Bay. I need >>> one that supplies sufficient power for an external hard drive, and >>> doesn't have any "known limitations" in the way. >> The cardbus card probably *can't* supply enough power unless there's a >> way of getting power to it from another source. I have a 4 x USB2 port >> cardbus card made by Pluscom which has a little power socket on the >> front in addition to the USB ports. It comes with a lead which plugs >> into a normal USB port just for the purpose of supplying power to the card. >> >> Do you have any other source of power for USB devices, such as a >> USB-based mobile phone charger? If so, you could try plugging one of the >> drive's plugs into *that* - which may solve the problem. >> -- >> Cheers, >> Roger >> ____________ >> Please reply to Newsgroup. Whilst email address is valid, it is seldom >> checked. > > The card has a hole in between the two USB port for a plug, but the > card didn't come with a cable. I checked E-bay. I could get a new > card that comes with a cable for the same price as just a cable. A USB1 port is limited to about 100mA. A usb2 port is limited to about 500mA. Actual computer implementations vary all over the map. Some just current limit and recover gracefully. I had one laptop that plain shut off the usb ports until I rebooted. An external hard drive can pull upwards of 1AMP depending on the model. Plugging an external hard drive into a laptop is a good way to FRY the ports. The reason they give you two usb connectors is so you can plug them in and get an amp total. But this can force one of the ports to current limit. That overstresses the current limit device and causes it to fail over time. Cardbus usb cards come in many variants. Some will run a hard drive even though they EXCEED the design limits of your laptp and can cause problems. Others just won't run the drive. I have one card that has ZERO 5V output until you run a cable from the hole in the card to a usb port or mouse port for power. External hard drive enclosures come in many variants. Many of the newer ones have no capability to add external power. Depending on the hard drive inside, you may or may not be able to run if from a laptop. They'll usually run from a desktop usb2 port. Or better yet, a powered hub. Older drive enclosures have a 5V power input so you can plug in a wall wart and they work fine. But they also have problems. The designers saved money by hooking the external 5V directly to the 5V usb line. Although it's bad, bad, bad practice, it works most of the time. Problem is when you turn off the laptop and the external drive tries to supply 5V back thru the usb port. This can cause significant destruction of the usb port, the hard drive as it thrashes trying to power up, etc. Another thing they do is use two diodes to isolate the two power supplies. That fixes the power problem, but now, you have less than 5V and the hard drive may have trouble running. I've addressed the problem three ways. Use a powered hub. That works, but depending on your OS and the hub, there may be problems with some software or hardware. I took a usb extension cable, cut the power wire and spliced in 5V from a regulated wall wart to power the drive. I'm very careful to start the laptop before plugging in the drive and removing the drive before shutting down the laptop. If your drive enclosure has an external power input, you don't need the modified wire. I had a laptop that I used as a permanent mp3 player. I modified the docking station by rewiring power for one usb port thru a fuse to the keyboard/mouse power socket. Risky in general, but ok for a dedicated application. So, why do you need the external drive anyway. Internal hard drives are huge these days. USB flash drives are BIG. If you blew the ports, you can get a flash reader that plugs into the cardbus slot. You can transfer files via the network connection. The backup problem is solved by having a small 8-16GB C partitoin and backing it up to the D partition. Then move the files to archive storage via the network of flash memory.
