Rookie question about external hard drive!

Discussion in 'Mac Accessories' started by anotherjoey, Aug 18, 2012.

  1. anotherjoey macrumors member

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    Jul 28, 2012
    #1
    I recently bought an external hard drive to use with my new Macbook Air, but the cable from the hard drive has a 2-ended cord. Only one (the thick end) makes the hard drive show up on the computer, the other one just makes the hard drive blink. So to my paranoid question - is it in some ways harming for the computer or its USB to plug in the usb-end that doesn't seem to start up the drive? I hope I haven't made it slow down or anything by trying to use that cable lol. :confused:

    I did some googling and it seems that the cord that doesn't make the hard drive show up is just for power supply, so I assume it's not harming at all to have plugged that in by itself? And is it enough to just use the thick one?
     
  2. miles01110 macrumors Core

    miles01110

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    #2
    If it comes with a power supply that will be required for the drive to function at all. It doesn't harm the drive.
     
  3. anotherjoey thread starter macrumors member

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    Jul 28, 2012
    #3
    No power supply, it just gets power from the USB (it's a 2,5")

    I meant the usb-cord itself that is 2-ended on one part, where there's one thick and one thin USB plug. I plugged in the thin one but it didnt do anything besides make the hard drive blink, it didnt show up on the computer screen, so I took it out and used the thick one which worked. My question was if I might have done something to the computer OR drive by plugging in the thin cable? How was I to know..And when Will the thin one Ever be necessary?
     
  4. annk Administrator

    annk

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    #4
    I have an external optical drive with a double USB like you describe. I think it's probably to give you the possibility to send even more power to the unit. As you experienced, one of the plugs is the main plug, and one is an auxiliary for additional power.

    I don't believe you've hurt anything by plugging in the wrong one. :)
     
  5. rbrian macrumors 6502a

    rbrian

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    #5
    USB ports are not all alike. Older ones output less power to peripheral devices - enough to power a mouse or keyboard, but not enough to power a spinning hard drive or DVD burner. For this reason those peripherals often come with an additional USB cable which is used solely for power, and isn't necessary on most current computers which output more power to each USB port.

    If it works with one cable, then you don't need the other.
     
  6. CWallace macrumors 603

    CWallace

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    Seattle, WA
    #6
    So it sounds like it comes with both a Type A plug (the larger rectangular one) and a Mini-B plug (the smaller, thinner one).

    Both should support providing 5V DC at up to 500mA, but it sounds like the Mini plug might not be doing so and therefore the drive is not receiving enough power to operate normally.

    Since the Type A plug is providing sufficient power to allow the HDD to operate, you can just use it and ignore the Mini-B.
     
  7. anotherjoey thread starter macrumors member

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    Jul 28, 2012
    #7
    Thanks guys! Will continue using the cable that works :)
     
  8. abthegreat macrumors regular

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    Jun 1, 2008
    #8
    As already mention the thick one is USB + power
    if the drive didnt power up with just the thick one plugged in means you need more power which the thin one is for power only. Hence your drive didnt get recognised
     
  9. LeandrodaFL macrumors 6502a

    LeandrodaFL

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    Apr 6, 2011
    #9
    Jesus, why can no one provide the right answer?

    Friend, in order for your hdd to work properlly, you have to connect BOTH ends of the cable to the computer, thats how this specific model you got works. Period. I happen to have a similar drive, in my case, a Trasncend drive.

    Now, you may need extra usb ports in order to do that. So get a macally 7-port USB hub, they have in grey to match the macbook (and white too)
     
  10. rbrian macrumors 6502a

    rbrian

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    #10
    You're the only one that gave the wrong answer! I too have an external drive with two USB leads, and the instructions quite clearly say that only one is required if you have enough USB bus power. This is borne out by the experience of myself and many others.
     
  11. hallux macrumors 68030

    hallux

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    Apr 25, 2012
    #11
    Actually, the quote below is correct, and was posted before you.

    In the case of most current Macs, yes. In the case of some older computers (Mac or otherwise) there may not be enough power from only one port (USB 1 and USB 2 were .5A power output per device/plug IIRC). FWIW, it won't hurt to plug both in even if only one is enough. That said, I had an IDE-USB adapter with the double plug like this (for a 2.5" drive) and don't recall NEEDING the second plug often, but after a few failed attempts with just the main plug I ended up just using both.
     
  12. CWallace macrumors 603

    CWallace

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    #12
    That would be correct for this type of cable:

    [​IMG]

    Where both the black and red large plugs would connect to the Mac and the small black plug would connect to the HDD.

    However, from how the OP is describing their cable, it sounds like what they have is a large and small plug on one end (either of which can be plugged into the HDD), and a large plug on the other end (which plugs into the Mac).
     
  13. annk Administrator

    annk

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    #13
    This is the type I have on the optical drive I described. I don't have to plug in both (but it's not always stable - I assumed that was because it was cheap, but maybe it's because I actually DO need to plug in both!).
     
  14. CWallace macrumors 603

    CWallace

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    #14
    In the cable above, the large black plug provides both data and power and the large red plug provides additional power. So it would certainly not hurt to keep both the black and red plug connected to USB ports as that way if the drive needs more power, it has access to it.
     

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