Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

[m0nk3y]

I have a Lenevo g580 that does not turn and there are no lights.

from what i was able to deduce from the web is that i should check the 5v and 3v rails.

PU4103 power regulator (page 41 on schematic) 3v (pin3) was good but 5v (pin13) was only giving ~1.6v - VIN from power supply 10.8V from battery terminal

while probing around the area for shorts to ground i accidently brushed up on the chip and the thing was burning hot. since i couldn't find any shorts i removed the chip and reapplied voltage. PU4104 nearly instantly heated up and was giving of a little smoke. the power supply was drawing 3amps (power supply limit is 3amp).

i found that the PL4102 coil had a short removing it showed that pin2 had the short to ground. i removed the capacitor next to it PT4102 but there is still a short.

now this is where i hit a brick wall. there are no more parts left in that area that could cause a ground to short.
PL4102 (pin2) and PT4102 (pin1) have a short to ground.

please advise

thank you

[piernov]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

There's no reason for VREG5 (pin 13) of TPS51225 to not be 5V in this case, it's an LDO which is not connected to many components (and I don't see where it could be shorted to ground), so PU4103 is probably bad. But you also need to find where the short on 3D3V_PWR comes from. 3D3V_S5 is used for many component so you will need to inject power on that line to see what's pulling it to ground.
However I must say that if PU4104 burnt, DCBATOUT may have been sent on this 3.3V line so there's little hope left for this motherboard…

[highpulse]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

you must chek , on the 51125 TPS , remove it , but dont ADD poweer to the board or else you can fry the 19 volts line !

CHek , with IC out of board , measure the ENABLE pins to GND also PHASE lines as also LDO lines , post here values of does pins

measure on 200 ohm scale and let us know

[m0nk3y]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

51125 TPS resistance to ground: only pin 12 (VIN) is giving 95ohm all other pins show no resistance (no value on meter).

[ridamouh159]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

We don't see many components -composants-in your foto.
i attached some fotos for a LENOVO G580 CORE I5 coming to me with problem

[m0nk3y]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

ridamouh159 this is the exact same board with same components but i forgot to take pictures before removing parts.

does yours have the same problem?

[m0nk3y]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

i have marked the short

[Nizarcherif]

Re: Lenovo G580 - Power Plane Regulator 5v3p3v - short to ground

Hi please did you solve the problem where the short circuit coming from i have the same board and the same problem short circuit in the 3v line and pu4103 burning hot when plugged i removed pu4103 and it is still shorted i found another forum saying that it's the kbc or io chip which is the npce88... In this board pls if you found something else about this problem tell me thanks