Can you identify or explain these? Inductor SMD for a Hard Drive!

Discussion in 'General Electronics Chat' started by Tacklebury, Jun 10, 2009.

  1. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
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    Hi everyone.

    My first post so please be gentle.....

    I have recently added a couple of hard drives to my PC and in doing so inadvertently knocked off one of the surface mount components from the PCB!!!!

    I've found what I believe to be the correct part but now its arrived I’m not sure. I have posted on another forum specifically about HDDs but I really need the knowledge of you guys really.

    Here we go.....

    The damaged part -

    http://www.btinternet.com/~simon.gurry/DSC_6078.JPG

    From this all I know is I need a 3R3 Component!! I have researched and it appears to be a Inductor coil. So this leads me to here:

    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=513-1454-1-ND

    Then someone suggests I need one of these:

    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=445-3834-6-ND

    The second parts dimensions are too large so I’m happy that’s wrong, but my new part is approx 1-2mm thicker, its other measurements are fine......

    Can anyone shed some light on what i need the drive is a ST3320620AS Seagate 320gb Sata Drive.

    Disk Details:-

    SN - 9QF1Q83H
    ST3320620AS
    P/N - 9BJ14G - 326
    FW - 3.AAE
    DATA CODE - 07266
    SITE CODE - TK

    Any help or advice would be very gratefully received!!!

    Thanks in advanced.

    Simon
     
    Last edited: Jun 12, 2009
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    It looks like an inductor. Do you have a meter?

    If so check the damaged one against the other. You won't be able to see the value of the component, but if they have similar continuity readings, the damage may just be cosmetic.
     
  3. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
    6
    0
    I have metered it but it gives a reading i didn't expect. Now I'm no expert. The old damaged part reads, with my crappy Draper meter set to 200 under the Ohm section reads 1.0 then drops to 0.8 and slowly descends down. The new part hits 1.0 instantly then slowly drops. I was expecting to see a reading of 3.3 ohms????

    Or am i being stupid!
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    No, an inductor only has a resistance (termed a reactance) when subjected to an AC voltage. Your changing conduction is probably due to a capacitor charging. The inductors may be functioning as a hash filter to keep motor noise out of the power line.

    Have you tried the drive? If the inductor passes current, it may only be cosmetically damaged.
     
  5. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
    6
    0
    Firstly, beenthere thanks for your time.

    No i have not tried the drive. It has 280Gbs of data on it. 57gb or 15 yrs of family photos etc, i really don't want to damage the data.... Also the damaged inductor had broken from one of its solder points so no current would have passed.

    Do you think its worth trying it before even soldering on the new parts?

    Thanks again.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Well my first guess would be 3.3uH but that sounds low as typical values I have seen around 100uH and 47uH, and there is another one on your PCB on the other side with 1R2 on it, again 1.2uH seems very low. All 3 of them appear to be buck or boost converters with their own 8 pin smps chip, so I'm thinking 33uH would be more like it. They might even be 330uH.

    You could unsolder the good 3R3 and get someone to measure it with an inductance meter altough many inductance meters are not real accurate for such low values, you need to find a decent one.
     
  7. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
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    0
    No, the drive was not dropped. It simple contacted my other drive as i slid it into the HDD enclosure. I'm 100% confident that it will still work.

    The damaged part is not good. It's case has all but gone and the copper coil can be seen. Are you saying if i wrap it back up (only a small 5-8mm section) and resolder it, it should work?

    My identical part from China is in the air as i type!!!!

    Thanks again for everyones advice and help.

    Simon
     
  8. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
    6
    0
    I think your right, maybe waiting is the way forward....

    The soldering i'm not too concered about. I'm a competent solderer and removal of the damaged part was very, very easy. I have added a tiny amount of good quality solder so it should just be a case of holding the new part in place and adding a touch of heat.

    Part still at 35,000 feet.......
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    The "casing" of the inductor is actually its ferrite core. It is very important for it to work. :)
     
  10. cjdelphi

    New Member

    Mar 26, 2009
    272
    2
    the core will be ferrite as well as long as it's soldered on it should work there will be other regulators in place to smooth the voltage out as well, but it should be enough to get the data off (not for long term use i might add)
     
  11. Tacklebury

    Thread Starter New Member

    Jun 10, 2009
    6
    0
    ITS FIXED!!!!

    I took delivery of 3 x 3R3 Inductors from a very kind user off a HDD specialist forum.

    I soldered one on and thankfully she works a treat.

    Thanks to everyone for there help and advice, i'm a very happy man!

    Simon
     
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