820-3476: No powering up. Missing PP5V_S4

[macRepairAmb]

Hello

Have a 820-3476 not power up. No sign of liquid damage. Here are readings have taken so far:

PPBUS_G3H - 12.59
PPDCIN_G3H_ISOL - 16.69
PP3V42_G3H - 3.42
PPVRTC_G3H - 3.34
PP5V_S5 - 5.01
PP5V_S4 - 0 but also pulsing

PP3V3_S5 - 3.34
PP3V3_SUS - 3.34

PCH_CLK32K_RTCX1 - 32.77KHz
SYSCLK_CLK25M_CAMERA - no sig
SYSCLK_CLK25M_TBT - no sig

Any suggestions on what else i could check.

Thanks

 

[macRepairAmb]

I did just ran into weird issue, using a MedUSA, i noticed that it wasn't able to read a serial number off the board, and said that the Sys block was missing. So i pulled the chip and extracted the bios from it and confirmed that the serial number was present. So, decide to try a different bios file. while trying to flash the bios chip with a bios from another machine using MedUSA it got locked at 18% and now the board is running (haven't tested with a display, but it chimes on). Not confident that it's fully fixed and now I can't read the chip using the medusa.

Going to refresh the chip with a clean bios file

 

[macRepairAmb]

Ok, seems refreshing the chip fixed it. But still can't flash using the MedUSA. Everything seems to run just fine.

 

[2informaticos]

Medusa fails to write sometime...
You must pull the chip then and solder it on A4064 adapter.
Medusa will do its job there.

 

[macRepairAmb]

Yeah that's pretty much what i did. I've ran the laptop for for about and hour and without issues.