Hi Everyone,

I have problem with ASUS TUF FX516PM-HN023T. I checked all resistances on coil and all looks fine. I checked motherboard a microscope and I didn't see anything disturbing.
When I soldered the plus and ground to the input plug, I noticed that on the first mosfet there was 19V at the input but behind it there was 0.020V

the second mosfet has 0.020V at the input and 4V at the output.
The main measuring resistor at the input is 4V.

When I soldered the measuring resistor, I saw that power was supplied to the 3 and 5V coil for a moment and then disappeared. The power supply consumption when the coils are powered is 0.100A

Using thermal imaging, I can see that the point that will only light up is the main 3/5V converter.


Does anyone have any idea?

Looks like you have short circuit on 3/5v pwm IC.
Please open datasheet for pwm IC and check for short-circuit all LDOs and outputs.


This is protect from shorts. It is normal

3V LDO have 145K ohm (pin #3)
5V LDO have 2,8M ohm (pin #13)

First mosfet it is: PKCH2BB
Second mosfet it is: QM3058M6AC
PWM CONTROLLER it is: SN51285ARUKR
Battery charger it is: ISL9238BHRTZ-T

1 mosfet
Drain on first mosfet: 19V
Source and gate - 0,02V up to 0,65V

2 mosfet
Drain 0,02V up to 0,65V
Source and gate ~4V

pin #4 on first and second mosfet have 0,02V up to 0,65V
pin #4 on first and second mosfet have 7,3M ohm resistance to ground

What about 8 and 18 pins of SN51285A?
And check this theme viewtopic.php?f=40&t=82166
(also check EC)

Hi,
thank you for your answers and help.

P_3vadsw_lx_30 - pin 8 - 13k ohm
+3VAO - pin 3 - 5,5k ohm
+5VAO - pin 13 - 3,5M ohm

When I set 15V on the service power supply and apply it to the input plug, the OCP and OVP protections do not turn on, but when I set 19V, the protection turns on.
I will read submitted topic
Best regards.