How can I know if a USB female soldered port is OK?

Discussion in 'General Electronics Chat' started by rambomhtri, Dec 25, 2015.

  1. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    Hi, my notebook has 3 USB ports. Two of them work just fine, but one of them is not working at all, I plug a memory stick in and nothing happens. An important fact to consider is that the original power supply was 65W (19V, 3.42A), but I lost it and I am using right now a 58W power supply (19V, 3.0A).

    Could it be a power supply issue?
    What can I do to troubleshoot this issue?

    I was gonna test if the current goes from the pin soldered on the MoBo, to the pin that is in the USB female port, but to do that, I must disassemble the notebook, and I want to avoid that if possible.

    Thanks
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Well unless you have X-ray vision, you are pretty much going to have to take the notebook apart to inspect the connector. Unless of course it is obvious from the outside that the connector is loose then you will need to take it apart anyway to fix it.
     
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  3. ISB123

    Well-Known Member

    May 21, 2014
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    Take an old male USB cable and solder LED and resistor between VCC and GND.If LED lights up that means that port is not Dead.
     
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  4. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    That's what I was talking about. Those are the pins of the two sides, right?

    I don't have a LED and a resistor. Can I use other common thing?
     
  5. spinnaker

    AAC Fanatic!

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    That is not going to do anything other than confirm if the PSU is working or not. Memory sticks don't work so it is moot if the 5VDC works. And if the LED does not light, there is still no way to know if it is a connector issue or some other issue. Chances are it is a broken connector unless the OP was doing something stupid like trying to power his own projects with the 5VDC out of the USB.
     
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  6. spinnaker

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    A volt meter?
     
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  7. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    It suddenly stopped working, and I have not used that port to connect any project of mine.
     
  8. spinnaker

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    Connectors are only on the bottom. What you see on the top are springs to hold the memory stick.
     
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  9. rambomhtri

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    Nov 9, 2015
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    All right, can I plug a USB male, and test with my multimeter the 2 pins?
     
  10. spinnaker

    AAC Fanatic!

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    There is a good chance it is the connector then, a fairly common issue. More common on the micro usb connectors that go into tablets and phones.
     
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  11. spinnaker

    AAC Fanatic!

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    VCC and Gnd

    [​IMG]
     
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  12. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    Thank you, I've done that in an older laptop, and it works, it marked 5.09V from the red VCC cable to all the rest.

    Nevertheless, I've read that you should not do this in a PC. I've read that PC's or laptops don't like it when you connect to their USB ports a cable that has no IC. Is it safe to test the voltage this way?

    I don't know what can go wrong using a male USB cable, but I've read it and may be there's something I don't understand about USB's.
     
  13. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    Alright, I've test that in the faulty USB port and there's no voltage between VCC and any other pin.
    What can cause this?
    A broken cable/solder joint?
    Something related with the 58W power supply? (the other 2 USB ports work, so I don't think it's the power supply)

    Any idea beside a bad joint?
     
  14. spinnaker

    AAC Fanatic!

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    Probably a bad connector or solder joint then.
     
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  15. dl324

    Distinguished Member

    Mar 30, 2015
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    You've been misinformed. The USB 1/2 spec says any device can draw 100mA without negotiating for a high power mode. For USB3, it was changed to 150mA.

    Devices that aren't capable of negotiating for high power are restricted to low power operation; but that doesn't stop makers of such "decorations" from attempting to do so. The USB spec has always called for protection that doesn't require manual resetting; but that doesn't mean it's always done...

    If you want accurate information, read the USB spec. The USB 3.1 spec is 600+ pages.
     
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  16. ian field

    Distinguished Member

    Oct 27, 2012
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    Old dynamo bicycle lights used to use a 6V 0.1A rear bulb - that would be just about OK to test the 2 outer power pins. If it was intermittent when wiggling the connector, the other pins are probably loose too.

    Some "grain of wheat" dial light bulbs are low enough current, 12V rating doesn't matter as long as it gives an indication.

    LEDs aren't hard to come by - my local £ store sells various LED flashlights with at least 5 white LEDs. Pretty much any modern equipment like a set top box will have a PWR LED, these can often be rescued from kerb side collection points - the kerbs should be pretty crowded after many people got something better for Christmas.

    Most resistors are SMD these days - a bit fiddly, but not impossible.
     
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  17. rambomhtri

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    Nov 9, 2015
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    Lol, I don't have time to read 600 pages. Here's one of the many places where I've heard that (minute 2:00):


    Is it the creator of that video wrong when he says you shouldn't use a male USB to check USB female ports in a MoBo, as they "don't like it" when you plug in a USB with no integrated circuit?

    Is it a good method to check the USB ports the way I've done it then?
     
  18. ian field

    Distinguished Member

    Oct 27, 2012
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    AFAICR: the original standard was 100mA limit unless a chip on the device negotiated for a 500mA limit.

    Many gave the full 500mA anyway, and I believe the spec has been upgraded since I studied what it was.
     
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  19. sailorjoe

    Member

    Jun 4, 2013
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    Yeah, the guy's comments are wrong. The computer doesn't know that a cable with nothing on the other end is even plugged in. However, with all those bare wires out there, if you accidentally shorted out a pair, the computer might not like that at all, but that's true of most short circuits. You're testing it right. Time to open it up and do a manual inspection. Also, go get the right power supply. You could be hurting other components in your computer, like your hard drive, if your power supply doesn't have enough capacity.
    Send us a picture if you open the laptop, please.
     
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  20. rambomhtri

    Thread Starter Member

    Nov 9, 2015
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    What happens if you short the ground and VCC of a USB port?

    There's just 0.5 (A)*5(V) = 2.5(W). What harm can 2.5 watts do?
     
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