can mbp power usb ext drive

Discussion in 'MacBook Pro' started by Gokhan, Sep 30, 2006.

  1. Gokhan macrumors 6502a

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    Oct 7, 2003
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    London
    #1
    hi ppl

    well i just discovered like many others that my powerbook g4 rev d will not power up a external usb 2.5 harddrive enclosure via a single usb port !!

    This is a known problem according to macintouch because the pb can only supply 5v max via usb where as an ibook can supply more and usb hardrdives function fine with it !!!

    I know because this enclosure worked fine on that machine (ibook g4) !!

    anyway my question is can the macbook pro power usb hard drives via a single usb port leaveing the other usb port spare for data or does it suffer from the same issue as the powerbook ???

    I have called apple and they claim that they dont know of this problem which is b.s as its all over the net (google powerbook usb issues)

    can someone with a macbook pro test to see whether it can power up a usb harddrive through one usb port ???

    I cant even use a splitter cable because then i have no more usb ports to use for data as both ports are occupied trying to power the thing up !!!

    i used to use my ibook on my travels (student) but thats sold now so if the mbp doesnt have this problem then i will demand my pb get replaced for a mbp as these machines (pb) are supposed to be portable not disabled and what the fk the ibook can perform this function while a high end pro machine cant ???

    come on apple !!!!
     
  2. Temujin macrumors 6502a

    Temujin

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  3. Gokhan thread starter macrumors 6502a

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    #3
    k

    thank you soo much !!!!

    looks like apple owe me a mbp fast !!!!
     
  4. miles01110 macrumors Core

    miles01110

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    #4
    Um, a hard drive consumes a lot of power for a USB port to handle honestly. I'm not sure what the specs are for the powered USB ports on the MBP, but it's not unreasonable that Apple did away with that feature to increase battery life.
     
  5. Bill Gates macrumors 68020

    Bill Gates

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    #5
    That should be for the user, not Apple, to decide.
     
  6. Sun Baked macrumors G5

    Sun Baked

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    May 19, 2002
    #6
    Important: Peripherals such as PCMCIA cards and USB devices that do not conform to the computer’s power management protocols prevent the computer from switching to sleep state and so deny the user the benefits of this energy-saving state.

    &

    http://developer.apple.com/qa/hw/hw82.html
     
  7. Gokhan thread starter macrumors 6502a

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    #7
    k

    well i already called apple so i will call again to push this matter through !!!
    it must be a problem they know about because they have corrected it in the new macbook pro's so ppl how can i get applecare to repalce my pb for a mbp seen as the pb is no good to me on my travels ???

    £1400 for a disabled product

    great :rolleyes:
     
  8. miles01110 macrumors Core

    miles01110

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    #8
    Good logic. I suppose that the user should decide how much they pay for the unit also?
     
  9. Gokhan thread starter macrumors 6502a

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    #9
    k

    the user has made the choice already !! like me !! By paying soo much over the odds for a PRO product , but that doesnt mean we as the user will expect anything less than perfect !!!!
     
  10. generik macrumors 601

    generik

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    #10
    Of course, where are you from, communist?
     
  11. Gokhan thread starter macrumors 6502a

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    #11
    k

    i seem to have hit upon something maybe ????
    when i use a 5v ac the harddrive works fine !!!!
    so the problem must be the ports not supplying the full 5v which is fckd up the thing should supply that voltage as its the spec for the usb port :mad:

    applecare for **** sake :confused:
     
  12. persep macrumors member

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    Sep 12, 2006
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    Spain
    #12
    Hi,
    it's got to do more with the current rather than the voltage.
    The USB 1.1 and 2.0 specification requires that each USB port delivers at least 500 mA of steady-state current; however the
    majority of systems provide 700 mA of steady-state current but not the 15" and 17" PowerBook. Most 2.5-inch disc drives meet this requirement only after they are
    already spinning and usually require a higher current during the initial spin-up profile. The majority of USB ports also allows for
    a higher current draw of 1000 to 1100 mA for a limited duration (instantaneous current) that allows the disc drive to spin up
    adequately. This capability varies from PC to PC and depends on a variety of factors such as the type of USB port, the USB
    controller used, the type of regulator and the type of capacitors at the host.

    You have the full explanation here http://www.seagate.com/docs/pdf/whitepaper/TP-535.pdf

    There was a post in the Apple forums from a guy from LaCie that could confirm this current limitation is to protect the laptop from external devices. Why didn't Apple use this protection scheme in their other computers beats me.

    The work around fixes are:
    - use firewire ( when the powerbook came out Apple was pro-firewire not pro-usb2)
    - use a Y usb cable, it' a usb cable with two plugs, one for data and power and the other one only for power)
    - use a selfpowered harddisk enclosure not buspowered
     
  13. sycho macrumors 6502a

    sycho

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    Oct 7, 2006
    #13
    All of those are really the best choice for a laptop. I would be careful pulling more then 250mA from a USB port, never mind 700mA, they are just not designed to source that much current. Firewire would most likely be the best option, since it can provide upto 48volts, I believe, not sure how much current, but it should also not use as much CPU time as USB.
     
  14. Sesshi macrumors G3

    Sesshi

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    #14
    My 120gb Freecom FHD-2's work flawlessly via bus power on all of the laptops I have... including the MBP.
     
  15. persep macrumors member

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    #15

    What harddrive does it come with?
     
  16. Gokhan thread starter macrumors 6502a

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    #17
    k

    yeah but why do i as a pro consumer have to suffer from fckd usb ports i know i could use firewire but again i have to fork out extra for a firewire drive ???

    nah the simple work around for me anyways is a new machine that does what i want and paid for to use the machine as a PORTABLE laptop!!!

    This is not cheap pc crap its top of line ! why should i have to compromise :mad:
     
  17. Grakkle macrumors 6502a

    Grakkle

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    Oct 6, 2006
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    Earth
    #18
    I use a Blue Snowball usb-powered mic with my macbook, and it works fine. Sucks battery power fast, though, so I usually plug in the macbook when I use it. I'd think the mic would use as much or more power than a hd.
     
  18. dukebound85 macrumors P6

    dukebound85

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    #19
    why not just plug in the harddrive to an outlet and not worry about this. that way you will for sure have enough power
     
  19. Gokhan thread starter macrumors 6502a

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    #20
    k

    well the phone call tommorow should be intresting
     
  20. persep macrumors member

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    #21
    How did it go?
     
  21. Gokhan thread starter macrumors 6502a

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    #22
    k

    the guy at apple was away and ill call next week because i want to speak with him personally but i may even just sell the powerbook on ebay if the price is right !!!

    but thats the last apple laptop for a while for me ! they are just too much high maintence

    sorry but they are :)
     
  22. persep macrumors member

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    #23
    I know what you mean. you'd expect a perfect laptop for that price and what you is nothing near it.
     
  23. Gokhan thread starter macrumors 6502a

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    #24
    k

    yep you get the elements to get the thing perfect but im just sick of having to correct apples mistake's software and hardware wise
     
  24. jtown macrumors 6502

    Joined:
    Jul 3, 2003
    #25
    Why get mad at Apple because a third party product doesn't conform to the published specifications of the USB interface? The specs are very clear. 5 volts, 500ma. If a device exceeds those specs, why rant at Apple? It doesn't make any sense. Go complain to the companies selling these external drives as "USB Powered" when the description is clearly misleading.

    Why do you think all those 2.5" USB drives have ports for power adapters? Because those manufacturers know that their devices exceed the limits of the USB specification. If the drives could work reliably on 500ma, those drives would not be designed to accept power adapters.
     

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