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Switching Power of hard drives ON and Off

Discussion in 'Electronic Repair' started by Vlad, Mar 30, 2005.

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  1. Vlad

    Vlad Guest

    Switching Power of hard drives ON and Off
    I have a few hard drives that are rarely used and in order to save the
    drives I am thinking of switching the +12 volts OFF when the drives
    are not required.
    I believe the +12 is the voltage used for the motor. If the motor
    doesn't run the drive will not be recognized by the BIOS.
    I realize the operation of those switches should only be done when the
    computer is off . I will be using toggle switches with a locking
    lever.
    Will this create any unforeseen problems?
    Thanks for the help
    Vlad
     
  2. Steve

    Steve Guest

    I question the wisdom of switching off only 12 v, and I presume
    leaving +5 v, if I understand what you are proposing.

    May I recommend this $7.95 solution?
    http://www.geeks.com/details.asp?invtid=GN210-BLK&cat=HDD

    Or I am sure you can find better quality ones from many sources.

    Alternatively, look at a USB external case for your IDE drive.
    Here is one for Firewire and/or USB. No reboot and "BIOS screwing"
    required.

    http://www.geeks.com/details.asp?invtid=DLX-185&cat=HDD

    Thanks, Steve
     
  3. Vlad

    Vlad Guest

    I am already using two USB drives and one of the drives that I want to
    stop is a serial and they don't work on the available boxes.

    Thanks

    Vlad
     
  4. I too. In general, unless the equipment specifically states that it
    is safe to switch off some of the supply voltages, I wouldn't recommend
    it. Not only might the equipment be damaged (though probably unlikely),
    but there could be peculiar behavior of anything attached to it (in this
    case, the computer).

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  5. Steve

    Steve Guest

    Vlad,

    Well, I guess I didn't have all the facts??

    Here is a USB to SATA case.
    http://www.cooldrives.com/nasadrenwiou.html
    Add a USB hub if you need to. Google helped find it.

    Or use the SATA interface directly, if the rest of your system has an
    external SATA connection. (And if it does, then there are
    cheaper SATA only external cases. Google for some.)

    Still confused as to why, then, the $7.95 solution
    won't work for one drive, which, I assume, perhaps incorrectly, is
    IDE?

    Please let "suggest" again that the 12 v switching isn't
    recommended. But maybe it will work. Prove me wrong. Report back to
    the group your results. Be sure to mention what drives you are
    talking about, exactly, since maybe what works for brand X, model Y,
    won't work for brand Z, model A. We'll all learn, which is the idea here.
    If it is a viable and universal solution, someone somewhere would
    be doing it commercially, which I'm quite unaware of.

    Good Luck and Thanks, Steve
     
  6. Ivor Floppy

    Ivor Floppy Guest

    Believe what you want - simply switching the 12V supply is asking for
    trouble. If your going to switch, you need both the +5 and the +12 supplies
    or you'll end up with a zapped drive.
    But the drive will still be connected; if the +5 is still active so would
    90% of the electronics (if drives were to work as simply as you suggest), so
    it would be recognized in the BIOS.
    Lots.
     
  7. Mark

    Mark Guest

    so what happens when windows puts the drive in power down mode...

    i think the key is you want to make sure the heads are parked before
    you spin down the disc, but you said you would only operate the switch
    when the computer is OFF.

    I say try it.

    Mark
     
  8. Ivor Floppy

    Ivor Floppy Guest

    Have a guess. I'll give you a big clue - Windows can't somehow disconnect
    the power leads to the drive.....
     
  9. So what? It's not the electronics that wear out. That may be good enough
    if you're really worried about the life of the drive.

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  10. James Sweet

    James Sweet Guest

    Why don't you just have the software spin the drive down after a period of
    inactivity?
     
  11. Franc Zabkar

    Franc Zabkar Guest

    If you disconnect the +5V supply, you may then have an improperly
    terminated IDE cable. I suspect this may cause problems with
    reflections.
    I know some drives (eg the old Quantum Fireball) make use of
    "discware", so an unreadable platter may cause the HD to be invisible
    to the BIOS.