From: BillW50 on 23 May 2010 17:21 On 5/23/2010 2:05 PM, mike wrote on Sun, 23 May 2010 12:05:23 -0700: > Plugging an external hard drive into a laptop is a good way to FRY the > ports. According to the USB specs, that isn't supposed to happen. As the specs say it should be designed to stop supplying power if the device wants more than 500ma for USB2. And when the load is removed, it is supposed to automatically supply power once again. But we both know it doesn't work that way in real life. I have two USB2 DVD drives from China that will shutdown my Asus EeePC netbooks if they are up and running. Oh they instantly reboot in a flash, but everything you were doing was lost. If you connect them up before turning on the netbooks, it isn't a problem. Even using only one USB for power. On my four Gateway laptops, this isn't a problem at all. Even these two devices you can suck lots of power if you want too. And they just don't care. Since they all have 4 USB2 ports, my guess that they allow all four or just one alone to suck up to 2 amps of power before they complain. USB ports are supposed to power down if the computer is off. Although this isn't true with my Asus netbooks either. As if it has AC power, they are always live. Only on battery power do they shutdown power on the USB ports. I am sure others might have other variations as well. And I would love to hear what they are. As there is supposed to be one standard. But we know better that not all follow it. -- Bill Thunderbird Portable 3.0 (20091130)
From: BillW50 on 23 May 2010 17:41 On 5/23/2010 2:05 PM, mike wrote on Sun, 23 May 2010 12:05:23 -0700: > The backup problem is solved by having a small 8-16GB C partitoin > and backing it up to the D partition. Then move the files to archive > storage via the network of flash memory. Are you sure that is necessary? As I really like having the whole drive partitioned as Drive C. The reason for this is because it makes sense to have all of the room you want without partitions splitting it up for you. And most backup programs you can select which files and folders you want to save anyway. So if you rather make separate backups of your data separate from the OS, it isn't really a problem. Heck I used to use BartPE to just copy files and folders to do a whole backup too. Worked great except for MS Works v8 which would be broken if you restored everything back. I don't know why this was as I never figured it out? My guess was copying from NTFS to FAT32 broke it. I didn't use MS Works much anyway and I have most of the versions of it. Mostly since it came with most of the computers I bought anyway. -- Bill Thunderbird Portable 3.0 (20091130)
From: Carl on 23 May 2010 18:25 On May 23, 3:05 pm, mike <spam...(a)go.com> wrote: > Carl wrote: > > On May 23, 12:37 pm, Roger Mills <watt.ty...(a)gmail.com> wrote: > >> On 23/05/2010 16:58, Carl wrote: > > >>> I have an HT-Link Cardbus/PCMCIA USB 2.0 2-port card (NEC / 32-bit). > >>> My external hard drive w/USB adapter won't work with it, and it will > >>> work plugged directly into a USB port on a different laptop. (My USB > >>> ports got fried.) I got the card off E-Bay. My MP3 player works > >>> plugged into that card. The drivers for the card say "Known > >>> limitations: High Speed Isochronus, USB Composite Devices." (No other > >>> details provided.) I don't know if the hard drive adapter is > >>> "isochronous" or "composite." I've read there are problems with too > >>> little power being supplied to the drive. The cable to the drive has > >>> two USB plugs on one end, and it doesn't make any difference if I plug > >>> both of them into the Cardbus card. > >>> What card should I get? I see many different brands on E-Bay. I need > >>> one that supplies sufficient power for an external hard drive, and > >>> doesn't have any "known limitations" in the way. > >> The cardbus card probably *can't* supply enough power unless there's a > >> way of getting power to it from another source. I have a 4 x USB2 port > >> cardbus card made by Pluscom which has a little power socket on the > >> front in addition to the USB ports. It comes with a lead which plugs > >> into a normal USB port just for the purpose of supplying power to the card. > > >> Do you have any other source of power for USB devices, such as a > >> USB-based mobile phone charger? If so, you could try plugging one of the > >> drive's plugs into *that* - which may solve the problem. > >> -- > >> Cheers, > >> Roger > >> ____________ > >> Please reply to Newsgroup. Whilst email address is valid, it is seldom > >> checked. > > > The card has a hole in between the two USB port for a plug, but the > > card didn't come with a cable. I checked E-bay. I could get a new > > card that comes with a cable for the same price as just a cable. > > A USB1 port is limited to about 100mA. A usb2 port is limited to about > 500mA. Actual computer implementations vary all over the map. > Some just current limit and recover gracefully. I had one laptop that > plain shut off the usb ports until I rebooted. > > An external hard drive can pull upwards of 1AMP depending