Lenovo K80M No power source or Off during boot

Introducción

Lenovo K80M does not turn on suddenly.

Rom : Android 4.4 Lenovo genuine.

No rooting history.

There is enough battery, the phone is turned off from the Android logo during boot.

The battery is normal, but the battery protection circuit attached to the battery is judged to have failed.

When power is supplied directly to the unit, it turns on normally.

However, the external power is supplied through the protection circuit

Does not work when power is input.

Using a battery with a battery protection circuit

When connected, it works normally. (It does not matter)

Do not replace the battery only because the protection circuit can not be used due to the failure of the built-in protection circuit. (To prevent danger even in case)

I plan to connect the 18650 battery to the phone and recycle it only to the game and car navigation.

Qué necesitas

Paso 1 Battery

Symptoms No photos ready. Please refer to Lenovo K80 / K80M disassembly video on internet and Youtube for disassembly method. It is not difficult to decompose than expected.

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Paso 2

The built-in battery was tested with a meter (electric tester). The external battery is connected directly without going through the battery protection circuit, so the mobile phone boots normally.

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Paso 3

The genuine battery was spot welded to each terminal in the red circle, but the battery was removed at first because it was considered defective.
Battery is OK and protection circuit is broken
Like the picture without the protection circuit DC 3.6V External power is input, so the phone operates normally.

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Paso 4

Temporarily test operation by inputting power of 18650 Li-Ion battery.
I connected this phone with an 18650 battery Games and car navigation, cousins are trying to recycle toys for kids
The part that could be a problem. If you enter the battery power as shown in the picture, you can charge the battery through your mobile phone. However, since there is no battery charge / discharge protection circuit I think the battery should be used with a charge / discharge protection circuit.
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