820-02020-A camera issue (M1 2020)

[formerunicornbroker]

A customer stepped on her screen and cracked it.
I replaced the screen and got a 'camera not connected' issue when testing in photo booth.
I put it down to a faulty camera in the display assembly (not the first time).
I replaced it again and the issue remains. Out of curiosity, I tested with the customers original screen and the issue is still present.
Has anyone experienced this before or know what I'm up against here?
The display cable looks fine and I cannot see any physical damage to the body of the unit.

I do not have FlexBV and the only schematics I can find for this one is a BVR file that can't be opened with openboardview so I am a little in the dark here.

 

[2informaticos]

Possibly the power rail fuse for camera is burnt.
LP610 goes to pin 46 of LCD connector, JP600.
Boardview available on the XinZhiZao server.

If the fuse is good, check the series resistors from data lines, LP602/3.

 

[formerunicornbroker]

Thanks for that, I found the boardview/schematic.

LP610 is good
LP602/LP603 both have values of 3.0 - 3.2 ohms between pins 1-4 and 2-3

 

[2informaticos]

Ambient Ligh Sensor works?

 

[formerunicornbroker]

It seems that it does not. Putting my hand over the sensor does nothing.

 

[2informaticos]

Do you get 5V_CAM at JP600?
Be sure all resistors RP650-7 and traces are good.

 

[formerunicornbroker]

5v at JP600 pin 46
0.2ohms on RP651, 653, 655, 657 (populated pads) and the area of the board all looks clean, traces fine

 

[2informaticos]

New LCD assembly, may not have ALS; is classic for chinese bullshits.
But the webcam should be good.
Check if ALS works with the original/broken screen assembly.
Try directing a flashlight to it.

Nothing appears on system report about camera?

 

[formerunicornbroker]

The old screen is very broken so it is hard to tell. I can only see light between the cracks but it doesn't seem to dim when the sensor is covered.
System report is blank under 'camera'
One other thing i noticed is that the touchbar works but sometimes takes some extra time to turn on after system has booted. Not sure if it is related.

 

[2informaticos]

Keyboard backlight must react when ALS is affected by direct light, not only screen backlight.

 

[formerunicornbroker]

Good thinking!
Keyboard backlight actually doesn't seem to be working at all with old or new screen

 

[2informaticos]

That is because ALS is not detected also.
ALS and camera have common 5V power rail.
Check if you get 5V at T-CON camera connector.

And on this machine, one may not work alone; possibly ALS and camera must be both detected.

 

[Kappy]

Thanks for that, I found the boardview/schematic.

LP610 is good
LP602/LP603 both have values of 3.0 - 3.2 ohms between pins 1-4 and 2-3

Sorry to jump in but can I ask where you found the boardview for this model. I too have the BVR but would really like the other version. I tried the XinZhiZao server but our company won't allow due to 'virus detected'

 

[2informaticos]

I didn't see the boardview in other place.
Let us know if you find it, even on paid website.

 

[formerunicornbroker]

Sorry I'm not sure what you mean by t-con camera connector.
Both sides of the fuse show 5v.
Or do you mean on the display board? If so, the test points arent marked..

 

[2informaticos]

On that board should be a small connector for camera.
Disconnect it and check if 5V arrives there, on any pin.
You can check in buzzer mode (without power), if 5V ALSCAM line has continuity with something on T-CON board.

 

[formerunicornbroker]

I cant seem to find 5v on either of those small connectors or continuity between LP610 and the connectors

 

[formerunicornbroker]

I am in the midst of getting another replacement screen to triple check the screen

 

[formerunicornbroker]

Still no luck with a new screen, this is a strange one

 

[2informaticos]

Remove T-CON from cracked screen assembly and check where the 5V ALSCAM should arrive on it.
You may have problems with the video cable from MLB to T-CON.