Is this solder?

Discussion in 'The Projects Forum' started by jjtjp, Mar 4, 2014.

  1. jjtjp

    Thread Starter Member

    Mar 3, 2014
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    I don't think the details are pertinent so I'll just get to it. I applied too much voltage to a diode bridge which I didn't build that was intended to withstand high heat. I am trying to replace the bridge and I realized my digital soldering iron won't melt the stuff at 850 *F. I know I can just clip it but I would like to remove all that build up, if possible. What could they have used and should I re-attach my diodes with the the same? Thanks.

    [​IMG]
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Try applying a little flux. If you don't have flux, apply a bit of new solder to get things started. Has worked for me in the past.
     
  3. KJ6EAD

    Senior Member

    Apr 30, 2011
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    If that's an ultrasonic transducer, it may be silver solder or some other high temperature "hard" alloy.
     
  4. jjtjp

    Thread Starter Member

    Mar 3, 2014
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    Thanks. I guess I posted too soon. Using a little solder on the tip with the temp all the way up did the trick. I was kind of wondering about a high temp solder though because every other electrical connection in the thing is crimp or rivet. Thanks again. What a great first post experience :)
     
  5. #12

    Expert

    Nov 30, 2010
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    Those are 1N4007 diodes rated at 1000 volts. I cringe to imagine how you got too much voltage on those!
     
    DerStrom8 likes this.
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Especially since they are soldered onto a small DC motor!

    Maybe the diodes were killed by excessive current, those DC motors can draw 10A or more under conditions like stall and startup.
     
  7. #12

    Expert

    Nov 30, 2010
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    I have some doubt that they died of over-current. They often fracture when that happens, and those look perfect from the outside.
     
  8. KJ6EAD

    Senior Member

    Apr 30, 2011
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    Of course it's a motor. What was I thinking/seeing! :confused:
     
  9. jjtjp

    Thread Starter Member

    Mar 3, 2014
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    Okay I guess more details are in order...

    The circuit originally took 110V from the wall and went through some heaters (dropping the voltage) before ending up at the rectifier bridge. I took those resistances out of the circuit and use 24 V from a transformer to power the motor. I accidentally applied the wall power across the circuit for just a instance (long enough to trip the breaker) so I guess that the amperage was in fact exceeded. The diodes have all lost their forward bias. I still applied too much voltage for the given circuit though, so that is why I made that statement. I guess I should be more careful in my wording.
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    I was wondering when you will realize that ? :D
     
  11. #12

    Expert

    Nov 30, 2010
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    Now it makes sense. The diodes don't fracture in the time it takes a breaker to trip on a hard fault.

    Try maxing out the load rheostat on an analog power supply that doesn't have current protection and you will see diodes fracture. I love the crackle of exploding thermoplastic in the morning. :D
     
    Last edited: Mar 5, 2014
    DickCappels likes this.
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