Anyone Know what this is and where I can get one

Discussion in 'General Electronics Chat' started by CRAIG VANDEKAMP, May 16, 2015.

  1. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    I burnt out a component on the PCB of my 1980's Japanese pinball machine (known as a pachinko machine) and was wondering if anyone can give me some info on it ... (see pic)

    its a 24 volt AC system and the component markings are:

    470K 411(?) where (?) is either a 9 or a symbol
    [​IMG]

    a). Tell me what it is and what its ratings specs etc. are?
    (I think it's a Zener Diode as the PCB has ZD3 marked below it)

    b). Where can I get a replacement

    c). can I substitue another component for it.

    thanks folks

    Craig
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Considering the legend on the pcb, I would guess it's a zener diode, however the 470k marking is puzzling. It's also an odd shape for a zener or a resistor.
     
  3. MrChips

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    Oct 2, 2009
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    Show us the rest of the circuit board.
     
  4. studiot

    AAC Fanatic!

    Nov 9, 2007
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    I agree with tracecom it doesn't look like a zener, it looks more like a capacitor.
    So could you need a new one simply because the wrong component has been inserted at some time past?

    Some detective work may be needed to find a circuit.

    Make and model numbers etc of board, machine and so forth please.
     
  5. paulktreg

    Distinguished Member

    Jun 2, 2008
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    Looks more like a 47VDC (30 ish VAC) MOV?
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
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    The markings on the device suggest MOV while the markings on the board suggest TVS (back to back zeners). Either is possible in the same location so the board may have been designed for a TVS then populated with an MOV.
     
  7. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    varistor
    at least the symbol is consistent with such.
     
  8. MaxHeadRoom

    Expert

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    The symbol is not the customary one for a VDR or MOV, Teccor use this symbol for their Sidactor SCR type suppresion devices.
    Max.
     
  9. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    Here it is fellas, thanks for the great response :)

    Its from a 1980's pachinko (japanese pinball)

    By the way I know nothing about electronics, but I'm willing to learn (I'm a computer programmer for the last 30 odd years so please don't hold it against me)

    Specs : 24 volts AC 3 amp 100VA

    The black connector right of the 13 pin connector is where the 24 volts AC goes in the other 4 colored ones go to the machine
    pachinko.PCB1024x768.jpg

    cheers and thanks again for the help

    Craig
    vandekamp.com.au - my profie here if you're interested[/QUOTE]
     
    Last edited: May 16, 2015
  10. MrChips

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    Oct 2, 2009
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    Thanks. So it is a 47V MOV.

    This is used for protection against voltage surges. If you remove this component it will not affect the operation of the circuit. It is faulty if it registers with low resistance when removed from the circuit board.
     
    Last edited: May 16, 2015
  11. CRAIG VANDEKAMP

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    May 14, 2015
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    Last edited: May 16, 2015
  12. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    What I think I did wrong is when I installed a 240v to 24v transformer I wired it up the wrong way (polarity wise) if this is possible with ac as it has no polarity
    I purchased a multimeter (shame on me for not using one in the first place :oops:) and the reading has a minus sign when I test the secondary 24v :rolleyes:

    Craig
     
  13. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    Thanks heaps MrChips

    Where can I get a new one or a substitute; I'll have a go at replacing it - need to learn sometime:)
     
  14. MrChips

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    Oct 2, 2009
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    AC does not have polarity. Reversing the leads would not damage the unit.
    If you swapped the primary and secondary windings you would zap the board with 2400V.
     
  15. MrChips

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    Oct 2, 2009
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    Remove the component. If the board does not work you have another fault some place else.
     
  16. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    Here is the back of the board with the component connections marked; do I need to jumper where I remove it to maintain the circuit and if so how;

    [​IMG]

    By way of thanks MrChips. if you ever have a coding problem (from upper level - down to microcode level) please give me a bell and I will help
    I am very experienced in all levels of coding from mobile apps to process/machine control etc. my email is on vandekamp.com.au

    Just to humor me; if I wanted to replace it what component number etc would I use to do this?
    I know you said it's not needed but I would like to get the PCB as close to what it was as I can
    YES I'M A BIT OCD THAT WAY :eek:
     
    Last edited: May 16, 2015
  17. studiot

    AAC Fanatic!

    Nov 9, 2007
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    If it is a MOV/Varistor it is a protection component and the board should function correctly (but sans protection) without it as MrChips says.

    No do not put a link in its place. That would short something.

    The question is why do you think it has failed, it does not operate in normal circuit action?

    And if it has failed (It protects by failing) then what else went wrong?
     
  18. CRAIG VANDEKAMP

    Thread Starter New Member

    May 14, 2015
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    I hooked up a brand new 250v Primary 24v secondary transformer turned it on and [SMOKE, SPARKS etc.] I instantly turned off the power.
    I know it failed because once looking at the board I saw this (pic below) hard to miss huh :p
    The reason for failure could be that the machine has been sitting in a warehouse for 25+ years unused so it may be just an age thing
    I have other machines of the same type and age from the same place and they worked fine.
    I am going to follow MrChips advice and remove it and then go through the whole circuit board to make sure it is clean as I can get it and all components look OK
    Then I'm going to power it up again (fingers crossed)

    [​IMG]
     
  19. MrChips

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    Oct 2, 2009
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    Remove the thing and test the board. Do not jumper across because that creates a short.
    Worry about sourcing the component later after you are happy that the board works.
     
  20. ian field

    Distinguished Member

    Oct 27, 2012
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    Its a metal oxide varistor - IIRC: it loosely follows the standardise component value scheme, except it stands for voltage.

    The first 2 digits are base value and the "0" is the multiplier - so I'd say its 47V.

    Looks like the Matsushita trade mark on it, they probably have data/catalogues online.

    Back in the early days of CTV, the first automatic degauss used a very basic 2-terminal PTC thermistor to produce the decaying burst of AC through the degauss coil - they had a problem that the residual current through the PTC energised the coil just enough to make the picture wobble.

    The solution they found, was to replace the degauss coil with a load resistor and feed the coil via a 68V MOV, as the PTC reached working temp, the voltage dropped below 68V and the coil was cut off.

    Those MOVs were very thin, but about 2" diameter.
     
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