Samsung NP350XBE - BA41-02737A - No power

[G_sene]

Hi, everyone!

Analyzing the input circuit, the first MOSFET had 19V at the drain and 0V at the source, with a 0V gate.
I replaced it and nothing. I injected voltage into the missing side, and the laptop turned on.

I found that the BQ24780s has 19V at VCC, 2.79V at ACDET, 0V at ACOK, and it varies in millivolts on the ACDRV pin.

Could it be the cause of the problem?

[mon2]

https://www.badcaps.net/forum/troubl...arging-circuit

Review the 2nd dc in mosfet. The gate pin of the first 2 DCin mosfets are often shared. If one becomes defective, the other one also suffers. It the 2nd one that is the first suspect.

[G_sene]

https://www.badcaps.net/forum/troubl...arging-circuit

Review the 2nd dc in mosfet. The gate pin of the first 2 DCin mosfets are often shared. If one becomes defective, the other one also suffers. It the 2nd one that is the first suspect.

I had already removed it, and when I removed it, the voltages returned to normal. I replaced the first MOSFET and nothing changed, so I assumed it wasn't bad and replaced it with the second MOSFET.

[mon2]

Test both of the dcin mosfets.

Remove all power. Meter in resistance mode.

Measure the resistance across the mosfet pins:

source & drain
source & gate
gate & drain

post each measurement.

[G_sene]

Test both of the dcin mosfets.

Remove all power. Meter in resistance mode.

Measure the resistance across the mosfet pins:

source & drain
source & gate
gate & drain

post each measurement.

First MOSFET:
Source/drain - 1.78M
Source/gate - 4.55M
Gate/drain - OL

Second MOSFET:
Source/drain - 1.30M
Source/gate - 4.44M
Gate/drain - OL

[mon2]

The measurements look ok.

Have you seen this video?

https://www.youtube.com/watch?v=6x9W...INFOTEC-ARLENO


Partial schematic(?) from a user forum referencing his same unit (out of Brazil):






https://eletronicabr.com/forums/topi...osfet-de-alta/

[G_sene]

The measurements look ok.

Have you seen this video?

https://www.youtube.com/watch?v=6x9W...INFOTEC-ARLENO


Partial schematic(?) from a user forum referencing his same unit (out of Brazil):






https://eletronicabr.com/forums/topi...osfet-de-alta/

I saw this video, but in my case I have ACDET (2.79v), but no ACOK (3.3v).
I also don't have (it varies in millivolts) ACDRV, ACN and ACP

[mon2]

Does this partial schematic match your board? If yes, which mosfets have you tested?

[G_sene]

Does this partial schematic match your board? If yes, which mosfets have you tested?

No, my motherboard is 02737A

[mon2]

What is the voltage of regn on the charger ic?

[G_sene]

What is the voltage of regn on the charger ic?

6v in REGN