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12V-100AMP Supply for $20.00!!

Discussion in 'Home Brew' started by unit_399, Jul 9, 2012.

  1. unit_399

    unit_399 EL CAPO

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    Many CB and Amateur operators (Moleculo, for one) are replacing their hi-amperage linear power supplies with switching supplies because of their light weight , relatively small size. and lower cost per amp.

    Mainframe computers have utilized high amp switching supplies for several years, and many of these supplies are now showing up on the surplus market. Last week, I purchased an HP mainframe supply from a surplus outlet in Medellin. This particular supply is rated at 12V-74Amps (110vac input) or 12V-106Amps (220vac input). The supply was "reconditioned": i.e. - cleaned, and run at maximum output (94 amp draw) for 12 hours. It measures 6"W x 4"H x 8"D, and weighs about 4 lbs. The cost was 49000 pesos (approx $22USD). Like PC supplies, this unit is "hot-pluggable", meaning it won't turn on unless it's connected to the mainframe. When I mentioned that I was going to use it to power some of my radio equipment, the store's tech showed me how to hot-wire it by connecting 3 pins on the plug together. He also showed me how to adjust the output voltage, and set it to 13.4vdc, which is the max the supply will do.



    I tried it out today, and it easily powered my 5-pill TX600 to 800W peak with negligible (.15V) voltage drop.

    The plan now is to build a housing with a voltmeter, ammeter, external voltage adjust control, and some high amp connectors. I also need to change the cooling fan to something quieter. I'll post some pics of the finished unit in a few weeks. 73s.

    - 399

    IMG_1175.png

    IMG_1177.png
     
    #1 unit_399, Jul 9, 2012
    Last edited: Jul 9, 2012

  2. ExitThirteen

    ExitThirteen Grumpy and Cranky

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    Ok, me likee! I want one of these! Where can I get one? Heck, I'd buy 3-4 of them! If I could find something in the 120 amp area, that'd be ideal. I'd put on in my X-Force amp I run. The current supply is about 80A and it's gets stressed at times on SSB.



    ~Cheers~
     
  3. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    I picked ip a 50 volt 60 amp supply for $30 to run my kilowatt six meter mosfet amp. Hard to believe a 3000 watt power supply can be so light.
     
    1 person likes this.
  4. dxhound

    dxhound Active Member

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    How are the birdies? Any noise on any bands 10-160m?
     
  5. ddbddg1

    ddbddg1 Senior Member

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    I`LL TAKE ONE

    OK....i want a couple too ....how or where do we get them?
     
  6. unit_399

    unit_399 EL CAPO

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    I've seen them listed on Ebay. One seller had them for less than $20.00 shipped.
     
  7. unit_399

    unit_399 EL CAPO

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    I didn't hear any hash from the supply on 10 or 11 meters. I can't comment on the other bands.
     
  8. SmackDown

    SmackDown Active Member

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    can you post the model number of that HP (Hewlett Packard) supply?


    3's
     
  9. unit_399

    unit_399 EL CAPO

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    Here┬┐s a link to a place on Ebay that sells them. They're sold out now, but there are other stores on Ebay that have them too. 73s
    - 399

    HP Proliant DL580 G3 Server Power Supply 1300W 337867-001 HSTNS-PA01 | eBay
     
  10. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

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    I often look at these but wonser about hash (static levels) produced in the recieve after hookingf these up. I know amaritron, MFJ and other companies have filtered thes and Im thinking one of those big capacitors for mobile or car audio setups would possibly filter some of this out.

    Im thinking with these other companies taking time to figure out filtering and spending a few dollars extra to filter their supplies to eliminate the hash noise other supply companies computer and radio companies alike will follow suite.
     
  11. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Usually a capacitor is not the answer. It usually takes running the power leads thru a large toroid using as many turns as you can.
     
  12. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

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    That was gonna be my next idea rf chokes. I remember someone telling me that those big capacitors would possibly filter some of that out. I didnt understand that theory but figured oneday Ide try it since I have one of those big digital readout caps here.

    I am wondering with those capacitors what the best thing for hookup would even be because I would think that the cap would be charged at shutdown and wouldnt that power backfeed into the power supply or whatever else is in line? How would a person set this up safley to bl;eed it off?
     
  13. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Turn the power supply off and then the radio gear. Let the radio gear discharge the cap. I have never seen a radio damaged by the voltage dropping out during receive but do not transmit.
     
    1 person likes this.
  14. unit_399

    unit_399 EL CAPO

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    I checked out the supply from 26.065 to 28.305 with the antenna disconnected, and didn't hear any hash noise from the supply. I have no way to test any of the other amateur bands. Connected the antenna ... same result-

    To be certain that an external cap discharges after shutdown, just put a bleeder resistor across it.

    - 399
     
    #14 unit_399, Jul 10, 2012
    Last edited: Jul 11, 2012
  15. 2Eight0

    2Eight0 Member

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    This thread is looking better every day. I so could use a powersupply of that nature.
     

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