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Thread: DIY ATX Power Supply Project

  1. #1
    Join Date
    Dec 2011
    Location
    Independence, MO
    Posts
    100

    DIY ATX Power Supply Project

    I made a fixed voltage power supply from an old ATX computer supply. There are a lot of how to tutorials available such as: http://www.makeuseof.com/tag/how-to-...n-old-atx-psu/
    I also made an adjustable power supply from an old ATX power supply and a DC buck converter to vary the DC ATX 12 volt line. Just got this unit up and running last week. I am still tweaking the size of the pots to maximize the voltage adjustability. Added some led's for fun.
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  2. #2
    Join Date
    Jun 2014
    Location
    Virginia
    Posts
    1
    Do you have the schematics for this?

  3. #3
    Join Date
    Dec 2011
    Location
    Independence, MO
    Posts
    100
    Quote Originally Posted by jimofsanston View Post
    Do you have the schematics for this?
    No, but I used the concept of this power supply: http://www.instructables.com/id/DIY-...pply/?ALLSTEPS
    I ordered this module and connected to the 12 volt of a ATX power supply instead of the plug in power supply he used. http://www.ebay.com/itm/251714436260
    I tried 10k pots but they were too big so I tried a 2k pot and it was too small. I have 5k pots on order.
    Here is a list of some of the parts I ordered. Don't remember what size the resistors were for the led's but I think they were 100k.


    http://www.ebay.com/itm/131301118823
    http://www.ebay.com/itm/321044248424
    http://www.ebay.com/itm/131347589426
    http://www.ebay.com/itm/251627913878
    http://www.ebay.com/itm/301354272178
    http://www.ebay.com/itm/181433738059
    http://www.ebay.com/itm/400729034325
    http://www.ebay.com/itm/181203893095...%3AMEBIDX%3AIT

  4. #4
    Join Date
    Jun 2013
    Location
    Orange County, California
    Posts
    118
    How much does the 5k pots reduce the power? What voltage are you looking for?

    John Andersen
    DR Racing Products

  5. #5
    Join Date
    Dec 2011
    Location
    Independence, MO
    Posts
    100
    Quote Originally Posted by drrufo View Post
    How much does the 5k pots reduce the power? What voltage are you looking for?

    John Andersen
    DR Racing Products


    I estimate that I need a 3.1K pot for the entire range of 1-12v with no extra dead space.
    Due to inefficiencies with the parts this project should "theoretically" get 1-11v + at 9 amps. I am under no illusion that this black box will offer any competition to a Korford or Wrightway. It is comprised of a old used ATX power supply and $20 of very cheap parts. I also don't know how clean the power is or if the magic smoke will be released from inside the box in the near future. So far it works great with the 2k ohm pot (at 1-8) volts for slot car motor break in and playing with electrical components.*

    *Disclaimer: Electricity is bad. It makes live things dead and cool things hot. Avoid electricity at all costs or wear a rubber suit 24/7.** (Please note that prolonged uses of electricity can make dead things also burn.)

    **Disclaimer to Disclaimer: Wearing a rubber suit 24/7 can be addicting (I am told). Better to just avoid all electrical power.

    Mark

  6. #6
    Join Date
    Dec 2011
    Location
    Independence, MO
    Posts
    100
    Quote Originally Posted by drrufo View Post
    How much does the 5k pots reduce the power? What voltage are you looking for?

    John Andersen
    DR Racing Products


    Forgot to answer the 5k question. Theoretically a 5k ohm pot should give an adjustment from 0-15v if I feed the module 16 volts or more. I only feed the module 12 volts. Most any 300 watt ATX will supply at least 15 amp at 12v DC. The -12v power is limited to under 1 amp so using -12 to boost output to 24v limits max amps to 1 total. At least I read that somewhere on the net so it must be true. There are many examples of fixed voltage ATX power supplies with 3,3v, 5, 12v, 17v and 24v available at different banana plugs if over 12 volt is needed in limited amounts.
    I assume you know a lot more than I do about electricity so jump in with comments. I only know what hasn't blown up.
    Mark
    Last edited by MrkCrwly; 03-03-2015 at 01:03 PM.

  7. #7
    Join Date
    Sep 2011
    Location
    Long Island,N.Y.
    Posts
    979
    "Wearing a rubber suit 24/7 can be addicting (I am told)."

    Mark[/QUOTE]
    That is an entirely different Blog.

  8. #8
    Join Date
    Jan 2008
    Location
    mechanicsville Virginia
    Posts
    366
    I set up an ATX power supply a few years back. It is very handy on the work bench.

    I didn't bother with the control chip circuit. I just wired out 3 of the voltage taps these things produce. I put 4 banana jax on the side and use a dual banana to select between them. 3 jax in a row are 12V, com, 3V. Then a 5V jac is centered below the common. So putting the dual to the left gives me 12v, to the right gives 3V and to the bottom gives 5V.

    I didn't bother with a different enclosure either the gray steel box it comes is seems fine to me. I just added an on off toggle switch.

    I also have the Wrightway for my pit box but the 3 fixed voltages work well. 3V for motor run 5 for the com and tire cutters. I use the 12 occasionally to really zing the tire truer when taking big donuts down in a hurry.
    Anything worth doing is worth overdoing

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