Help on identifying this resistor or inductor

Discussion in 'Datasheets, Manuals and Component Identification' started by Kcrypto, Jul 7, 2018.

  1. Kcrypto

    Kcrypto

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    Hello All, I have a burnt out component on my pcb board. Its square in shape with coils inside, so i think its a shielded SMD inductor.
    There are numbers on the component:

    1R5
    1784

    Any one have a clue the value?

    Help greatly appreciated :)

    Ken.
     

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    Kcrypto, Jul 7, 2018
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  2. Kcrypto

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    That's an inductor. Note the designation on the board of L5.

    It could be 1.5μH
     
    (*steve*), Jul 7, 2018
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  3. Kcrypto

    kellys_eye

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    Could be part of a buck or boost circuit and such inductors may burn out because the switching device has gone short - they rarely 'go' on their own.
    Worth checking the adjacent circuit(ry).
     
    kellys_eye, Jul 7, 2018
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  4. Kcrypto

    davenn Moderator

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    and why do you think it is burnt out ?

    it looks in good condition
     
    davenn, Jul 8, 2018
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  5. Kcrypto

    KJ6EAD

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    I'll venture a guess that the one pictured is another of same value as the failed one but Kcrypto will have to confirm or deny.

    By the way, the 'B' in the acronym 'PCB' represents the word 'board' making the term "PCB board" redundant.

    P.S. Should the decimal place holder for an inductor designation be 'L' instead of 'R' such as 1L5 instead of 1R5?
     
    KJ6EAD, Jul 8, 2018
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  6. Kcrypto

    Kcrypto

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    Thanks for the reply guys, much appreciated really.

    I have three boards. One component on one board is good (its working) and the other 2 boards are dead. I've included a pic of the 'burnt out' component and the opposite side. I can find 1R5 inductors (Inductance 1.5 μH), but theres many variations such as the Amps and Resistance (Ohms).

    I'm no expert in electronics, so no idea in how to test other parts of the circuitry.
     

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    Kcrypto, Jul 8, 2018
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  7. Kcrypto

    davenn Moderator

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    so the burnt out component may not be the inductor ?
    But the upper right component under the finned heatsink has let out the smoke

    So you need to find out what the heatsink is on top of
     
    davenn, Jul 8, 2018
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  8. Kcrypto

    Kcrypto

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    The board visually looks good except for that inductor which has bulged and burnt.
    What seems to be residual of smoke from the heatsink is in fact dust from a powerful fan which sits beside the board blowing in.
     
    Kcrypto, Jul 9, 2018
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  9. Kcrypto

    davenn Moderator

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    OK :)


    A little difficult without knowing what current is usually flowing through that part of the circuit

    The significant thing is, it's a 99.999999% probability that those inductors just die on their own, it pretty much doesn't happen
    This means that something to the right of it failed and is drawing excess current

    what are the components I have arrowed ... list what is written on them

    there seems to be a mirror of components to the left and right of a centre line of that larger central chip I have labelled A

    I'm picking that the 2 squarish chips immediately to the right of the left inductor and to the left of the right inductor are probably some sort of switching regulator

    one or more may be cooked .... do you have SMD IC removal and replacement skills ? .... you are going to need them

    upload_2018-7-9_12-43-46.png



    Dave
     

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    davenn, Jul 9, 2018
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  10. Kcrypto

    Kcrypto

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    Thanks Dave for your help.

    The Chip labelled A is dsPIC33EP16
    2 Chips either side is 3110A PSGN
    4 Outer chips are NIKOS PKCH2BB GUE6TD01

    The board consumes ~37A @ 12v DC

    As for SMD removal....I have a soldering iron haha thats a start.
    I might try removing one of the good 1R5 chips and placing it onto the burnt out boards to see if it works. I really dont fancy removing those chips mentioned :( If it does, its a matter of finding the value for a replacment 1R5.

    Thanks again for the help :D
     

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    Kcrypto, Jul 9, 2018
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  11. Kcrypto

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    The one labelled dsPIC33EP16 is a microcontroller that is programmed. If this is damaged then you probably can't fix the board.
     
    (*steve*), Jul 9, 2018
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  12. Kcrypto

    Kcrypto

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    Hi All.

    Managed to make good of one board of the two. Took a good 1R5 inductor and replaced the burnt out one. all is working now. Seems like the inductor is the only faulty part. Now have a board with two missing 1R5 inductors. :(

    Thanks for everyone who helped. Great forum too. Keep it up!!
     
    Kcrypto, Jul 10, 2018
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  13. Kcrypto

    davenn Moderator

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    Awesome .... thanks for reporting back :)
     
    davenn, Jul 10, 2018
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  14. Kcrypto

    73's de Edd

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