MBP 2019 16" (A2141) LCD went out.

[Ajm121]

Hey Friends,
I have an MBP 2019 16" (A2141), i9/64Gb/1Tb, and recently the LCD went out. Not flexgate or Dustgate. Backlight is on and works, the board still works and posts to an external monitor. Not a software issue, absolutely nothing shows up onscreen except for backlight glow. opened the bottom cover and resistor L8504, a 120 ohm resistor (I believe) is fried, and fell off the mobo with a gentle touch. after it fell off, same problem with zero change observed which is why I think it is the issue. That resistor, acc to the 820-01700 motherboard schematic, goes straight to pin 46 on the Apple J8500 "EDP" display connector, which goes to the daughterboard on the screen.

I am seeking help as to how I can fix this, this level of technicality is new to me. Thank you in advance. I am an experienced solderer, but heating up microelectronics is also new to my skill set. That being said, I am willing to do any repair to save the machine.

73.

[reformatt]

L8504 is what Apple call a filter. It's not a resistor but an inductor. Its power for the Ambient Light Sensor in the camera assembly. So the MAC may have put your screen brightness to minimum level (see if you can alter it via Fn buttons or in Display settings on external monitor.

You'd need to ascertain why the filter has detached. Is there a short on this line or was it from some kind of liquid damage. First thing for me would be to check inside the connector for J8500 on the motherboard and on the LCD daughter board. This often gets liquid damaged and destroys U9850.

[Ajm121]

Thank you so much my fellow badcaps legend! Does this mean I have to rob a filter part from another device? By the way, I can adjust the backlight brightness with the touch bar and see a visible result. I also was looking at the schematic and wondered why the camera sensor would have such an affect on the screen. thanks again for the reply

also the liquid damage idea is a good one and I will look right away!

73

[anhbanxoi]

Try to measure EDP_INT_AUX_P and EDP_INT_AUX_N signals in Diode mode. I think you will need to change U9850. I got the same problem in few A2141s.