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  1. #1
    Silver Lounger t8ntlikly's Avatar
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    Wink Source of laptop problems

    Just thought Iwould pass this on as well as to say thanks for all of you that came up withsuggestions.

    My laptop isan older HP Dv5000, with a Turion64 processor,Win7. I also use a USB hub, that Iplug my MAXTOR external HD into, as well as my Lexmark printer, and a coupleother items.
    Up until about 6 months or so back it was running flawlessly and then I startedhaving problems with the connection to the external drive. The printer wouldalso act up on occasion but that never caught my attention.
    Sometime back, I posted here asking for help. The problem appeared at that timeto lead to a bad MB, because it appeared that my USB connectors were acting up.After trying out different things as posted on this forum I decided to call ina live tech. As it turns out, that was a waste of my time and money, and Idecided to start looking for a new laptop.
    Well, I hadn't found anything that caught my eye, so I just kept rebooting asneeded, doing hard shut downs at night.....
    So to see if it helped, I unplugged my external drive from the USB hub, ehhh!it did help a little but the laptop still wasn't acting right.
    For no particular reason, a month ago I decided to set my printer up wirelessly,and now my laptop is functioning as it should, as is the external hard drive.

    Was theprinter causing the problem all along, or was it a combination of the externalhard drive and the printer running off of a USB hub? I’ll never know, because Idon’t intend (at least for now) to plug the external hard drive back into thehub.

    Thanks Again All!

    Thanks John
    Teamwork is essential; it gives the enemy other people to shoot at. (Murphy's War Laws #39)

  2. #2
    Super Moderator RetiredGeek's Avatar
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    t8ntlikly,

    Is the HUB powered? Sounds like the devices were drawing too much power for the one port the hub was plugged into.
    May the Forces of good computing be with you!

    RG

    PowerShell & VBA Rule!

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  3. #3
    Silver Lounger t8ntlikly's Avatar
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    Yes the hub is a Belkin 7 port USB powered Hub
    Thanks John
    Teamwork is essential; it gives the enemy other people to shoot at. (Murphy's War Laws #39)

  4. #4
    Plutonium Lounger Medico's Avatar
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    It could be that this older laptop is just not capable of the ext devices anymore. Perhaps it's PS is getting a little "tired" itself. Make sure your Images are kept Up To Date, you data back ups as well. Keep your eyes open for a new replacement. You never know when something will pop up that suits your fancy.
    BACKUP...BACKUP...BACKUP
    Have a Great Day! Ted


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  5. #5
    3 Star Lounger
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    If in doubt, unplug all USB devices, **including** the USB hub. Then reboot to see if problem goes away.

    Recently, through reading reviews on USB hubs and also my own experience, I find a hardware problem on USB hub.

    Warning:
    USB hub, and/or with other USB devices, may damage your laptop, or render your PC not bootable. The solution is to unplug the hub from the PC/laptop.
    This *only* applies to self powered hub and/or its plugged in devices which are also self powered.

    I'll include hardware info here as well.

    To be peace of mind, buy a hub with the logo of the USB Standards Committee (the familiar USB logo). Only certified USB devices are allowed to have the logo. (To obtain the logo, the hub must to submitted for tests, and to pay a fee.)

    There are many non certified USB hubs in the market. Most are OK. Some may cause problems, and may even damage your laptop. (Desktop PC is more robust, less easily damaged.)

    The sin of some non certified hubs: Improper isolation of the 5V lines, between the PC 5V line (via the USB cable), the hub's AC adapter 5V, and the plugged in device 5V (if they have their own AC adapter).

    There are reports of laptop being damaged, or PC/Mac cannot boot up when a USB hub is plugged in. These are caused by the hub's AC adapter, or by the external device (one with its own AC adapter).

    Voltage source should never be tied together as a practical matter. Else they will burn each other up.

    A properly designed USB hub is supposedly to isolate all 5Vs.

    Basically, when the 5V of the hub, or the 5V of a USB device (which plugs into the hub), connects directly to the 5V line of the PC (when the PC is off), we'll have problem.

    Pressure of ever higher current loading from USB devices may push into a minor design 'improvement' on USB hubs.

    One method is rid of the 600mA-current-limiting analog switch IC, making the hub's 5V directly available to the USB ports. Some even remove *another* isolation chip so that the PC 5V goes directly to ports.
    With this design 'improvement', to providing more current to USB devices, it inadvertently tie all the 5Vs together!

    When the PC is off, the AC adapter of the hub, or the 5V from the USB device, now tries to power up the 5V line of the PC! It is a no-no and no!
    For some laptops, the internal supply may not be robust enough, and maybe incur damage.
    On a PC, the robust internal power supply can handle the abuse. It may just have boot problem, or other operational problems, but may not be damaged.

    Solution:
    1. Buy certified USB hub. Or
    2. Crack open the hub, add a blocking diode between the 5V line from the PC, and the hub's 5V line. The diode effectively isolates PC's 5V from the hub and its plugged in devices.

    Usually USB devices, with its own AC adapter, seldom is so sloppily made that its 5V line goes directly out. But I find myself seeing a few cases recently. All the more the reason to use certified USB hub.

    Also, for a certified hub, every USB port, EACH, is protected by a current sensing analog switch. It will limit the current to about 600mA. Non certified USB hubs may not have this protection. The advantage of omitting the IC is that each port can now handle large current load, not limited to 600mA. The bad is the 5Vs are now interconnected!

  6. #6
    Bronze Lounger DrWho's Avatar
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    Intelestink! Velly Intelestink!

    In high voltage DC circuits, even as low as 12v, a diode in line can be very effective for isolation purposes, but be aware,
    a silicon diode will have a .5v forward voltage drop. Meaning that if you're running 5v in, you only get 4.5v out. That may
    not seem like much to the untrained, but to a device looking for 5v, it can be a game changer.

