please help friend's thinkpad T480 NM-b501 dead, VSYS_OUT 9.2v, thank you

[Mahesa09]

1) Dalam database skematik saya, ditemukan studi kasus terlampir:



Studi kasus NM-B501 BIOS / Baterai SAJA - Badcaps

2) Bagaimana Anda mencoba memberi daya pada laptop? Apakah Anda menggunakan adaptor USB Tipe C? Apakah adaptor daya cocok untuk memberi daya pada laptop ini dan memiliki daya yang cukup untuk mengisi daya baterai?

3) Pastikan voltase ke ground sekring di:

PF2 ; periksa kedua sisi
PF1

PL2
PL1

USBC_CC1_CONN
USBC_CC2_CONN

3) Apakah Anda memiliki meteran USB Tipe C? Gunakan untuk mengukur voltase dan arus yang diambil dari adaptor daya. Jika arus yang diambil rendah dari adaptor daya eksternal ini, maka masalahnya ada pada sirkuit pengiriman daya yang berada di antara IC pengisi daya dan konektor USB Tipe C.

PF2; KIRI KANAN 5V
PF1 KIRI KANAN 0V

PL2 KIRI KANAN 5V
PL1 KIRI KANAN 5V

USBC_CC1_CONN 1.6V
USBC_CC2_CONN 0V

[mon2]

1) In my schematic database, found the attached case study:



NM-B501 BIOS / Battery ONLY case study - Badcaps

2) How are you attempting to power the laptop? Are you using a USB Type C adapter? Is the power adapter suited to power this laptop and has enough power rating for charging of the battery?

3) Confirm the voltage to ground of the fuses at:

PF2 ; check both sides
PF1

PL2
PL1

USBC_CC1_CONN
USBC_CC2_CONN

3) Would you have USB Type C meter? Use it to gauge the voltage and the current draw from the power adapter. If the current draw is low from this external power adapter then the issue is in the power delivery circuit that is between the charger IC and the USB Type C connector.

[Mahesa09]

Suggest to replace both of these parts. They are tiny (WLCSP8 package) so buy a few spares. Make a note of location of pin # 1 of this device.

TPS22971YZPT Texas Instruments | Integrated Circuits (ICs) | DigiKey

hello sir can you help me pleas. i have to t480 charging stuck 5v. my laptop can to power which batery only

[rbvndonh]

PU1 and PU2 replaced, but nothing changed.
on power switch i get 3,3V, and it GND when pushed.

On other board from Lenovo A485 i have 9,2V, but all other voltages are on the board. Maybe charger is faulty, as it is thinking it is on battery, cause voltage is on PR151, but on AC adapter it shouldn't?

[rbvndonh]

It will take long time to delivery to me, as only aliexpress have reasonable price. Even donor motherboard could be cheaper.

Mayby i will desolder them could connect by wire IN and OUT for test purpose?

Edit- i will check if it give powergood signal

[mon2]

Suggest to replace both of these parts. They are tiny (WLCSP8 package) so buy a few spares. Make a note of location of pin # 1 of this device.

TPS22971YZPT Texas Instruments | Integrated Circuits (ICs) | DigiKey

[rbvndonh]

Just found PU1 and PU2 with cracked top cover, need to compare it's behavior with working board.

Edit: sorry for double post, i tought i was editing last post..

[rbvndonh]

Unfortunatelly with batteries, tamper switch pushed, power adapter it even don't give led light on board. There is 0,00-0,01A consumption only.

PQ103
1-5 2,49MR
1-4 600KR waiting 2 minutes and it is still rising over 1,2MR. Strange
4-5 11,5MR and slowly rising

PQ108
1-5 2,5MR and slowly rising
rising
1-4 510KR
4-5 3MR

I flashed with outimage with clean ME from working board, but no change in operation.

Working board switch on with only power adapter.

[mon2]

1) Have notes in my database that this board requires a charged battery to power on the logic board.



2) Would you have a chip programmer to reflash the bios devices onboard?

3)

I think U101A ans U101B is same chip

Yes.

4) Remove all power. Meter in resistance mode.

Measure the resistance (not DIODE mode) across the mosfet pins as follows:

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 in ohms for PQ103. Then repeat for PQ108.

