MSI AIO MS-AC17 no power

[Dumah Brazorf]

It's a desktop but is notebook hardware (19V 6.32A) with big screen.
At the moment I measure 19V after the first (and only?) mosfet then there's 2 power supply that are completely shut-off. I'm not sure if one of them is 3.3V which is not present around the superio and the power button. I have not found shorts except both the first mosfets of the 2 power supply mentioned have gate and source connected (shorted? both? ic driver kaput?). I have a thermocamera and with the power supply connected everything is stone cold.
I'd really appreciate if someone have the schematic.

Motherboard MS-AC171 ver:1.0

[SMDFlea]

Re: MSI AIO MS-AC17 no power

It's a desktop but is notebook hardware (19V 6.32A) with big screen.
At the moment I measure 19V after the first (and only?) mosfet then there's 2 power supply that are completely shut-off. I'm not sure if one of them is 3.3V which is not present around the superio and the power button. I have not found shorts except both the first mosfets of the 2 power supply mentioned have gate and source connected (shorted? both? ic driver kaput?). I have a thermocamera and with the power supply connected everything is stone cold.
I'd really appreciate if someone have the schematic.

Motherboard MS-AC171 ver:1.0

post some pictures please of the whole board, front back and the mosfet area

[Dumah Brazorf]

Re: MSI AIO MS-AC17 no power

Hi, thanks for answering.
I made some photos and studied the board.
On the backside there's the TPS51125 Dual-Synchronous, Step-Down Controller that controls the 2 lines i was studing obtaining 5V (big coil) and 3,3V (little coil). It's not running. It has and internal ldo for producing 3,3V and 5V for standby, i checked pins 8 and 17 and indeed there are 3,3V and 5V but i did not find where those line are used. Enable pin has 1,8V and Reference 2V so it should startup i think.
Wandering around the board i found a power supply near the southbridge with output almost short. Does southbridge have a low impedance like a cpu?
Then i found a chip near the power connector called INA219 Zerø-Drift, Bidirectional Current/Power Monitor. I measured a short on the Vs pin. Having the termocamera and a power supply I injected 2Amps, then 3Amps, the voltage rose maximum to 1,3-1,4V. The only thing that warmed up was the southbridge.
So i think i have to give up.