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  • USB hub problems

    Hey I am trying to power my usb hub from the molex 5v. Since my hub didnt come with an AC adapter i bought one from radio shack and soldered the wires onto it. Then i connected one to the red (5v) wire on the molex and the other onto the black ground wire right next to the red wire. This is what happens:

    The hub works fine before and after i plug the 5v in.
    While the 5v is plugged in the hub powers off and the computer doesnt detect it.

    I have tried reversing the polarity.

    What am i missing please help.
    04 Corolla CARPC

    Progress: 95% done (its never done)

    http://www.mp3car.com/vbulletin/showthread.php?t=97518

  • #2
    i had this similar problem. the car pc cannot provide enough amps to run the hub. even if it can your dc wires from the computer to the hub may be too long and dc voltage drops with distance. the best option is to buy the 12 to 5 volt dc regulator and hook it up right next to the hub. also hook the 12v wires on the regulator straight to the cars dc voltage. it is unregulated and runs at about 14.4v and is just about the extra voltage you need to get the amps you need to run the hub.
    If its not broken, take it apart anyway to see how it works!

    2005 Jeep Grand Cherokee Limited
    Progress [########O#] 90% - All but ODBII working!

    [Old Projects]
    2000 Saturn SC2 - 100%
    2000 Sebring JXi - 90% - Dash mod went bad, sold car.

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    • #3
      Which adapter from radioshack did you buy?
      Fusion Brain Version 6 Released!
      1.9in x 2.9in -- 47mm x 73mm
      30 Digital Outputs -- Directly drive a relay
      15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
      Buy now in the MP3Car.com Store

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      • #4
        Hey thanks for the advice.

        Today i tried bringing the hub home and hooking it up to the molex connector on one of those usb > ide adapters that are self powered and come w/ a molex connector. i hooked 1'' of 16awg wires to the red n black and again same result: the hub kept turning off everytime i plugged the plug in

        2k1toaster: i dont know the model no. but i bought the only plug from radioshack that fit into my usb hub. it also fit into 2 other usb hubs so i assume its somewhat a standard for usb hubs.
        04 Corolla CARPC

        Progress: 95% done (its never done)

        http://www.mp3car.com/vbulletin/showthread.php?t=97518

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        • #5
          Well the standard is mostly electronic jacks. I would guess it is a 2.1mm barrel connector. THe only difference usually is what the centre pin is. Ground or positive. And that leads me to my conclusion actually.

          When you first wired it up, you probably forgot to check the polarity, and plugged it in. Since USB hubs have VERY LIMITED reverse current protection for the most part. Something went zzzzzap! So you switched the wires on the connector and tried again. So if the first round didn't kill it, then the second round probably did.

          I would try with another hub. Since you have a radioshack by you I suggest borrowing one of their self powered ones. I used to work at a RadioShack, and I know what to do and such and I even know how to get the discounts and all. But all you need to do is buy it, use it, put it back the way you bought it and return it no questions asked for 30days. Even if you fry it, they will replace it. When they replace it, go to another radioshack and return it. That way you can test it out.

          I know this is the not so good way of renting, but it is RadioShack. They pay their floor people minimum wage and charge a markup of usually over 400% for Radioshack brands. Less for other brands. So stick it to 'em!

          Try the "borrowed" unit out but be careful to note the polraity needed by the connector. See if it works. If it does, hooray! And you can keep the one you bought. And if it doesn't work, return it.
          Fusion Brain Version 6 Released!
          1.9in x 2.9in -- 47mm x 73mm
          30 Digital Outputs -- Directly drive a relay
          15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
          Buy now in the MP3Car.com Store

          Comment


          • #6
            Originally posted by 2k1Toaster View Post
            Well the standard is mostly electronic jacks. I would guess it is a 2.1mm barrel connector. THe only difference usually is what the centre pin is. Ground or positive. And that leads me to my conclusion actually.

            When you first wired it up, you probably forgot to check the polarity, and plugged it in. Since USB hubs have VERY LIMITED reverse current protection for the most part. Something went zzzzzap! So you switched the wires on the connector and tried again. So if the first round didn't kill it, then the second round probably did.

            I would try with another hub. Since you have a radioshack by you I suggest borrowing one of their self powered ones. I used to work at a RadioShack, and I know what to do and such and I even know how to get the discounts and all. But all you need to do is buy it, use it, put it back the way you bought it and return it no questions asked for 30days. Even if you fry it, they will replace it. When they replace it, go to another radioshack and return it. That way you can test it out.

            I know this is the not so good way of renting, but it is RadioShack. They pay their floor people minimum wage and charge a markup of usually over 400% for Radioshack brands. Less for other brands. So stick it to 'em!

            Try the "borrowed" unit out but be careful to note the polraity needed by the connector. See if it works. If it does, hooray! And you can keep the one you bought. And if it doesn't work, return it.


            sounds good to me. its very hard to feel sorry for anyone who charges $3-5 for a small plug and another $2-3 for wires connecting to the plug if you dont want to do the soldering.

            Your description sounds correct. For future reference is there any way of checking the polarity before you zapp the hub.

            also do you think radioshack would mind if i cut the wires to the ac adapter to their hub to connect it to the 5v or is that pushing it?
            04 Corolla CARPC

            Progress: 95% done (its never done)

            http://www.mp3car.com/vbulletin/showthread.php?t=97518

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            • #7
              just bought a radioshack hub and their ac adapter works on my hub perfectly. Considering i tried the polarity both ways before im gonna assume that the actual old plug was the problem.

              My next question: (pardon its noobness)

              when i cut up their ac adapter and hook it up to my car how do i know which goes to gnd and which to the red 5v on the molex?
              04 Corolla CARPC

              Progress: 95% done (its never done)

              http://www.mp3car.com/vbulletin/showthread.php?t=97518

              Comment


              • #8
                That's what a multimeter/circuit tester is for. Get one, you'll get a lot of use out of it. Which wire has connectivity with the inside and outside contacts.

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                • #9
                  Originally posted by romanman69 View Post
                  just bought a radioshack hub and their ac adapter works on my hub perfectly. Considering i tried the polarity both ways before im gonna assume that the actual old plug was the problem.

                  My next question: (pardon its noobness)

                  when i cut up their ac adapter and hook it up to my car how do i know which goes to gnd and which to the red 5v on the molex?
                  For a generic wire with markings, you don't know. clip on the alligator clips and test with a multimeter. If it is supposed to be centre pin positive, then attach it one way and put the red lead from the meter into the hole, and the black lead to the casing. If the voltage read is positive, then you guessed right. If not, reverse the gator clips and essayez-vous une autre fois.

                  usually there is a different colour polka-dotting one of the wires, but seeing as how it is radioshack stuff, I don't think it does.

                  And just to clarify, when testing with the meter, never plug the hub in until you are sure!
                  Fusion Brain Version 6 Released!
                  1.9in x 2.9in -- 47mm x 73mm
                  30 Digital Outputs -- Directly drive a relay
                  15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
                  Buy now in the MP3Car.com Store

                  Comment

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