820-00138 no keyboard

[zockysworkshop]

there is power on all pins except 1 2 and 3 and that lead me to U4850 and when i measured the pins on U4850 i get voltage on pin 4 10 and 6 --- so on pin 4 i have PP3V3_S4, and pin 10 is PP3V42_G3H and pin 6 is SMC_TPAD_RST_L and the rest of the pins 0 volts. Any ideas ?

 

[dukefawks]

First try a known good trackpad cable.

 

[zockysworkshop]

The trackpad is working. The only thing ive noticed on the power pads im getting 2.4v and i have another working computer same model and on that one im gettin 3.4v. So my problem is SMC_ONOFF but where this signal comes from ???

 

[zockysworkshop]

I've replaced U5110 and now i have 3.4v on pin 5 on the keyboard but when i short the power pads computer doesn't shut off

 

[dukefawks]

What makes you think a working trackpad proves that the trackpad cable is ok. Just look at diagram how this all works. SMC_ONOFF is just the power button and has nothing to do with the rest of the keyboard. First get the keyboard to work then look at why power button is not working.

 

[zockysworkshop]

I'm confused now. I haven't work on retinas a lot. Do i need the trackpad cable plugged in in order for the keyboard to work ? And i cant also understand why i can't start or shut off the board thru the power pads. Do i have problems with the SMC?

 

[zockysworkshop]

Give me a hint man where is the connection between the Trackpad cable and keyboard there is no board view on this model it so hard to work on this board im using similar board view. I've had Bios issues on this board i've solve that i had LCD issue i fix that too after had SSd issue i fix that too this board drives me crazy.

 

[dukefawks]

You already did lots of things to this board. I need to know what they were. You cannot just swap BIOSes on these.

U4820/30 are keyboard controllers and are on i2c bus to trackpad so keyboard issue can be trackpad or cable/connector too.

 

[zockysworkshop]

i didn't swap Bios i fix the via's around the bios. Thanks for the hint ill check it now

 

[zockysworkshop]

i can't find U4820 and U4830 on board view because u use similar board view, Any suggestions please ?

 

[zockysworkshop]

Here strange thing I've noticed i started to measuring voltage on the trackpad connector and since all the board views i have all trackpad connectors have 22 pins bit this has 44 so it helped me just with the orientation of the connector so the pins closest to the edge of the board taking number one from the SPI side are 1 3 5 7 9 11 and 13, all of this pins are shorted to ground and the other side pins 2 4 6 8 10 12 14 they all have 13volts on them, and according to the schematics the pins 2 6 and 14 should be ground. Any ideas ?

 

[dukefawks]

You have not tried a known good trackpad and cable. Without eliminating that there is no use in any further trouble shooting.

 

[zockysworkshop]

i will order cable do you think i'll need to try different trackpad too ?