[rbvndonh]

Thanks for fast reply

working board":
PQ108 1-3 pins Power supply only 10,2V
Battery only 11,98V (differ after reconnecting in range of 0,5V)
Borh 12,93V

Vregin20 on PD13 pin1
Power supply only 9,7V
Battery only 12,44V
Both 12,4V

I2C_CLK_CHARGE 3,3V
I2C_DATA_CHARGE 3,3V

Damaged board:
Power adapter only
PQ108 1-3 pins 9,23V

I think U101A ans U101B is same chip, just they divide it on schematic due to lack of space. As U101 is BGA, i only could measure this
Vregin20 on PD13 pin1 8,71V
R413 pin2 8,724V pin1 8,720V
R422 pin2 8,724V pin1 8,720V
R8777 pin1 8,691 pin2 8,720V

It don't charge any of batteries
On external battery on PQ108 1-3 pins jumps for a while 11,2V and then voltage slowly drops down, as comething cut off this line.
internalt battery dont show this voltage

[mon2]

Carefully measure the voltage on each side of R413 and R422. You should see the same voltage on each side of these resistors and should be VREGIN20 = 9v6. Study the good board for a comparison.

It is also possible that U101B is defective and causing this voltage to be lower than normal.

To confirm, remove all power -> meter in resistance mode. Measure the resistance to ground of the VREGIN20 rail. Then continue to check the same till it reaches U101B and measure directly at the pins of U101B. We are checking if there is a trace break or a partial defective series resistor in the path from VREGIN20 to the U101B IC.

Need to do some shopping..will check back later. PS: The above are following the original posted details but do review the same..

VREGIN20 i have 8,6V

Review the resistance to ground on this rail. Compare it to the working board.

I2C_CLK_CHARGE i have 0V

Review the resistance to ground on this rail. Compare it to the working board.

Confirm that the I2C pull-up resistors have the mandatory pull-up voltage.

[rbvndonh]

Hi. I have very similar problem with 9.2V on VSYS.
PF7,8,9 and D12-D14 are OK.

I2C_CLK_CHARGE i have 0V
VREGIN20 i have 8,6V

On good board i have:
PQ103:
1-3 10,2V
4 10,2V
5 20mV (almost 0V)

PQ108
1-3 10,2V
4 2,27V
5 10,2V

PR151 0V

Bad board:

PR151 9,26V

PQ103
1-3 9,26V
4 3,3V
5 9,26V

PQ108
1-3 9,26V
4 8V and slowly falling down
5 1,6V and falling down

Faulty PU101?

[fredyjbi]

Excellent With a reflash of the bios? Was that the last step of the fix?

yes sir, reflashing the bios board can turn on, once again thank you very much sir for taking the time to help me

[mon2]

Excellent With a reflash of the bios? Was that the last step of the fix?

[fredyjbi]

It's working, sir, thank you very much for your help

[mon2]

Good. Have you attempted a bios reflash? I believe I have a flash image that can be posted if there is an interest.

[fredyjbi]

sir there is good news I replaced the broken PF9 now I have 10.2v on VSYS_OUT but the board won't turn on
SYS_OUT 10.2v
PL201 VCC5M 5v
PL202 VCC3M 3.3v
PL701 VCC1R0_SUS 1.05v
PL702 VCC1R8_SUS 1.8v
The board can't turn on yet, where should I investigate so that this board can turn on, sir, thank you

[mon2]

See attached.

The issue is probably with the diodes in series. Investigate PD14. It is probably defective. Do inspect the resistance to ground of VREGIN20 and compare to the known good board.

[fredyjbi]

IMO, the 10 ohms difference is very small. To completely rule out the charging IC -> carefully (!!) measure the voltage to ground of each pin on both boards and post the full table of values.

It is possible that the working board is sending out a 'power good' signal to inform the rest of the board to power up and the non-working board is missing such a signal. Be sure of your soldering of the replaced parts. As far as I know, the actual output voltage is configured using the I2C / SMBUS SCL & SDA lines. The ultimate would be to monitor this bus traffic to understand what communication is ongoing from the SMBUS master and this SMBUS slave chip (charger IC). If there is a fault condition, the SMBUS analyzer logs will reveal them.

Consider to measure the voltage to ground of each pin on the charger IC with a known good power adapter on this board. Then repeat with the working board.

Sir, I just measured the normal board on the U101B VREGIN20, it measured 9.6v, and on the problematic board it was only 1v, maybe this is the problem, please help me investigate this, sir, thank you

[mon2]

IMO, the 10 ohms difference is very small. To completely rule out the charging IC -> carefully (!!) measure the voltage to ground of each pin on both boards and post the full table of values.

It is possible that the working board is sending out a 'power good' signal to inform the rest of the board to power up and the non-working board is missing such a signal. Be sure of your soldering of the replaced parts. As far as I know, the actual output voltage is configured using the I2C / SMBUS SCL & SDA lines. The ultimate would be to monitor this bus traffic to understand what communication is ongoing from the SMBUS master and this SMBUS slave chip (charger IC). If there is a fault condition, the SMBUS analyzer logs will reveal them.

Consider to measure the voltage to ground of each pin on the charger IC with a known good power adapter on this board. Then repeat with the working board.