Lenovo G40-80 ACLU3 ACLU4 NM A362 not charging

[G_sene]

Battery only:

Pin 1, 2 and 3 - 0v

I will put PQ996 back and remove the capacitor to test ACDET

[mon2]

What is the voltage on the battery being used with this board? Is it now at 0v?

[G_sene]

What is the voltage on the battery being used with this board? Is it now at 0v?

14.4v

I'll measure again

[mon2]

If the battery is at this voltage, then VMB2 cannot be 0v. There should be a voltage on pin #3 of PU202A. Confirm this. There should be a reduced voltage on pin #3 sourced from the battery.

Next, remove all power. Meter in resistance mode.

Measure the resistance across the mosfet @ PQ303:

source / drain
source / gate
gate / drain

Post each measurement. This mosfet should be on only when powered by battery.

[G_sene]

Battery has 14.4v

PU202A
Pin 3 - 2.16v

PQ303
Source/Drain 61.72k
Source/Gate 3.166M
Gate/Drain 4.69M

[G_sene]

Connect only the battery and measure the voltage on PU202A

pins 1, 2 and 3.

No power adapter. What is the voltage on the battery?

Also, the ACDET is not the proper voltage based on the adapter voltage and the shared resistor values for the voltage divider.

Suggest to flux and remove PC316 which may be affecting this voltage. The resistor values look ok for now. What is the ACDET voltage after removing PC316? For this ACDET testing, place back the PQ996 component on the board.

I removed PC316, and ACDET has 2.6v, but still not charging.

[mon2]

PQ303
Source/Drain 61.72k

This is very low for a good mosfet.

Flux and remove this mosfet. Then power up again without this mosfet to test the charging.

[G_sene]

This is very low for a good mosfet.

Flux and remove this mosfet. Then power up again without this mosfet to test the charging.

Nice!

Notebook recognized the power supply.
I need replace this mosfet for a better charging, right?

For a while the icon showed the battery bar going up, but now it has stopped and only shows that it is connected

[mon2]

Good. Yes, do replace it because it was leaking. A good mosfet should be hundreds of k ohms or higher. Test again after the replacement. We can continue the review if required. Do test with other good batteries if they are available to you. Just to rule out a defective battery.

The battery charging can stop if there is an excessive current draw or it believes there is too high of a current consumption. Not at my desk but review the full path resistance of the battery charge circuit. There is a resistor in the path. Remove all power and measure the resistance at the charger ic pins on the N and P pins. What is the resistance?

To clarify, with no power and no battery to the board, measure the resistance between pins 12 & 13 directly on the charger IC. These are SRN & SRP pins which measure the amount of current for charging the battery. This total path resistance should be close to ~17 ohms. Post your measurement. If this resistance is higher then the charger IC will assume something is wrong and will power down the charging feature.

For completion, also consider to measure the high side mosfet @ PQ309 and the low side mosfet @ PQ311 using the same resistance check as before. Again, if the resistance is low, suggest to flux and remove the mosfet -> allow it to cool and then measure it again for a low resistance. If required, replace the mosfet(s). Suspecting that whatever event took out the battery mosfet, may have caused some additional stress to other mosfets. Will not hurt to measure these parts.

[G_sene]

Good. Yes, do replace it because it was leaking. A good mosfet should be hundreds of k ohms or higher. Test again after the replacement. We can continue the review if required. Do test with other good batteries if they are available to you. Just to rule out a defective battery.

The battery charging can stop if there is an excessive current draw or it believes there is too high of a current consumption. Not at my desk but review the full path resistance of the battery charge circuit. There is a resistor in the path. Remove all power and measure the resistance at the charger ic pins on the N and P pins. What is the resistance?

To clarify, with no power and no battery to the board, measure the resistance between pins 12 & 13 directly on the charger IC. These are SRN & SRP pins which measure the amount of current for charging the battery. This total path resistance should be close to ~17 ohms. Post your measurement. If this resistance is higher then the charger IC will assume something is wrong and will power down the charging feature.

For completion, also consider to measure the high side mosfet @ PQ309 and the low side mosfet @ PQ311 using the same resistance check as before. Again, if the resistance is low, suggest to flux and remove the mosfet -> allow it to cool and then measure it again for a low resistance. If required, replace the mosfet(s). Suspecting that whatever event took out the battery mosfet, may have caused some additional stress to other mosfets. Will not hurt to measure these parts.

Okay, I understand.

So far I've seen the following:

Pins 12 and 13 show 17.8 to 17.9ohm

PQ311 source/gate 192k
PQ309 source/gate 135k

I don't have another PQ303 to swap, so I'll need to swap it to see if it charges again.

[mon2]

The current sense loop looks ok to me. You can touch your meter probes together to gauge the baseline of your meter @ 0R ohms. Subtract this value from your actual measurements.

Do measure each permutation of the mosfet resistance. Assuming the posted values are the lowest measurements, they do appear low. This may be because they are in-circuit so the suggestion is to flux and remove them from the board. Then allow each to cool down and measure them again while they are on your work bench. If the values remain this low, they are defective and must be replaced.

