Lenovo Legion 5 Pro - NM-D601 REV1.0 Turns off with battery conected

[judamex]

Can you confirm the gate voltage of PQ5407 WITH battery & power adapter? It does not look right.



A few other points:

1) remove all power -> measure the resistance of the 4k resistor @ PR5405. Confirm this resistor matches the schematic value of 4k. Concern is that in your measurements, the CMSRC voltage to ground is lower than the power adapter voltage.

2) double check the BATTERY only measurement for pins 1 & 2 on the charger IC.

3) repeat the measurements WITH BATTERY & power adapter for pins 1 & 2 on the charger IC. Pin # 2 (ACP) should be a higher voltage than pin # 1 (ACN). In either case, the voltage measurements should be very close to each other. Note the voltage drop across ACP and ACN junction when using only the power adapter. Higher voltage difference when the battery is used or when both battery & power adapter is used.

With no power to the board and no battery, confirm the resistance from pin # 2 (ACP) directly on the charger IC to the current sense resistor @ PR5401. Then repeat the same test with pin # 1 to the same current sense resistor. Both checks should be ~0 ohms. Touch your meter probes together and this is the same resistance measurement you should have for this current sense resistor path.

Also, I think that for the BATTERY only, the pin # 19 measurement was missed in the above table. It should be the same voltage as pin # 20.

Rectify the voltages on pin 23 gate of PQ5407 and it is still 0.5 with battery+charger, rectify the battery and charger alone and it is still 0V.

Rectify measurement in PR5405 and it is 3.99Kohms

Rectify measurement on pins 1 and 2 only with battery connected, they remain at 15.5 on both pins
-battery+charger 20.4 on both pins 1 and 2

measurement pin 1 and 2 with respect to PR5401 in both cases was 0.6 ohms

I correct the measurement on pin 19 only with 15.74V battery pin 19 and 20

[judamex]

Can you confirm the gate voltage of PQ5407 WITH battery & power adapter? It does not look right.



A few other points:

1) remove all power -> measure the resistance of the 4k resistor @ PR5405. Confirm this resistor matches the schematic value of 4k. Concern is that in your measurements, the CMSRC voltage to ground is lower than the power adapter voltage.

2) double check the BATTERY only measurement for pins 1 & 2 on the charger IC.

3) repeat the measurements WITH BATTERY & power adapter for pins 1 & 2 on the charger IC. Pin # 2 (ACP) should be a higher voltage than pin # 1 (ACN). In either case, the voltage measurements should be very close to each other. Note the voltage drop across ACP and ACN junction when using only the power adapter. Higher voltage difference when the battery is used or when both battery & power adapter is used.

With no power to the board and no battery, confirm the resistance from pin # 2 (ACP) directly on the charger IC to the current sense resistor @ PR5401. Then repeat the same test with pin # 1 to the same current sense resistor. Both checks should be ~0 ohms. Touch your meter probes together and this is the same resistance measurement you should have for this current sense resistor path.

Also, I think that for the BATTERY only, the pin # 19 measurement was missed in the above table. It should be the same voltage as pin # 20.

Update: bought a small oscilloscope to take the reading of pin 23 for PQ5407 attached a photo

I did the readings with and without battery and the result was 0

[judamex]

Update 2:

Check the measurements regarding this video
(https://www.youtube.com/watch?v=ODcc...LaV0BS&index=7) in diode mode and everything is fine except PIN 17 with a value in the video of 0.6622 and on my motherboard it is 0.501. It is the only difference I noticed, everything else is fine with respect to ground (RED ground, BLACK to the IC pins)

Or what oscilloscope measurements can I take?

[mon2]

As suggested by mcplslg123 , test with a known good battery. You can buy from Amazon and return it if not required. The issue may be with the battery itself (deep discharged state and is now locked or similar).

[judamex]

As suggested by mcplslg123 , test with a known good battery. You can buy from Amazon and return it if not required. The issue may be with the battery itself (deep discharged state and is now locked or similar).

