820-00840-01 ALS dont work

[ntcR]

Defective C7420 (burst) on PPBUS_G3H_CPU was exchanged.
During the test HWMonitor Mainboard shows 128 ° C (possibly no sensor?)

ALS does not work
The system hangs, windows close by themselves. PRAM reset (3x) and SMC reset do not help
Could use some help

 

[2informaticos]

The machine works good disconnecting webcam?

 

[mbcontrol]

Hello 2informaticos, it's now me working on this machine (ntcR is a work colleague from me).

Disconnecting webcam means disconnecting the display (LVDS)?
Or is there another connector only for the cam?
The machine runs now for 1/2 hour without problems over ext. HDMI

 

[2informaticos]

The webcam connector is on T-CON, in the LCD assembly; the smallest connector.
Disconnecting LCD from MLB and using external monitor, also disconnects ALS...

 

[mbcontrol]

ok, the machine runs now 1,5h without any problem. Before, the longest time was ca. 40 minutes.
What does that mean.

 

[2informaticos]

As I said, reconnect internal monitor and disconnect only webcam from T-CON.

 

[mbcontrol]

It's running now more than 4.5h without any problem - with only webcam disconnected from T-CON.

 

[2informaticos]

Then is ALS issue.
You can try removing R8556/58, but camera may not work anymore.

 

[mbcontrol]

I removed R8556 and R8558, but the camera is still running.

 

[2informaticos]

If camera still works and ALS problem disappeared, that's good.

 

[mbcontrol]

ALS don't work. I am now testing whether the crash problems still exist.

 

[2informaticos]

ALS doesn't work, of course; that's the reason to remove R8556/58.

 

[2informaticos]

Somehow, ALS screws the I2C bus communication.
And SMC cannot read the other sensors connected to an interface from the same bus.