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Thread: auto turn on atx power supply with capactitor

  1. #1

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    auto turn on atx power supply with capactitor

    finally found this again

    converted to pdf and attached

    can we sticky this please

    converted original pdf at 465 kilobytes to djvu, now only 88 kilobytes
    djvu reader for windows in a post of mine further down
    Last edited by @lien_Zed; 10th January 2010 at 05:04 PM.
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

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    Just to add to this if you use an ATX P/S instead of a switching P/S for your arcade cab and want it to turn on when you power up the cab find the green wire inside the 20 pin plug loom and cut it off at the plug end then just ground it permantly

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    i went hunting and found a photo that shows how to force atx power on by modify the wiring of the atx power supply as well. this mod will be great if you use the atx psu to power a car amp for your mame cab

    photo attached

    also, check your pc bios there is on newer boards a setting you can change so that it will restart after power loss
    Attached Images Attached Images
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

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    also went hunting and found a tutorial on how to convert an atx psu in to a benchtop power supply

    i tried to convert it to pdf, but at 150 dpi it was 8 megabyte in size!!!

    so i converted it to djvu format instead and the same file is now about 250 kilobyte long

    get a freeware viewer here

    http://windjview.sourceforge.net/

    if u use ubuntu, theres a djvu reader built in to it
    the file attached i had to convert to a pdf or the forums would not upload it

    also attached "the fix"
    the fix will describe how to put on a dummy load to the psu to keep it running. some atx psu will not run if a load is not on there and shut down
    Attached Files Attached Files
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

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    thanks this is just what i was looking for

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    Quote Originally Posted by IMPURE View Post
    thanks this is just what i was looking for
    excellent

    there was someone else the other day who made a post and wanted to know about auto turn of of atx psu's

    that was what reminded me to go hunting the net and save it in pdf or djvu for future reference for all of us
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

  7. #7

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    The cap trick is a bit different to the green to black ATX power on.

    To clarify:

    The cap trick is used to turn on a motherboard/pc without having to press the powerbutton.

    The "green to black" trick is to power up the power supply without needing a motherboard (to use as a bench supply or an arcade psu).

    Thanks for posting the cap trick - I had forgotten all about it!

    ~~~~~~~

    Oh, and the polarity of the cap - why is that important? If it is hooked up backwards, it will heat and then boil internally over time, and then go off like a firecracker

    Cheers
    Jacob

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    Quote Originally Posted by AskJacob View Post
    ~~~~~~~

    Oh, and the polarity of the cap - why is that important? If it is hooked up backwards, it will heat and then boil internally over time, and then go off like a firecracker

    Cheers
    Jacob
    it wont blow up...not enough current for it to do that

    the capacitor in this case is being used as an "electronic switch" so to speak

    if wired up back to front,it wont work, plain and simple

    How It Works:

    A capacitor's discharged state is shorted. When you apply power to the unit,
    the cap acts as a short between the pins, activating the power supply.

    With 5V flowing through the cap, it's shorted state becomes an open state,
    allowing the board to boot normally.

    When you power down the unit, the capacitor will discharge, and resume its shorted
    state, allowing it to do this the next time you power up.
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

  9. #9

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    It might not blow up, but it will fail (possible shorted) if subjected to reverse polarity for too long.
    "Everyone's always in favour of saving Hitler's brain. But when you put it in the body of a great white shark, ooohh! Suddenly you've gone too far!"

  10. #10

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    Quote Originally Posted by Mickey Juice View Post
    No offence intended, but what's wrong with PDF?
    Just re-distil at a lower quality...

    the big difference between pdf and djvu is filesize

    djvu uses a lossy format similar to jpeg to save files

    the picture quality is just as good as pdf, but the file size is usually a hell of a lot less then pdf

    why bother to recompile documents at a lower quality when you can get almost the same quality and much smaller document size using djvu?

    last year i spent 6 months scanning and converting over 6000 pages of old computer magazines to pdf format

    i kept the pdf format and converted the lot to djvu and usually the djvu file come in at under 10% of the original file size with quality just as good as the pdf and uploaded the djvu format to ftp servers in the usa for others to share & use.
    Ubuntu User #16304 Linux User #450903 rc forums ultimaterc.com looking for cabinet plans?click here pc atx power supply for 12/5 volt for mame cabinet and turn it on auto-magically? click here
    if your new to electronics and want to learn more, click here **how to attach images to posts click here** my youtube channel

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