820-00850-A no Camera

[mbcontrol]

I'm working on a A1989 with 820-00850-A. The machine came with the following issues: Camera not working, all four USB-C Ports not working and the battery needs to be changed. This Macbook was the dirtiest one I've ever seen. The entire machine was completely full of dust inside.
The contacts of the four USB-C Ports was heavy damaged and some of them was also shorted together. I think this came from a non original Charger or adapter. After cleaning the machine and changing the DC-In Flex-Cabels the MB works fine. Only the Camera issue is still present.

ALS is working.
I tried a known good Display/Camera - same behavior.
The Oszi shows no Datacommunication on I2C_FTCAM_SCL and I2C_FTCAM_ISOL_SCL.
I2C_FTCAM_SDA and I2C_FTCAM_ISOL_SDA looks normal.
I changed the U8502 without any effect.

PP1V8_G3S = 1.80v
SEP_CAM_DISABLE_DFF_L = 1.80v

 

[2informaticos]

Compare diode mode readings between SCL/SDA lines.
Be sure R5336 and R8508 are good.

Also check MIPI_FTCAM lines.
Pay atention to series coils and traces continuity.

 

[mbcontrol]

The resistors R5336 and R8508 seemed ok, but I replaced them just in case.
I can't find any problems with the traces

Here are my Diodemode measurements SCL/SDA:
I2C_FTCAM_ISOL_SCL = 0.72v
I2C_FTCAM_ISOL_SDA = 0.72v
I2C_FTCAM_SCL = 0.45v
I2C_FTCAM_SDA = 0.47v

Here are my Diodemode measurements for the MIPI_FTCAM lines:
MIPI_FTCAM_CLK_N = 0.72v
MIPI_FTCAM_CLK_P = 0.72v
MIPI_FTCAM_DATA_N = 0.72v
MIPI_FTCAM_DATA_P = 0.72v
The OBData values for this lines are something around 0.53v. Could this be an indication of the cause of the error?

MIPI_FTCAM_CLK_ISOL_P = 0.76v
MIPI_FTCAM_CLK_ISOL_N = 0.75v
MIPI_FTCAM_DATA_ISOL_P = 0.72v
MIPI_FTCAM_DATA_ISOL_N = 0.75v

MIPI_FTCAM_CLK_ISOL_FILT_CONN_P = 0.75v
MIPI_FTCAM_CLK_ISOL_FILT_CONN_N = 0.75v
MIPI_FTCAM_DATA_ISOL_FILT_CONN_P = 0.72v
MIPI_FTCAM_DATA_ISOL_FILT_CONN_N = 0.75v

What do you think could be the cause here? Is it a problem with the T2?

 

[2informaticos]

Change again U8502.
Be sure to get good solders.

 

[mbcontrol]

I changed U8502 again. And i renewed R5335, R5336, R8507 and R8508.
I also paid particular attention to the soldering.
Same behavior.

Do you have another tip for me? Or do I have to give up the camera function.

 

[2informaticos]

Did you change small video cable too?

 

[mbcontrol]

Yes i did. And i tested with two known good Displays. i'm pritty sure it's an issue from the logicboard.
Like i wrote in my first post - The Oszi shows no Datacommunication on I2C_FTCAM_SCL and I2C_FTCAM_ISOL_SCL. On two other known good boards there is a short Datacommunication at 6-9 seconds after starting the board. At this board there is only straight 1.64v - see also picture in the attachment ...

 

[2informaticos]

Just in case, save data and try DFU restore.