820-4924 No Keyboard/Trackpad

[bjf]

This board had some minor liquid-damage but nothing near the keyboard or trackpad connector. The board works fine but has no trackpad or keyboard, just the click works. The trackpad doesn't work beyond that - no movement. No response from keyboard. Not sure where to go with this. Everything is measuring fine that I can think to check.

 

[JohnB8812]

Have you tried a known good trackpad flex and trackpad?

 

[2informaticos]

TP/KB not working on OSX and boot menu too?
If yes, try known good TP board/flex.

 

[bjf]

Yes, definitely tried known-good trackpad, cable and keyboard. I have a bunch of these boards around so I double-checked with a good board and all of the test parts are confirmed good.

 

[2informaticos]

"TP/KB not working on OSX and boot menu too?"
???

 

[bjf]

Yes, it does the same thing in the boot menu. Just has the trackpad click. No Force Touch click. No movement. No keyboard.

 

[2informaticos]

First, check basic voltages for J4802.
Next, post U4910 voltages; both cases, boot menu and OSX logged in.

 

[bjf]

Thanks, that helped get me there. It's a strange one. 3V3_S3 was unstable at around .5V for a few seconds at startup and then would come up to 3.3V. That was keeping the trackpad from getting power initially which seemed to keep it off after that. I switched out U8010 and 3V3_S3 comes up to 3.3V immediately now. All is good. Thanks.

 

[2informaticos]

Good job man...