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Guide How to make a Molex to USB (power only) cable

Discussion in 'Modding' started by theshadow27, 3 May 2005.

  1. theshadow27

    theshadow27 What's a Dremel?

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    How to make a USB to Molex power only cable
    By TheShadow May 2005 Rev 1.0
    Originaly posted by Me, for XoxideForums.com

    There comes a time in every modder's life when they find some cool, useless, USB powered trinket that they want to put inside of their computer without wasting a USB port. This guide will show two ways to make a USB to Molex power cable that will let you do just that.

    If your device has a "USB-B" port on it (the square boxy connector on the non-computer end of a standard cable) -OR- if you don’t mind cutting off the "USB-A" (the one that currently plugs into the computer for power) connector, then you can use the first way. It will come out nicer in the end, and can be made to a custom size.

    However if you ever want to use your device outside of a computer again, then your probably not going to want to cut off the connector. For these less hard core modders out there, I have included a second, less intrusive way of doing this.

    First things First

    Let’s get down to business with the first way. You will need 1 spare USB cable (with male A and B ends), an old male Molex connector (doesn’t matter where it is from) and:
    >soldering iron, solder
    >heatshrink (best) or electrical tape
    >wire clippers of some sort

    Let’s start this off with this scrap male Molex connector that was cut off from its female counterpart many moons ago... (If you don’t have as big of a junk bin as I do, I would recommend something like this)
    [​IMG]

    We don’t need the 12v pins; they are just going to get in our way. But I am way too cheap to buy a Molex pin remover! So grab a BIC pen (standard ball point. no, ink color doesn’t matter) and get cracking:
    [​IMG]
    What you want out of that whole ordeal is the ink reservoir. The back (keyword, back, you don’t want ink on your Molex pins fits perfectly over the pins! imagine that... (well you don’t have to, here is a pic)
    [​IMG]
    So you push it in all the way, then pull the wire out from the back. The 2 wires you want to pull are 12v and the ground closest to 12v. It should look a little something like this:
    [​IMG]
    And when you’re done, you are left with a beautiful 5v only Molex connector:
    [​IMG]


    Now moving right along to our USB cable. It has 2 ends, an "A" and a "B":
    [​IMG]
    Since the "B" end plugs into your fun toy, we want to keep some slack on that end for wire management. I decided to keep the whole thing, and just cut off the "A" end. Mmm, USB, tasty
    [​IMG]
    I assume everyone knows how to cut a wire...
    [​IMG]
    I’m going to put aside the "A" end for something later. Anyway, we now have 4 wires, and a shield:
    [​IMG]
    You want to keep the red and the black wire. Unless you are colorblind, this should be pretty easy:
    [​IMG]
    So, let’s sit back and think. We have 2 red wires, and 2 black wires. Gee, I wonder :confused: what we are going to do with them
    [​IMG]
    So get some heatshrink (electrical tape works if your lazy/cheep/don’t have heatshrink) and a soldering iron out...
    Note: you have to put the heatshrink on BEFORE you solder.
    [​IMG]
    And with one magical flick of a cheap lighter, you have a brand-spankin-new USB-Molex power cable!

    So you don’t want to cut up a cable, eh?
    well there is another way to do it. You will need a USB motherboard adapter (like this, any computer store will have it) and a resistor of any value. Also:
    >a soldering iron/solder
    >electrical tape

    so you just bought the USB thing. Okay. We are going to assume that you are up to here:
    [​IMG]
    if you are not, follow the steps above. You now have a Molex connector with two wires.
    At first, I was going to cut off the end of the USB thing. This would make it exactly like the steps above. If that’s how you want to do it, you can figure it out. The following way keeps all parts reusable, and doesn’t require heat shrink.

    The resistor doesn’t matter, as long as it has leads. Bend them like this:
    [​IMG]
    Solder the Molex’s wires to it:
    [​IMG]
    Now, you can cut off the resistor, leaving only its leads:
    [​IMG]

    Cut the leads down to about 7mm:
    [​IMG]

    Okay, lets see what we can dig up… This has two connectors molded into one, but it doesn’t matter. We will only be powering one
    [​IMG]

    here is the motherboard end of it:
    [​IMG]

    Since most people wont have the male version of this plug, I think a using resistor leads is an elegant solution. You can hook the red to the red and the black to the black by sliding the resistor leads into the female motherboard connector:
    [​IMG]

    If you don’t have at least one resistor lying around, I guess you’ll just have to cut off the box like connector and solder the wires directly. (like the cable above)

    Now make it happy with electrical tape, making sure to wrap both leads individually before wrapping them together, and then finally a third wrap to the connector:
    [​IMG]

    Remember that spare “USB-A” connector that I cut off? Ill use it just to show that this works (0 ohms = connection):
    [​IMG]

    so now you can power your disco ball, electric toothbrush, ipod, ect without wasting an actual USB port. Minimum cost = $0.0, maximum cost = $
    [​IMG]
     
  2. Who_me_33

    Who_me_33 What's a Dremel?

