Acer vn7-793g no boot black screen

[azemar]

hello I have an acer VN7 793g which does not boot.
I have the keyboard which turns on the fan runs for 30 seconds at normal speed then stops for 5 seconds and restarts at full speed.
the screen remains black.
3.3v okay
5v okay
cpu rail ok
gpu rail ok
Dram rail ok
.
I flashed a new bios no change.
thank you in advance for your help

"here is the schematic and my original bios"

[mcplslg123]

Re: Acer vn7-793g no boot black screen

DRAMRST# present?? Powergood signals checked?

[azemar]

Re: Acer vn7-793g no boot black screen

DRAMRST# present?? Powergood signals checked?

Hello thank you I would like to check but without boardview it is very complicated. If someone can have it that would be great

[azemar]

Re: Acer vn7-793g no boot black screen

Hello, after some verification I have just seen that the cpu coils are at 0v. On the gpu I have 0.8v and it heats up slightly.

[mcplslg123]

Re: Acer vn7-793g no boot black screen

Hello thank you I would like to check but without boardview it is very complicated. If someone can have it that would be great

Pin#108 of ram slot is DDR4_DRAMRST#.

[azemar]

Re: Acer vn7-793g no boot black screen

Pin#108 of ram slot is DDR4_DRAMRST#.

Hello after verification I have DRAMRST at 0.059v.

[mon2]

Re: Acer vn7-793g no boot black screen

With this very low voltage, this signal line is being parked in the RESET state.

This line is active low from the '#' suffix so if a low voltage, the line is stuck in the RESET state.

[azemar]

Re: Acer vn7-793g no boot black screen

thanks for the info, but where to look now? I don't know enough about this part.

[Sephir0th]

Re: Acer vn7-793g no boot black screen

Known good RAM, another known good BIOS, output voltages and PGood at RAM controller all present and if still nothin, you can slowly think about to get rid of the device.