It either works or does not, depending on the phase controller. But it wont break anything.

If it works, you should test the card with a short stress test in different scenarios. The GPU core still could have got fried and may crash under certain loads....

I've got this very strange problem on two Asus boards, a B560M-K and a H410M-A, where the CPU VRM (and all other voltages) are running when the mainboard is powered on without CPU. On the B560, the power draw is about 700mA. But with the CPU installed, the CPU Vcore and another 1V rail (but not the I/O rail with 0.95V though) will not run. The CPU (Celeron G5905) works fine on another board.

The phase controller is an onsemi NCP81243 (Link to datasheet: [URL]https://www.onsemi.com/pdf/datasheet/ncp81243-d.pdf[/URL]). Enable and VR_RDY are high even with the CPU inserted. The PWM signal...

As the DRMOS are connected to the ground plane by a massive pad, the PCB sucks away all the heat.

I would suggest lifting the inductors one by one to disconnect the GPU from the VRM. Measure the resistance of 12V to GND after each removed inductor. Then you know which DRMOS is at fault.

If the issue persists, remove the coils/step down converters of the other rails as those also connect 12V to the GPU.

I checked the signals again and it does seem like O_APU_PWRGD# is missing. Its hard to find as the schematic of the Gaming I version is a bit different then the one of the Gaming II. But There is one resistor next to the socket, which also exists on the Gaming II, carrying no current. It is not being pulled down though. I assume that O_APU_PWRGD enables the chipset, which barely gets warm in the current state.

What could lead to the CPU not outputting a PWRGD#-signal? I am certain that all voltage rails are running...

Thank you for your answer. I went ahead and checked every voltage you have listed and indeed, S_PLTRST# is low. The other voltages are fine, exept that 1.05V is at 1.03V, but I guess that should not matter (?). Any idea on how I can continue? Do you know what S_PLTRST# is supposed to do?

Hey y'all,

I am currently working on an Asus ROG B450-F Gaming II ATX Mainboard. The board is in very good condition (no missing components/scratches), but when I power it on using a Ryzen 3 1200 and one stick of DDR4, it gets stuck at 1,4A with none of the POST-LEDs lighting up.

I checked all voltages, which are present. The CPU gets slightly warm.

What I did try:
-Resetting CMOS
-Reflashing BIOS (manually and using the flashback tool)
-"cleaning" the socket with isopropyl alcohol
-using several sticks of DDR4 in every slot...

Hey there, I do board level repair as an hobby and I'd like to be part of this community! So far, the posts here have been really helpful!