820-00426-A vcore present fan spin, chime, but not turning on

Yoel Ren

Member
This came in with massive thermal paste at cpu and gpu heatsink, clean it off, and i get the symptom like in the title, I have replaced 3 fdmf6708n new from mouser.. but still the same.. i got chime but no usb activity, fan spin will go loud after a while, but idk if its because the cpu itself is hot or because its the 'symptom'..-
-board doesnt start in smy bypass
resistance between 17/18 & 27/28 is 3 ohm and 20 ohm
PPBUS : 12.57V
ALL_SYS_PWRGD : 3.3V
CPUVR_PGOOD : 3.3V
SYS_PWROK_R : 3.3V
PM_S0_PGOOD : 3.3V
SMC_DELAYED_PWRGOOD : 3.3V
 

Yoel Ren

Member
i once work at this board and i remember i try to swap bios with another i found from internet, someone say "its working thanks". but i still don't really trust the bios.. and i forget to backup original bios ( yeah i fucked up, sorry) .. can anyone provide 820-00426-A bios maybe ?
 

Yoel Ren

Member
i flashed that file, at first, I was having a fan spin, but no usb activity still, and after a while, i don't have fan spin anymore, and i feel some heat generated by u1100, other part of the board is cool
 

Yoel Ren

Member
well, i see that pp3v3_S5 is shorted to ground at 18 ohm.. i never check pp3v3_s5 because I have fan spin, but do you think i have one before i flash this bios ? ( still have fan spin ) , or some bios flashing mechanic trigger a short on this line ?
 
Last edited:

2informaticos

Administrator
Staff member
BIOS cannot drop 3V3_S5.
18 ohm is very low and some component is damaged there.
Injection voltage doesn't help too much, unless you can check with a thermal camera.
 
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