please help friends thinkpad T490 NM-B901 rev 1.0 dead no power usb type C 20v 0amp thank you

[mon2]

Need full details of the fault and the history of the unit to proceed.

In general, any laptop that makes use of the USB Type C interface for power will incorporate a PD (power delivery) controller. Such a controller demands a full software stack to negotiate through the many permutations of the power delivery contracts (voltage & current = power). In the end, the PD controller on the target logic board (laptop) will select the best PD contract and is usually 20V.

Next, use a Type C meter to gauge the current draw. If the current draw is low then something in the power path is defective. Will need to trace how far the 20V travels onto the board. Eventually the power path will lead to the charger IC and more buck converters that will lower this 20V down to lower rails to charge the battery pack and power low power circuits like the CPU / GPU, etc.

[arber97]

any solution for this problem i have same problem with t490

[fredyjbi]

The board is now powering ON and only the camera is not working?

The camera appears to be a USB driven design. Check your device manager for the presence of the camera. Check your security settings.

Remove all power. Meter in DIODE mode. Red meter probe to ground.

Black meter probe to:

USBP8-
USBP8+

Post each measurement. These USB pair of lines appear to be linked to the camera USB function @ JCAM1.

Do confirm that the fuses used by JCAM1 are not blown.

sorry for the delay in replying sir and sorry if my English is not good I use google translate, like this sir I have 6pcs of this board, 1 unit lights up normally only the camera has a problem, 5 units are completely dead, with the same problem - PWRSHUTDOWN is missing 0v, so I took the UTE1B chip from the problematic camera case board and installed it on the board with the PWRSHUTDOWN 0v case, but the result is still the same so I don't think the problem is with the UTE1B chip, what else should I try to check sir, thank you

[mon2]

The board is now powering ON and only the camera is not working?

The camera appears to be a USB driven design. Check your device manager for the presence of the camera. Check your security settings.

Remove all power. Meter in DIODE mode. Red meter probe to ground.

Black meter probe to:

USBP8-
USBP8+

Post each measurement. These USB pair of lines appear to be linked to the camera USB function @ JCAM1.

Do confirm that the fuses used by JCAM1 are not blown.

[fredyjbi]

Is the UTE1B a known good part? Not sure if the device requires a pre-flashed firmware to operate correctly. Or is the firmware applied through a bios update? Was it removed from a donor board?

Also, what is the voltage to ground of SHUTDOWN (R9515) ?

Sir, I tried to replace the UTE1B from a donor with the same board series, it turns on normally, only the camera has a problem, SHUTDOWN (R9515) 3.3v, I have several of these boards with the same problem, thank you very much sir for your interest in helping me

[mon2]

Is the UTE1B a known good part? Not sure if the device requires a pre-flashed firmware to operate correctly. Or is the firmware applied through a bios update? Was it removed from a donor board?

Also, what is the voltage to ground of SHUTDOWN (R9515) ?

[fredyjbi]

The resistance to ground of VCC3SW is ok. It is not shorted. For now, we do not know if UTE1B is defective or not. From my understanding, if pin # 45 has a voltage from the external power source and pin # 43 (3SW_OFF#) is a logic HIGH, then VCC3SW should enable.

Pin # 43 (3SW_OFF#) of this IC is the enable pin for this missing power rail. What is the voltage to ground on pin # 43 ?

This pin label has a suffix (ending) of '#'. This means if this signal is logic LOW (0 volts for example) then the VCC3SW pin will be OFF. That is, this is an 'active LOW' signal to turn the rail OFF.

sir, I just replaced the UTE1B chip, now VCC3SW is ok 3.3v but PQ0008 pin1 0v lost voltage -PWRSHUTDOWN, R9512 pin 2 3.3v pin 1 0v, the measured resistor is fine 33k even I also tried replacing R9512 the result is still the same -PWRSHUTDOWN 0v, thank you love

[fredyjbi]

The resistance to ground of VCC3SW is ok. It is not shorted. For now, we do not know if UTE1B is defective or not. From my understanding, if pin # 45 has a voltage from the external power source and pin # 43 (3SW_OFF#) is a logic HIGH, then VCC3SW should enable.

Pin # 43 (3SW_OFF#) of this IC is the enable pin for this missing power rail. What is the voltage to ground on pin # 43 ?

This pin label has a suffix (ending) of '#'. This means if this signal is logic LOW (0 volts for example) then the VCC3SW pin will be OFF. That is, this is an 'active LOW' signal to turn the rail OFF.

sorry for the delay in replying sir, because I am in Asia, sir I checked Pin # 43 (3SW_OFF#) 19v and pin VREGIN20 20v, can it be confirmed that the UTE1B IC is damaged, thank you

[mon2]

The resistance to ground of VCC3SW is ok. It is not shorted. For now, we do not know if UTE1B is defective or not. From my understanding, if pin # 45 has a voltage from the external power source and pin # 43 (3SW_OFF#) is a logic HIGH, then VCC3SW should enable.

Pin # 43 (3SW_OFF#) of this IC is the enable pin for this missing power rail. What is the voltage to ground on pin # 43 ?

This pin label has a suffix (ending) of '#'. This means if this signal is logic LOW (0 volts for example) then the VCC3SW pin will be OFF. That is, this is an 'active LOW' signal to turn the rail OFF.

[fredyjbi]

See attached. I believe that VCC3SW is created by an internal LDO regulator inside of UTE1B.

The arrows show the direction of the power path. Diodes are oriented to stop a reverse feed to the source(s).

Thank you for your help sir, someone wants to ask, what voltage is needed for the UTE1B chip to produce a VCC3SW LDO, sorry if my English is not good, I use Google Translate

[fredyjbi]

See attached. I believe that VCC3SW is created by an internal LDO regulator inside of UTE1B.

The arrows show the direction of the power path. Diodes are oriented to stop a reverse feed to the source(s).

sir, that means if the resistance of VCC3SW is 600k, then I replaced UTE1B because it didn't produce LDO, thank you

[mon2]

See attached. I believe that VCC3SW is created by an internal LDO regulator inside of UTE1B.

The arrows show the direction of the power path. Diodes are oriented to stop a reverse feed to the source(s).

[fredyjbi]

Remove all power. Meter in resistance mode (not diode). Measure the resistance to ground of VCC3SW.

Thank you sir for your help, sir, is it true that the source of the VCC3SW is the CMOS battery
VCC3SW. meter auto range resistace 550k

[mon2]

Remove all power. Meter in resistance mode (not diode). Measure the resistance to ground of VCC3SW.

[fredyjbi]

please help friends, I have 3 T490 units with the same case, the USB type C is completely dead, showing 20v 0 amp, loss of voltage VINT20_IN resistance to ground is fine, thank you

I think the problem is that I lost the voltage at PQ0008 pon 1 -PWRSHUTDOWN which should have been high which was picked up by R9512 VCC3SW, thank you very much for your help

PF0002 20v
PQ0005
pin 5 20v
pin 1.2.3 19.8v
pin 4 19.8
resistance
source & drain 2,4 m
source & gate 100k

PQ0006
pin 1.2.3 19.8v
pin 4 19.8v
pin 5.6.7.8 0v missing
resitance
drain 5.6.7.8 1,2m
source & drain 2,4 m
source & gate 100k

PQ0007
pin 1 3.3v
pin 2 2.5v
pin 3 19v

PQ0008
pin 1 0v missing -PWRSHUTDOWN
pin 2 gnd
pin 3 0v
resistance pin 1 600k


F9502 20v
UTE1B
pin 44 BAT_VOLT 11v
pin 45 VREGIN20 20v
VCC3SW missing 0v