HP EliteOne 27" 1000 G2 - Shorted USB - MainBoard DAN11AMB8H0 REV:H

Dear forum members,
I'm trying to repair this All-in-one machine that had a problem in the usb-c port, maybe the owner connected some shorted device and caused a disaster.
I found that were shorted :
Southbridge Intel Q370 SR404 (shorts on main core, 3v rails and data lines on usb ports)
U89 Intel JHL7340 Thunderbolt controller
U22 MX25L8006E Thunderbolt controller firmware IC (with a little bump on it)

When I unsoldered these 3 ICs , the main 3v line has returned to a normal value, around 400mV (measured with red probe on GND and black one on the rail).
I then soldered a brand new southbridge Q370, cleaned the ME area of the U21 MX25L25635E and, since I don't have available now the usb-c/thunderbolt controller nor its firmware, I gave power to the board by a compatible power supply with a 3 pin plug.
The board reacts to power, it starts automatically and within 20 seconds it reboots itself, it stays alive but even waiting 20 minutes, it doesn't output any video signal.
To be more precise, the 24" display lights up at around 18/19 seconds from powerup and displays the message "Display going sleep", then it reboots and you can see the same message again after other 20 seconds, but after then it stay always black.

Power off doesn't work as it should on an HP machine, i.e. shut it off by just 1 press, you have to keep the power button pressed for more than 4 seconds to shut it down.
After a forced power down, internal speakers beep (3 long + 4 short) and power light makes some flashes (3 red + 4 white), and basing on the code table seen on the maintenance and service guide dedicated to this machine, it means "The system board displays a power failure (crowbar).*", where the asterisk means "Indicates hardware triggered event; all other events are controlled by the BIOS".

Original CPU is an i7-8700, I've changed it to an i5-9400 but the behaviour was the same (I'm not completely sure that this board or bios can accept a 9th gen CPU).
Without CPU, lights and are 3 Red and 5 white, and beeps accordingly (3 long + 5 short)
Without RAM it gives 3 Red (long beeps) + 2 white (short beeps), accordingly to the service guide.

Looking from a wide angle, it seems that the system starts its power sequence and reads the BIOS but it can't reach the last step to make the video out, as it lacked something.
According to you, can it be that the EC is expecting the (missing) usb-c controller to output it pwrdg signal to pullup ALL_SYS_PWRGD?
Or may it be caused by a not-properly-soldered ball under the PCH?

Since I have no datasheet nor boardview of this board, I'm trying to go further only by experience, and reading some pcb writings.
I didn't find any info also on the EC NPCD318HA0DX, even schematics for other boards that use this EC...Do you have any?
I've taken some measurements on the board, but I can only write them as I found on the board, and I don't know where to measure signals as PLT_RST, ALL_SYS_PWRGD.
I've found a spot near the cmos battery where you can read some nice signal names, but it's not clear which pad correspond to which signal, anyway here they are:

JEN1
1 312 3.24 (connected to 8th pin of U68 EC IC)
2 777 1.80-1.90
3 GND 0.00
4 782 / 1.80-1.90
5 GND 0.00
6 784 1.80-1.90
7 / 0.00-0.25
8 781 1.80-1.90
9 GND 0.00
10 / 0.00-0.25
11 / 0.00-0.25
12 / 0.00-0.25
13 / 0.00-0.25
14 836 3.24
15 GND 0.00
16 / 0.00-0.25
17 GND 0.00
18 / 0.00-0.25
19 GND 0.00
20 / 0.00-0.25

CATERR# 0 / 0.00-0.10
SLP_A# 0 / 0.00-0.10
CRL 0 / 0.00-0.10
SLP_S5# 0 / 0.00 0.00-0.10
SLP_S3# 0 / 0.00 0.00-0.10
SLP_S4# 0 / 0.00 0.00-0.10
RSMRST# 444 / / 0.00 3.24
AUX/CPUPG# 0 / 0.00 0.00-0.10
PSON# / / 0.00-0.10 0.00-0.10
PG_170V5 / / 444

Has anyone a schematic or boardview for this board, or a reference for the EC NPCD318HA0DX from which I could compare signals?
Please, can anyone suggest something to look for?
Thanks

Hello,
one week passed, can anyone give me some advice on this machine?
Have you seen schematics or boardview somewhere?
Thanks

Hello,
more than two months later...any suggestion?

This computer does only support Intel 8th generation processors, according to the manufacturer's information: https://support.hp.com/gb-en/document/c06060620. So it means you will need to buy the original 8th gen CPU to further testing the computer. Does it have a dedicated AMD graphics or, it does only work on an integrated Intel one?

The other question: where did you actually get that new PCH chip from? I found that many BGA chips I have purchased on eBay or Aliexpress (from China in general) won't work - they're most likely a used and not tested chips sold as new, and so they are DOA.

Thank you Vogelek23 for your advices.
This mainboard has only the Intel GPU, not the AMD one.
I will search for another 8th gen CPU and test it, and maybe test the original i7-8700 in another mainboard.

Usually I buy BGAs from a reliable seller in China (SEE-IC) but since I had to buy only one piece, this time I bought the PCH from a friend of mine, who has his reliable seller....maybe he wasn't so reliable as mine

The main problem is that I can't find any document about this mainboard, not a schematic nor a boardview, so it's very difficult to trace where the problem lies...