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Compaq Presario not charging battery...

Discussion in 'Electronic Repair' started by Chris Webster, Nov 10, 2005.

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  1. Hi,

    A friend of mine has a Compaq Presario1200 which apparently has stopped
    charging the battery. The mains power LED and battery charging LED lights
    up when connecting the mains. However when I pull the mains plug the
    computer shuts down immediately as if there was no battery at all. Same
    behaviour with a brand new battery.

    Any hints or tips highly welcome

    regards

    Chris
     
  2. JANA

    JANA Guest

    Check the charger circuit with a DVM to see if it is putting out voltage to
    the battery. If so, the battery must be replaced.

    Most of the time, the failure in this case, is a defective battery.

    --

    JANA
    _____


    Hi,

    A friend of mine has a Compaq Presario1200 which apparently has stopped
    charging the battery. The mains power LED and battery charging LED lights
    up when connecting the mains. However when I pull the mains plug the
    computer shuts down immediately as if there was no battery at all. Same
    behaviour with a brand new battery.

    Any hints or tips highly welcome

    regards

    Chris
     
  3. As I said, we have tried with a brand new battery too, same result. I
    mainly wanted to know if there is some kind of fuse or something in the
    Compaq notebooks power supply management which may break in certain
    situations. With all components being SMD it not much one can do without
    proper equipment if there is a component failure.

    Any clue how much a new powersupply (which I assume includes the charging
    circuits, may cost?

    Chris
     
  4. Guest

    Guest Guest

    : Any clue how much a new powersupply (which I assume includes the charging
    : circuits, may cost?

    : Chris

    Google is your friend.

    I google searched "multi voltage pc laptop power supply" and got many hits.
    One was: http://www.laptopacadapter.com/compaq/

    b.
     
  5. Dave D

    Dave D Guest

    Assuming this is a reasonably recent laptop, ie newer than about ten years
    old, the power supply is almost certainly just that and nothing more- a
    power supply.

    The management of battery charging is taken care of by the laptop circuitry,
    not the PSU. If the power supply is powering the laptop normally, the power
    supply is most likely OK.

    There are usually surface mount fuses inside laptops, and it's possible one
    has blown. However, more likely the charging circuit has failed because of a
    bad battery with shorted cells. Repair may well be uneconomical or
    impractical.

    Dave
     
  6. I beleive he ment the internal power supply..
     
  7. Bledge

    Bledge Guest

    The Compaq power supply just supplies 19V dc at 2A -3A.
    The charging circuits are on the motherboard. The battery pack has
    a battery guage circuit which monitors and records the amount charged
    or discharged and sends this info when queried by the PC over the
    SMBus/I2C.

    Had the same problem with a Presario 1200XL405 notebook.
    Tried the same solution, new battery pack but still would not charge.
    Worse, the notebook would occasionally shutdown as if it lost power
    suddenly when using mains supply without a battery plugged-in.
    When a battery is plugged-in, it slowly gets discharged even when
    powered by mains.

    Finally, built a NiMH battery charger based on the MAX712 datasheet.
    Used the Presario's 19v power supply as the supply for the charger.
    Hacked a switch with 3 flat prongs which fit into the battery contact
    slots as the output for the charger. Removed the innards(spring + pilot
    lamp + rocker contact) of the switch.

    The charger is fixed for 8 cells at about 1A charge rate as the
    battery pack was 9.6v 4000mAh.
    The MAX712 can be programmed for 1 to 16 cells.

    This was a cheaper solution than a motherboard swap.

    /bledge 14 Nov 2005
     
  8. distar97

    distar97 Guest

    My Compaq 1610 always had battery problems of one sort or another. One
    more thing to consider is that Compaq may have a power management
    driver upgrade/fix available for your model. Check under support on the
    Compaq site. They had a software fix that actually worked in my
    computer. Also some Compaq models have the power management circuit
    available as a replaceable part.
     
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