Why did two of our MacBooks die overnight?

Good Morning Reddit

I have a few questions about two of our Macbook Pros that died overnight. FYI I don't know much about the internal of the Logic Board, so please talk simply.

The story of both MacBooks are about the same, the only difference is that one is a 14', the other is a 16'. So here is what happened.

One evening one of my coworkers had shut down their laptop. I dont belive that there was an update recently before that, but it is possible (I can't check, because it's bricked). When he tried to start it back up in the morning, nothing happened. No fans, no screen, nothing. So he brought it to us. So we opened it up and looked around the board to see if anything was wrong. All looked good, so we disconnected the trackpad to get to the battery, but at that point it spun to life (you do have to start the wake up sequence, but it did start up). But even though it started up, only in some sort of fail safe boot mode (Fans at 100%, no screen). I believe it does this because of the heat sensors in the trackpad. But that would mean that there is either a short on the trackpad, or on the logic board on the way to the trackpad. The next thing I wanted to try was to get it into DFU mode. But that also didn't work. The MacBook that I connected it to, saw that a MacBook was connected to it (I just looked in system information), but I couldn't get it in to Apple Configurator. After that I also tried swapping out the trackpad with a known good one, and it still didn't work. So as a last resort I went to test it with a multi meter. The setting on the multi meter was 200 Ohm, and black was always on one of the screws. After that I checked the connector on the logic board for the trackpad. I went through and checked the measurements of all the pins (this next part is only when you look at the connector, when the trackpad is at the bottom, left to right, also im not quite sure if the PIN numbers are quite correct, they are so small). Top Row: Pins 1-8 measured nothing, pin 9 measured about 1.3, pins 10-14 measured nothing, pins 15 - the last three measured from 1.2 - 1.5, the last 3 measured nothing. The bottom row is similar, but a bit different. Pins 1-8 measured nothing, pin 9 measured 1.3, pins the last 8 - the last 3 measured 1-4 - 1.5, and the last 3 nothing. I checked to see if anything looked corroded or a bit of, and all looked good.

Here are also a few more observations. When charging for about 5 mins, a component near the trackpad connector got a bit warm (warmer than anything else). The label on top of it was 2R7, I was told it is some sort of thing for the electricity. So the short must be in between that and the connector. Also when I boot it up (I first have to disconnect the trackpad) and than after that I connected the trackpad, it worked like before, fans at 100% and no screen, but as soon as I connected a MagSafe Cable, it shut down instantly.

Both of the MacBooks died about a month apart. First the 16', than the 14'.

That's about all I have, and I would be very grateful for any help on this case. If it would be possible, I would like to fix it myself, because it would be a nice way to start micro soldering and they are already bricked, so I can't make it worse.

I hope you guys have a wonderful rest of the day. Be blessed!