    I'll go with the suggestion to only buy Certified USB Hubs that already have all the protection built in by people who know what they are doing.

    USB Hubs are so cheap today, that it's just not advisable to muck about with one that's not working correctly.
    Just a thought.......

    The Doctor
    Experience is truly the best teacher.

    Backup! Backup! Backup! GHOST Rocks!

  7. #7
    Silver Lounger
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    Doc, hello.
    I was going to mention this .5v loss in forward voltage, you stole my thunder. I use a hub here too but I have a 5v power supply connected on it, I never thought that I should rely on the USB supplied voltage to keep up the good work. This PS is from a defunct modem. At one time, I had the 5 USB ports feeding the Acer and its own 4 USB ports also connected, just for fun, I had trouble keeping it all straight in my mind. I would be curious to know if this added diode did work ??? Be good.

  8. #8
    Bronze Lounger DrWho's Avatar
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    Sorry about stealing the Thunder.

    As an old Electronics Tech, who has designed and built hundreds of power supplies and other circuits, I'm painfully aware of the pitfall of Voltage Drops across circuits. A little resistance here and a little resistance there can add up to a real game changer.
    Some cheap power supplies can have very poor regulation, as the load changes. That can cause all sorts of problems, and if you don't have an o'scope to monitor the Voltage/Signal levels, troubleshooting the problem can be a real hair puller.


    Sometimes, not often, I forget where I got something.

    I was trying to run a USB to LAN adapter on an OLD Compaq laptop, with a four port USB hub and I couldn't get it to work.
    I just guessed it was because of not enough power coming from the old laptop. The hub had a socket on it for an external power supply but to my knowledge, I never got an external supply for it.
    So I dug around in my junk box and found a monstrous 5v supply from some long lost device. I soldered on a new plug that would fit the hub and I was in business.

    For me is was just a matter of patching something together to get the job done. For the novice, it might mean a trip to Radio Shack or some other Electronics supply store, for the proper Power Supply.

    But the bottom line is,,,,,, that you can get into trouble trying to draw too much power out of the USB ports on a laptop.
    All too many people have learned that lesson, the hard way.

    Cheers Mates!
    The Doctor
    Experience is truly the best teacher.

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  9. #9
    Silver Lounger
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    Doc, hello.
    There is enough thunder to spare for both of us. ;-) Sorry for being tardy here in replying to you, I got busy, away for a week and the fixing the garage opener. Done.
    My little 5 v supply does fine as your large one. It is fun fooling around and showing some ingenuity. I know that you are miles ahead of me but I still have fun. JP.

  10. #10
    Bronze Lounger DrWho's Avatar
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    Cool

    If you're making your living designing electronic circuits, precision in design is very important.
    Durability during huge temperature swings can be paramount, if the circuit has to work in all sorts of environments.
    All the circuits I designed for CAT, for instance, had to operate 100% at -40 degrees F, to almost +200 degrees F.
    They also had to be free of any ground loops and oscillation. Since everything I designed had to be able to operate
    on a 'track type' vehicle, (Bull Dozer) they had to withstand 10 G's of vibration, without falling apart.

    That's a lot different than something that's going to sit on your computer desk and power up a small device like a USB Hub.
    Thank God and Radio Shack, we can usually get what we need to power up just about anything.
    For weird voltages, I use a little regulated power supply that I built, oh so long ago now.
    Well, it's so old that the rectifier/regulator board says "Univac" on it. I picked up that little jewel at a HamFest,
    many years ago now.


    One day, when I was bored stiff, I whipped up this little LM317 regulator board. It's fully regulated and voltage adjustable, from 3v to 24v.

    The two red wires are the input power, either AC or DC.

    I don't do design work anymore, since I don't have access to a Printed Circuit Board lab. That was sure fun though, to be able to build anything my imagination could come up with.

    Now I'm just an auld-fahrt, relying on other peoples imagination to come up with what I need. I've gone from designer to appliance operator.

    But it's been a good run.

    Cheers Mates!
    The Doctor
    Experience is truly the best teacher.

    Backup! Backup! Backup! GHOST Rocks!

  11. #11
    Super Moderator RetiredGeek's Avatar
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    Nice surgery Doc!
    May the Forces of good computing be with you!

    RG

    PowerShell & VBA Rule!

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  12. #12
    Gold Lounger
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    Doc,
    LM317 !!! Brings back many memories!...Regards Fred
    PlainFred

    None are so hopelessly enslaved as those who falsely believe they are free (J. W. Von Goethe)

  13. #13
    Plutonium Lounger Medico's Avatar
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    I did not design, but I tested electronic computers for flight controls and weapons controls in environmental conditions for jet fighters. We're talking -65 to +165 with high vibration levels at both temperatures. We would shock, power off, to -65, turn on power, turn on vibration and start test. Had to pass from there to +165. These were also not purchased at Radio Shack or Best Buy, or where ever. Boy were those the days. Try T/S a vibration failure at -65. What a B!!!
    Last edited by Medico; 2012-03-02 at 17:30.
    BACKUP...BACKUP...BACKUP
    Have a Great Day! Ted


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  14. #14
    Silver Lounger
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    Ted, you wrote : in environmental conditions in jet fighters.
    Did I fly any of them ? NA F-86 ! Or was I before your time ??? ;-) JP.

  15. #15
    Plutonium Lounger Medico's Avatar
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    Before my time. F4, F5, F15, F16, F18 (I actually debugged the environmental test stations and tested the first flight computers for the F 18 flight control computers) Sorry to have gotten off topic everyone!
    Last edited by Medico; 2012-03-02 at 17:32.
    BACKUP...BACKUP...BACKUP
    Have a Great Day! Ted


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