Macbook A1706 touchpad and keyboard not working. Please help

[B2L_Repairs]

Hi guys i am new to macbook repairs (i mostly do microsoldering on iphones and android devices. I need your assistance with macbook a1706 (touchbar edition) that came in without touchpad and keyboard functionality. External keyboard and mouse does work but the keyboard and touchpad on the macbook does not work. I changed the touchpad flex, also replaced the touchpad but the issue persisted. I then measured voltage on the board and found that PIN 44-50 of the touchpad connector (J4501) got 11.2V instead of 12.6V. Those pins required 12.6v and they get their 12.6v from PPVIN_S4-TPAD_FUSE . I measure the voltage by PPVIN_S4_TPAD_FUSE and got 11.2V by the PPVIN_S4_TPAD_FUSE instead of the required 12.6v as required by the trackpad connector (hence I am getting 11.2v by the trackpad(j4501) connector pin 44-50). I checked the ppvin-s4-tpad-fuse , it get its power from ppbus_s4_hs_tpad..and the ppbus_s4_hs_tpad get its power from the ppbus_g3h. I measured the voltage on ppbus_g3h it's inputting also 11.2v instead of the 12.6v hence the MacBook is not getting sufficient voltage for the trackpad. So now I don't know how I can restore the required 12.6v on the ppbus_g3h. I don't know if there is a cap that might be short or maybe an ic. Somebody said its an SMC issue but I am new to Mac repairs so i dont know much on how i can check the smc, your help will be highly appreciated

[reformatt]

Re: Macbook A1706 touchpad and keyboard not working. Please help

PPBUS_G3H will vary up and down depending on the voltage of the battery, so I don't believe that is the source of your problem. Measure it without battery connected and it will be 12.6V if everything is normal. Naming changes on these rails due to them going through sensors etc.

Check for presence of PP5V_S4, PP3V3_S4, PP3V3_S0 and SMC_LID at the connector. If the board has been previously worked on, then I would go over the entire board looking for damage (like missing hall sensors on either side of the board and damaged Touchbar connector etc).

[B2L_Repairs]

Re: Macbook A1706 touchpad and keyboard not working. Please help

i do have pp5v-s4, pp3v3 s4 and pp3v3-s0...just that i have 11.2 instead of 12.6v on the fuse. The smc lid is readimg 3.4v.

[B2L_Repairs]

Re: Macbook A1706 touchpad and keyboard not working. Please help

PPBUS_G3H will vary up and down depending on the voltage of the battery, so I don't believe that is the source of your problem. Measure it without battery connected and it will be 12.6V if everything is normal. Naming changes on these rails due to them going through sensors etc.

Check for presence of PP5V_S4, PP3V3_S4, PP3V3_S0 and SMC_LID at the connector. If the board has been previously worked on, then I would go over the entire board looking for damage (like missing hall sensors on either side of the board and damaged Touchbar connector etc).

the board was not worked on before, only battery was replaced. As mentioned i do get 5v on PP5V_S4, 3.3V PP3V3_S4 and 3.3V PP3V3_S0. I also meaured the smc lid on the connector and i get 3.4V. Only voltage that is less than normal is the 11.2V instead of 12.6V on the fuse. So i dont konw what else to check. I was thinkink maybe smc line as somebody once said in another group. What voltage should i inject into the mac because when i measure the voltages the mav will be plugged in to a normal type c cable (its my samsung type c cable, not original mac type c cable)

[B2L_Repairs]

Re: Macbook A1706 touchpad and keyboard not working. Please help

PPBUS_G3H will vary up and down depending on the voltage of the battery, so I don't believe that is the source of your problem. Measure it without battery connected and it will be 12.6V if everything is normal. Naming changes on these rails due to them going through sensors etc.

Check for presence of PP5V_S4, PP3V3_S4, PP3V3_S0 and SMC_LID at the connector. If the board has been previously worked on, then I would go over the entire board looking for damage (like missing hall sensors on either side of the board and damaged Touchbar connector etc).

smc lid is reading 1.8 in diode mode but it's supposed to be OL. Might that be problem aswell