LENOVO NM-A841 Missing 5v/3v voltages

[kalilinux25]

Hi board CG521 NM-A841 REV 1.0
NO POWER

PU301
PIN1 - 19V
PIN2 - 19V
PIN3 - 19V
PIN4 - 19V
PIN5 - 19V
PIN6 - 5.8V
PIN7 - 0V
PIN8 -0V
PIN9 -0V
PIN10 -0
PIN11 -0V
PIN12 -19V
PIN13- 19V
PIN14 -19V
PIN15 - 5.8
PIN16 - 0V

PU401

PIN1 - 0V
PIN2 - 19V
PIN3 - 19V
PIN4 - 19V
PIN5 - 19V
PIN6 - 0V
PIN7 - 0V
PIN8 -0V
PIN9 -0V
PIN10 -0V
PIN11 -19V
PIN12 -0V
PIN13- 0V
PIN14 -0V
PIN15 - 0V
PIN16 - 0V
PIN17 - 0V
PIN18 - 0V
PIN19 - 0V
PIN20 - 0V

Hi i hope someone can help me with this issue

checling coil impendace PL501,PL401,PL402 is ok no shorted

[Sephir0th]

Re: LENOVO Missing 5v/3v voltages

Is this with battery removed? Check if PQ309 and/or PQ303 is shorted (D/S/G). 19V on Battery Charging Rail is too much in my opinion.

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

Is this with battery removed? Check if PQ309 and/or PQ303 is shorted (D/S/G). 19V on Battery Charging Rail is too much in my opinion.

yes without the battery sir

pq309 and pq303 is not shorted sir

[Techtiger]

Re: LENOVO Missing 5v/3v voltages

Check again pin11 PU401 cannot be +19V it should be approximately 3V-3.3V

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

Check again pin11 cannot be +19V it should be approximately 3V-3.3V

sorry pin 11 has 0v sir

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

Pin 17 is vcc internal ldo output should be 3.3v here

Pin 11 is enable2 can be 19v as connected to input supply, needed to turn on ic


Pin12 is enable1 pin coming from KBC ec-on


Pin---17=0 no ldo supply check again

Pin---12=0 volt no en to generate pwm operation coil supply

Pin11=supply to turn on ic

[Techtiger]

Re: LENOVO Missing 5v/3v voltages

Test all requirements of SIO & pin 85 ? Yep correct EN2 is +19V EN1 can go up to +4.5V I have to get a new pair of glasses

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

Pin 17 is vcc internal ldo output should be 3.3v here

Pin 11 is enable2 can be 19v as connected to input supply, needed to turn on ic


Pin12 is enable1 pin coming from KBC ec-on


Pin---17=0 no ldo supply check again

Pin---12=0 volt no en to generate pwm operation coil supply

Pin11=supply to turn on ic

pin 17 has 0v
pin 12 0v
pin 11 0v

so the ic is dead? or other aprts?

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

Input voltage supply is missing, first check pin---11 voltage and how is it possible that you have 19v at pin 5 and not at pin11

Can not tell now

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

Input voltage supply is missing, first check pin---11 voltage and how is it possible that you have 19v at pin 5 and not at pin11

Can not tell now

can i try to pump voltage in pin 11 sir?

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

No

Check pin 5 voltage 19v stable or dropping

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

No

Check pin 5 voltage 19v stable or dropping

very stable sir nothing is going drop

[SMDFlea]

Re: LENOVO Missing 5v/3v voltages

Look at the trace on pu401 pin 11 ,are there any resistors connected to it. Don't inject any voltage on pin 11 ! .The LA-C371P schematic has pin 11 as ENLDO_3V5V ,it goes through a voltage divider.

https://drive.google.com/file/d/1NK6...OCOaFraFV/view

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

Pin11 has no resistor as per schematic but check again

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

Look at the trace on pu401 pin 11 ,are there any resistors connected to it. Don't inject any voltage on pin 11 ! .The LA-C371P schematic has pin 11 as ENLDO_3V5V ,it goes through a voltage divider.

https://drive.google.com/file/d/1NK6...OCOaFraFV/view

nope sir I dint inject it .

[SMDFlea]

Re: LENOVO Missing 5v/3v voltages

Pin11 has no resistor as per schematic but check

According to the nm-a841 schematic no ,but schematics aren't always right even though you expect them to be. It can't be 19v on pin 11. Let's gets other members views and fix this together

.

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

I agree, physically check any resistor attached to this pin---11

At least ldo should come out at pin---17 but since ic is not getting vcc no chance

[kalilinux25]

Re: LENOVO Missing 5v/3v voltages

I agree, physically check any resistor attached to this pin---11

At least ldo should come out at pin---17 but since ic is not getting vcc no chance

whats the verdict sir?

[stingerchamp]

Re: LENOVO Missing 5v/3v voltages

Trace pin 11 to any resistor attached or not in beep mode

[SMDFlea]

Re: LENOVO Missing 5v/3v voltages

whats the verdict sir?

Have you found any resistors connected to the pin 11 trace or does it go into a via through the board ? A board view would help but I'm not sure if it's available. Take a picture of pu401 with the surrounding parts