Hi i need help with a Dell latitude 14 5420 GDF40 LA-K491P Rev 2.0 (A01) 2020-11-16

[djpaesgana]

Hi i need help with a Dell latitude 14 5420 GDF40 LA-K491P Rev 2.0 (A01) 2020-11-16 , it charges on usb type C i checked the charger with a pd decoy and a electronic charge its ok when, i tested the usb c jack with a tail tester it reads ok (photo incluided), then with a usb charge tester it looks like its trying to negotiate the PD but ressets i openned the laptop and with a thermal camera i noticed 3 ICS getting hot the TPS65994 (UT3) the ISL95860HRTZ (PU601) and the IC SLGC55544CVTR (UI1) this one checking it on the micoscope looks damaged visually (picture incuided) and looking on the Boardview im not 100% sure if the ic it shows on the board view its correct could you guys helpme if its correct or wrong

[djpaesgana]

the ic that gets more hot is the the TPS65994 (UT3) , i removed the UI1 IC that looked damaged, and tested again, with the tail tester and comparing it to the port 2 and my phone it looks like pins 04,09,16,21 are on short(its my first time using this tool) and my first usb type c charger laptop im trying to fix, it still doesnt turn on, the TPS65994 (UT3) still getting very hot and the ISL95860HRTZ (PU601) is getting also but not that hot, ill check where those pins go and see if its the TPS that is on short or what

[djpaesgana]

found the pinouts for the tail tester now to check them on the boardview

[djpaesgana]

YUP.... its in SC

[djpaesgana]

i was making some readings

[djpaesgana]

i removed the ut3 and some caps and still read on short where the caps pads, tested with the tail tester and the short went to open

[djpaesgana]

following the net of 5v_alw_a_tbtthis caps and the test point also reads on short, so following the testpoint should i inject 1V 1A on it to see what else gets hot or should i test component 1 by 1 on that list +5v_alw hmmm....

[djpaesgana]

UI1 is already removed and motherboard still on short

[mon2]

Which pin on UI1 is showing the short? Post the full details of the pin # and also the resistance to ground in ohms.

[djpaesgana]

Which pin on UI1 is showing the short? Post the full details of the pin # and also the resistance to ground in ohms.

this are my readings, the ic was getting hot and also looked like damaged i havent tested the ic outside the mobo

[djpaesgana]

readings on UT3

[mon2]

Attached.

[djpaesgana]

the pic was taken after taking the readings, and still reads the same after cleaning

[djpaesgana]

i aplied 1v 1a to the pad 8 of UI1 nothing happened, aplied 2v 1a and pu601 came hot , nothing else

[mon2]

Review the topside middle 2 pads again. There is still a solder short that is visible.

[djpaesgana]

same readings after cleaning it

[mon2]

Review if there is a bottom side part under the area that is heating on pu601.

[djpaesgana]

pu601 readings from ground to caps

[djpaesgana]

this is the area behinmd the pu601

[mon2]

PC640 is ~21R ohms to ground? This is the +5V_ALW rail and this resistance is very low. Confirm it. Remove PC640 and test the resistance to ground again.