on the model. > > Plugging an external hard drive into a laptop is a good way to FRY the > ports. > > The reason they give you two usb connectors is so you can plug them in > and get an amp total. But this can force one of the ports to current > limit. That overstresses the current limit device and causes it to fail > over time. > > Cardbus usb cards come in many variants. Some will run a hard drive > even though they EXCEED the design limits of your laptp and can cause > problems. Others just won't run the drive. I have one card that has > ZERO 5V output until you run a cable from the hole in the card to > a usb port or mouse port for power. > > External hard drive enclosures come in many variants. Many of the newer > ones have no capability to add external power. Depending on the hard > drive inside, you may or may not be able to run if from a laptop. > They'll usually run from a desktop usb2 port. Or better yet, a powered hub. > Older drive enclosures have a 5V power input so you can plug in a wall > wart and they work fine. But they also have problems. The designers > saved money by hooking the external 5V directly to the 5V usb line. > Although it's bad, bad, bad practice, it works most of the time. > Problem is when you turn off the laptop and the external drive > tries to supply 5V back thru the usb port. This can cause significant > destruction of the usb port, the hard drive as it thrashes trying to > power up, etc. > Another thing they do is use two diodes to isolate the two power > supplies. That fixes the power problem, but now, you have less than > 5V and the hard drive may have trouble running. > > I've addressed the problem three ways. > > Use a powered hub. That works, but depending on your OS and the hub, > there may be problems with some software or hardware. > > I took a usb extension cable, cut the power wire and spliced in 5V > from a regulated wall wart to power the drive. I'm very careful to > start the laptop before plugging in the drive and removing the drive > before shutting down the laptop. If your drive enclosure has > an external power input, you don't need the modified wire. > > I had a laptop that I used as a permanent mp3 player. I modified the > docking station by rewiring power for one usb port thru a fuse to the > keyboard/mouse power socket. Risky in general, but ok for a dedicated > application. > > So, why do you need the external drive anyway. Internal hard drives > are huge these days. USB flash drives are BIG. If you blew the ports, > you can get a flash reader that plugs into the cardbus slot. You can > transfer files via the network connection. > > The backup problem is solved by having a small 8-16GB C partitoin > and backing it up to the D partition. Then move the files to archive > storage via the network of flash memory. The USB cable has two USB plugs on one end, and one of those is on a thinner cable (after the "Y"). Someone told me that other plug was for attaching another USB device (so you can attach two devices to one USB port on your computer), but I thought it was for more power, like you are saying. I might be interested in cutting that 2nd one off, and wiring it to a 5 volt/500MA wall plug (do you know a good source?). I'm not an electrician - I want to use the right wires and get the polarity right. Do you have any additional tips? Which wires in the USB cable to use? BTW - I ALWAYS plug in the external hard drive AFTER the computer is on, and I ALWAYS use "safely remove hardware" before unplugging it, and I NEVER turn the computer off with it plugged in.
From: mike on 23 May 2010 20:14
Carl wrote: > On May 23, 3:05 pm, mike <spam...(a)go.com> wrote: >> Carl wrote: >>> On May 23, 12:37 pm, Roger Mills <watt.ty...(a)gmail.com> wrote: >>>> On 23/05/2010 16:58, Carl wrote: >>>>> I have an HT-Link Cardbus/PCMCIA USB 2.0 2-port card (NEC / 32-bit). >>>>> My external hard drive w/USB adapter won't work with it, and it will >>>>> work plugged directly into a USB port on a different laptop. (My USB >>>>> ports got fried.) I got the card off E-Bay. My MP3 player works >>>>> plugged into that card. The drivers for the card say "Known >>>>> limitations: High Speed Isochronus, USB Composite Devices." (No other >>>>> details provided.) I don't know if the hard drive adapter is >>>>> "isochronous" or "composite." I've read there are problems with too >>>>> little power being supplied to the drive. The cable to the drive has >>>>> two USB plugs on one end, and it doesn't make any difference if I plug >>>>> both of them into the Cardbus card. >>>>> What card should I get? I see many different brands on E-Bay. I need >>>>> one that supplies sufficient power for an external hard drive, and >>>>> doesn't have any "known limitations" in the way. >>>> The cardbus card probably *can't* supply enough power unless there's a >>>> way of getting power to it from another source. I have a 4 x USB2 port >>>> cardbus card made by Pluscom which has a little power socket on the >>>> front in addition to the USB ports. It comes with a lead which plugs >>>> into a normal USB port just for the purpose of