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What component is this?

Discussion in 'General Electronics Discussion' started by Viktor, May 8, 2017.

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  1. Viktor

    Viktor

    21
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    May 8, 2017
    I'm new to electronics and while trying to repair a module, I gave it a visual inspection and could see an inductor that was broken. (I suppose it's an inductor since it's L marked.)

    However, I can't seem to find a component that looks like it.. Does anybody know what type of component this is?

    I would appreciate any suggestions.
     

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    12,465
    2,988
    Nov 17, 2011
    Welcome to EP.
    L is indicative for an inductor or a ferrite. However, from the photo it is impossible to tell which one and/or a value.
    Your chance lies in the neighbouring component which seems to be o.k. You could de-solder it and measure the inductance, then try to find a suitable replacement.

    As this component seems to have died from excess thermal energy (aka burnt), there is a risk that somewhere else another component is defect, causing too much current through this part. You should (try to) locate that other part by following the traces from the burnt part into the pcb.
     
  3. Cannonball

    Cannonball

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    May 6, 2017
    Goos advise. You may want to get a schematic on this circuit.
     
  4. Cannonball

    Cannonball

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    May 6, 2017
    I am sorry about my spelling. I mean that is good advise
     
  5. davenn

    davenn Moderator

    13,993
    2,019
    Sep 5, 2009
    you mean, advice ;)
     
  6. Cannonball

    Cannonball

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    May 6, 2017
    yep
     
  7. Viktor

    Viktor

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    May 8, 2017
    It's damn near impossible to get a schematic for the products that I'm repairing. They are not common products and it's prefered to not buy a new one, as the price for an used item ranges from about $1000-6000
     
  8. Harald Kapp

    Harald Kapp Moderator Moderator

    12,465
    2,988
    Nov 17, 2011
    Without a schematic or a bill of materials measuring the (hopefully) good part is mho your only choice.
     
  9. Viktor

    Viktor

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    1
    May 8, 2017
    I was looking for similar looking components and found something that looks like it. Which is
    EMI-filter SMD 2 A 2706, NFE61PT102E1H9L, Do you think that could be it? And they have a rated capacitance, so would the best way to figure out the appropirate value by measuring the capacitance of the neighbor component?

    Also, I have two other similar boards laying around who needs to be repaired and both have the same component.
     

    Attached Files:

    • EMI.jpg
      EMI.jpg
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  10. Viktor

    Viktor

    21
    1
    May 8, 2017
    Here's another picture of the circuit, and you can see this component is frequently used across the board.. Maybe an experienced person can tell what it is?
     

    Attached Files:

  11. Harald Kapp

    Harald Kapp Moderator Moderator

    12,465
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    Nov 17, 2011
    The component you found looks really similar, but I wouldn't bet my house on it.

    If that's an option: salvage the parts from one of the other boards to make 2 working boards from 3 defect ones.
     
  12. Viktor

    Viktor

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    May 8, 2017
    Considering the price for each circuit, I'd have to avoid that as long as possible. Somehow I need to figure out exactly what type of component it is so it can be replaced. Preferably without using a circuit for parts.
     
  13. Viktor

    Viktor

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    May 8, 2017
    I found a picture with details about the product.
    [​IMG]
    Turns out it's a filter with built in ferrite bead. Hence why they mark it with L???

    If I'm lucky this is it.. But I would I go about measuring the component to make sure the variables get somehow correct?
     
  14. 73's de Edd

    73's de Edd

    3,352
    1,404
    Aug 21, 2015
    Sir Viktor . . . .frum Sveden . . .

    I had already pulled and prepped my inserts prior to your data sheet posting but am going to include them also.

    L-C-L  Series Filter .jpg

    I was also going to ask you to put a strong rare earth magnet against the unit to confirm the ferrite presence.

    Pulling a unit and measuring the ceramic capacitor would confirm the low end specs of the filtering.

    And to be having that current handling spec, along with the inductive resonances involved would have the two ends inductors at the low micro henry or sub micro henry range.

    Looking at the full board . . .of circa 1995-96 vintage . . . at its left bottom you can see the minor 5V , 3 terminal regulator supply and the bit heftier UM1001 potted power supply module and finally RIGHT at your “ problem parts” doorstep is the 78SR115 hybrid power supply unit.

    Over on the two earlier mentioned supplies you have 5 or so YELLOW color dry tantalum bypass capacitors . . . . . sometimes being problematic to shorting.

    AND a BLACK C926 . . .22ufd at 6VDC ? is right beside your current overloaded / bad part.

    If my unit to be working with, I would go up into the top of the board at the RJ connector P302 and see if one of those cluster of 12 . . .L401-L411, or L307 L305 might not even be used / handling any signal.

    That gives you a same part or the option to replace it with a L-C-L discrete set replacement at the P302 area and use a scoping of the line to initially compare the original inductor to the sub, in their bypassing apabilities..

    That gives you the original part type to go in down at the power supply buss, bad parts position.

    BUT I would initially be OHMMING out that downstream power circuitry for a short or overload and then, probably be using a sacrificial ½ ohm resistor instead of the valuable inductor / filter on its initial power up testing.

    BTW That unit certainly has a whole “shit pot” of Maxim 701 I.C. power supply monitors !

    Also, this unit reminds me a lot of some “ Westernly Electric” power supplies made back in the ‘90’s.

    73's de Edd
     
    Last edited by a moderator: May 9, 2017
  15. Viktor

    Viktor

    21
    1
    May 8, 2017
    The capacitor underneath the burnt component has an ESR of about 95 ohms.. and on a healthy board it's about 0.3ohm??

    Could that little capacitor be the root of the problem or should I try to troubleshoot somewhere else?
     
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