820-3435 - Minor Liquid Damage, dead

baker_jeff

Member
820-3435 - Minor Liquid Damage, dead

It was actually on when I got it. Shut it down for inspection and it hasn't come back on since. SMC Reset changes the magsafe light, and PPBUS is 8.6v.

There was corrosion on U8005, and C8005 right beside it. I replaced both.

I have PPBUS, PP3V42_G3H, PPVRTC_G3H, PP5V_S5.

I'm missing PP5V_S4RS3. Missing PP3V3_SUS at BIOS, and missing SUS_EN as well.

At this point I'm beyond my limited expertise with power issues. Thanks for any advice!
 

baker_jeff

Member
PCH_SRTCRST_L is 3.3v
PCH_CLK32K_RTCX1 is 0.4v
PM_DSW_PWRGD is 0.00v
PCH_DSWVRMEN is 1.528v
PM_BATLOW_L is 3.3v
PP3V3_S5 IS 3.4V
 

2informaticos

Administrator
Staff member
"Check PCH's RTC signals"
You have some time on the forum, should know what I asked for.

"PM_DSW_PWRGD is 0.00v
PCH_DSWVRMEN is 1.528v"
Bad signals, both.
Post voltage on both pins of R1450.
Check S5_PWRGD level too.
 

baker_jeff

Member
Ah apologies, thanks for the explanation.

RTC_RESET_L is 3.3v
PCH_SRTCRST_L is 3.3v
PCH_INTRUDER_L is 3.06v
PCH_INTVRMEN is 3.2v

S5_PWRGD is 3.4v

R1450:
Pin 1: 3.337v
Pin 2: 3.24v
 

2informaticos

Administrator
Staff member
"PCH_DSWVRMEN is 1.528v
------------------------
R1450:
---
Pin 2: 3.24v"
Are you really sure???
Please, check the schematic and try to understand it...
 

baker_jeff

Member
Pin 2 of R1450 is truly 3.24v. R1450 is 330k as per schematic. Not sure why I got 1.528 before... sorry.

PM_DSW_PWRGD is still 0.00v
 

2informaticos

Administrator
Staff member
If S5_PWRGD is high, PM_DSW_PWRGD should go high too.
This signal is controlled by SMC, but I suppose the pull-up resistor is inside PCH.
Heat PCH area until 180-200 degrees, for 15-20s; use quality flux, not chinese honey.
 

baker_jeff

Member
Ok... desperately searching PDF but no 0.47K resistor on the 3435 donor. Any suggestions for where you would commonly find one?
 
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