A2338 820-02773 5V PPBUS at 11V

[Instafixx]

PPBUS at 11V pulsing between 11V and 12V.

PP3V8_AON is 3.8V

Unable to enter DFU with key combinations.
Jumper method wont work as S2 lines have 0.3 to 0.5V.

PP5v_S2 is 2.3V and pulsing
3v3_s2_LDP is 1.3V

Bad CD3217?

 

[Instafixx]

Did a thermal scan. UE501 was heating up. SMC_FAN line shorted. Replaced UE501 - short gone.
UP701 was burst. Replaced. Had to reconstruct a trace as well. But its still the same.

Did thermal scanning again now UP710 heating up.

 

[2informaticos]

Any history available?
Tested the board alone on the desk?

 

[Instafixx]

All findings are with board on desk.

Currently 3v3_s2_WLBT_ISNS is shorted. Injected voltage. IC suspected

 

[Instafixx]

Removed the WIFI IC. Short gone. Machine boots now. I get chime and external video but no internal image or backlight .
NO IMAGE and NO BACKLIGHT.

UP701 was burnt and was replaced . I had to reconstruct trace for EDP_PANEL_PWR_EN.
I get 3.3V there very briefly before it goes down to 0V.

Tried known good display as well.

 

[2informaticos]

"I get 3.3V there very briefly before it goes down to 0V"
Can you catch 3V3/5V_SW_LCD at same time?

 

[Instafixx]

5V_SW_LCD is constant 5V
3v3 is 0V throughout

 

[2informaticos]

3V3_Sw_LCD should pulse at same time with EDP_PANEL_PWR_EN.

Maybe I understood you wrong.
"I get 3.3V there very briefly before it goes down to 0V"
Was this reference about EDP_PANEL_PWR_EN?

 

[Instafixx]

3V3_Sw_LCD should pulse at same time with EDP_PANEL_PWR_EN.

No it's not pulsing. EDP_PANEL_PWR_EN goes upto 3.3V very briefly.

 

[2informaticos]

Correct dioe mode at 3V3_SW_LCD rail?

Check UP701 solders and traces.