supplying power to the card. >>>> Do you have any other source of power for USB devices, such as a >>>> USB-based mobile phone charger? If so, you could try plugging one of the >>>> drive's plugs into *that* - which may solve the problem. >>>> -- >>>> Cheers, >>>> Roger >>>> ____________ >>>> Please reply to Newsgroup. Whilst email address is valid, it is seldom >>>> checked. >>> The card has a hole in between the two USB port for a plug, but the >>> card didn't come with a cable. I checked E-bay. I could get a new >>> card that comes with a cable for the same price as just a cable. >> A USB1 port is limited to about 100mA. A usb2 port is limited to about >> 500mA. Actual computer implementations vary all over the map. >> Some just current limit and recover gracefully. I had one laptop that >> plain shut off the usb ports until I rebooted. >> >> An external hard drive can pull upwards of 1AMP depending on the model. >> >> Plugging an external hard drive into a laptop is a good way to FRY the >> ports. >> >> The reason they give you two usb connectors is so you can plug them in >> and get an amp total. But this can force one of the ports to current >> limit. That overstresses the current limit device and causes it to fail >> over time. >> >> Cardbus usb cards come in many variants. Some will run a hard drive >> even though they EXCEED the design limits of your laptp and can cause >> problems. Others just won't run the drive. I have one card that has >> ZERO 5V output until you run a cable from the hole in the card to >> a usb port or mouse port for power. >> >> External hard drive enclosures come in many variants. Many of the newer >> ones have no capability to add external power. Depending on the hard >> drive inside, you may or may not be able to run if from a laptop. >> They'll usually run from a desktop usb2 port. Or better yet, a powered hub. >> Older drive enclosures have a 5V power input so you can plug in a wall >> wart and they work fine. But they also have problems. The designers >> saved money by hooking the external 5V directly to the 5V usb line. >> Although it's bad, bad, bad practice, it works most of the time. >> Problem is when you turn off the laptop and the external drive >> tries to supply 5V back thru the usb port. This can cause significant >> destruction of the usb port, the hard drive as it thrashes trying to >> power up, etc. >> Another thing they do is use two diodes to isolate the two power >> supplies. That fixes the power problem, but now, you have less than >> 5V and the hard drive may have trouble running. >> >> I've addressed the problem three ways. >> >> Use a powered hub. That works, but depending on your OS and the hub, >> there may be problems with some software or hardware. >> >> I took a usb extension cable, cut the power wire and spliced in 5V >> from a regulated wall wart to power the drive. I'm very careful to >> start the laptop before plugging in the drive and removing the drive >> before shutting down the laptop. If your drive enclosure has >> an external power input, you don't need the modified wire. >> >> I had a laptop that I used as a permanent mp3 player. I modified the >> docking station by rewiring power for one usb port thru a fuse to the >> keyboard/mouse power socket. Risky in general, but ok for a dedicated >> application. >> >> So, why do you need the external drive anyway. Internal hard drives >> are huge these days. USB flash drives are BIG. If you blew the ports, >> you can get a flash reader that plugs into the cardbus slot. You can >> transfer files via the network connection. >> >> The backup problem is solved by having a small 8-16GB C partitoin >> and backing it up to the D partition. Then move the files to archive >> storage via the network of flash memory. > > The USB cable has two USB plugs on one end, and one of those is on a > thinner cable (after the "Y"). Someone told me that other plug was > for attaching another USB device (so you can attach two devices to one > USB port on your computer), but I thought it was for more power, like > you are saying. You can tell if it's a plug or a socket. I've only seen ones with two plugs. I might be interested in cutting that 2nd one off, > and wiring it to a 5 volt/500MA wall plug (do you know a good > source?). You don't want a 500mA wall plug. You want at least an amp Don't cut the cable, get a wall wart with a usb socket in it designed to do exactly what you need. You can get on at any computer store. Or for cheap if you order it out of china. Check ebay. I'm not an electrician - I want to use the right wires and > get the polarity right. Do you have any additional tips? Just buy one, they're cheap. Which wires > in the USB cable to use? BTW - I ALWAYS plug in the external hard > drive AFTER the computer is on, and I ALWAYS use "safely remove > hardware" before unplugging it, and I NEVER turn the computer off with > it plugged in. That's what I said until about the third time I did it and the laptop internal hard drive started banging itself against the stops. Now, I just admit that I don't always do everything right. |