Omen laptop DA0G3EMBCD0, shor circuit from USB

[ryogadan78]

Good morning guys. I have my Omen laptop (DA0G3EMBCD0) that now gives no signs of life (no LED).
During the night I misplugged a slim usbdrive which had the shield damaged, I guess I caused a short because the laptop turned off and never turned on again.

After taking it apart I noticed with the thermal imaging camera that two ICs on the mainboard reach 100 degrees Celsius. Thanks to the boardview I saw that they are PU8600 and PU8601. I tested the pins of these ICs and found these anomalies compared to the schematic

PU8600
6 (3VS5_LX) - 5 OHM to ground (normal?)
14 (3VS5VOUT) - SHORT TO GND
17 (+3VPCU) - SHORT TO GND
19 (3VS5_LX) - 5 OHM to ground (normal?)


PU8601
6 (5VS5_LX) - GND
19 GND - SHORT TO GND
20 GND - SHORT TO GND

Suggestions on how to proceed?

[mon2]

Have not reviewed the schematics yet but locate the local usb load switch for the shorted usb port.

Is that part defective on the vbus rail? Post the resistance to ground measurement. No power during this measurement.

[ryogadan78]

Have not reviewed the schematics yet but locate the local usb load switch for the shorted usb port.

Is that part defective on the vbus rail? Post the resistance to ground measurement. No power during this measurement.

Hi Mon2, you are always so kind to reply.
I only have the boardview of this board and probably wouldn't have the experience to read a schematic. Could you help me? identify the components to be tested by the name they have in the boardview?

[mon2]

Certainly. Apparently, I also have only the boardview in my database service.

The process is to locate the USB port name that faced this shorting event. Then find this port on the boardview diagram. Select the pin that is linked to the VBUS power rail.

Using internet (google), the USB connector pinout should be public since this is an industry wide specification. That is, if the connector is USB 2.0 -> search for USB 2.0 pinout. If USB 3.0 connector -> search for USB 3.0 pinout. The insulator in the connector is used to identify the speed from the outside of the logic board.

Black insulator = USB 2.0
Purple / Blue insulator = USB 3.x.

Your focus is to identify the port name and then VBUS on that port. Once you highlight this pin, the next component in line will be lit up in the boardview drawing.

Often, there are local USB load switches which act like current limited electronic fuses. They 'should' prevent damage to the board but often fail and do not react in time.

[ryogadan78]

Certainly. Apparently, I also have only the boardview in my database service.

The process is to locate the USB port name that faced this shorting event. Then find this port on the boardview diagram. Select the pin that is linked to the VBUS power rail.

Using internet (google), the USB connector pinout should be public since this is an industry wide specification. That is, if the connector is USB 2.0 -> search for USB 2.0 pinout. If USB 3.0 connector -> search for USB 3.0 pinout. The insulator in the connector is used to identify the speed from the outside of the logic board.

Black insulator = USB 2.0
Purple / Blue insulator = USB 3.x.

Your focus is to identify the port name and then VBUS on that port. Once you highlight this pin, the next component in line will be lit up in the boardview drawing.

Often, there are local USB load switches which act like current limited electronic fuses. They 'should' prevent damage to the board but often fail and do not react in time.

OK the procedure should not be complicated also because I caused the short on the only USBC port. I have to leave the lab now but I will do the research as soon as possible and update you

[ryogadan78]

OK the procedure should not be complicated also because I caused the short on the only USBC port. I have to leave the lab now but I will do the research as soon as possible and update you

In the boardview, the USBC connector is marked as CNP1. The TBTA_VBUS_L pin is connected to pin 10 of an IC marked on the boardview as UP1. I enclose a photo pointing out that two nearby capacitors are shorted to ground on both pins

[ryogadan78]

Hi Mon2, I don't know if you saw my answer. Unfortunately I don't really know how to proceed considering that the VBUS comes to this IC. Any suggestions?

[mon2]

Flux and remove each of these capacitors. Keep notes of their locations. Then measure the resistance again without these parts. No power to the board.

[mon2]

Not sure if our posts are in sync but note that there is a VBUS input from the external power source / adapter then there is the secondary side of this power rail that follows after some internal mosfets inside of this power delivery (PD) controller. If you are truly noting a shorted region on the board like the 2 highlighted caps then flux and remove each. Then test the resistance to ground on the same pcb pads to confirm if the shorts are removed or not.

[ryogadan78]

Flux and remove each of these capacitors. Keep notes of their locations. Then measure the resistance again without these parts. No power to the board.

Done, the short circuit still seems to be present. Resistance to ground is 0.4ohm

[ryogadan78]

I injected 1V on the 5V pin of one of the capacitors on which I detected a short to ground. With the thermal camera, I identified an area of the mainboard that I had not inspected and found this nice surprise. Based on the boardview IC it is PU8700. Any suggestions?

[ryogadan78]

Flux and remove each of these capacitors. Keep notes of their locations. Then measure the resistance again without these parts. No power to the board.

Hi Mon2, I don't know if you have seen the latest updates, I need your help. I really wouldn't know how to go on

[mon2]

What are the topside markings on PU8700?

The region of this area looks to be burnt or is this bad flux?

Also, share a larger pic of this area. We are reviewing the same boardview and to me, this is not PU8700. The surrounding parts do not match your board pic.

[ryogadan78]

Hi Mon2, sorry I have not been present. Health problems. Here I am with you. I am enclosing a photo where you can see the initials above the chip and a photo showing a larger area of the mainboard. I actually noticed too that the boardview file does not match 100%.

The region of this area is burnt

Topside marking of IC

51486
TI OA8
AEP5

[ryogadan78]

What are the topside markings on PU8700?

The region of this area looks to be burnt or is this bad flux?

Also, share a larger pic of this area. We are reviewing the same boardview and to me, this is not PU8700. The surrounding parts do not match your board pic.

Hi Mon2, do I start disconnecting ICs and cleaning the mainboard?

[ryogadan78]

What are the topside markings on PU8700?

The region of this area looks to be burnt or is this bad flux?

Also, share a larger pic of this area. We are reviewing the same boardview and to me, this is not PU8700. The surrounding parts do not match your board pic.

I don't want to bother you, just to know if you think I can go ahead with the repair or is it too complicated

[mon2]

Review the bottom side of the 51486 chip - appears that one pin (at least) is missing. There should be 5 contacts on the bottom side that appears to be 'burnt' looking.