Lenovo G40-80 ACLU3 ACLU4 NM A362 not charging

[mon2]

Yes. We need to study the cluster of parts that are in this region of the board to confirm PQ303 is enabled and disabled for the proper cases.

[G_sene]

PQ303

Only adapter:

Source 19.97v
Drain 19.97v
Gate 0v

Only battery:

Source 13.86v
Drain 13.86v
Gate 0v

Battery and adapter:

Source 14v
Drain 14v
Gate 0.020v

[mon2]

The gate voltage should not be @ 0v for each of these cases.

Confirm that you have a resistor @ PR304. The one side will be mating to the Vin voltage and the other side = gate pin = a lower voltage. It appears that PR304 is missing if the gate voltage remains @ 0v.

[G_sene]

The gate voltage should not be @ 0v for each of these cases.

Confirm that you have a resistor @ PR304. The one side will be mating to the Vin voltage and the other side = gate pin = a lower voltage. It appears that PR304 is missing if the gate voltage remains @ 0v.

PR304 has the jumper I made. I'll check the voltage on the other side without VIN.

[mon2]

I am not following. There must be a resistor onboard at pr304. To one side of pr304 will be the wire to Vin. The other side of pr304 resistor must be connected to the gate of the battery mosfet. See the schematics. This resistor should be close to the schematic value.

Do you have a resistor at pr304? It seems to be missing since gate voltage is always 0v.

[G_sene]

I am not following. There must be a resistor onboard at pr304. To one side of pr304 will be the wire to Vin. The other side of pr304 resistor must be connected to the gate of the battery mosfet. See the schematics. This resistor should be close to the schematic value.

Do you have a resistor at pr304? It seems to be missing since gate voltage is always 0v.

PR304

With adapter

Side VIN - 19.98v
Side PQ303 0.024v

With battery

Side VIN - 0v
Side PQ303 - 0v

With battery and adapter

Side VIN 0.020 - 0.030v
Side PQ303 - 0.020 - 0.030v

PR304 has 47k

[mon2]

Very interesting measurements.

Confirm that one side of PR304 does mate with the gate pin of PQ303. This should be ~0R ohms. Otherwise there is a broken PCB trace here.

Next - Locate PR305. Confirm this resistor is ~10k ohms across the tips of this part.

Locate the dual mosfet @ PQ308.

Share the voltage to ground measurements for:

pin 3
pin 5
Pin 4 is ground so ignore.

pin 6
pin 2
Pin 1 is ground so ignore.

We need to review the PQ308 voltages for each case - adapter only; battery only; both battery & adapter.

[G_sene]

Very interesting measurements.

Confirm that one side of PR304 does mate with the gate pin of PQ303. This should be ~0R ohms. Otherwise there is a broken PCB trace here.

Next - Locate PR305. Confirm this resistor is ~10k ohms across the tips of this part.

Locate the dual mosfet @ PQ308.

Share the voltage to ground measurements for:

pin 3
pin 5
Pin 4 is ground so ignore.

pin 6
pin 2
Pin 1 is ground so ignore.

We need to review the PQ308 voltages for each case - adapter only; battery only; both battery & adapter.

One side of PR304 has 0ohm with the gate of PQ303.
PR305 has 10k.

PQ308:

Adapter only:
Pin 3 - 0.086v
Pin 2 - 3.54v
Pin 4 - 0v
Pin 5 - 0.076v
Pin 6 - 0v

Battery only: Pin 3 - 0v
Pin 2 - 0v
Pin 4 - 0v
Pin 5 - 0v
Pin 6 - 0v

Adapter and battery:
Pin 3 - Varying greatly between 0.100v and 0.275v
Pin 2 - 0v
Pin 4 - 0v
Pin 5 - 0.020v - 0.075v
Pin 6 - 0.020v

[mon2]

Pin 3 - 0.086v
Pin 2 - 3.54v
Pin 4 - 0v
Pin 5 - 0.076v
Pin 6 - 0v

Pin 5 = gate to the 2N7002 mosfet. If gate voltage is ~0v, then this mosfet should be OFF. When OFF, the pin 3 voltage should be floating to the Vin voltage through PR304.