Measure:

source / drain
source / gate
gate / drain

The replacement mosfets do not have to be exactly the same part #. There are many compatible mosfets out there.

Compatible mosfet should be:

a) same physical size
b) same pinout (almost everyone uses the same pinout)
c) same type (P-channel or N-channel) - check the datasheet of the original part to match
d) support the source / drain voltage of the original or higher (30V for this P-channel @ battery mosfet)
e) support the same current or higher (often can compare the Rds value; lower is better but will be higher on $$)
f) brand names - typically the major brands sold on DK / Mouser / Arrow are more reputable than sourcing through Aliexpress which may be fakes with fake names / logos
g) donor boards are fine to use if you trust the donor board - test the resistance like above to confirm before using

[G_sene]

I'm not able to measure the resistance of the MOSFETs off the board.

Another question, I measured the resistance again, black lead on the source and red lead on the gate (with the MOSFET on the board), and the resistance was 180k. When I invert the leads the resistance goes to 110-120k, which is correct?

But with the MOSFETs off the board, I didn't have as big a change as with the PQ303 which went to M OHM.

[G_sene]

Excuse my ignorance, but what would be the correct way to connect the multimeter leads for this test?

source / drain
source / gate
gate / drain

[mon2]

In resistance mode, there is no polarity. Place the meter lead of either color onto the source pins (1-2-3 - select any of these since they are bonded to one point - check the bottom side of the part to confirm); other meter lead to drain (5-6-7-8 - pick any of them since they are also shorted - check the bottom side to confirm). Measure the resistance. Certainly swap the meter lead to confirm the measurements. They should be close. In each of the tests, the resistance measurement should be hundreds of k ohms or higher if the part is not defective.

IMHO, if the resistance is low or even a suspect, replace the mosfet since they are low cost and often available from a donor board. The parts are common to many makes / models of motherboards. Be sure they are within specs outlined earlier. If in doubt, post the original part # and the part # you wish to use for the replacement and someone will assist to confirm if the replacement is a valid one or not.

[G_sene]

In resistance mode, there is no polarity. Place the meter lead of either color onto the source pins (1-2-3 - select any of these since they are bonded to one point - check the bottom side of the part to confirm); other meter lead to drain (5-6-7-8 - pick any of them since they are also shorted - check the bottom side to confirm). Measure the resistance. Certainly swap the meter lead to confirm the measurements. They should be close. In each of the tests, the resistance measurement should be hundreds of k ohms or higher if the part is not defective.

IMHO, if the resistance is low or even a suspect, replace the mosfet since they are low cost and often available from a donor board. The parts are common to many makes / models of motherboards. Be sure they are within specs outlined earlier. If in doubt, post the original part # and the part # you wish to use for the replacement and someone will assist to confirm if the replacement is a valid one or not.

Here we go, I'll post the complete measurements.

PQ309
Gate/source 207k (141k inverting the tips)

Gate/drain 1.40M (950k inverting the tips)

Source/drain 1.30M (1.21M inverting the tips)

PQ311
Gate/source 191k (131k inverting the tips)

Gate/drain 458k (476k inverting the tips)

Source/drain 327k (244k inverting the tips)

Unfortunately I don't have any scrap since I'm a beginner, so I'm taking the opportunity to see if I'll need to buy any more MOSFETs that are defective.

[G_sene]

Hi, everyone!

My new PQ303 (4407A) arrived, I soldered it, but it still won't charge and won't recognize the charger.

[mon2]

Can the charger power on the logic board? What is the voltage to ground of ACDET? ACOK?

See attached - something we should have checked much earlier. Disconnect the power adapter cable and view inside of the round connector.

There should be a needle like pin in the center of this connector. This pin is the ADAPTER_ID pin and must be present. This is the only method used here to detect the presence of the power adapter. The EC reads this pin to determine the integrity of the power adapter.

Do you see the needle like pin or is it bent to one side or perhaps missing? If possible, share a pic of this connector & pin.

[G_sene]

Can the charger power on the logic board? What is the voltage to ground of ACDET? ACOK?

See attached - something we should have checked much earlier. Disconnect the power adapter cable and view inside of the round connector.

There should be a needle like pin in the center of this connector. This pin is the ADAPTER_ID pin and must be present. This is the only method used here to detect the presence of the power adapter. The EC reads this pin to determine the integrity of the power adapter.

Do you see the needle like pin or is it bent to one side or perhaps missing? If possible, share a pic of this connector & pin.

Yes, the charger powers the board normally.
I tested the ADAPTER_ID on pin Possible prob on a Gigabyte board of the EC; it has 3.3V.
I'll check if it's bent or something.

[G_sene]

Yes, the charger powers the board normally.
I tested the ADAPTER_ID on pin Possible prob on a Gigabyte board of the EC; it has 3.3V.
I'll check if it's bent or something.

Sorry

I tested pin 84 ADAPTER_ID_ON(3.3v) and pin 72 ADAPTER_ID (1.44v)

[mon2]

That is fine but have you confirmed if the needle of the power adapter is present? Requested a pic and confirmation if the needle is bent or not.