820-2915-B: CPU fan always on high (and some other issue)

[dukefawks]

I'd first try a known good trackpad+cable. Is the keyboard working without the trackpad connected?

 

[Antonio]

Strange... Now when I turn it on, regardless of the keyboard or mouse being plugged in it takes a long time to start up, loads for a bit, then goes to a window showing me how to turn on a bluetooth keyboard and mouse... Does it when they're both plugged in, neither plugged in, or just one of them.

 

[dukefawks]

Check voltages on U5701. Also run ASD to check for errors.

 

[larossmann]

my guess is on pp3v3_s4 missing

 

[Antonio]

pp3v3_s4 is present and at 3.34v on the keyboard and trackpad connector. pp18v5_s4 however, is not giving enough power. I'm getting VERY little from it, less than 1 volt. I'm still in the process of tracing it back to see where it's getting dragged down, but as I am new to this and quite stupid, trying to understand the schematic isn't the easiest thing. How important is pp18v5_s4?

 

[Antonio]

P18V5S4_FB is putting out like .2mV right off U5805

 

[Antonio]

Pin 2 of U5805 has the full 5V coming in to it perfectly fine, so that means U5805 itself is bad... Right..? Or is there something else outside that should be boosting it that i'm not understanding?

 

[dukefawks]

Trackpad must be connected to enable the 18V, Z2_BOOST_EN!

 

[Antonio]

Well crap. That further complicates things. It doesn't look like anything is missing in that case.

Completely lost at this point.

 

[dukefawks]

Dead U5701 maybe?