NF4UK8AA - Is this Lazarus, just sleeping?

[прямо]

Oh damn! The controller chip is probably dead now.

So aside from the CPU, something else is able to set VID. Perhaps that jumperless overclock IC is the culprit. I was pretty sure that without a CPU installed, VID would be all pulled to low, telling the PWM chip to turn itself OFF, but instead it is set to always put out 1.0V

which is really weird, because if 1.0V VCORE is like the default start up setting, but the CPU obviously need more than that to start, then it's no brainer that the mainboard doesn't work and can't POST.

[socketa]

I was sure that the high and low side mosfets were shorted to ground
Now, after checking again, it's only the high side mosfets drain and source shorted together, and not to ground
I found the faulty mosfet (was the same position that the previous one went short), and replaced it

Now, with the CPU removed, the board starts, but this time no VCORE, and the VID begins at 11111 (off), and then, over the course of about ten seconds, VID0 falls to low to make 11110, but still nothing on VCORE
When i push the power button with the CPU installed, VID is 11111 (off), but still no VCORE
Unlike last time, grounding VID4 (or any of the other pins), while powering up, with, or with or without the CPU installed, fails to bring up any VCORE voltage.

Another odd thing is that all of the pull up resistors are now measuring about the same in-circuit (3.4 - 3.5kohm); whereas before, across VID3's resistor, there was 1.3Kohm

So now it seems to be behaving as you expected
or maybe that's what happened if the controller clapped out (no working controller to pull the VID lines down)

Regardless of whether i ground any VID pins or not, there's now no voltage on any of the PWM OUT pins.

[прямо]

I suppose the controller output is pretty much toast because of the short to ground accident.

I guess the next logical move is to replace the chip.

[socketa]

Yep, have ordered some
Will update when the chip has being replaced

[socketa]

Well, it looks like that VRM controller chip was possibly OK
because i replaced it, and there's still no voltage on it's PWM out pins, even when grounding the VID pins (which are all high)
so no Vcore
and the board won't shut down using the power button

[socketa]

The VID pins of the VRM controller chip are direclty connected to the VIDOUT pins of the jumperless overclock chip
It seems like the job of the overclock chip is to override the voltage that the controller chip is putting out.
Shorting pins VID 3&4 of controller chip to ground should give 00111 (1.35V)
But this new PWM controller chip is also not sending out any PWM signal voltage to the drivers.
The three driver chips each have 12V power at VIN, and voltage on drains, and the controller chip has PGood voltage,
and the jumperless overclock chip correctly detects when a CPU is installed
I get the feeling that this is something simple
Maybe the original controller chip was going faulty, but i suspect that when i accidentally blew up the mosfet twice, that that may have created some extra damage, because before that i could turn off the board with the power switch, but can't now, and was also getting some codes on the PCI slot analyzer card, but now there is nothing.

[socketa]

Maybe due to this?
Top right and bottom right

Bent the CPU pins a bit, when taking it in and out, so wiggled it into the socket
Bad move!
If the CPU doesn't fall in by itself, do not apply any pressure whatsoever
Tried to open a socket 754 socket once, but destroyed the top of of in the process - they break really easily, and you'd be very lucky to remove it without breaking the plastic,
and this looks like the same deal
The damaged hole is MEMDATA[105], but that's to do with the RAM, so it's possibly not the reason why there is no VCORE or any POST
Checked the holes for VID0 to VID5, and they all look good

[прямо]

Have you tried CMOS reset? it seem like the jumperless overclock IC gets a configuration from somewhere (from a previously saved BIOS setting most likely) and it's overriding what the CPU is actually telling the PWM controller.

[socketa]

Yes, i disconnected the PSU and moved the CMOS reset jumper to reset position and then back again
I also flashed the BIOS because it's checksum had changed
So even though i ground the VIN pins that go to the controller which tell it what voltage to regulate at, there seems to be something disabling the chip from outputting signals to the drivers,
Like you say, maybe the overclock chip is telling the controller chip to not output, irregardless of whether i try to force VCORE by grounding the VID pins
I found a schematic of a board with that overclock chip
https://elektrotanya.com/gigabyte_ga.../download.html
and see that the VIN pins of the overclock chip go to the CPU (and on the other side of the chip are VIDOUT pins which go to the controller's VID pins)

On the overclock chip there is a watchdog timeout reset # pin which is low (does the # indicate that it's active low?),
and the CPU change detect pin still correctly shows when a CPU is present or absent

And on the VIDIN pins of the overclock chip, from VIDIN0 to VIDIN5, which i think are connected to the CPU VID pins, there is 101001, which could possibly mean that part of the CPU is asking for VCORE to regulate at 00101 (1.425V), or 01001 (1.375V),
1.375V is between what CPUworld says should be the CPU voltage (1.35 - 1.40V)

I'm guessing that the CPU needs VCORE before the BIOS will POST

I found a video of how to remove the cover from a AM4 socket, so i might try that if i have to
https://www.youtube.com/watch?v=JTWgNGoylo8

[прямо]

I'm not sure if # symbol means the signal is active low, but you can probably verify it by toggling it between active low and active high and see what happens to the chip.

And yes, it does seem the chip receive VCORE setting directly from the CPU and then passes it onto the PWM controller chip. In this middle man position, the chip can also overrides what the CPU has requested.

I think you need to temporarily disconnect the chip VIDOUT pins from the PWM controller to see if the controller will then respond to your manual VID settings.

[socketa]

Removed the overclock chip, so it's VIDOUT pins are definitely disconnected now
But lower mosfets still don't turn on when shorting VIN pins to ground

[socketa]

Ok, so i lifted the three legs of the PWM controller, and there was no voltage on it's OUT pins that are going to the three drivers, even when shorting the VID pins to ground.
Then i put the overclock chip back in, and there is the same voltage on each of the PWM controller's OUT pins (50-250mA - it changes each time that i power it up)
Shorting the VID pins to ground makes no difference.