need help identifying a part

Discussion in 'General Electronics Chat' started by gregkb2, Jul 29, 2014.

  1. gregkb2

    Thread Starter New Member

    Jul 29, 2014
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    Here's the deal I have a mini metal lathe and it quit working the other day it keeps blowing the fuse when I turn it on I've narrowed it down to the board then realized there was a piece on it that looks burnt behind it I want to replace it (solder a new one in) but I don't know what its called to order it if someone could help me identify it I would appreciate it so much
     
  2. Jony130

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    Feb 17, 2009
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  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    It's a high current diode
     
  4. wayneh

    Expert

    Sep 9, 2010
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    Does the photo show the burn that you refer to? It looks like something funky has happened there but I'm not convinced the part is bad just from that photo. You can remove it and see if it is shorted.

    And of course it may have been burnt because something else failed.
     
  5. gregkb2

    Thread Starter New Member

    Jul 29, 2014
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    OK I took the screw loose and it doesn't look burnt on the back (I know that doesn't mean much) but I took a couple more pictures I just assumed it was that because it has that burnt look on the heatsink ts attached to and none of the others do could someone tell me how to test it if I take it off I have a multimeter but not sure what to do with it to test this thing. Thanks for all the help guys I really appreciate it!!!
     
  6. buteman

    New Member

    Jan 5, 2014
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    Set your multimeter to a resistance range.
    Connect one of the pins to the black meter lead and the other to the red lead. Note the meter reading.
    Then connect the pins the opposite way round to the meter leads. Note the reading.
    One way it should be a very high resistance and the other way it should be very low.
    If both are high then it is faulty - open circuit.
    If both are low then it is faulty - short circuited.
     
  7. wayneh

    Expert

    Sep 9, 2010
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    Many multimeters also have a diode test function. It's not much different than the test described by buteman, but it will report the millivolt drop across the diode when connected correctly. It should read 500±200mV.
     
  8. gregkb2

    Thread Starter New Member

    Jul 29, 2014
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    Alright thanks guys I'm going to see if I can figure this out as soon as I get home.
     
  9. shortbus

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  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Unless it is a PWM controller, there should also be two SCR's to check, these look the same as the Rectifiers but have 3 leads.
    Is there a name on the controller?
    Max.
     
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