Zephyrus Duo 15 No Display or Power

[Brown sugar builds]

I got this laptop as a trade and from what I can find, there's no power on the motherboard other than the power coming from the charger. I can find 20v by the charger but no other power rails anywhere else. Is this a bad charging ic or what would cause this. I've used a thermal imager and there's nothing hot.

[mon2]

1) Review the charger circuit sticky above by piernov - great reading on how charger circuits function.

2) Be sure that the power adapter is suitable for this laptop.

3) Trace the DCin power connector to locate the DCin mosfets. What are their topside markings? The mosfets will be black in color with 8 pins (4 on each side). Following these 2 * DCin mosfets will be a charger IC that is responsible to enable / disable these mosfets. The gate pin # 4 of the mosfets will often be controlled by the charger IC. Share quality pics and/or details of the topside markings of the charger IC.

4) Remove all power -> meter in resistance mode -> measure the resistance to ground of these DCin mosfets. Checking for a low resistance which may confirm that there is a shorted component in the power path of these mosfets -> causing the power supply to be shut off.

5) If available, share a link to the schematic (do not post it here) -> post the schematic in the dedicated schematic forum.

[Brown sugar builds]

1) Review the charger circuit sticky above by piernov - great reading on how charger circuits function.

2) Be sure that the power adapter is suitable for this laptop.

3) Trace the DCin power connector to locate the DCin mosfets. What are their topside markings? The mosfets will be black in color with 8 pins (4 on each side). Following these 2 * DCin mosfets will be a charger IC that is responsible to enable / disable these mosfets. The gate pin # 4 of the mosfets will often be controlled by the charger IC. Share quality pics and/or details of the topside markings of the charger IC.

4) Remove all power -> meter in resistance mode -> measure the resistance to ground of these DCin mosfets. Checking for a low resistance which may confirm that there is a shorted component in the power path of these mosfets -> causing the power supply to be shut off.

5) If available, share a link to the schematic (do not post it here) -> post the schematic in the dedicated schematic forum.

After looking it up, I believe the ic chip markings are IT8299E120A
2021-CXA
S18CGA
I'll continue to do #4 to see if I can find any shorts. I did get a short to ground probing I think it would be pin 5 of one of the mosfets

[Brown sugar builds]

Yeah so far more than one I've gotten 0 ohm shorts on pins 4 and 5

[mon2]

IT8299E120A = SIO controller and used for the keyboard + real time clock and few other functions. This is not your charger IC. Review around for a leadless square IC which should be smaller in size than this one. Perhaps is on the opposite side of the mosfets (ie. top / bottom side of the circuit board).

Could be with a 'BQ' markings = Texas Instruments or another brand. Being Asus, chances are slim that there is a schematic for your logic board but we may be able to figure it out without one.

What are the topside markings of the mosfets near the DCin power connector? Using Google, we should be able to figure out if they are N-channel or P-channel type of mosfets.

[Brown sugar builds]

IT8299E120A = SIO controller and used for the keyboard + real time clock and few other functions. This is not your charger IC. Review around for a leadless square IC which should be smaller in size than this one. Perhaps is on the opposite side of the mosfets (ie. top / bottom side of the circuit board).

Could be with a 'BQ' markings = Texas Instruments or another brand. Being Asus, chances are slim that there is a schematic for your logic board but we may be able to figure it out without one.

What are the topside markings of the mosfets near the DCin power connector? Using Google, we should be able to figure out if they are N-channel or P-channel type of mosfets.

Ahh ok. Then the mosfets look something like
64 UUB
6W0K04 or 6W0KD4

[Brown sugar builds]

And would the ISL9238BH be what you're looking for the IC

[mon2]

ISL9238BH - yes This is the charger IC for your logic board. No hits on the mosfets. Can you post a pic of this region?

They should look something like the attached:

[Brown sugar builds]

Alright here's a few pictures.

[SMDFlea]

Ahh ok. Then the mosfets look something like
64 UUB
6W0K04 or 6W0KD4

G4 UUB , G4 *** PE616BA https://www.badcaps.net/forum/troubl...86#post1672286