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Hello everyone, today we are going to learn about the SMC chip in Apple mainboard

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SMC in Apple mainboard is also called EC,

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embedded controller, it is a single chip microcomputer

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It has an integrated processor, storage space, registers, and so on

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It looks like this, it's a small one,

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and it has a lot of pads on the bottom

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It is a BGA chip

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The EC controls the timing of most important signals during system startup

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In the shutdown state,

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the EC keeps running and waits for the user to power on

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Whether you turn it off or on, it is always in the process of working

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When it's off, we plug in the adapter, it keeps running

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It also manages the charge and discharge of the battery,

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monitors the battery level, and waits for the boot at any time

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After it is turned on, it controls the speed of the fan,

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and monitors the power supply current and voltage of the system

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Also adjust the fan, control the status of various indicators

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Apple's EC is a little different from the EC of ordinary brand laptops

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Apple's EC doesn't have a management keyboard or touchpad,

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and the EC is almost built-in, it comes with programs inside

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When repairing, we need to find the same mainboard to disassemble

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Apple's EC also has a lot of hardware detection capabilities

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If the hardware is not compatible,

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it will cause slow entry into the system

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Special attention should be paid to the machine with water,

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such as water in the keyboard and touchpad,

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which will lead to slow startup

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There are also some voltage and current detection

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For example, the SMC_PBUS_VSENSE signal here is the voltage detection of PBUS supply

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And CPU current detection, and DCIN's ISENSE and VSENSE,

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current and voltage detection

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There are some other 5V, 3.3V current detection,

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DDR memory current detection, LCD backlight current detection, and so on

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So this EC is very powerful

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Any one of the supply voltage, current problems, will cause some strange faults

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Such as power-off, no display, slow startup and so on

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Okay, so that's the EC of Apple