Hi, I just come to this laptop with symptoms from owner - it stop charging. Thought it would be easy USB-C replacement (matebooks known issue) I took it. But port is good. After charging battery from power supply laptop is still dead. No power to EC chip. I'm out of ideas what to check next.
Next to 3.3V LDO which is only active rail after main rail is a circuit which sends voltage to EC chip. I don't understand at all function of this circuit. It consist of 2 PNP transistors few resistors and P-channel mosfet. Below is a circuit diagram of that part with explanation. Does anybody have an idea how it is supposed to work? Mosfet don't get negative charge to gate. I didn't find any other connections going by good multimeter in beep mode around the board. Also in diode readings are all open line after desoldering these components. Only thing which could work is directly supply ground rail to gate but cannot find which chip and why is that complicated circuit there?
circuit diagram explanation - switch is there to simulate what happen when LDO will get disabled/enabled, lamp is at the output where is EC chip. I tried to locate components similar to the board layout to not get confused.
Thanks
Next to 3.3V LDO which is only active rail after main rail is a circuit which sends voltage to EC chip. I don't understand at all function of this circuit. It consist of 2 PNP transistors few resistors and P-channel mosfet. Below is a circuit diagram of that part with explanation. Does anybody have an idea how it is supposed to work? Mosfet don't get negative charge to gate. I didn't find any other connections going by good multimeter in beep mode around the board. Also in diode readings are all open line after desoldering these components. Only thing which could work is directly supply ground rail to gate but cannot find which chip and why is that complicated circuit there?
circuit diagram explanation - switch is there to simulate what happen when LDO will get disabled/enabled, lamp is at the output where is EC chip. I tried to locate components similar to the board layout to not get confused.
Thanks
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