Is this rectifier dead - BYC8-600 ?

Discussion in 'General Electronics Chat' started by UnnamedUser159, Sep 30, 2016.

  1. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    I see
    0.365 between cathode 1 and anode
    0.365 cathode2 and anode

    and the other direction shows:
    .0L

    :)

    It`s from computer power supply.
     
  2. #12

    Expert

    Nov 30, 2010
    17,887
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    0.365 whats?
    On what range of the meter?

    I think they are Shottky diodes and they are good, but you really must provide more information.
     
    MaxHeadRoom likes this.
  3. RichardO

    Well-Known Member

    May 4, 2013
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    Also, are these measurements done out of circuit?
     
  4. bertus

    Administrator

    Apr 5, 2008
    17,105
    3,001
    Hello,

    The BYC8 is a single diode.
    The cathode is also connected to the tab.

    Bertus
     
  5. UnnamedUser159

    Thread Starter Member

    May 3, 2016
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  6. ci139

    Member

    Jul 11, 2016
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    Last edited: Oct 1, 2016
  7. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    So it`s good or bad? :)

    I just know what should be the forward voltage as the rule for the diodes (silicon) - between 0.5 and 0.8.
     
    Last edited: Mar 23, 2017
  8. ci139

    Member

    Jul 11, 2016
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    the general thinking goes that in ?"normal" operating conditions the voltage drop on PN junction is something 0.6 to 0.8V
    while in small signal oscillator circuits the lower limit for diodes is somehere 270mV and BE junction 380mV
    depending on diode the large signal maximums may go over 2V

    the good or bad depends where you intend to use it
    as what i can come up from datasheet it's not used as rectifier rather reverse diode for mosfet or gate protection
    random find for FR rectifier STPR1620 has somewhat half the voltage drop of that on BYC8-600
    witch makes it more considerable to be used and for rectifier bridges - while the latter i wouldn't put there
     
  9. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    I have one computer PSU and i have desoldered the heat sinks from the board and check the elements that are linked to them.

    Took off the diod from the heatsink and want to check it.
     
    Last edited: Mar 23, 2017
  10. ci139

    Member

    Jul 11, 2016
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    if you go mad make it beneficial as energy source for staying alert
    (join local martial arts club to get better insight while required)

    what you did (FW conductance path verified, BW blocking verified) is usually sufficient

    hypotetical : if your diode hadn't significant conductance at below 1V your std. meter's "diode FW cond. check" might had failed
    so alternate procedure : is constant current or current limit and sufficient higher voltage voltage source
    also may be needed for darlingtons´ base emitter FW conductance
     
  11. BR-549

    Distinguished Member

    Sep 22, 2013
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    I have never checked an isolated diode, with a multimeter, on the volts setting.
     
  12. ci139

    Member

    Jul 11, 2016
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  13. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    So we go in this case
    0>0.4V >> Short ?
    I dont see the diod to be Shottky in the PDF so it has no excuses/:)/ to does show these voltage if it`s not shorted.

    Sorry for my last Reply. I was nervous
     
  14. ci139

    Member

    Jul 11, 2016
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    i get nervous when the computers (world.processes) are slow - that means - almost uninterrupted
    that's why i have to file my nails - they go numb of drumming the table :confused::cool: continuously
     
  15. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    It`s me again.

    Prepare you tranquilizers :D

    About the diod ok. I am pigheaded.

    When i read about atx repairing i see on the heat sinks "some elements".

    In them i dont see Bridge Rectifier with 4 pins. >> dont have info about them checking.

    Is there a authoritative way to test it out of circuit and unmounted from heat sink ?
     
  16. ci139

    Member

    Jul 11, 2016
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    you're complicating your life coz your testing limits are set by an availability of the schematic you debug e.g. what nearby components can be shorted off / cut out from your test e.c. or you must already be experienced of testing it under limited operating conditions knowing the proper operational voltages at the check points + have a good equipment×methodology to know whether your test results are credible
    ?? re your question :oops: what ATX model# you have in hand - the component there
    (the general solutions always more complicated than specific ones) ♪♫
     
    Last edited: Oct 20, 2016
  17. ci139

    Member

    Jul 11, 2016
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  18. renemonte

    New Member

    Oct 7, 2016
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  19. renemonte

    New Member

    Oct 7, 2016
    13
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    the diode is o.k. a diode in a pwr supply usually shorts first, then breaks open due to excessive current.this is why, when tested,it shows an open
     
    UnnamedUser159 likes this.
  20. UnnamedUser159

    Thread Starter Member

    May 3, 2016
    269
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    It`s gone a time from my last check of the thread. Now i read it again and maybe analyze the things other way.

    I have buyd before time the NXP analogue of this Philips Diod.

    Now i measure it and it has 0.409 between Cathod1/2 and Anode.

    I have no reason to doubt in this piece goodness.

    For one diod if it`s Silicon the dvm should show 0.5-0.8.

    If it`s Shottky it is very lower - for example 170mV

    There is some reason these pieces to have different voltage to basic silicon and shottky?

    Is this "ultrafast" or "low switching loss"

    And P.P

    The PSU is Fortron Epsylon 700.

    Thanks
     
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