Strange problem with computer charger

Discussion in 'General Electronics Chat' started by adam555, Nov 26, 2013.

  1. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Hi, I'm having problems figuring out what's the problem with a computer charger that doesn't seem to work; well, the computer doesn't charge or turn on when I connect it.

    I used a multimeter to check if the charger was working, but I'm getting a strange result.

    The charger is meant to be 19V, and has this type of plug...
    [​IMG]

    ... when I measure the voltage between the outside and the inside pin, I only get 15V (4V less than I should). But when I measure the voltage between the outside and the inside wall of the cylinder -not the pin- then I get the right voltage (19V).

    How can that be?
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    It is a three terminal plug; not a two terminal plug...?

    What is printed on the charger? Is it the Original Charger that came with the computer, or is it an substitute charger?
     
  3. tcmtech

    Well-Known Member

    Nov 4, 2013
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    If it gets used like my wife treats hers the odds are the wiring is ripped out inside the plug body where the cord gets soldered to the actual plug. :(

    That can cause odd voltage readings and problems with not charging even though the power pack seems to be working just fine.
     
  4. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Yes, it's an original HP charger 519330-004 series PPP012A-S.

    It says output 19V and the symbol for DC; it doesn't say anything about a third connection or an alternative voltage.
    The plug is the exact same one on that picture, and it only states 2 terminals on the diagram below; that's why I'm puzzled.

    In case it has 3 terminals; what's the third for?
     
  5. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    It's from a girlfriend; so I'm pretty sure it also gets a similar treatment. :D

    I proposed to her taking the plug off and resolder it or replace it with a new one; without having to buy the whole charger. But I would hate to do that without being absolutely sure of what's wrong with it.
     
  6. MrChips

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    Oct 2, 2009
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    Congratulations! What was her response?
     
  7. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I just read on the internet that some chargers have a third pin for a temperature sensor. Could there be something wrong with this instead; that's why it's not charging?
     
  8. MrChips

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    Oct 2, 2009
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    You have to be careful with words.
    Once when I was in the hospital a very pretty nurse was being very efficient setting up my IV.
    I said, "You don't fool around, do you?"
    She responded, "No, I'm married".
     
  9. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    She said yes to whatever I proposed... except to that proposal. :)
     
  10. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Cutting the cord would answer the question. Cut it about a foot from the moulded-on plug. Three conductors or two?

    Continuity check to the plug. If the plug connections are good, then splice the cord (heatshrink is your friend)

    This brings you to the most likely scenario; that the jack is broken where it solders to the mother board inside the laptop. Big job to disassemble the laptop if you don't do it all the time. Maybe time for the Geek Squad...
     
    adam555 likes this.
  11. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I usually have that problem with English words; and often got in trouble for it. Like the time I was texting another girlfriend, and wrote to her "witch", instead of "which". :)
     
  12. MrChips

    Moderator

    Oct 2, 2009
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    I could never find the courage to propose to a girl.
    I never actually proposed to my girlfriend except indirectly.
    It still got me into trouble because she accepted directly to my indirection.
     
  13. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    In that case I'm going to wait until she brings the computer later on today. If the most likely scenario is a broken jack, then I prefer to check it before I cut the cord.

    Thanks for the help.
     
  14. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I know very well how that works. My wife has wrecked three of them now and every time according to her her laptop unrepairably dead and she needs a brand new one which she figured I should pay for.

    She gets up and drags the power pack around while it's still plugged in by its cord like a dog dragging a dead squirrel on a rope until it either yanks the AC side cord out of the power pack or rips the plug out of her laptop never breaking her stride while doing it. :mad:
     
  15. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Congratulations.... I hope. :p

    The truth is, I proposed her to come home with me so we could fix it together, and she said no to that; so I didn't get the chance to make the other proposal. :(
     
  16. t06afre

    AAC Fanatic!

    May 11, 2009
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    Laptop chargers have an IC that communicate with the charger unit. If charger fail to ID it self properly. The laptop may not start up at all. If I remember correct, the communication pin is in the middle. In a three terminal plug. It is not an uncommon error that latter IC give up. And reduce the charger to a paper weight
     
  17. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    If that's the case; is there any way to fix it... or at least confirm that's the problem?
     
  18. wayneh

    Expert

    Sep 9, 2010
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    Your symptoms could all result from a bad motherboard. I had that exact situation with an HP laptop recently.

    My "solution" came after I purchased on craigslist a nearly identical working model. With that to experiment with, I quickly diagnosed that both chargers were fine. I was then surprised to learn that the dead computer worked fine with the other battery, and that the dead battery worked in both laptops once charged by the good laptop.

    It wasn't long until I sorted out that the bad computer worked fine in all respects except that it could not use AC power to operate or charge its battery. I looked into repairing it but ultimately sold both laptops. I actually made a few bucks, because I turned a dead brick into an almost-working computer.

    Point is - don't tear stuff apart until you can do some experiments to locate the problem.
     
  19. t06afre

    AAC Fanatic!

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    It could also be other things. Ask around for charger similar to yours. And see if your computer boots with that. You could also try to take out the battery and see if it boots up then.
     
  20. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I agree. I was just thinking where I could get the spares for testing.
     
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