820-2936 No liquid damage- green light no fan spin

ALB-Repairs

Member
Hi Guys, Got a odd one here.
820-2936 with no liquid by the looks of it. i mean its very very clean!
gets a green light, heres what ive done so far with no success.

PPBUS_G3H 12.6V
PP3v42 3.4V
SMC_RESET_L 3.4v

Heres where it gets interesting, SMC_PM_G2_EN_L Jumps up and down, hence so do 5V and 3v3
ive replaced the SMC with no change.
 

ALB-Repairs

Member
Acts the same with the SPI rom removed. This seems to be an fully S5 related failure. my guess is something on pp5v_s5 or PP3v3_s5
 

ALB-Repairs

Member
when the PP3v3_S5 coil is removed it stops jumping up and down. Gota be something that runs of PP3v3_S5 :( This boards a pain. Checked all rails for shorts, nothing seemingly out of place with anything.
 

ALB-Repairs

Member
Isolated the voltage jumping up and down as an issue on the PP3v3_SUS line, as ive already replaced the bios, looks like the PCH has failed. odd symptoms though!
 

ALB-Repairs

Member
S5_PWRGD cannot be present if SMC_PM_G2_EN_L is jumping up and down.....

Sorry, i skimmed that a little bit, When the PP3v3_SUS mosfet is removed SMC_PM_G2_EN_L remains solid. PP3v3_S5 remains solid too. Hence thinking its down to the SUS line and suspecting PCH.
 

ALB-Repairs

Member
PCH replaced, Same symptoms, With the pp3v3_SUS pull-up R7933 removed the current stabilises out. Clock Gen changed and crystal changed, no change in symptoms. Its something in PCH support.
 
Top