820-00138: Not recognizing keyboard

[macRepairAmb]

Have a board that doesnt recognize any keyboard, except external. Trackpad confirmed good. Tested on multiple frames with same results. Cap lock light doesn't come on either. Voltage on cap lock pin "WS_KBD15_CAP" is 2.4v. Since all keys aren't responding, is there a common items between both.
PP3V3_S4 is also present

 

[2informaticos]

Manual SMC reset key combination works?

Inspect U4820/30 area.
Check for activity on I2C_IOXP_SCL/SDA lines when pressing any key.

 

[macRepairAmb]

SMC reset works.

Regarding I2C_IOXP_SCL/SDA, Would you have a correct boardview for this board. The one i have isn't quiet correct and i've not been able to find the true board view. Or any suggestion on what probe points to use

 

[2informaticos]

No real boardview available for this board.
You can compare the U5820/30 area with 00163.
The surrounding resistors should be placed in similar postion.

 

[macRepairAmb]

So, measured around and found IOXP2_INT_L. Diode mode reading was 1.38. On another similar board, though dead, had measurement of 0.68. Confirmed on 2 of my donor boards with the same 0.68 reading. I check the surrounding pins on J4801. Unless you think of something else, i'm going to order and replace U4830.

 

[2informaticos]

Probably bad solder because of corrosion.
Remove the chip, put leaded solder on the board pads and resolder it.
Or directly change it with one from donor board.

 

[macRepairAmb]

Replaced U4830. Now fixed.
Thanks for the support as always.