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Can’t find a 0.35 ohm 5% resistor anywhere

Discussion in 'Power Electronics' started by ZedsDeadd, Jun 27, 2021.

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  1. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    Where do I find one or can I get one made?
     
  2. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
  3. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
  4. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
    Hello,

    0.35 Ohms is not a standard value.
    0.348 will be the closest, but with 5% tollerance, a wider change may apply:
    vishay_color_E_series_big.png
    Bertus
     
    davenn and Martaine2005 like this.
  5. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    Here’s a picture of the resistor right in the middle
     

    Attached Files:

  6. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
    Hello,

    Why do you think the resistor is faulty?
    It looks quite ok to me.
    Did you measure the resistor?

    Bertus
     
  7. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    That’s a screenshot of the same board as mine mine is blown
     
  8. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
     

    Attached Files:

  9. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
    Hello,

    According to the table I posted, it could be a 0.36 ohms resistor.
    That should be more easy to find.

    Bertus
     
  10. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
  11. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    it’s about 10mm x 3mm which is a guess I don’t have anything to measure it by. It’s just smaller than a USB port
     
  12. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    .36 would mean the second band is blue but It definitely looks green
     
  13. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
    Hello,

    A 2 Watt resistor would be about 9 X 3.5 mm.

    Bertus
     
  14. 73's de Edd

    73's de Edd

    3,105
    1,312
    Aug 21, 2015
    You might also want to have a look (at) WHY the resi s tor burned.

    Refer to post 7's photo of HIS board and then . . . . .
    Look at the nearby . . . fractured outward . . . . case of a POWER FET and expect this burnt open part to be its source resistor, with the POWER FET being dead shorted internally.
     
    bertus likes this.
  15. bertus

    bertus Moderator

    1,906
    715
    Nov 8, 2019
    Hello,

    @73's de Edd , Yes, you are right, the transistor shows severe damage.
    @ZedsDeadd , Can you take a picture from the front of the transistor?
    It will need to be replaced.

    Bertus
     
  16. davenn

    davenn Moderator

    13,838
    1,952
    Sep 5, 2009

    3 is orange the resistor in the photo the first band looks brown = 1 and a 0.15 Ohm would be a standard value

    .15, 1.5,15,150, etc
     
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  17. ZedsDeadd

    ZedsDeadd

    9
    0
    Jun 27, 2021
    1- screenshot of the same resistor that I found on google images

    2- my blown resistor

    3- transistor
     

    Attached Files:

  18. Bluejets

    Bluejets

    4,875
    1,018
    Oct 5, 2014
    I make it 0.15 ohm 5%.
     
  19. 73's de Edd

    73's de Edd

    3,105
    1,312
    Aug 21, 2015

    Sir ZedsDeadd . . . . .


    All right now . . . . with R802's value being nailed down EXACTLY.

    And since you could / did not come back with . . . the . . .or any . . .part numbering on the fractured power FET . . .don't you now think that it is due time that you should reveal this circuit boards numbering identifier, as well as its brand of manufacture and the sets model number.

    The most to be seen from the snippet view of this board, is that it relates to a power supply board, with its related / assigned 800 series of device numbers.
    The subject R802 resistor should be in the POWER FET source to ground and be having a current sense sampling voltage being fed back to the PWM controller.
    BUT the instant that the junction on the POWER FET failed, it DUMPED the whole ~340VDC at 100'ish milliamperes (that's being ~34W . . .babycakes ! ) from the raw DC supply, right into this puny little 2W resistor.
    So, you can now see the resultant double ended sparking /blasting out of that resistor, and expect that the now fused together FET D-G-S junction blob has ALSO sent a HEALTHY / 340V destructive voltage back down the gate feed path into the FET's controller IC.

    This boards use of a Cy prefix for HV ceramic caps, relates to a similar assignment used by Samsungs.

    Is this being your first attempt of repairing a board . . . instead of just your mass pulling of donor boards . . . . . ?

    https://shortcircuitsolution.com/pages/about-us

    https://www.google.com/maps/place/S...3b87c!8m2!3d35.0608551!4d-90.0004258?hl=en-US



    73's de Edd . . . . . .

    upload_2021-6-28_13-52-35.png






     
    VenomBallistics likes this.
  20. VenomBallistics

    VenomBallistics

    214
    45
    Aug 30, 2018
    Mother of Zeus child ... you might want to wipe the isotopes off that capacitor before you replace things too.
    Looks like a scene of Saving Private Ryan was filmed in there.
     
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