Also, when pin 2 on PQ308 is 0V, then PQ308A should be OFF. Again, pin 6 on PQ308 should be at Vin voltage through PR306 but is @ 0v.

It appears that PQ308 dual mosfet is defective. Suggest to flux and replace it. Confirm this case again before replacing this part.

[G_sene]

Pin 5 = gate to the 2N7002 mosfet. If gate voltage is ~0v, then this mosfet should be OFF. When OFF, the pin 3 voltage should be floating to the Vin voltage through PR304.

Also, when pin 2 on PQ308 is 0V, then PQ308A should be OFF. Again, pin 6 on PQ308 should be at Vin voltage through PR306 but is @ 0v.

It appears that PQ308 dual mosfet is defective. Suggest to flux and replace it. Confirm this case again before replacing this part.

I have a board with the 2N7002DW, apparently compatible.

[mon2]

Yes - looks like a valid replacement. Proceed to replace it and test again.

[G_sene]

Yes - looks like a valid replacement. Proceed to replace it and test again.

I removed and replaced it, but it still won't recognize the charger and charge.
The VIN jumper for PR304 is still done

PQ308:
Adapter only:
Pin 3 - 19.88v
Pin 2 - 3.54v
Pin 4 - 0v
Pin 5 - 0.054v
Pin 6 - 0v

Battery only: Pin 3 - 0v
Pin 2 - 0v
Pin 4 - 0v
Pin 5 - 10.81v
Pin 6 -11.18v

Adapter and battery:
Pin 3 - 0v
Pin 2 - 0v
Pin 4 - 0v
Pin 5 - 10.96
Pin 6 - 11.30v

[mon2]

These look like good voltages to me. Much better than before.

Measure the voltage to ground on ADAPTER_ID which is supplied by the power adapter to identify the adapter.

Measure this @ PC1266 or similar.

[G_sene]

These look like good voltages to me. Much better than before.

Measure the voltage to ground on ADAPTER_ID which is supplied by the power adapter to identify the adapter.

Measure this @ PC1266 or similar.

0.900mv

[mon2]

On your board, is the PQ995A & PQ995B present? They are marked with '@' so may not be stuffed on the board.

Remove all power. Measure the resistance to ground of ADAPTER_ID. Disconnect the power adapter during this test. We want to check the resistance to ground to understand if the TVS diode at PD304 has triggered or not.

Next, measure the resistance of the power adapter from the center pin to the outside ground pin of the connector. Do not plug the adapter into the wall. We are only measuring the internal resistor of the Lenovo power adapter which announces the power rating through the resistance value.

Here is a video on this topic:

https://www.youtube.com/watch?app=de...YMariusElectro

[G_sene]

On your board, is the PQ995A & PQ995B present? They are marked with '@' so may not be stuffed on the board.

Remove all power. Measure the resistance to ground of ADAPTER_ID. Disconnect the power adapter during this test. We want to check the resistance to ground to understand if the TVS diode at PD304 has triggered or not.

Next, measure the resistance of the power adapter from the center pin to the outside ground pin of the connector. Do not plug the adapter into the wall. We are only measuring the internal resistor of the Lenovo power adapter which announces the power rating through the resistance value.

Here is a video on this topic:

https://www.youtube.com/watch?app=de...YMariusElectro

I don't have a PQ995 on the board.

Another point: I still have the jumper on the ADAPTER_ID to ground, with a 560 ohm resistor.

ADAPTER_ID resistance - 537 ohm
Adapter center pin resistance - 561 ohm

[mon2]

Remove the extra resistor to ground on this pin. Then test this line again on the motherboard but do not connect the power adapter. We want to know the resistance without the power adapter.

[G_sene]

Remove the extra resistor to ground on this pin. Then test this line again on the motherboard but do not connect the power adapter. We want to know the resistance without the power adapter.

5.50k

[mon2]

Now connect the adapter but do not power it. What is the resistance now? Then power up to test again.

[G_sene]

Now connect the adapter but do not power it. What is the resistance now? Then power up to test again.

Adapter connected but not turning on - 544ohm
Adapter connected, notebook on - OL