Capacitor...

french_guy Mar 8, 2021

  1. french_guy

    french_guy TrainBoard Member

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    Last year, I've equipped a Kato P42 Genesis N scale with a Digitrax sound decoder
    It was a true drop in installation by the way
    It comes with a 100uF 25V capacitor, and I noticed the sound was resetting sometimes
    I was thinking to install larger capacitors (such as 2 x 220uF 25V in parallel) that should fit in the shell
    Will I need to install as well a resistor and a zener diode? Or I should be fine with these 440uF?
    Thanks
     
  2. woodone

    woodone TrainBoard Member

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    If you have room use three. You can use surface mount capacitors to save room. Get the 25 volt caps. Watch polarity !
     
  3. french_guy

    french_guy TrainBoard Member

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    The ones I have are electrolytic.....3 won't fit !!!
     
  4. woodone

    woodone TrainBoard Member

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    If two will fit go with that, no need for a resistor nor a zener diode.
     
  5. french_guy

    french_guy TrainBoard Member

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    Well, it doesn't fit entirely: the shell is not going all the way down (missing something like ~2 mm max to sit perfectly where it should)
    I see 1 option if I really want to install the 2 x 220uF/25V capacitor:
    1 - I've already de-soldered wires from the existing capacitor (100uF) and the led
    2 - Remove the gray plastic cover (and not re-install it)
    3 - Cut a portion of the contacts going along each side of the engines (shown in red on only 1 side, but will do both of course)
    4 - Solder a piece of wire between contact and truck (shown in pink - contact on the truck is accessible once plastic cover is removed)
    Kato P42.jpg

    WIth the plastic cover out and the contacts cut off, the shell fits as it should now
    Is this a good idea, or a bad one? Will i have issues with wires soldered bewteen trucks and contacts from the frame?
     
  6. french_guy

    french_guy TrainBoard Member

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    This is what I'm trying to install by the way:
    20210310_175555.jpg
     
  7. woodone

    woodone TrainBoard Member

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    I don’t think removing that part will be a good idea. I would hold off on this until you can get some surface mount capacitors. They will take up 1/2 the room and do the same job. You should be able to find the capacitors on our friend the bay. You want 100 uf at 20 volt caps, wire in parallel . That would give you 200 uf .
     
  8. french_guy

    french_guy TrainBoard Member

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    I have hard time to find SMD capacitors being 20V...I can find 16V on some online store, but I'm concerned 16V is not enough.....
    Stock capacitor is 100uF, and I was planning to go with 440uF (2x220uF)
    However, going with 2x100uF SMD (which means doubling the stock capacitor) should already be an improvement, right?
     
  9. woodone

    woodone TrainBoard Member

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    Two of the 220 uF ‘s just will not fit has you have discovered. Keep looking for the 20 volt 100 uF surface mount caps. I know they are available . See if I can find a link to send to you via a PM.
     
  10. french_guy

    french_guy TrainBoard Member

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    Cool....thanks
     
  11. woodone

    woodone TrainBoard Member

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    sent you a PM.
    Jerry AKA WOODONE
     
  12. french_guy

    french_guy TrainBoard Member

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    Saw it....but they are 10V !
     
  13. Rasputen

    Rasputen TrainBoard Member

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  14. Sumner

    Sumner TrainBoard Member

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    MK likes this.
  15. woodone

    woodone TrainBoard Member

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    The ones Sumner showed you will work. $1.64 if you get 10.
     
  16. Sumner

    Sumner TrainBoard Member

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    Ok I think since I just got a XL sound decoder to try in an N scale U50 I need to also try a capacitor or two in it. I'm using a 12 volt supply now with DCC++EX and might at some point go to a 14 volt supply I have but no higher.

    I see where SBS4DCC has a 220 uf 16v capacitor with .292 x .176 x .118 dimensions that they recommend for sound decoder installs....

    ( https://store.sbs4dcc.com/SBS4DCC220uF16V2917SMDCapacitor.aspx )

    The one I found in the digikey link above (20TDC100MYF) is 100 uf 20v with .287 x .169 x .18 dimensions. About the same dimensions but you would need two of them to get close to the 220 uf of the 16v one above.

    I know next to nothing about capacitors except what they do. What are one's thoughts on using the 16v one with the 12 volt power supply or even a 14 volt one? It would be a lot easier to find a space for it compared to two of the other ones,

    Sumner
     
  17. french_guy

    french_guy TrainBoard Member

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    I think the 16V with 14V power supply is WAY TOO RISKY !!!
    I would myself not go under 20V rated capacitor (and I'm running at approximately 12.5V on the tracks)
    By the way: how do you like your XL decoder? Any pics of the install?
     
    Last edited: Mar 13, 2021
    MK likes this.
  18. Sumner

    Sumner TrainBoard Member

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    Not sure if I'll ever go to the 14v power supply so might try the 16 volt capacitors as I could probably get two of those in pretty easily in my install. I just got the decoder a couple days ago so haven't done the install yet. I did just start an install page on my site here...

    http://1fatgmc.com/RailRoad/Decoder-1/page-10.html

    and will try and get the install done in the next week and finish the pictures and if it works will try and post a video with sound. This will be my first install of a sound decoder so will be a learning experience. Here are a couple pictures and there are more at the link above. I'll be following your install also.

    [​IMG]

    [​IMG]

    [​IMG]

    Sumner
     
  19. french_guy

    french_guy TrainBoard Member

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  20. S t e f a n

    S t e f a n TrainBoard Member

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