Laptop HP Classmate Notebook PC doesn’t turn on at all

First case: HP Classmate Notebook PC won’t turn on, when you plug the AC adapter into the laptop, there are no lights, all led off. When you push on the power button, nothing happens, all led stays off, and there are no sounds. The laptop appears to be completely dead.

Possible problem:

·         The AC adapter failed and the battery has no charge left, the motherboard doesn’t receive any power from the adapter. In this case test the AC adapter with a voltmeter. If it’s dead, replace it with a new one.

·         Power jack failed and the battery has no charge left, the motherboard doesn’t receive any power from the AC adapter. In this case measure the voltage on power jack connection if there is no voltage, the power jack has to be replaced.

·         Some electronics components on the motherboard failed, in most case there are a short in some SMD capacitor or MOSFET directly after power jack. Test the continuity with a voltmeter and check electronics components temperature with your finger. The failed electronic component has to be replaced (If you have AC adapter with led and the adapter led turn off every time you plug the adapter into laptop that is sign of short in electronic component after the power jack).

·         BIOS failed, System power (3V/5V) work fine, you can measure the 3.3V and 5V on the motherboard, No electronics components have short or overheating and 3.3V on the power button, BIOS has to be reprogrammed (flash bios).

·         Motherboard completely dead. The motherboard has to be replaced, if it’s not too expensive. Otherwise get ready to buy a new laptop.

Second case: HP Classmate Notebook PC won’t turn on, when you plug the AC adapter into the laptop, the charge led come on, but when you push on the power button, nothing happens, the power led stays off, and there are no sounds. The laptop appears to be dead.

Possible problem:

·         Power button failed, power button has to be repaired

·         Electrostatic charge in the motherboard, the laptop has to discharge electrostatic. Take off the laptop battery, unplug the AC adapter and push the power button for 1 minute then plug the AC adapter and turn on the laptop ( in some case you have to take off the CMOS battery too).

·         Some electronics components on the motherboard failed, in most case there are a short in some MOSFET. Test the continuity with a voltmeter and check electronics components temperature with your finger, test system power (3V/5V/+V1.8/+V1.25S/+VGFX/+VCCP), CPU power (VCC_CORE), you need Electronic Schematic Diagram for Laptop Laptop HP Classmate Notebook PC doesn’t turn on at all. The failed electronic component has to be replaced.

·         BIOS failed, System power (3V/5V) work fine, you can measure the 3.3V and 5V on the motherboard, No electronics components have short or overheating and 3.3V on the power button, BIOS has to be reprogrammed (flash bios).

·         Motherboard completely dead. The motherboard has to be replaced, if it’s not too expensive. Otherwise get ready to buy a new computer.

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