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I have a Toshiba Satellite S55-B5280.

Occasionally, the laptop will stop running on battery power. Meaning, if the AC adapter is unplugged, the laptop won't turn on; while the laptop is turned on, if I unplug the AC adapter, it shuts down immediately.

Once it gets into this state, it continues until I remove and reinstert the battery, which reliably fixes it. After the problem is fixed, the laptop runs fine on battery and the battery life is normal.

At first I suspected it may be an issue with the physical connection at the battery connector, but the laptop sometimes enters this state while sitting undisturbed on a table.

What could be the cause? Is it more likely to be a fault in the battery, the laptop's power circuitry, or the battery connector?

edit: upower shows a battery voltage of 16.7 V. Laptop has stopped running on battery entirely.

edit: I tested the battery with a multimeter, and 16.7 V is accurate. I'm not sure if that rules out the battery as a problem or not.

I tested the two fuses PF1 and PF2 (white rectangles with a "Y" on them in the photo below), and they are both short (which I assume means they are good):

enter image description here

You can see above one of the fuses, there is a zero ohm link, possibly named PR74. This connects to the pulldown to enable the battery. If I insert the battery (AC power unplugged) and measure the voltage at PR74, it is 3.1 V. Then, I try pressing the laptop power button, and PR74 remains 3.1 V. I'm not sure if this might indicate a problem.

PR74 connects to R671 (bottom right), which is 1kohm. I'm not sure where it goes after that.

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    Is there any correlation with heat? There may a temperature-sensing circuit being tripped that does not reset without removal and reinsertion of the battery. Batteries typically have these sensors, and the OS can query this ( msdn.microsoft.com/en-us/library/aa372698(v=vs.85).aspx ) and shut off the battery circuit based on temperature.
    – Yorik
    Commented Dec 13, 2016 at 18:56
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    @Yorik That's an interesting theory. I think there is no correlation with heat, because it sometimes happens when the laptop is sleeping (so, rather cold) and sometimes while I'm using it (warm, but not too hot).
    – Owen
    Commented Dec 14, 2016 at 4:38

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I'd say there is an issue with the motherboard (laptop's power circuitry). When issues like this appear, I call up warranty service and describe the problem. Their only answer is to replace the motherboard.

Is your laptop still under warranty? Are there any firmware updates for the motherboard?

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  • I see. That's too bad. I will look into it.
    – Owen
    Commented Dec 14, 2016 at 4:39
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    keep in mind that "replace the motherboard" is generally the service center's default response when they have no idea what the problem is
    – Blaine
    Commented Dec 17, 2016 at 5:10

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