Macbook Pro 16" 2019 stopped turning on one day, SMC reset doesn't help

danryu wrote:

However, I see that "failing to power on" is not in the list of symptoms that this is supposed to address. But maybe it is still worth attempting, once I can secure another Mac to do so.

How do you know for sure the laptop is not powering on? There are very few indicators to know this on these USB-C Macs. Even when I open up these laptops I cannot always tell if the laptop is powered on or not. I'm considering the possibility that the laptop may be powering on, but has no video, or has an issue with the T2 security chip which controls a lot of this laptop's activities.

Question: when you wrote "the tiniest little things" what kind of thing are you referring to?

It can be noticing a slight flicker, or noticing a very slight faint sound, or perhaps the absence of something. It is just something techs develop with years of experience troubleshooting systems including intuition. If you happen to use Apple Configurator to perform the DFU firmware Revive, then you may be able to see the laptop changing states since Apple Configurator does sometimes inform the user, but it is just very basic information.

I've already experienced the required repetition issue you described. I feel like if you could convey a bit of your insight, I might just crack this :)

Even with my experience with these T2 Macs which I support for my organization, I cannot always be sure what is or is not happening with these laptops. At some point I just have to give up after multiple attempts. It is extremely frustrating. When we've replaced the Logic Boards on some of these laptops, the laptops work again, but there is no way to be sure until a known good Logic Board is used to test the laptop. Now that I've seen so many Logic Boards fail (or suspect they have failed due to inspecting Kernel Panic logs) I no longer recommend repairing them due to the exorbitant costs knowing the replacement board will have the same potential issues. This forum has many recent posts of people having their MBPro 16" (2019) Logic Boards replaced.....even the replacement Logic Boards have failed within days of receiving the repaired laptop back.

Having an experienced tech examine the laptop and trying these steps is the best option to confirm the diagnosis since an experienced tech is more familiar with performing these tasks. I still have problems getting some of these Macs into DFU mode.

I would be pleasantly surprised if you are able to revive this laptop without a hardware repair.

It is extremely hard to troubleshoot these USB-C Macs because they provide no feedback to what is occurring (no LEDs, many times no startup chime, no sounds to know it powered on, even the fans don't always spin even momentarily). Even a working USB-C can get into a state where it is hard to power it on especially after an SMC Reset. It is nearly impossible to provide remote assistance for this particular issue because it requires being able to notice the tiniest little things, plus sometimes you need to repeat the processes multiple times where you may get lucky to have the system react.

You can try a DFU firmware Revive to see if that makes any difference. In my experience it rarely does anything for the Intel Macs, but it does not hurt to try.

I really hope you have a good backup since it may be impossible to access the data on the internal SSD now.

Talk to the vendor and see if they can be accommodating is some way. For example, maybe they would try to exchange or fix it for a modest a fee. If their modest warranty has expired, they don't "owe you". Remember to be polite and professional, because then you might be salvageable as a happy repeat customer.

Users who scream and threaten to sue everybody will never be a happy customer, so they get no accommodations and get shown the door.

I suspect you're right (sorry); a logic board failure could well be the issue. Do you have any warranty on your Mac?