820-02773 Crashing When Screen connected

CRC2018

Member
So i've got an A2338 in with the 820-02773 board and a very strange issue. Whenever the internal display is connected the machine sometimes works for a bit, sometimes doesnt even load the OS and keeps purple screening and rebooting. The behavior is the same with another 820-02773 board which I tried in the machine - it causes this board to start purple screening also.
For an experiment I removed LP610 to kill the 5V to the webcam just in case that was causing the problem but unfortunately the fault remains - machine works fine on external with the screen disconnected but will not stay on and keeps crashing and purple screening with the display connected. I've put the board into a known good base housing and it continues to reboot with its display connected.

I do not have another known good screen to test this board on but i'm assuming that given I tried another known good motherboard that the fault lies within the screen assembly. Is there anything I can do to identify which part of the screen assembly is causing the issue and disable it? The display itself looks and works great for the few seconds it stays on!
 

2informaticos

Administrator
Staff member
Camera can't cause image artifacts.
Check if 3V3_SW_LCD and LPDP_INT_HPD have stable voltage.

Are you sure nobody connected an Intel based screen before (for testing purpose)?
 

CRC2018

Member
There are no image artifacts - when the screen works it works great. The issue is it's crashing the board and making it reboot. Unsure about the history of this board to be honest. As I said before I tried a different board in the machine and that one also crashes and reboots when this screen is connected. Both boards work perfect when connected to external monitor. Occasionally it will stay on for hours without issue with the screen connected.

The only slightly weird behaviour which occurs with both boards - they both still think the internal display is connected even when it's unplugged - I presume that is a quirk of the M2 chip?

I'll check those voltages and report back!
 
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