Lenovo Yoga 530-14ikb, no charging, NM-B601

[hopkok]

Hi masters, I have on bench strange Lenovo Yoga. It is working from charger and it is working from charged battery too. But if battery is connected and I plug charger in, not charging and works from battery. Not opening first mosfet, N1 point in schematic has 0V and N2 point has battery voltage, around 7,6V.

BQ24780s changed but the same.
voltage on BQ24780, battery connected:
VCC-19V
ACN-7.7V
ACP-7.7V
CMSRC-0V
ACDRV-0V
ACOK-3.3V
ACDET-2.7V
REGN -> 6 V
BTST -> 7.4V

Any help really appreciiated, many thanks in advance.

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove the PQ312 mosfet = 2nd DCin mosfet.

Power up again and check the voltage of N1 test point.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove the PQ312 mosfet = 2nd DCin mosfet.

Power up again and check the voltage of N1 test point.

Hi,
N1=0V

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove the 4k resistor (PR310) that is between the ACDRV pin and the gate pins of the DCin mosfets.

Power up again -> measure the voltage to ground of the ACDRV pin pad (PR310, pin #2).

Is the voltage on ACDRV now ~25 volts ?

Remove all power.

Meter in resistance mode.

Check the resistance across the first DCin mosfet as follows:

source (1-2-3) & drain (5-6-7-8) ; pick one pin from each group
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement.

Also...post the resistance values of the first mosfet. Need to check if this mosfet is defective.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

2nd mosfet needs to be attached back to board before this step?

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

No. Leave it off.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove the 4k resistor (PR310) that is between the ACDRV pin and the gate pins of the DCin mosfets.

Power up again -> measure the voltage to ground of the ACDRV pin pad (PR310, pin #2).

Is the voltage on ACDRV now ~25 volts ?

Remove all power.

Meter in resistance mode.

Check the resistance across the first DCin mosfet as follows:

source (1-2-3) & drain (5-6-7-8) ; pick one pin from each group
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement.

Power up again -> measure the voltage to ground of the ACDRV pin pad (PR310, pin #2). Voltage on PIN 2 is 0V

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove all power. Meter in resistance mode.

Measure the resistance from N1 test point to pin #3 (CMSRC) on the charger IC. What is the measurement?

Check the resistance to ground of the same ACDRV pin (PR310, pin #2).

Next, place the meter in DIODE mode.

Red meter probe, yes red to ground.
Black meter probe to the same ACDRV pin (PR310, pin #2).

Post each measurement.

Updated the wrong post ... do post the mosfet checks for the first mosfet. Need to confirm it is not defective.

Can you post a pic of the charger IC placement? It should be soldered down properly.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Sorry, now have to leave office, here is 19:30. I always soldering under SCOPE, it is soldered 100 percent good. It was same with old IC. Will post measurements as soon as possible. Many thanks for try to help. See you soon.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Resistance from N1 test point to pin #3 (CMSRC) on the charger IC -> 4,2Kohms

Check the resistance to ground of the same ACDRV pin (PR310, pin #2) -> no resistance

Next, place the meter in DIODE mode.

Red meter probe, yes red to ground.
Black meter probe to the same ACDRV pin (PR310, pin #2) ->0,646

Meter in resistance mode.

Check the resistance across the first DCin mosfet as follows:

source (1-2-3) & drain (5-6-7-8) ; pick one pin from each group ->11,5Mohms
source (1-2-3) & gate (4)->no resistance
gate (4) & drain (5-6-7-8)->no resistance
Anyway, I checked these DC in mosfets in diode mode before, no shorts...

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Remove all power. Check the resistance of the mosfets at PQ316 and also the battery mosfet at PQ314.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Resistace S-D, S-G and D-G same measuring as 1st DC in mosfet?

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Yes. Suspecting that one of the other mosfets is leaking and forcing the charger IC to turn off ACDRV.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Hi,
PQ316
S-D-> 280Kohms
S-G-> 62Kohms
D-G-> 1,2Mohms

PQ314
S-D-> 4,3Mohms
S-G-> 0,48Mohms
D-G-> 1,2Mohms

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

PQ316 is too low on the measurements.

Can you remove it and then check the same resistance when the part is on your work table?

This part may be shorted.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

if I put red probe to S and black on D (in resistance mode) and vise versa, getting different readings, 280Kohms VS 4,4 Mohms... PQ316

[mon2]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Can you test now without this mosfet installed? The battery should have a pre-charge on it.

Just checking if the adapter and battery still fight it out on your logic board or not.

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Do you mean take PQ316 off and do same measuring?

Anyway, can this be ITE issue? I tried to read with SVOD 4 and not recognized...?

[SMDFlea]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

Do you mean take PQ316 off and do same measuring?

Anyway, can this be ITE issue? I tried to read with SVOD 4 and not recognized...?

You might have to power the board once .

ITE series not detected in svod Solution.https://www.badcaps.net/forum/showthread.php?t=66674

[hopkok]

Re: Lenovo Yoga 530-14ikb, no charging, NM-B601

motherboard powering up itself after charger connecting...