Lenovo Ideapad S145-15IWL Model 81MV Water damage.

[M1ch4L]

Hello.

First, I would like to extend my wishes for a Happy New Year to everyone.

... so I got this notebook for repair. The ntb is not turning on. A small amount of water was spilled on the keyboard and I found only 2 dried spots, patches on the motherboard. One around Mosfet PQ5302 but is not damaged and the second on JEDP1 connector.

I measured:

Mosfets:
PQ5301 PIN:4 25,35V
PQ5908 PIN:5 GT_PH shorted to the ground
PQ5902 PINs 1-4 shorted to the ground

Coils:
PL5901 shorted to the ground
PL5902 shorted to the ground

Part:
U3301 - PIN5 +3VS is 3,305V
PU3601 - PIN24 +5VALW is 5,09V

When I put in the power supply only the motherboard (without RAM ,keyboard, ...etc) takes immediately 0,46A and it goes up to cca 0,73A (maybe more) and like the Ampere the PCH heat makes the same, after a few seconds the coils PL5901 and
PL5902 are getting hot too. I am afraid that the PCH has gone to the other world. Would like to get some instructions how to check it deeper. Thanks in advance!

[M1ch4L]

The PCH is getting hot, so I started to looking after the voltages what are going to this chip. Part RPC807 have no short, the PINs 3 and 4 should have 3V but they have 3,3V. RPC810 no short 3,3V. Part UC1302 PIN 1-2-6-7=1,05V ALW, PIN 4=5V ALW, PINs 13-14 +VCCIO are shorted when power supply is off, when on there is 1,05V, PIN 5 VCCST_EN 3,2V. PIN 3 VCCIO_EN 3,3V. PU3601 PIN17 VCC should be 1,35V but is 4,85V.

[M1ch4L]

I lifted one side of the Coils PL5901, PL5902, PL5904 and the shorts disappeared from mosfets, only Mosfet PQ5902 was shorted Source to Gate. I removed it and tested, PMOS test in Diode mode shows 0,5+V, Resistance check 10+Mohm, continuity test ok too ... so next I removed PU5801 from the other side of the board, after that the short was not there anymore ... but after the coils the short remains, at least I know that the mosfets are good.

...On the VGA side I lifted coils PL801 and PL802, the mosfet PQ802 pin5 is shorted to the ground and the mosfet PQ801 is connected to this via pins 1,2,3 they are shorted too. Coil PL802 to the way to mosfets is not shorted, but way to VGA is shorted. Coil PL801 is shorted both ways. In the near is chip PU801 and it looks that is damaged too.

BoardView can be found here: Lenovo IdeaPad S145 Compal FS441_FS540 NM-C121 - Badcaps

[mcplslg123]

Totally wrong direction and approach. the way you're proceeding, mb may get killed.(eg as per post#2,you think VCC should be 1.35V whereas its correct at 5V)

Measure resistance to GND and voltage on all coils.

Resistance should be measured without power.

What you deem as short on coil may not be short at all as there are rails which will show very low resistance to GND and thats fine.