820-00923-A Touch Bar Problems (no signs of liquid)

[KC Micro Tronix]

hello, I have a 820-00923-A I can not find any indication of liquid damage in any way. The Touch Bar display works and is normal but it does not respond to touch. I verified that the power rails to the touch bar are good. I have no clue as to the data and do not have a touchbar laying around to test with.

Has anyone seen this? Does anyone have additional insight to which data lines are for what and what they should look like?

Thanks
Randall

 

[tcampbell34]

I just had a A1707 (820-00281) with the same issue and found that R4453 was missing from the board. R4453 is a 0 ohm resistor that connects DFR_TOUCH_SPI_MISO to DFR_TOUCH_SPI_MISO_R. Once that was replaced, the touch bar started responding to touch again.

 

[2informaticos]

J4401 is for display and J4402 for touch function.
SPI communication is used for touch, so check all related resistors.
Don't forget to check reset and detect signals.