    I also seem to recall that a HD is invisible when it fails to spin up
    due to stiction.

    - Franc Zabkar
     
  12. Franc Zabkar

    Franc Zabkar Guest

    I suspect the +12V rail merely powers the mechanical assemblies. A
    healthy +5V rail would probably guarantee the drive's sanity, and
    would probably be sufficient to ensure that the IDE interface was not
    in a "hung" state. Having said that, I wonder if any chip that expects
    dual supplies could be damaged by latchup?


    - Franc Zabkar
     
  13. Vlad

    Vlad Guest

    YES yes yes James!

    That is the best idea but unfortunately Windows XP turns off ALL
    the drive/s not only the ones we want.
    So if the XP can spin down the drives may be there is a software way
    to spin down the ones you want. It should include "serial" and
    external drives, if possible.
    If such program doesn't exist, it may be created.
    There is a need for that. If we stop the drive/s used for a backup,
    that in my case is once a week, the drive should last 5 to 7 times
    longer.
    Ideally it should control the BIOS because the hardest action on the
    drive is the starting.

    Thanks to all of you
    Vlad
     
  14. Mark

    Mark Guest

    well it does "disconnet" the drive motor because it parks the heads and
    spins it down...

    I know this "disconnect" happens within the drive itself and not within
    the power supply or the cable.

    Disconnecting the 12V probably is about the same.... IF YOU PARK THE
    HEADS FIRST!

    I suggest you test this on a drive that you don't care about first.


    Mark
     
  15. Ivor Floppy

    Ivor Floppy Guest

    Thats quite an important difference. Telling the drive to stop (as Windows
    does) means the drive *knows* its not supposed to be running, and goes into
    sleep mode waiting to be awoken.
    I doubt its anything like the same. The drive is expecting the 12V supply to
    be there - under all normal operational circumstances it would be, so
    there's no reason for the drive to have any form of protection or safety
    checking against such an event. As the drive will be assuming the 12V is
    present, it will be constantly trying to get the motor running, putting
    who-know-what strain on the motor drive circuitry.
    ... nice get out clause there....:)
     
  16. Vlad

    Vlad Guest

    I just wonder if we disable a drive on BIOS it stops it from running ?
    I don't think so. It only prevents it from being accessed,

    Vlad
     
  17. Asimov

    Asimov Guest

    "Vlad" bravely wrote to "All" (31 Mar 05 15:38:33)
    --- on the heady topic of "Re: Switching Power of hard drives ON and Off"

    Vl> From: Vlad <>
    Vl> Xref: aeinews sci.electronics.repair:44617

    Vl> I just wonder if we disable a drive on BIOS it stops it from running ?
    Vl> I don't think so. It only prevents it from being accessed,

    9cm drives for portables are like that and they only startup when the
    bios queries them. These are meant to be frugal with battery power.

    A*s*i*m*o*v

    .... New computer? But I like my vacuum tubes... They keep me warm.
     
  18. Vlad

    Vlad Guest

    That's interesting. I must try that.
    Thanks
    Vlad
     
  19. Bad idea. The heads should be parked first. Some operating systems offer the
    option of turning off the hard drive(s) after a preset time interval.

    Mark Z.
     
  20. Asimov

    Asimov Guest

    "Mark D. Zacharias" bravely wrote to "All" (02 Apr 05 05:26:33)
    --- on the heady topic of "Re: Switching Power of hard drives ON and Off"

    MDZ> From: "Mark D. Zacharias" <>
    MDZ> Xref: aeinews sci.electronics.repair:44760


    MDZ> Bad idea. The heads should be parked first. Some operating systems
    MDZ> offer the option of turning off the hard drive(s) after a preset time
    MDZ> interval.

    Mark,

    Have you forgotten that modern HD's autopark the moment the supply
    power goes off. What is a BIG problem is powering off without flushing
    the write cache. Windows is a real pig for this and is the reason why
    it needs to be shutdown before turning off the power supply. The
    lovely lost clusters left all over the HD can make a grown man cry, or
    at least tear his hair out.

    A*s*i*m*o*v

    .... New computer? But I like my vacuum tubes... They keep me warm.
     
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