Thanks, that's what I'll do and order a new compatible replacement battery and I'll do the test. I will update the post with the result

[judamex]

As suggested by mcplslg123 , test with a known good battery. You can buy from Amazon and return it if not required. The issue may be with the battery itself (deep discharged state and is now locked or similar).

Update: i Buy a replacement battery from amazon and still in the same error, I saw the BQ24780S get a little hot with the battery and charger connected.

[mon2]

Carefully , measure the voltage to ground on each pin on this charger IC. Post your full list of measurements.

[judamex]

Carefully , measure the voltage to ground on each pin on this charger IC. Post your full list of measurements.

I took the following measurements with the new battery connected just in case, I noticed several details that may be important:
1- the motherboard restarted after several seconds, it did not turn off completely, it just restarted
2- a strange oscillation in the ACDET, it only did it once and then showed stable voltage

New Batery + Charger
20.36
20.25
20.17
25.26
25.27
2.98
0.31
0.011
0.113
3.32
3.3
3.3
GND
N/C
0.31
1.48
16.37
16.26
16.35
16.39
1.53
GND
0.58
6.06
21.33
20.24
16.49
19.55

[mon2]

Power down immediately. ACOK pin #5 should never be so high of a voltage. It appears to be shorted to the ACDRV pin #4.

Flux the ic well and reflow it and gently nudge the chip with tweezers to remove the short condition. This event can cause damage.

Double check your work with the meter to confirm the short is removed.

[judamex]

Power down immediately. ACOK pin #5 should never be so high of a voltage. It appears to be shorted to the ACDRV pin #4.

Flux the ic well and reflow it and gently nudge the chip with tweezers to remove the short condition. This event can cause damage.

Double check your work with the meter to confirm the short is removed.

I resoldered and resoldered again and it now shows me 2.98

[judamex]

Power down immediately. ACOK pin #5 should never be so high of a voltage. It appears to be shorted to the ACDRV pin #4.

Flux the ic well and reflow it and gently nudge the chip with tweezers to remove the short condition. This event can cause damage.

Double check your work with the meter to confirm the short is removed.

I resolder and took different measurements with a different charger, I realized that with the 12 amp charger the charging IC heats up to 48°C, so I decided to try with a charger with less amperage that is enough to keep it on, I put the measurements below.
I also attach measurements with only the battery connected and the laptop always on (I had to turn it on every 1 minute because it turns off)

[mon2]

Does the laptop power up correctly still with only the power adapter? The laptop will function ok till you power down if using only the adapter?

[judamex]

Does the laptop power up correctly still with only the power adapter? The laptop will function ok till you power down if using only the adapter?

That's correct, if I use the power adapter ONLY without a battery connected, I can even run benchmarks without a problem, but as soon as I use the battery alone or with the charging adapter connected, the laptop turns off. ONLY when the battery is connected does it turn off.

[mon2]

The above table of measurements should really have pin #s and also the same pin labels as used by the datasheet for the charger IC. It will make the review much easier to study.

Not sure what the GND followed by N/C means. Best to repost with the latest values.

What is the voltage to ground of pin # 15 = BATPRES# on the charger IC? This is a critical voltage that should be a logic low = '0' = 0 volts to denote that the battery is attached.

You may have other charger IC pins shorted but will review with a fresh table of measurements with pin #s and pin labels.

[judamex]

The above table of measurements should really have pin #s and also the same pin labels as used by the datasheet for the charger IC. It will make the review much easier to study.

Not sure what the GND followed by N/C means. Best to repost with the latest values.

What is the voltage to ground of pin # 15 = BATPRES# on the charger IC? This is a critical voltage that should be a logic low = '0' = 0 volts to denote that the battery is attached.

You may have other charger IC pins shorted but will review with a fresh table of measurements with pin #s and pin labels.

Sorry for not indicating the number of pins, I update the table with the number of pins and their description based on the boardview of the motherboard, the charging IC corresponds to the BQ24780S

[mon2]

Much cleaner. Thanks.

