ASUS ROG GX502LXS-HF049T - nie włącza się wogóle - NAGRODA 100PLN!

Now, please measure the resistances of both resistors (PR8904 and PR8905) directly on their pads, not in reference to ground. Please first disconnect all the power, wait 1-2 minutes for all capacities to discharge and then, perform the measurements.

PR8904 - 43.69KΩ
PR8905 - 18.65KΩ

Please desolder PU8900 and repeat the above measurements. All the power must be disconnected. Important: Never connect power supply to the logic board which has any SMPS chip removed until clearly requested otherwise, or until the SMPS chip is soldered back.

Desoldered PU8900.

PR8904 - 43.34KΩ
PR8905 - 18.62KΩ

I think I have found the problem. PC8907 (47PF/50V) appears to be fully white, but it should be brown. Is it damaged? I have measured it and obtained a reading of 0. Here is a photo:

vlol hat geschrieben:PC8907 (47PF/50V) appears to be fully white, but it should be brown

The colour of that capacitor is good, 47pF is very small capacity so it should not be brown but white or light grey, actually. I'm more concerned about the dirt visible on the right side of that capacitor, please clean it out with isopropyl alcohol.

vlol hat geschrieben:I have measured it and obtained a reading of 0

What did you measure actually? Resistance, capacitance, voltage drop? What range did you set your multimeter to during these measurements? Anyway, at this stage please desolder PQ8902 transistor (keep PU8900 removed too), connect the power supply and measure the voltage directly on PR8905 resistor pins (not in reference to ground).

NOTE: This is the case I mentioned above - I have requested connecting power supply to the motherboard although the charger chip has been desoldered - the safety measures we take here is to desolder PQ8902 to prevent the voltage reaching an unsecured PQH8901/PQL8901 transistors (floating gates).

Vogelek23 hat geschrieben:What did you measure actually? Resistance, capacitance, voltage drop? What range did you set your multimeter to during these measurements? Anyway, at this stage please desolder PQ8902 transistor (keep PU8900 removed too), connect the power supply and measure the voltage directly on PR8905 resistor pins (not in reference to ground).

Sorry for my mistake. Initially, I measured resistance, but then I re-measured and found a capacitance of 0.17nF (I know I need to desolder it to test). The multimeter was set to auto range.

Desoldered PQ8902.

PR8905 - 1.727V

Replace PR8904 with 120kΩ and remeasure the voltage on PR8905 resistor. Do not solder any other components back yet.

Replaced PR8904. (old resistor measured 127kΩ and new resistor measured 120kΩ.)

PR8905 - 1.787V

Please measure the resistance to ground on pin 1 and 2 of PU8900 charger chip (do not connect any power).

PU8900:
pin 1 & pin 2 - 0.7Ω

vlol hat geschrieben:pin 1 & pin 2 - 0.7Ω

It means you have a short circuit at the main power rails. Please perform a "short-test" described in TRAININGS subforum: post5699.html#p5699 (there is an English version added below the original one).

Vogelek23 hat geschrieben:Do not solder any other components back yet.

Still no progress on soldering components back yet?


That's correct? My power supply is providing 20.67V, the laboratory power supply should be set to 20.67V or a maximum of 19V? Where should I check for components? In the area of the PU8900 charger chip?

vlol hat geschrieben:Still no progress on soldering components back yet?

No, please do NOT solder anyting back yet.

vlol hat geschrieben:That's correct?

Not correct. Please inject max 1V (current limiter set to 2A initially) into ACBAT_SYS power rails, best is to connect the red (positive) wire to PJP8600 jumper. Location of this jumper below. Please do not increase the voltage at this stage.

The laboratory power supply shows 01.00V, 00.88A, 0.880W. Everything seems to be good with no damages.

Increase the voltage to 2V and repeat a short-test. Search for any warm/hot components or areas of PCB.

Second 2V repeated short-test - The laboratory power supply shows 02.00V, 01.99A, 3.8960W. Everything seems to be good with no damages.

vlol hat geschrieben:2.00V, 01.99A, 3.8960W

Nearly 4W of power must dissipate as heat somewhere - do you clearly understand what the "short-test" is for and what does it help to do? Please search for any signs of heating on the logic board while it is connected to the power supply set to 2V and consumes 1.99A of current. If you do not know how to search for heat, please refer back to TRAININGS subforum linked in post #31.

Vogelek23 hat geschrieben:do you clearly understand what the "short-test" is for and what does it help to do?

Yes, the "short-test" is designed to identify any signs of heating or overheating on the logic board while it is connected to the power supply. This test helps in assessing the dissipation of power as heat and ensuring that the components are functioning properly without any excessive heat buildup.


This is the PL8901 (2.2UH), heating up to +33. Is that okay?

vlol hat geschrieben:This is the PL8901 (2.2UH), heating up to +33. Is that okay?

Not okay. Please check PQL8901, PQH8901 resistance between pin 1 (source) and 8 (drain). Please measure the resistance to ground on PL8901.