MacBook Pro 13" 820-00239 No boot no display

[ielectron]

Hi,
I get MacBook Pro 13 A1706 after someone else screen replacement attempt, that doesn't boot.
Once I tried power it on touch pad clicks but no display tried another screen new LVDs cable
Touch Bar is not displaying anything, caps lock does not lighting up.
I tried to disconnect trackpad once this is done FAN is spinning on max RPM.
Laptop is taking charge 20V around 2,3 A
After measure I noticed that there is no enable signal on u8500
PANEL_P5V_EN 0.02V
PP5V_S0 5V
PP3V3_G3H 3,41V
PPVCGT_CPU_PH3 0.7V
PPVCGT_CPU_PH3 0.7V
L7410 0,5V
L7210 0.9V
L7900 1.2V
L7030 11.23V - 11.73V it is jumping
LB700 0V
F4500 12.36V
CPU getting hot as all voltages around present, FAN also starts spinning once CPU reach temperature point

Any idea what should I check more or what the fault could be ?

 

[2informaticos]

VCORE stuck at 0.9V means the board doesn't really boot; only stays on.
No reason to search for video; missing USB activity also.

Check for knocked off components and damaged traces.
Machine was booting before screen replacment attempt?
If someone worked on it without disconnecting battery, the damage can be letal.

 

[ielectron]

According to customer it was booting and working but screen was loosing backlight, than someone try replace screen due to flex gate issue and after this there was no boot anymore.
I already checked for damages under microscope didn't notice anything unusual board is clean.
Just looking at board view is it possible if someone didn't connect properly cable damaged CPU that way I mean it is not dead completely as in it is powering on but stuck as you said at 0.9V on Vcore voltage ? Like there is 2 lines going directly to CPU EDP_INT_AUX_N and EDP_INT_AUX_P just next to backlight VOUT
I know it is hard to judge but just looking for some hint on this board to try, maybe its not brain dead

 

[2informaticos]

Backlight output shouldn't be present, when LCD cable is not inserted.
But PPBUS_G3H is present on the board, if battery is not disconnected (at least its data cable).
Other people reported to got their board damaged, because of such reason.
A dropped screw on the board is sufficient to kill it; depending where it drops.

We also know about some "technicians" who intentionally remove components when then fail to complete the repair.

 

[ielectron]

Thanks for response 2informaticos, I was thinking to try BIOS, as I didn't try this yet, chance is slim but worth to check this. Do you have good, known BIOS file for this model by any chance ? Thanks man