IBM Lenovo Thinkpad T20-2647 | Nie uruchamia się

Unfortunately it's not the place you are looking for. Resistors marked in the the picture are R4 and R366. Also, none of the 3-pin components are diode D69.

- Measure the resistance between pin 3 of transistor Q24 and pin 3 of chip U72.
- Measure the voltages to ground on pins 3 , 4 of transistor Q24.

- Measure the resistance between pin 3 of transistor Q24 and pin 3 of chip U72. - 5 kohm
- Measure the voltages to ground on pins 3 , 4 of transistor Q24. - 3- 2.2V, 4- 8.5V

- Measure the resistance to ground on pin 3 of transistor Q24.
- Measure the voltage to ground on pin 5 of transistor Q24.

pin 3 - 1.6Kohm
pin 5 - 3,2V

Replace the transistor Q24.

Wymieniłem na AO4812, laptop dalej się nie uruchamia.

Remeasure the voltages to ground on pins 3, 4, 5 of transistor Q24.

3- 2.2V
4- 8.5V
5- 3.2V

Takie same jak ostatnio.

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Measure the voltage between pin 3 and pin 4 of transistor Q24.

Nie chciał bym zrobić jakiejś głupoty. Co masz na myśli pomiędzy pin 3 i 4.

Nothing special, put the red probe on pin 4 and the black on pin 3 of transistor Q24 and read the value from the meter.
Also do the same thing between pin 5 and pin 3.

3,4 - 6.3V
5,3 - 1V

Up

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Please, check your measurements on transistor Q24 with another meter.

Pomiary są takie same.

Do you have an oscilloscope?
If so, use an oscilloscope to measure the voltages to ground on pins 3, 4, 5 of transistor Q24.

Niestety nie mam oscyloskopu.

The measurements on G and S of Q24 indicate that this transistor is in the saturation region (fully opened), but the measurements on D and S contradict this and show that the transistor is in the linear (resistive) region.

Possible causes:
a) The measurements are wrong.
b) The transistor alternately turns on and off with rapid pulses, but the multimter doesn't detect this and shows an average value. It should be checked with an oscilloscope.
c) The transistor is damaged.

Unfortunately I don't know how to proceed without an oscilloscope.