Asus x541UV no power

[zolie]

Hello everyone,

I'd like to fix it and ask for help here. The error: cannot be turned on.

PQ8901 (QM3056M)
D: 19V S: 0V G: 0V

If I shorted D and S, it will start and run continuously until I turn it off. I guess the gate won't open because it won't get anything. Can anyone help me solve this error?

Thanks

[piernov]

Re: Asus x541UV no power

https://www.badcaps.net/forum/showthread.php?t=90356

[mon2]

Re: Asus x541UV no power

Post the markings of the this and the next mosfet that follows this one.

Post the markings on the charger IC that is linked to these 2 mosfets.

Then remove all power. No battery, no adapter. Meter in resistance mode (2k scale or similar).

Check and post the resistance for the first mosfet:

Source (1-2-3) and drain (5-6-7-8)
Source (1-2-3) and gate (4)
Gate (4) and drain (5-6-7-8)

Searching for any low resistance reading which will likely mean the mosfet is defective.

Repeat with the 2nd mosfet.

Post your resistance values.

If the resistance is more than the meter scale, the meter should show OL (over limit). This is ok. You can then change the meter scale to the next higher scale till there is a good reading.

[zolie]

Re: Asus x541UV no power

M3056M
S-D:0.510 k
S-G:0.373 M
G-D:0.922 M

M0930M
S-D:0.525 k
S-G:0.375 M
G-D:0.7 M

BQ24780S

[mon2]

Re: Asus x541UV no power

Mosfet resistance readings look ok.

Still with no power to the board, meter in resistance mode, check the resistance to ground for the drain (5-6-7-8) of each mosfet. Repeat for the source pins (1-2-3).

Checking for a low resistance which may be due to a shorted capacitor. Post the measurements.

If the readings are not low, then continue.

Carefully, very carefully, measure and post the voltage readings of each pin of the charger IC. Do not short pins with the meter probe which can damage the charger IC.

Meter in DC 20v scale.

Red meter probe on the pin to measure, black meter probe to ground (shield is ok).

Post the voltage readings.

[zolie]

Re: Asus x541UV no power

M3056M
D-GND: 108k
S-GND: 0.370M

M0930M
D-GND: 2.890M (the value is slowly increasing)
S-GND: 0.430M (the value decreases continuously)

Is the charging IC still without voltage? I'll continue soon.

[zolie]

Re: Asus x541UV no power

I could only measure it now.