Allwinner A23 No Power

Discussion in 'Allwinner Based' started by hoserj, Jun 18, 2015.

  1. hoserj

    hoserj Member

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    I have a Prontotec Axius 7in tablet with a
    Allwinner A23 processor and main board A70H-V3

    The tablet will not power on.

    I have no idea if a main board or screen problem.
    Battery is good and charges.
    Have power at USB port.

    Any suggestions on how to check what may be wrong
    will be appreciated.
     
  2. leeshor

    leeshor Senior Member

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    Your post is a little confusing. If the battery is good and charging then it should power on. Try a very long press of the power button. If no response plug it into a running PC for at least 5 hours and try again.

    Does you tablet have a system reset hole?
     
  3. hoserj

    hoserj Member

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    I have tried everything I know to get this tablet to power on.
    Power button with Vol up.
    Power button with reset.
    Power button for 10 seconds and then Power on for three to five seconds.
    Opened case and checked battery.
    Plug into computer but no luck since no power on tablet.
     
  4. chiko84

    chiko84 Member

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    and you checked the battery with a voltmeter? to see if it gets load

    Charger tablet connects the wing and when to loading
    check the format voltimeter.si With the load comes standard. It Means That right. test and unsolder the two battery wires are welded plate wing That .You unstick mother for a few minutes and try buelves welding and turn your tablet,

    warning remember to do careful not to hit the wires
     
  5. hoserj

    hoserj Member

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    Thanks for your reply. Do not know if I understand.

    I need to clarify that the tablet does not seem to power on or at least nothing to screen.

    I did de-solder the battery from the mainboard and then soldered the battery back on after about 30 minutes.

    This tablet has two usb ports, one standard and one micro

    Voltage at battery is 4.04v
    Voltage at standard usb 4.01v when no external power
    Voltage at standard usb 5.06v when external power thru micro usb
    Voltage at micro usb 0v when no external power

    Took an old usb cable and cut to expose wires so I can check the current flow from battery to standard usb. Positive to positive pins.
    When tablet is off reading of -54ma and when I think may be power on reading of 972ma. Just tried this today.

    So seems like the power button is doing something.
    The screen never flickers or shows anything.

    Any suggestions on how to check screen would be appreciated.
     
  6. TinderboxUK

    TinderboxUK Senior Member

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    Try holding the power button for at least 20 seconds.

    If that does not work, you could try draining the battery till it is empty it may cause the motherboard to reset.

    John.
     
    • Agree Agree x 1
  7. hoserj

    hoserj Member

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    Thanks for your reply.

    Why drain the battery when you remove the battery wires from the mainboard results in the same thing.

    Holding the power button down for a long period of time does not seem to do anything more that holding it for 10 seconds. On other tablets when they are on and you hold the power button for at least ten seconds to force power down you can hear a little click when they power down. I have not heard this with this tablet.
     

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