Lenovo NM-D562

[hopkok]

Hello.

1) Remove all power. Meter in resistance mode. Measure the resistance to ground @ P3 label = main power rail to the logic board. What is the resistance in ohms? If the resistance is low = shorted part on the rail, then the DCin mosfets will remain OFF.

2) To check the DCin mosfets @ PQ5401 / PQ5402 -> remove all power -> meter in resistance mode.

Measure the resistance to ground of:

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. Check both DCin mosfets. Checking for a low resistance = defective mosfet.

Hi Mon 2, I have got same problem, no voltage at point2. All input mosfets OK, no low resistance.

Chager IC BQ24780s has VCC presented -20V.
ACDET at pin 6 has 2,7V
ACOK pin 5 - 0V

I tried to replace charging IC, but the same.

From charged battery, its working.

Do you have any idea? Thank you

[mon2]

Hi. Best to remove all power -> measure the resistance across each mosfet. Post each measurement for a review. A good mosfet should be hundreds of kohms or higher.

What is the voltage to ground of ACDRV on the charger IC? A good working charger IC should be ~25 volts = adapter voltage + REGN (~6v) = 19v + 6v

[hopkok]

ACDRV - 0V,
PR5404 - OK
PR5402 - OK
REGN - 6V

Let me double check mosfets tomorrow

[mon2]

ACDRV is 0v so something is wrong. As per sticky above by piernov on charger ICs, the Dc-in mosfets are suspects. Need the exact resistance measurements. Likely at least one of these is defective.

[hopkok]

Hi mon2, PQ5402 was faulty, resistance more than 20 kohms, checked in diode mode too, 0,5V drop, seemed to be OK, I tried to replace anyway and its working...thanks for hint