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  1. #1
    DF PwNagE ss30's Avatar
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    Default Diode replacement

    After a bit of advice, I have a 24v wave maker in my marine fish tank and the controller died so I took it apart and where the power connects to the cuircut board the first component is a diode.

    I de-soldered the diode and replaced it with a solid copper wire and it now works, I want to put a new diode on the pcb what would be suitable?

    The transformer powering it is 24v 2amp.

    Thanks

    Paul

  2. #2
    DF Jedi coin-op's Avatar
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    Default Re: Diode replacement

    You do know that a diode is not the same as solid copper wire ?

  3. #3
    DF Jedi rids's Avatar
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    Default Re: Diode replacement

    What's the power plug like ? If it's like a figure 8 (olds tape player type) don't turn it round you got lucky.


    Sent from my iPhone using Tapatalk

  4. #4
    DF PwNagE ss30's Avatar
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    Default Re: Diode replacement

    Yes I know what a diode does and I know that a piece of copper wire is not the same.

    It's a 24v transformer with a jack plug, not 240 volt!

  5. #5
    DF Jedi Soulassassin's Avatar
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    Default Re: Diode replacement

    The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.

  6. #6
    DF Jedi coin-op's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by Soulassassin View Post
    The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.
    Also, since there is no rectification, and I'd guess a smoothing capacitor in there somewhere, that will be the next to go. The negative excursions that the diode would be blocking will now reach the capacitor - electrolytics don't like that.

  7. #7
    DF Jedi plug1's Avatar
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    Default Re: Diode replacement

    It will be a tvs diode or even ferrite bead , if it works when you short it out its probz a fb .

    Thanks to plug1

    ss30 (16th August 2014) 


  8. #8
    DF Jedi CallmeGoose's Avatar
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    Default Re: Diode replacement

    i genuinely read this post as "Dildo Replacement" everytime I see it appear on my new posts list.....

  9. #9
    DF PwNagE ss30's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by Soulassassin View Post
    The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.
    The transformer output is 24v dc

  10. #10
    DF PwNagE ss30's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by CallmeGoose View Post
    i genuinely read this post as "Dildo Replacement" everytime I see it appear on my new posts list.....
    Too much time spent on boats surrounded by seamen!

    Thanks to ss30

    CallmeGoose (16th August 2014) 


  11. #11
    DF PwNagE ss30's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by plug1 View Post
    It will be a tvs diode or even ferrite bead , if it works when you short it out its probz a fb .
    Thank you plug1 for answering the question

  12. #12
    DF PwNagE ss30's Avatar
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    Default Re: Diode replacement

    Here is a pic of the diode in place

    It's the first component after the power enters the board on the centre pin of the jack plug supplying 24v DC

  13. #13
    DF Jedi tronads's Avatar
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    Default Re: Diode replacement

    Looks like one of these to me... [Only registered and activated users can see links. ]

    Thanks to tronads

    ss30 (16th August 2014) 


  14. #14
    DF Jedi braymond's Avatar
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    Default Re: Diode replacement

    I think the fact it's labelled d01 pretty much confirms it's a diode ;-)


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  15. #15
    DF Jedi cosmicma's Avatar
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    Default Re: Diode replacement

    looks like a simple protection diode to stop reverse polarity killing the board / voltage regulator
    you could leave it as it is if you are confident you will never switch + and - the wrong way round but better to replace it

    why it would go open circuit is a bit if a mystery they usually short circuit when they fail
    [Only registered and activated users can see links. ]

  16. #16
    DF Jedi coin-op's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by cosmicma View Post
    looks like a simple protection diode to stop reverse polarity killing the board / voltage regulator
    you could leave it as it is if you are confident you will never switch + and - the wrong way round but better to replace it

    why it would go open circuit is a bit if a mystery they usually short circuit when they fail
    Unless it's been severely reverse biased - that would tater it.

  17. #17
    DF Jedi tronads's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by cosmicma View Post

    why it would go open circuit is a bit if a mystery they usually short circuit when they fail
    i would disagree with that and state the opposite....but it has been over 20 years since my electronic engineering qualifications were gained. ive slept since then.

  18. #18
    DF Jedi cosmicma's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by coin-op View Post
    Unless it's been severely reverse biased - that would tater it.
    it certainly would but they tend to short out unless they fry

    looking a bit closer at the board it looks like the left leg of the voltage regulator has gone dry ( dry joint ) which might need a touch with a bit of solder

    [Only registered and activated users can see links. ]

    did you check the diode with a meter ?
    Last edited by cosmicma; 17th August 2014 at 02:02 PM.
    [Only registered and activated users can see links. ]

    Thanks to cosmicma

    ss30 (17th August 2014) 


  19. #19
    DF Jedi cosmicma's Avatar
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    Default Re: Diode replacement

    Quote Originally Posted by tronads View Post
    i would disagree with that and state the opposite....but it has been over 20 years since my electronic engineering qualifications were gained. ive slept since then.
    it's a long time for me too mate they were still teaching fault finding on thorn 1500 hybrid chassis when i was at college things have moved on a long way since then ( thank feck )

    my recollection of diodes in power supplies tend to short circuit and fry because of it which i suppose ultimately leads to an open circuit but in this case if the photo is of the diode when it failed it looks to me as if that wasn't the problem unless it did indeed go open circuit
    if that is a dry joint on the regulator that would be the cause of the board failing but not the diode

    hard to say from a photo
    [Only registered and activated users can see links. ]

  20. #20
    DF Jedi tronads's Avatar
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    Default Re: Diode replacement

    Yes, it was its final state, and state when fault finding i was referring to.

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