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    I liked the mod, and how you dont have to cut the usb product of your gadget. However, using the backpane could be a bit messy, what about using the female end of a usb extension lead (they are dirt cheap), to tidy things up a bit.
     
  3. theshadow27

    theshadow27 What's a Dremel?

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    you could do that too, but I treat extention A-male to A-female like gold, i can never find them!
     
  4. TheAnimus

    TheAnimus Banned

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    please, please, please, please. put a warning on this.

    YOU MUSTN'T TAKE MUCH POWER.

    ur allowed i think its 6ua (not even enough to begin lighting an LED) without requesting, and been granted more.

    now on most desktop mainboards it goes straight on the 5v aux line (used by PCI etc).

    so its not a good idea to start stealing power, the new USB specs i htink allow 0.5A of power tops. This isn't enough to make a HDD spin round! (well mabye a slow laptop one).

    on laptops this can often kill them, because of hte power management. As such i wouldn't recomend this for ANYTHING.

    if you want some power, tapping it from a spare molex inside the PC isn't too hard.

    and for your liability Shadow, i'd put a big disclaimer at the top of this one. Because its in DIRECT violation of the specs. This WILL kill some laptops.

    but you can have 6uA of power!
     
  5. Who_me_33

    Who_me_33 What's a Dremel?

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    From what I can see, it is taking power from the molex, and giving it to the usb gadget, saving using up a molex connector. I think what you are thinking is that the connector is the other way round (taking power from a usb connector, and giving it to a molex connector. ANd about the usb extension lead being like gold, you can find the usb connector (a female is it) at your local electronics shop.
     
  6. lord nicon21

    lord nicon21 sexy *******

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    sorry mate but this must be done "SB powered trinket that they want to put inside of their computer without wasting a USB port"

    molex to USB not the other way around but thanks for poniting the power thing out :thumb:
     
  7. Firehed

    Firehed Why not? I own a domain to match.

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    Yeah TheAnimus... you're a tad backwards there.
     
  8. theshadow27

    theshadow27 What's a Dremel?

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    yeah the idea was for someone to plug a USB Discoball into a molex connector, not to have a 5v device with a molex run off a usb port, but thanks for the concern
     
  9. K.I.T.T.

    K.I.T.T. Hasselhoff™ Inside

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    but i think he siad it beacuase in the title and the first few lines of the mod decription it is referred to as a 'USB to Molex power only cable'
     
  10. TheAnimus

    TheAnimus Banned

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    indeed, but i should of read the rest of the post.
     
  11. Dr.Roboto

    Dr.Roboto What's a Dremel?

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    my psu blew up and now i only have 2 molex's!
     
  12. TheAnimus

    TheAnimus Banned

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    Que?

    u overloaded ur PSU, so now only 2 molex's work? If u overloaded it enough to course that much damage, its not safe to use the PSU .
     
  13. theshadow27

    theshadow27 What's a Dremel?

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    im sure our fellow here shorted his usb's power cables together. this is a great way to fry the motherboard, psu, and anything else hooked up to the wall.

    great job, i clearly said to use electrical tape or heatshrink
     
  14. Dr.Roboto

    Dr.Roboto What's a Dremel?

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    oh it wasn't doing your mod... randomly happened one day.
    just thought i'd share.
     
  15. theshadow27

    theshadow27 What's a Dremel?

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    ah. well, since this is a thread, the idea is to keep responces limited to the subject of the thread. im sure there is a genral forum somewhere that would love to hear about your adventures in psu explosion. but this thread is about a Molex to USB wire adapter.

    gj though :thumb:
     
  16. g0th

    g0th What's a Dremel?

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    How can you blow up a PSU such that only 2 molex's work? All those wires are connected together to the output rails in the PSU.
     
  17. MrStim

    MrStim What's a Dremel?

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    powering a case fan of USB?

    Hi,
    Looked through the tutorial and it seemed simple enough.
    But I had a question, why wont I be able to power..say a case fan of a USB connection.

    I know they supply different voltages, but wouldnt it still work?
    thanks
     
  18. notatoad

    notatoad pretty fing wonderful

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    as theAnimus said above, you need to request power from the USB connection if you want to draw that much power.
     
  19. abi_allan

    abi_allan What's a Dremel?

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    hi

    First of all i would lik to say thanks for those use full info...

    it was very much used for me...

    in the beginning i dont know any thing abt electronics gadgets

    but now im wellversed

    so again thanks a lot :clap:
     
  20. darren

    darren What's a Dremel?

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    I am willing to give it a try myself, I have all the possible instructions here and I also have this die casting China resource as further support, how hard can it be?
     
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