TechSpot

External USB disk not recognized

By pinkfloydforeve
Jan 5, 2007
  1. First of all, I'm new. Hello everybody and a have Great New Year.
    Reading some posts in forums, I believe my problem is very common.
    But I can't solve it.
    I had an external case USB (2,5 without ext AC power) with HD 80 Gb. My old notebook Asus was short in HD so I used Acronis True Image to clone internal disk on external one, flagging "maintain old drive".
    Then I opened the cases and I put the ext.disk inside and viceversa.
    The Asus is OK.
    But the ext case is no more recognized by PC.
    When i plug in the USB cable, the disk run, PC tell me I've connected an USB dev., Device Mgr see the device (hard disk Hitachi bla bla), device flag is green, but Disk Mgt does not see it.
    I tried TestDisk Utility to search for disk repairing: TestDisk sees the disk but does not see any partition any more.
    I tried to use MBR write option in Test Disk or Partition Table rewrite option, but TestDisk says it can't read or write MBR and Partition Table.
    Please help
    I'd like to store the disk (it contain the original OS, if something goes wrong with the new disk installed ...)
    Thank you
    Bye
     
  2. Ididmyc600

    Ididmyc600 TechSpot Chancellor Posts: 2,251

    Hi Pinkfloydforeve and welcome to the TS Forum

    I recently acquired a USB to IDE adaptor for work purposes, of course I took it home and played with it, it worked OK with a 20 and a 40 GB laptop drive, but did exactly the same thing as yours when I tried an 80GB 3.5" drive, figuring it to be a size issue I asked a collegue, who scratched his head (splinters) and said that he had no problems, in the end it was because the drive was set as CABLE SELECT, once set to Master the drive was seen in Disk management and I was able to format it Ok...

    Is there jumpers on the drive you have put in the case, if so take them off or see if there is any legend to say how to set it to master...

    Regards
     
  3. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,942   +167

    Ididmyc600 is correct,
    also you might need to supply a +5 volt source to your external enclosure. I can run a 30GB notebook hard drive without using external power, but my 100GB notebook drive has to have external +5 volts applied inorder to be detected. The external +5 volts comes from an adapter from the keyboard port to the hard drive enclosure
     
  4. pinkfloydforeve

    pinkfloydforeve TS Rookie Topic Starter

    I'm quite sure that the jumper settings are on Master (I downloaded the data sheet of Hitachi 20 Gb drive). Maybe, for some strange reasons even if the previous disk in the case (a Toshiba 80 Gb) was on Master too, now it prefers Cable Select or Slave ...
    Unfortunately, I have only jumpers for 3,5 disk and with those ones I can't connect the circuit on back of disk.
    I'll try to search for 2,5 jumpers to do some test.
    Thanks
    Bye

    Tmagic650 says
    "Ididmyc600 is correct,
    also you might need to supply a +5 volt source to your external enclosure. I can run a 30GB notebook hard drive without using external power, but my 100GB notebook drive has to have external +5 volts applied inorder to be detected. The external +5 volts comes from an adapter from the keyboard port to the hard drive enclosure"

    Maybe also this could be the problem.
    Both disks require +5 V. But previous working hd in the case was a Toshiba 80 Gb with 4.5 W Peak/Maximum on Start, while the Hitachi 20 Gb I installed now wants 4,7 W Peak/Maximum on Start. Maybe the couple USB Port/Case can't give 0,2 W more.
    Another try will be to search for a case with indipendent power.
    Thanks
    Bye
     
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