General Question about USB connectors

Discussion in 'Asus' started by Rhino, Jun 21, 2011.

  1. Rhino

    Rhino Guest

    While working on my DMA issue yesterday, something happened that raised a
    general question about USB connectors, specifically the Type A Jack (4
    position). There is a picture here for reference purposes:
    http://www.l-com.com/content/Article.aspx?Type=L&ID=468

    While replugging one of my USB cables, I noticed that a little white plastic
    rectangle fell out of the USB jack. I had seen something white inside USB
    jacks before but had never imagined that the white part could fall out of
    the jack! This, of course, is the piece that is sitting horizontally in the
    bottom portion of the jack in the picture at the link.

    So, with the context established, what is the deal with that white plastic
    rectangle falling out of the jack? I'm not sure what it is doing there - my
    best guess is that it ensures that the incoming plug is correctly positioned
    vis-a-vis the four pins in the jack - but I would have thought it would be
    manufactured in such a way that it wouldn't fall out at the slightest touch.
    (I'm guessing that I put the plug in at a slight angle by accident and that
    knocked it out of position. Since the case was slightly angled at that
    moment, it fell out onto the ground.)

    Is this just nature's way of telling me to make sure the jack is always
    perfectly straight up and down and left and right and not to ever put the
    plug into it slightly at an angle? That would seem unduly rigid to me. Or do
    I have a defective USB jack where the white plastic part hasn't been
    properly bonded into the jack?

    This is actually the second such jack on this computer. One of my other USB
    jacks developed a problem many months ago, after which I was never able to
    seat a USB cable in it correctly and simply used another jack. After
    yesterday's experience, I looked closely at the jack and found that it was
    missing the white piece too. Obviously, it fell out at some point. I don't
    remember seeing the white piece fall out; perhaps it landed beside the
    computer and then got picked up by the vacuum?

    Anyway, if I go to an electronics store, will I find that they sell little
    packages with replacement white pieces that I can put into USB jacks when
    people lose them? Or do I need to replace the entire jack and just be more
    careful the next time?

    It's not like I've been deliberately abusing my gear but the Type A _plug_
    does not have the most obvious orientation: I tend to try to put them in
    upside down, then find that it doesn't fit right, then invert them. I
    suppose that tends to loosen the white pieces to the point where they fall
    out after a few such occurrences.

    I'd be curious to know what smarter people like you guys do to prevent this
    problem....
     
    Rhino, Jun 21, 2011
    #1
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  2. Rhino

    Paul Guest

    The white plastic has four contacts resting on it.

    http://media.digikey.com/photos/Assmann Photos/A-USB-A-E-R.JPG

    If you break the plastic, the contacts will not be supported and
    the connector isn't going to work. And if the contacts get bent
    and short together, well, that can't be good for it.

    The plastic may have snapped at the stress point inside the base
    of the thing.

    The plastic is used as a key, to prevent wrong insertion. But it also
    is a surface for the four contacts. The power and ground contacts
    are slightly longer, to help support safe hot plugging.

    Stop using a motherboard jack, which has "lost its plastic". That
    would be my advice.

    Since I've never had one break, I can't advise on whether the plastic
    had a jagged broken edge, or it was simply a plastic wafer that
    fell out.

    In theory, the "USB logo" is supposed to be on a particular side.
    But I have items here, with squiggly logos (black on black, no contrast),
    on both sides, which makes the logo thing useless as a quick guide
    to correct orientation. I'd need to get out my microscope to
    see what's printed on it.

    If you break the connectors, or blow out the motherboard USB ports,
    a four port PCI USB2 card with a NEC branded chip on it, can be used
    as a substitute. The only thing that won't work properly in that
    case, is entering BIOS setup options with a USB keyboard. So if
    you're going to ruin all your USB connectors, save at least
    one motherboard connector for the keyboard :) All your other USB
    devices can be connected to a PCI USB2 add-in card, if need be.
    And if you ruin or break the connectors on that, swap in a
    new add-in card and away you go.

    Paul
     
    Paul, Jun 22, 2011
    #2
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  3. Rhino

    Rhino Guest

    In my humble opinion, it doesn't work well as a key!
    One of my broken USB jacks is on the front of my computer case but I haven't
    used it since the plastic broke because nothing would seat correctly in it.

    The other is in a new USB hub I bought recently. When the plastic fell out
    yesterday, I put it back in and then put the plug back into the jack. But
    I'm not sure if the device itself is working. I'll have to look at it
    tomorrow; it's past my bedtime.
    Exactly! I hate it when the printing is the same colour as the surface it is
    printed on but you see it far too often....
    Yeah, I'm not really all that worried about the USB thing. My USB hub has 7
    ports, two of which are not in use, and only cost $20 so I could buy another
    one without breaking the bank if I need to.

    Thanks for your advice on this issue, Paul!
     
    Rhino, Jun 22, 2011
    #3
  4. Rhino

    Rob Guest

    USB ports aren't the strongest things in the world - I often
    get laptops in for repair, where the bit of plastic you
    mention has been broken off. A good tip is to use short
    USB extension cables and leave them permanently connected
    to the motherboard ports, and only plug devices into the
    end of the extension. A bit messy, I agree, but that is
    the only way to protect them. At least you can add a PCI
    USB card to a desktop as Paul mentions, but a laptop/netbook
    which has all of its USB ports broken is a pretty useless
    thing these days! My original training was as an electronics
    technician, but attempting to replace a laptop USB port
    would be something I would only give a 50/50 chance of
    being able to do without possibly causing damage to the
    motherboard..

    Cheers,
     
    Rob, Jun 23, 2011
    #4
  5. But then again, what do you have to lose by trying if the laptop is
    toast otherwise?


    --
    "Shit this is it, all the pieces do fit.
    We're like that crazy old man jumping
    out of the alleyway with a baseball bat,
    saying, "Remember me motherfucker?"
    Jim “Dandy” Mangrum
     
    Nobody > (Revisited), Jun 23, 2011
    #5
  6. Rhino

    Rhino Guest

    [snip]
    Good thing I've got a desktop then ;-)

    I like your idea of having short USB extensions dangling out of the
    motherboard ports. It _is_ a bit inelegant but it would be a lot
    easier/faster/cheaper to replace one of those extensions than trying to
    replace the actual motherboard port. I looked at the broken one on my case
    and I was not able to follow all the wires which intimidates me as far as
    swapping out the broken port. (There are two USB ports then a microphone
    port, then a speaker port, all side-by-side. I'd just want to replace one of
    the USB ports but it may be a "package deal" where I have to take the whole
    kit-and-kaboodle out and replace with the same.)

    By the way, you were kind enough to reply to my other thread ("M3A and
    Unknown Device") but I haven't seen your reply to my followup questions.
    Could you possibly look at that and give me your thoughts?
     
    Rhino, Jun 23, 2011
    #6
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