LANAH KOMPUTER

n this post I will summarize most common laptop hardware related problems and give some suggestions how to troubleshoot or repair them. Problem 1. Computer doesn’t turn on at all. When you plug the AC adapter into the laptop, there are no lights turning on at all. When you push on the power button, nothing happens. The laptop appears to be completely dead, makes no sounds, no indications of life. Possible problem: – The AC adapter failed and the battery has no charge left. In this case test the AC adapter with a voltmeter. If it’s dead, replace it with a new one. – DC jack failed and the motherboard doesn’t receive any power from the adapter. In this case the DC jack has to be replaced. – Motherboard failed. The motherboard has to be replaced, if it’s not too expensive. Otherwise get ready to buy a new computer. Here are some tips for testing AC adapter and DC jack . Also, make sure to read step-by-step instructions for troubleshooting dead laptops ....

The machine has been water damaged.  It does not have system standby power, which are 3V and 5V. Check Max8724(the battery charging chip) first, because to make system has standby power this chip must work correctly. This is a 28 pin chip, we only need to test 1, 2, 4, 8, 10, 11 pin. They are VIN(main power for chip), LDO(provide 3.3V for chip itself in order to set REF voltage, also provide signal to drive 2 MOS to charge battery), REF(set reference voltage of the chip), SHDN#(enable/disable chip, a switch), ACIN(indicate the power supply has plugged in), ACOK#(power adaptor ok with mainboard). Everything ok except 10 pin, ACIN is 0V. This is incorrect, mainboard doesn’t detect there is an adaptor! Trace it backward and find it is very simple – mainboard use 2 resistors to pull the input voltage(19V, directly from dc socket) down to about 4V, so test the first resistor and find it opened. Change it and 3V/5V power come up and mainboard be able to switch on. Then...