A2141 820-01700-A MacBook Pro (16-inch, 2019) 2.3GHz i9 32GB RAM 1.0TB SSD - Unable to wake from extended sleep

[zeg12345]

If the lid is closed or the system is put into sleep mode for more than 30 minutes or so, then when I try to wake it back up by tapping a key or by tapping the power button I get no response. The device is warm but the CAPS lock light on the keyboard is unresponsive. To get it to reboot and be functional again I have to hold down the power button to force it to power off, then when I press the power button it reboots normally. I erased the system and reinstalled macOS to do a factory reset, and the issue still persists. I replaced the logic board and the issue is resolved with a separate known good logic board. I installed the logic board with the issue in a separate known-good same-model computer and it brought over the issue, indicating to me that this is a hardware issue with the logic board.

The question that I have is, how can I diagnose the cause of the issue on the logic board? What are the first steps and how can I begin to approach fixing the logic board?

Thank you for any help you can provide!

[Stephen]

Sleep issue seems to be going on with the board, I would pull up the schematics and look at the sleep area and use a good known logic board and check the readings on each area related to sleep. Could have a simple resistor that is failed or cap, not 100% but without knowing what your readings are it would be hard to help until we get some readings. Do you have board view and tools to repair the board?

[zeg12345]

Thank you for the response! That's a great idea. Yep, got the boardview/schematics and equipment. I'll explore with a similar model and see if I can find a difference in readings. Thanks!

[zeg12345]

So I'm finally getting around to testing this out, but I'm having difficulty finding out which components on the board are related generally to the sleep / wake functionality. I'm finding that U3900 has a lot of connected lines labeled with "WAKE" and "SLP", and I've also thought about checking out which components are in line with the lid angle sensor connector, but I'll admit I'm not very knowledgable in this area and it's difficult to find good resources online. Anyone able to educate me or point me in the right direction? Thank you!