Asus Rog Strix starts but no screen or other signs of life

[ongobongo]

Hi Guys,
I'm trying to repair this Asus ROG Strix notebook for a longer while now.
Mainboard is G531GW rev. r1.6
When attaching power notebook straight up turns on but no picture or similar signs of life. Voltages are all there (VCCCORE, VCCSA, NVVDD, 1.05V, 1.2V, 5V, 3V, 12V …. Only VCCGT is missing, but that is ok as far as I read), no obvious shorts on any rails. CPU gets hot quickly without heatsink, GPU gets moderately warm and PCH gets warm as well. EC should be good: power button responds to a long press and after a while the CPU fan kicks in.
What I have found out is that I can measure PLT_RST# with 3,3V but I'm missing DDR4_DRAMRST# (only ~120mV when turned on) so I guess this is the reason it won't proceed.
I read that the bios could be reason for that. I received the notebook as is so I don't know if it was tampered with or not. I read the bios, cleared ME-region and wrote it back with no changes. I also uploaded the bios here (https://www.badcaps.net/forum/troubl...-rog-bios-dump) and got a version from hoaca388, unfortunately not working as well. So I'd say bios can be ruled out.
Now I have two options, from my point of view:

1. On page 19 of the schematics (attached a snippet) the DRAMRST signal is showing as coming directly from the CPU without any logic in between. This would point to a dead CPU and the end of my attempts to repair
2. On page 68 of the schematics, the DRAMRST# signal seems to come from/go to the PCH which would point into the direction of a bad PCH.

I'm not sure how to read or judge this.
As a possible hint for option 2) I attach a picture from my thermal camera from the pch when turning on. It looks suspicious as heat doesn't spread evenly at the die but I'm really not sure how to go on with this problem.
Can anyone help with this?

[mcplslg123]

Ram is reset by CPU and not PCH.

[tesnic]

Hi Guys,
I'm trying to repair this Asus ROG Strix notebook for a longer while now.
Mainboard is G531GW rev. r1.6
When attaching power notebook straight up turns on but no picture or similar signs of life. Voltages are all there (VCCCORE, VCCSA, NVVDD, 1.05V, 1.2V, 5V, 3V, 12V …. Only VCCGT is missing, but that is ok as far as I read), no obvious shorts on any rails. CPU gets hot quickly without heatsink, GPU gets moderately warm and PCH gets warm as well. EC should be good: power button responds to a long press and after a while the CPU fan kicks in.
What I have found out is that I can measure PLT_RST# with 3,3V but I'm missing DDR4_DRAMRST# (only ~120mV when turned on) so I guess this is the reason it won't proceed.
I read that the bios could be reason for that. I received the notebook as is so I don't know if it was tampered with or not. I read the bios, cleared ME-region and wrote it back with no changes. I also uploaded the bios here (https://www.badcaps.net/forum/troubl...-rog-bios-dump) and got a version from hoaca388, unfortunately not working as well. So I'd say bios can be ruled out.
Now I have two options, from my point of view:

1. On page 19 of the schematics (attached a snippet) the DRAMRST signal is showing as coming directly from the CPU without any logic in between. This would point to a dead CPU and the end of my attempts to repair
2. On page 68 of the schematics, the DRAMRST# signal seems to come from/go to the PCH which would point into the direction of a bad PCH.

I'm not sure how to read or judge this.
As a possible hint for option 2) I attach a picture from my thermal camera from the pch when turning on. It looks suspicious as heat doesn't spread evenly at the die but I'm really not sure how to go on with this problem.
Can anyone help with this?

Hi! i have exactly the same problem... And my thermal camera show me the same image. How did you solve it? bad PCH? thanks!!

[FriedFred]

You can check those ICs with a very little voltage, for example 0,5V and 200mA of current. A dead short will exist also with a very low voltage, right? EC chip works usually with 3,3V and therefore you can test this area with 1V. CPU VCORE and GPU can use 0,75V or sometimes less. So in this delicate area need to use very low voltage to test for dead short. But can.
Or you supply 0V with 500mA max. and slowly raise the voltage. If you can see slowly a conducting up from 0,6 Volts, all is okay in this area.

[mcplslg123]

If DRAMRST# is pulled low, it can be 'coz of bios/bad cpu/missing ram requirements.

Check communication on SDA/SCL pins of ram slot with a DSO. There should be 2-3 quick pulses if ram is detected and only a single pulse if ram is not detected.
Another thing to check is ODT pins on ram slot. It should be 1.2V without ram and when you insert ram stick it should go down to 0.9V approx.

[tesnic]

Thanks all for your help. I check DRAMRST#, it's 1'2V and pulled low when laptop reset at startup. SDA and SCL is 3,3V, i dont have oscilloscope... ODT pins never go 1,2V, only 0'9 aprox when ram is inserted... i try different ram sticks with same results....

[tesnic]

You can check those ICs with a very little voltage, for example 0,5V and 200mA of current. A dead short will exist also with a very low voltage, right? EC chip works usually with 3,3V and therefore you can test this area with 1V. CPU VCORE and GPU can use 0,75V or sometimes less. So in this delicate area need to use very low voltage to test for dead short. But can.
Or you supply 0V with 500mA max. and slowly raise the voltage. If you can see slowly a conducting up from 0,6 Volts, all is okay in this area.

I inject voltage on PCH coil, and only consume 7mA.... i dont see any short anywhere.... And for more information, with DDR4 ram slot inserted, the consume try to go to 1'4A and boot again. without ram, it stuck at 1A and dont boot or loop....

[mcplslg123]

As per your post#3, i thought you too is facing DRAMRST# pulled low as OP has mentioned but it seems your problem is different.
Have you flashed bios?

[tesnic]

Yes i flashed new bios with clear me, but nothing...

[tesnic]

I think i found it finally! The PWM GPU controller, uP9027R was shorted! I will replace and hope it works. Thanks!