ASUS ROG GL503VD-FY154T doesn't start

[Tapawan_oxiba]

Hello,

I have an issue with an Asus ROG Laptop with motherboard DABKLMB28A0 rev: A .

Symptoms are as it follows:

-Charging led is on when charger is connected
-When the power button is pressed, the keyboard blinks one time and then stop.

On the motherboard:
-Linear 3.3V is present
-Linear 5V is missing
-3.3VALW is missing
-5VALW is missing

On the SIO Chip:
-+3VPCU is present
-S5_ON is missing

The SIO receives no reset signal

Does anyone have an idea of what the problem could be ?

Thank you in adavance for your replies.

[Tapawan_oxiba]

Up

[mon2]

-Linear 5V is missing
-3.3VALW is missing
-5VALW is missing

For each missing rail -> remove all power -> meter in resistance mode -> measure the resistance to ground. Any low resistance values?

Confirm the enables for such rails are present.

Are schematics available for this logic board? If yes, share the links but post in the schematic forum (not here).

[Tapawan_oxiba]

Hello,

No low values on those rails. The enables are not present for 3.3VALW and 5VALW (same chip).

Unfortunately there is no schematics available for this motherboard.

:/

[noname2024]

Hello,

No low values on those rails. The enables are not present for 3.3VALW and 5VALW (same chip).

Unfortunately there is no schematics available for this motherboard.

:/

boardview
https://www.badcaps.net/forum/troubl...-2-2-boardview

[Tapawan_oxiba]

Oh, my bad then!

Thank you the boardview.

[mon2]

RT6575DGQW = is a part that must always have the LDO rails for 3v3 and 5v0 ENABLED.

Since 5v0 is missing, remove all power. Meter in resistance mode. Measure the resistance to ground on pin # 13 (VREG5) of PU28 (RT6575DGQW).

What is the resistance in ohms?

Can you also confirm that this IC was not replaced before you? Confirm the SMD markings against the schematic.

[Tapawan_oxiba]

Hello,

Resistance to ground on pin 13 is 6.4k Ohms.

Yes I confirm that the chip hasn't been replaced before. The SMD marking is corresponding to R6575DGQW.

[mon2]

Flux and replace this chip.

[Tapawan_oxiba]

Okay,

I'll order the chip. Since I live on an island it can take a bit of time until I receive it.
I'll keep you updated as soon as possible.

Thank you.

[Tapawan_oxiba]

Hello everyone!

Just a little update. I ordered 5 chips on December 2024, and received them yesterday. I replaced the chips and..... with two of them I have 1.00V on phase 2 and 0.65V on phase 1, with two other: nothing at all, and the last one just blew on my face....

I'll reorder this chip from another supplier and see what happens.

Have a nice day.

[Tapawan_oxiba]

Hello,

As I said in the previous post I reordered the chip from another supplier. And after resoldering the chip everything is fine now ! The laptop starts and run fine!

Thank you for your help!

Have a good day!