Lenovo 305-15IBD - completely dead - no signs of life

[Andrzejj]

Hi,

I have a Lenovo 305-15IBD. It's dead.
No power, No lights, no reaction to power button.

I have taken a look inside and tested the DC jack. I have 20.76V on 2 pins on JDCIN1 socket on the motherboard.

I also have exactly the same laptop but fully working. I did some measurements and the working motherboard have 3.3V and 5V on PU202 (when charger connected, before power button pressed). Dead motherboard doesn't have 3.3V and 5V on PU202.

Could you please give me some advice on how to test/diagnose the motherboard further. I'm not sure what to do next as I'm a beginner. I would like to learn. Thank you

[diif]

Re: Lenovo 305-15IBD - completely dead - no signs of life

Check the voltages on the mosfets near the DC jack.

[Techtiger]

Re: Lenovo 305-15IBD - completely dead - no signs of life

Try this Schematic
Test Pl101 Pl102 for +20V
ADP_ID 3.3V ,AC Adepeter 90W?
RTC Battery 3.3V
PQ301 fet pin 5.6.7.8 +20V pin4 8.8V pin 1.2.3 +20V
Voltage on PQ302 must be the same measurements

[Andrzejj]

Re: Lenovo 305-15IBD - completely dead - no signs of life

PL101 and PL102 - 20.75V
RTC Battery - 3.32V
PQ301 - pin 1.2.3.5.6.7.8 - 20.75V, pin 4 - 8.79V
PQ302 - pin 1.2.3.5.6.7.8 - 20.75V, pin 4 - 8.79V
PQ302 - pin 1.2.3 - 20.75V, pin 4 - 20.26V, pin 5.6.7.8 - 20.69V
ADP_ID 3.3V ,AC Adepeter 90W? - I'm not sure how to check this. AC Adapter is 65W

[Techtiger]

Re: Lenovo 305-15IBD - completely dead - no signs of life

Now test 5/3ALWS Voltage page 46 Schematic PL402 PL404
PU401 pin5 and PU402 pin7

[Andrzejj]

Re: Lenovo 305-15IBD - completely dead - no signs of life

PL402 - 0V
PL404 - 0V
PU401 pin5 - 0V
PU402 pin7 - 5.19V

[Techtiger]

Re: Lenovo 305-15IBD - completely dead - no signs of life

test Voltage on PU301 pin 1 2 5 6 16 20 ?

desolder jumper PJ401 and test both sides of the JUMPER with the multimetre on Diode mode 1-2 jumper) ?
PU401 pin 5 test with the multimetre on Diode ?
PU401 Voltage on pin 7 8 2 ?
PU402 Voltgae on 1 5 8 ?
desolder jumper PJ402 and test both sides of the JUMPER with the multimetre on Diode mode 1-2 jumper) ?