Lenovo NM-C111 REV 1.0 no AC_OK signal no power

[kalilinux25]

Hi I have a BOARD FS440FS541 NM-C111 REV 1.0 2019-01-08

It has no power
Ive check all coils no shorted coils

I already change the CHARGER IC ( BQBQ24780S )

Pins

ACDET - 2V

CMPOUT - 5.4V

REGN -6V
BTST - 5.6V
VCC -19V

[mon2]

Re: Lenovo no AC_OK signal no power

1) Link or post schematic if available.

2) ACDET is too low. Only if ACDET is > +2v4 will the ACOK go high. Post the current voltage reading for ACOK pin.

3) Next, power down and inspect the resistor voltage divider on that should be +19v on the HIGH resistor. Are the 2 resistor values similar in resistance like the attached ? The TI website has the full datasheet for this component.

Post your updates.

[mcplslg123]

Re: Lenovo no AC_OK signal no power

Are you getting +19V on pin5-8 of 1st dc in mosfet?? Gate voltage for same mosfet on pin4??

[kalilinux25]

Re: Lenovo no AC_OK signal no power

PQ311
pin 5 -20v
pin1,2,3 - 0v
pin 4 - 0v

AC_OK has 0v

PR302 has correct value and also the PR310

I test the voltage of the pr302 and PR310 it has 0v value

Ive chech the ACDET 2 resistor the (PR313,PR315) has correct value tested the PR313 pin 1 has 20v, pin 2 has 2.8v

[kalilinux25]

Re: Lenovo no AC_OK signal no power

Are you getting +19V on pin5-8 of 1st dc in mosfet?? Gate voltage for same mosfet on pin4??

PQ311
pin 5 -20v
pin1,2,3 - 0v
pin 4 - 0v

[kalilinux25]

Re: Lenovo no AC_OK signal no power

1) Link or post schematic if available.

2) ACDET is too low. Only if ACDET is > +2v4 will the ACOK go high. Post the current voltage reading for ACOK pin.

3) Next, power down and inspect the resistor voltage divider on that should be +19v on the HIGH resistor. Are the 2 resistor values similar in resistance like the attached ? The TI website has the full datasheet for this component.

Post your updates.

What do I need to test next sir?

[mon2]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

(PR313) pin 2 has 2.8v

This is a good voltage for ACDET.

Q1: What is the voltage on ACOK pin # 5 of PU301 ?

If ACOK is 0volts, confirm that the pull-up resistor @ RE42 is still present. Post the voltage reading on pin 1 and 2 of RE42 resistor (100k). This resistor is required as the ACOK pin is an open-drain style. This means there is a logic low support for ACOK but NO LOGIC HIGH. The resistor @ RE42 is used to soft-pull up the line to the +3v3 rail for the logic '1' state. Open drain = pin becomes OPEN when it is a 'high' state. Again, a pull-up resistor must be applied on this ACOK line.

Does RE42, pin #1 read @ +3v3 @ +3VL ?

+3VL is vital to the proper operation of this logic board so confirm it is there.

Also confirm that resistor RE74 (0 ohms) is present.

All this then must lead to the EC chip under ACIN# label.

Next, power down, remove all power. Meter in resistance mode (200 ohms).

Check & post the meter readings for:

a) PQ311 - source (1-2-3) & drain (5-6-7-8)
b) PQ311 - source (1-2-3) & gate (4)
c) PQ311 - gate (4) & drain (5-6-7-8)

then move to inspect PQ312

d) PQ312 - source (1-2-3) & drain (5-6-7-8)
e) PQ312 - source (1-2-3) & gate (4)
f) PQ312 - gate (4) & drain (5-6-7-8)

Confirm PU3501 (pin #5) is creating the +3VLP rail. Post the voltage reading.

This +3VLP rail is then used as +3VL after the jumper (solder short) @ PJ3505. Confirm that the +3VL rail is correct at this short jumper short.

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

RE42 pin #1 - 0v

QE2 pin #1 - 0v
pin #2 - 0v
pin #3 - 0v
RE42 9 kioOhms outboard


Check & post the meter readings for:

a) PQ311 - source (1-2-3) & drain (5-6-7-8) -60Kohms
b) PQ311 - source (1-2-3) & gate (4) ----6 ohms
c) PQ311 - gate (4) & drain (5-6-7-8)----400kiloohms

then move to inspect PQ312

d) PQ312 - source (1-2-3) & drain (5-6-7-8)----2ohms
e) PQ312 - source (1-2-3) & gate (4)-------2ohms
f) PQ312 - gate (4) & drain (5-6-7-8)--------4ohms

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

PU3501- PIN 5 has 0V
PJ3503 - 0v

[mon2]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

1) On coil PL3501, what is the voltage on pin # 2 ?

2) PR314, pin #1 ? This is the voltage that is required to power the charger IC so that it can function to deliver the V20B+ rail.

3) Be sure that the charger IC has been soldered properly in the rework.

4) Appears that mosfet PQ312 may be defective but first confirm that the IC is soldered OK and is being powered through PD302 (dual common cathode diode). Pin 28 of PU301 must be a valid power rail to function.

Once PU301 is confirmed to be powered, post the voltages on pins 3 & 4 of PU301.

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

1) On coil PL3501, what is the voltage on pin # 2 ?

2) PR314, pin #1 ? This is the voltage that is required to power the charger IC so that it can function to deliver the V20B+ rail.

3) Be sure that the charger IC has been soldered properly in the rework.

4) Appears that mosfet PQ312 may be defective but first confirm that the IC is soldered OK and is being powered through PD302 (dual common cathode diode). Pin 28 of PU301 must be a valid power rail to function.

Once PU301 is confirmed to be powered, post the voltages on pins 3 & 4 of PU301.

PL3501 pin 1 has 0v
PR314 19.74V
Charger is soldered properly

PU301
pin 3 --- 0v
pin 4 ---- 0v

[mcplslg123]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

PQ312 is clearly shorted. Replace it.

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

PQ312 is clearly shorted. Replace it.

After cahnging it sir the Board has power but its consuming around 50miliamps
without pressing the power on , blinking light power led

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

Pu301 -
pin 3 -19.95v
pin4-25v

pl3501
-stable 3.3v
pl3502
-stable 5.1v

[mon2]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

What is the voltage of the ACOK pin on PU301 now?

Is every power rail normal now on the logic board?

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

What is the voltage of the ACOK pin on PU301 now?

Is every power rail normal now on the logic board?

all power rails is normal

PU301 Pin 5 has 3.2v

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

+3VL_EC present
PLT_RST# 3.3v
SYS_PWROK_EC 3.2v
+1.8VALW present

JCMOS1 3.1v

[mon2]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

So it is working properly now?

[kalilinux25]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

So it is working properly now?

No sir its only taking 50milliamps. And the power led is blinking. I know its not normal it should be around 100 or 200

[mon2]

Re: Lenovo NM-C111 REV 1.0 no AC_OK signal no power

You may have to reflash the bios but personally do not have experience with this. If you have the tools, desolder and back up the current bios contents.

Then consider to erase and flash a fresh image to test again. Or wait on advice from others but often this is the next suggested step.