820-00165-A fan spin, vcore present, but no all_sys_pwrgd ( weird )

[Yoel Ren]

Hi, so this came in dead.
i see that fan is spinning and i got 1.7v at vcore, but its braindead ( no usb activity / capslock light/ chime/ image/bl)
but when i try to probe measure all_sys_pwrgd voltage,fan spin immediately turn off. ( no vcore ).
i have encountered this kind of problem before, one time it was smc.
but in this case, i have replaced smc with no avail.
i have try to remove q8150 but still no all_sys_pwrgd.

 

[Yoel Ren]

when fan spin stop ( after i probe all_Sys_pwrgd), voltage is stuck at s5 state. so no voltage beyond that point.
pp5v_s5 : 5v
pp3v3_s5 : 3.3v

ppvrtc_g3h : 2.9v ( suspicious ) diode mode 0.490
pp3v3_sus : 3.3v
smc_pm_g2_en : 3.4v
pch_intruder_l : 1.7v
pch_intvrmen : 2.4v

 

[2informaticos]

"pch_intruder_l : 1.7v"
Too low, correct it.
Could be bad PCH, which will explain the drop of PPVRTC_G3H too.

Inspect for corrosion around U1900, remove C1910.
Also look at C0890-92.

 

[Yoel Ren]

theres indeed some flux around u1900 from previous tech work, i cleaned it, ppvrtc is 3.3v now.
but intruder_l is still 1.7v.
like the usual, try playing with resistor value, if still low then try to heat pch, then to trash bin right ? trying to build the workflow haha.

 

[2informaticos]

Yeah, that's the way to follow...