Concerned about the gate voltage of the battery charge (PQ5404 & PQ5406) and also the battery mosfet (PQ5403). Each is a suspect.

We know that the battery voltage is the voltage at pin #27 (CHG_LX) = 16 volts. For the battery to power the logic board, the battery mosfet gate voltage @ PQ5403 should be boosted to enable this N-channel mosfet. Yet, this gate voltage is the same voltage as on the source pins.

Remove the power adapter. Connect only the battery. What is the voltage to ground of the drain pins on PQ5403 = main power rail to the logic board?

In this condition, the drain pins should be ~16 volts and the laptop should function ok.

To fully turn on PQ5403, the gate voltage needs to be boosted.

Next, remove all power and disconnect the battery. Meter in resistance mode.

Measure the resistance of PQ5403 as usual:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement. The mosfets @ PQ5404 & PQ5406 are also suspects so does not hurt to review their resistance in the same manner.

[judamex]

Much cleaner. Thanks.

Concerned about the gate voltage of the battery charge (PQ5404 & PQ5406) and also the battery mosfet (PQ5403). Each is a suspect.

We know that the battery voltage is the voltage at pin #27 (CHG_LX) = 16 volts. For the battery to power the logic board, the battery mosfet gate voltage @ PQ5403 should be boosted to enable this N-channel mosfet. Yet, this gate voltage is the same voltage as on the source pins.

Remove the power adapter. Connect only the battery. What is the voltage to ground of the drain pins on PQ5403 = main power rail to the logic board?

In this condition, the drain pins should be ~16 volts and the laptop should function ok.

To fully turn on PQ5403, the gate voltage needs to be boosted.

Next, remove all power and disconnect the battery. Meter in resistance mode.

Measure the resistance of PQ5403 as usual:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement. The mosfets @ PQ5404 & PQ5406 are also suspects so does not hurt to review their resistance in the same manner.

The drain of PQ5403 is 16V in standby and 15.8 on
The gate voltage of pq5403 is 22.06 in standby and 21.73 on,

I monitored this voltage using the oscilloscope and noticed a very fast voltage drop and instantly the laptop turned off.

The measurements of pq5403
source (1-2-3) RED & drain (5-6-7-8) BLACK: 0.88 Mohms
source (1-2-3)RED & gate (4) BLACK: 114 Kohms
gate (4)RED & drain (5-6-7-8)BLACK: 1.66 Mohms

The measurements in PQ5404
source (1-2-3) RED & drain (5-6-7-8) BLACK: 0.80 Mohms
source (1-2-3)RED & gate (4) BLACK: 8.18 Kohms
gate (4)RED & drain (5-6-7-8)BLACK: 0.95 Mohms

The measurements in PQ5406
source (1-2-3) RED & drain (5-6-7-8) BLACK: 0.80 Mohms
source (1-2-3)RED & gate (4) BLACK: 8.18 Kohms
gate (4)RED & drain (5-6-7-8)BLACK: 0.95 Mohms

[mon2]

The source to gate resistance of each mosfet appears to be low for a good mosfet.

Consider to flux and carefully remove both PQ5404 and PQ5406 off the board. After you have done this, check if the source & gate resistance increases for PQ5403.

Allow the removed mosfets to cool. Then measure their source to gate resistance for each while they are on your workbench. Each measurement should be a high resistance unless they are defective.

[mcplslg123]

pin15 rises to 3.3V when battery is dosconnected?
Pin19 & 20 should read same voltage.

[judamex]

The source to gate resistance of each mosfet appears to be low for a good mosfet.

Consider to flux and carefully remove both PQ5404 and PQ5406 off the board. After you have done this, check if the source & gate resistance increases for PQ5403.

Allow the removed mosfets to cool. Then measure their source to gate resistance for each while they are on your workbench. Each measurement should be a high resistance unless they are defective.

The resistance directly on the motherboard is 7.9 Kohms source RED, Gate BLACK.
the mosfets on the outside mark O.L, they do not mark any measurement in Ohms
I tested the mosfets in diode mode and everything seems to be in order