820-2838 Green light, now fan or power.

[gcain]

I'm having a bad run with MBAs this week... :/
2879-B I can fix in under 15 minutes 95% of the time, but these things I always struggle with.



I'm getting PP3v3_S5 but no PP3v3_S3.

S5 creates S3, I believe (can someone confirm?), so I need to find that chip in the schematic and see what it's pushing out.


The board shocks me periodically too. Is this a sign something is shorting to ground?


Does Q7910 create S3 power rail?

Q7910:1 = ~88mV (PP3V3_S3)
Q7910:2 = 8mV (PP3V3_S3)
Q7910:3 = 3.3v (P3V3S3_SS)
Q7910:4 = 3.3v (PP3V3_S5
Q7910:5 = 0v (PP3V3_S3)
Q7910:6 = 20mV (PP3V3_S3)

The way I read the schematic (page 59), is that Q7910 takes PP3v3_S5 and creates PP3v3_S3 from it, however it is not putting out PP3V3_S3 thus it is faulty.

Sound right?

 

[dukefawks]

These do not power on by themselves. Does PM_PWRBTN_L toggle when you try to power it on? If that seems ok what is the voltage on both pins of Y2810?

 

[gcain]

I didn't know that.
Will check when I'm back at the office in 12 hours.

 

[gcain]

Laptop boots on the bench, but not in the case...

Really weird...

 

[dukefawks]

Really easy, bad power button on keyboard or bad flat cable/connector/trackpad.

 

[gcain]

I don't think so.
There are no cables plugged in and I am starting it by shorting the pads.

 

[dukefawks]

Well, what is connected in the case and not on the bench? Different IO board?