Lenovo Thinkpad T410 no power

[kalilinux25]

DEVICE: Laptop
Model: lenovo thiinkpad t410
Board Id: 09A33-3 48.4FZ09.031
NZM1H-8
ISSUE: NO POWER

From the first mosfet 20v is not passing through, pin 4 has 19.5v and the first mosfet is a P-CHANNEL mosfet (SI7121DN) i think the pin 4 should be lower to active the 1st mosfet to allow the 20v to pass to second mosfet ive check all for shorting in the board , i did;nt find in rails, so ive check the schematic and im suspecting that, my Q61 is faulty due to its pin 1 is 0.47ohms? im not pretty sure, hope someone can help me figure out this issue.

Q61 pin 1 is connected to DISCHARGE2

Q107 - DTA114EEA -
PIN1-19.62
PIN2-19.58
PIN3-19.24

Q61-2SK3541
PIN1-0V
PIN2-0V
PIN3-19.62

Q51-DTC115EE
PIN1-18.37
PIN2-18.72
PIN3-19.11

Q78-2SK3541
PIN1-0V
PIN2-0V
PIN3-18.72

Q79-2SK3541
PIN1-0V
PIN2-0V
PIN3-18.37

Q107 PIN 2 IS CONNECTTED TO Q61 PIN 3

my Q61 (2SK3541) pin 1 has 0.47ohms to gnd and its connected DISCHARGE2
Q61-2SK3541
PIN1-0V
PIN2-0V
PIN3-19.62

and my Q107 - DTA114EEA -
PIN1-19.62
PIN2-19.58
PIN3-19.24

[mon2]

Post the schematics in the schematics forum and link it here.

The gate pin of the Q61 mosfet should not be shorted to ground. Be sure you are in resistance mode and with no power to the board.

[kalilinux25]

https://www.badcaps.net/forum/troubl...ematics-please

here is the schematic and boardview ive used

q61 without no power and cmos it measure 0.47ohms even ive swap my probes

[mon2]

Remove all power. Meter in resistance mode. Flux and remove Q61 off the board with care. Then measure the resistance of the gate pad again. Is it still low? BRB later.

[kalilinux25]

Remove all power. Meter in resistance mode. Flux and remove Q61 off the board with care. Then measure the resistance of the gate pad again. Is it still low? BRB later.

remove the q61 done still having low resistance on Gate, tried to trace R229 and remove the DISCHARGE line is where the low resistance was coming from and tried to locate it to a R891 that is pulled by gnd?
i think R891 is a pull-down resistor for the DISCHARGE line.?

[mon2]

We are reviewing DISCHARGE2 netname. See attached.

Flux and remove Q44 and keep it separate from the othe removed part. After removal, is the resistance to ground on DISCHARGE2 line still a low resistance?

[kalilinux25]

Q14 and Q44 and R228 is not present on board ONLY the R229 and C210

[mon2]

Post a pic of the meter face while measuring this short condition.

[kalilinux25]

Post a pic of the meter face while measuring this short condition.

DISCHARGE2 -has 45.3 ohms but if I remove the R229 im having 45.3 ohms in DISCHARGE line.

[mon2]

According to the schematics, R229 is marked with 'NO ASM' so it is not stuffed. Measure the resistance across this part you suspect to be R229.

[kalilinux25]

According to the schematics, R229 is marked with 'NO ASM' so it is not stuffed. Measure the resistance across this part you suspect to be R229.

it measure 0hms if i measure resistance to gnd im having 0.45 ohms also

[kalilinux25]

According to the schematics, R229 is marked with 'NO ASM' so it is not stuffed. Measure the resistance across this part you suspect to be R229.

i thi the boardview has some missing parts also like there is no GPU chip present on the board view and the schematic is for NZM1H-0 not NZM1H-8

[kalilinux25]

Ill just upload it here

[mon2]

Is there a Q78 onboard? If yes, flux and remove it and measure again.

[kalilinux25]

Yes there is Q78 after removing it checking the resistance to ground to the DISCHARGE it still gives me 45.3 ohms

[kalilinux25]

Also I noticed ACDC_ID has 0v after testing the middle pin of the charger there is no voltage in the middle charger pin , i take apart the charger it only have 2 wires , showing its just a replacement charger , will this affect our cheking? also i noticed that VCC3M as low resisance to gnd around 1.1ohms to gnd, tried pumping voltage 1v 1amp didnt do anything no heating , possible its just normally low reistance.

[mon2]

VCC3M as low resisance to gnd around 1.1ohms to gnd,

Not a good thing. This rail is also linked to the PCH / CPU. Is it possible that the heatsink is hiding who is heating up?

[kalilinux25]

Not a good thing. This rail is also linked to the PCH / CPU. Is it possible that the heatsink is hiding who is heating up?

removing the CPU it didnt change the value , i pump 3v on the line it just consume 260ma. No short on VCC3M — the rail is likely healthy or in standby load condition.
After pumping voltage the resistance to gnd changes to 18 ohms to gnd resistance

[kalilinux25]

• Adapter source (Q9 Source) → 20 V present
• Q9 Gate → ~19 V (only 1 V lower than source → MOSFET OFF)
• Q9 Drain → 0 V (no pass-through)
• Q9 body diode test → GOOD
  • RED on Drain → BLACK on Source = 0.510 V
  • Reverse = OL
• Q9 Drain NOT shorted → ~341 kΩ to GND
• After removing Q61 & lifting R229 → still 0 V at Q9 drain (confirmed there’s a second MOSFET in series).

[mon2]

Ok. Continue to confirm the DCin mosfets but use resistance mode checking.

Remove all power. Meter in resistance mode.

Test resistance across:

source / drain
source / gate
gate / drain

Post each measurement for each DCin mosfets.