820-3115 backlight, no display, no keyboard no trackpad, external display good

grmacs

Member
I'm lost with this board. Now I have no 18.5V at tracpad connector J5800. no Z2_Boost_EN WITH trackpad connected (tried multiple AND new j5800 just out of desperation). Does keyboard ALSO need to be connected? I have 3V3_S4 at J5800. Something must not be getting to J5800 for it to send 3.3V to Z2_Boost_EN?
 

2informaticos

Administrator
Staff member
TP is independent, no need to connect KB.
Did you try known good TP and flex?
Check your job on U2700; resolder original U5701 and U2700.
 

grmacs

Member
Yes J4700 works. I was able to get 18.5V back at j5800. I'll check voltage again TO U2700 but if that's ok i assume its a trace from U2700 to next stop but not sure what the data output pins are on U2700 OR it looks like USB may also come through U2700?
 

2informaticos

Administrator
Staff member
J4700 port do not pass through U2700.
Seems that you have a problem with U2700, or its communication with PCH.
 

grmacs

Member
Best I can tell it has to be PCH. Could I run jumpers to send data through USB? or different route to test or maybe as alternative to junking the board?
 

grmacs

Member
No change. I MUST have an issue with U5701 then, correct? I've tried other tracks and keyboards... tried completely different top case, etc... as well as I think this was the 3rd U5701!
 
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