820-00164

[MDY]

Found little corrosion arround Bios

PP3V3_S5 - present
32khz PCH present
PM_PWRBTN_L -3V
PM_RSMRST_L -3V
PPVRTC_G3H -3V
RTC_RESET_L -3V
PM_SLP_S5_ L -0V
PP5V_S4 - 0V missing

Checked resistor arround bios and are ok. Corrosion was very very little.

I lift U6101 and clean and resolder again.

Chip Select (/CS) on BIOS pin 1 is in 0.30V sometimes goes to 1V

Should be on 0V or 3V?

 

[dukefawks]

Is the whole machine power cycling? Check traces and resistors around U6100.

 

[MDY]

No power cycling. Cannot see nothing on S4 rail. traces and resistors are ok. Only chip Select (/CS) on BIOS pin 1 is in 0.30V sometimes goes to 1V


Should be on 0V or 3V?

 

[dukefawks]

If that sometimes goes to 1V something is power cycling.....picture of affected are plz.

 

[MDY]

No Title

 

[dukefawks]

I already see a suspect take to probe 736 and possible corroded probe 737.

 

[MDY]

i resolered U6101 again and now I have all rails and CPU rails too.
PPBUS - 8.18V
No video, no mouse.
Reflowed SMC

8.18V means bad SMC?

 

[dukefawks]

Adressed probe 736/37? 8.2V on PPBUS means at least SMC data bus to battery is fucked. Could be crap under SMC, dead SMC or dead ISL6259.

For the record this board was power cycling as there was a BIOS issue. This is a symptom you need to be able to identify in the future.

 

[MDY]

I did a jumper to U6101 as 3V was missing and now they are stable always. Do you think replacing SMC will solve the problem with no video or this is another problem? I have all rails and CPU rail appear for 20 seconds and then goes to 0V. Any idea here?

 

[dukefawks]

Why don't you answer my question about TWO (2) probe points?

 

[MDY]

How do you find these probe points?

 

[dukefawks]

With board view. Don't think you can search them, there are only a few in the area.