820-3435 - Minor Liquid Damage, dead

[baker_jeff]

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!

 

[2informaticos]

Check PCH's RTC signals, PM_DSW_PWRGD and PCH_DSWVRMEN.
Also check PM_BATLOW_L.
Do you get 3V3_S5?

 

[baker_jeff]

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]

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

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...

boards.rossmanngroup.com

"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]

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]

"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]

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]

Looks like SMC issue, reball it.

 

[baker_jeff]

I replaced SMC to be safe, no change in voltages on R1450. PM_DSW_PWRGD still 0.00v

 

[2informaticos]

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]

I have AMTECH from Rossman store . Done... no change.

 

[2informaticos]

Force PM_DSW_PWRGD with 10K resistor to 3V3_S5.

 

[baker_jeff]

Done, 0.035v after the resistor on PM_DSW_PWRGD. No change otherwise.

 

[2informaticos]

Did you get SMC from donor board, same model?

 

[baker_jeff]

I did yep.

 

[2informaticos]

As last resource, try 470 ohm resistor as pull-up.

 

[baker_jeff]

Do you mean "Force PM_DSW_PWRGD with 10K resistor to 3V3_S5" but with a 470k resistor instead?

 

[2informaticos]

NO, I said 470 ohm (0.47K).

 

[baker_jeff]

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

 

[2informaticos]

What about 390, 430, 560, 680 ohm???
Anyone can serve here.