Lenovo ideapad 330s-15ikb not turn on

[tsiga]

Hello everyone!

I need some guidance.
My client brought to me aLenovo ideapad 33s15ikb with wather damage. motherboard number: 330s_KBL_MB_V07 REV:MP
The motherboard several points are oxidized.
I checked with microscope after i cleaned with ultrasonic cleaner,
Every oxidized component,joins looks clear, and shiny. I didn't see any missing solder pins or components.

When i'm trying to turn it on, the power button led is light up, and the power on led also light in amber.
I tried to start with lab power suppy, but picks up 6-700mA and the U6002 pwm ic gets very hot.
I measured voltage on coils
L6001: 5V
L6002: 3.6V
and coil to ground:
L6001:20Kohm
L6002 3.7Kohm
L5901:27Kohm
L6100: 163ohm
i have boardview and chematic.
plz help!
thanks!

[mon2]

Re: Lenovo ideapad 330s-15ikb not turn on

In my opinion, L6002 should not be 3v6, it should be close to 3v3. As you have noted it being very hot for U6002, consider to at least reflow it but recommend that it be replaced.

Aliexpress should offer these but be 100% sure it is with the same markings as the original.

https://www.aliexpress.com/item/4000...e9a97ee8d10606

Before going on the shopping trip, do confirm the status of the first 2 mosfets that enter at the board => Q5901 & Q5902.

Remove all power and check their resistance for possible shorts.

Resistance (2k scale on the meter):

source & drain
source & gate
gate & drain

Searching for any low resistance readings on the mosfet which indicates the mosfet is likely defective and must be replaced.

[tsiga]

Re: Lenovo ideapad 330s-15ikb not turn on

Thank you for your advace!
I did measure these mosfets, as you asked. Each looks good.
i will order this power ic, i hope this cause the problem.