nm-b451 - lenovo ideapad - 320-15ikb - not starting

[rediii]

hey guys, got a lenovo board here. all always on rails present. board drawing 0.03 amps with 19.5 v. when pressing start button no rise in amps. led stays on and goes of, while board is in reset mode. deeper measurements gave me the idea of an pch error, because pm_slp_sus# is dropping from 3.3 v (pch side) to 2.3 v (ec side). already replaced kbc (programmed it). no pm_slp_s3 nor s4 etc. any ideas what could be wrong here? under the ir cam nothin' is getting intense "hot", just pulsing ec temps in a normal range. thanks so far .

rails present:
+3VALW
+5VALW
+3VALW_PCH
+1.8VALW
+1.0VALW
+3VL_EC

on schematic sheet 47 of 60 all steps until number 5 are fulfilled.

got rev 1.0 instead of 0.2...

[mon2]

Re: nm-b451 - lenovo ideapad - 320-15ikb - not starting

As you are only consuming 30ma on the adapter, review the charger circuit on page 53.

Remove all power. Meter in resistance mode (200 ohms).

Check and post the resistance of each mosfet as follows:

Source to drain
Source to gate
Gate to drain

Then meter in dc volts mode (30v or higher).

Next, power up with adapter and measure the voltages of each pin of the charger ic on page 53. Post the readings.

[rediii]

Re: nm-b451 - lenovo ideapad - 320-15ikb - not starting

As you are only consuming 30ma on the adapter, review the charger circuit on page 53.

Remove all power. Meter in resistance mode (200 ohms).

Check and post the resistance of each mosfet as follows:

Source to drain
Source to gate
Gate to drain

Then meter in dc volts mode (30v or higher).

Next, power up with adapter and measure the voltages of each pin of the charger ic on page 53. Post the readings.

thanks for this advice!

msfets are intact... measured while turning the device on/pressing pwrbtn

1: 19.5 V
2: 19.5 V
3: 19.5 V
4: 25 V
5: 3.25 V
6: 2.78 V
7: 50-55 mV
8: 175-180 mV
9: 45 mV
10: nearly nothing, around 5 V
11: 3.27 V
12: 3.27 V
13: around 1.308 V
14: around 1.7 V
15: 3.09 V
16: 1.06 V
17: 0.206 V
18: 0.214 V
19: 0.218 V
20: 0.218 V
21: 0.79 V
22: 0 V
23: 0 V
24: 5.98 V
25: 0-6 V, fluctuating while pressing button
26: 8.41 V
27: 19.1 V

NO BAT present, just naked pcb!

thank you

[rediii]

Re: nm-b451 - lenovo ideapad - 320-15ikb - not starting

thanks for this advice!

msfets are intact... measured while turning the device on/pressing pwrbtn

1: 19.5 V
2: 19.5 V
3: 19.5 V
4: 25 V
5: 3.25 V
6: 2.78 V
7: 50-55 mV
8: 175-180 mV
9: 45 mV
10: nearly nothing, around 5 V
11: 3.27 V
12: 3.27 V
13: around 1.308 V
14: around 1.7 V
15: 3.09 V
16: 1.06 V
17: 0.206 V
18: 0.214 V
19: 0.218 V
20: 0.218 V
21: 0.79 V
22: 0 V
23: 0 V
24: 5.98 V
25: 0-6 V, fluctuating while pressing button
26: 8.41 V
27: 19.1 V

NO BAT present, just naked pcb!

thank you

measured while turning the device on/pressing pwrbtn (this refers to measuring on ic)

10: nearly nothing, around 5 V => 5 mv!!!

[rediii]

Re: nm-b451 - lenovo ideapad - 320-15ikb - not starting

As you are only consuming 30ma on the adapter, review the charger circuit on page 53.

Remove all power. Meter in resistance mode (200 ohms).

Check and post the resistance of each mosfet as follows:

Source to drain
Source to gate
Gate to drain

Then meter in dc volts mode (30v or higher).

Next, power up with adapter and measure the voltages of each pin of the charger ic on page 53. Post the readings.

so i doubt it's a charger issue. but thanks for your help