Dell Inspiron N5040

[raajkumar]

I had problem on a Dell Inspiron N5040 laptop it is switch on only one time and it will off within 5 seconds. Thereafter if i press power switch it is not working. i checked 3v/5V regulator it is very hot and also it is not giving output. So i replaced it TPS51125. But the problem not solved and it is making hot again. i checked everything around that chip. later i removed 3v3 and 5V coils and checked for shorting. I found 3v3 line was shorted. I inject 2volts on 3v3 line and checked for heating any components. I found the heat on Wifi card. I just removed it and checked the short. Bingo i solved that problem. i soldered supply coils (3v3/5V ) again and i replaced new wifi card. Now the laptop working.