Chosen Solution
Bit of background - my wife’s Macbook A1534 had a broken screen and chassis due to physical damage. I bought a comparable model with a dead logic board on eBay, and I transplanted her logic board into the new one. Everything worked fine for a few weeks, until she was recently unable to turn it on after letting the battery die. There is no power, nothing. I tried resetting SMC and PRAM to no avail. So I decided to pop it open again and replaced the I/O board flex cable and tried plugging it in before I reconnected the keyboard and reassembled everything. Surprisingly, it turned on again! But the keyboard wasn’t plugged in, so I couldn’t turn it back off… so I let the battery die again, and reconnected the keyboard and reassembled everything. This time, I couldn’t get it to turn on. I spent a bunch of time troubleshooting… tried removing and re-inserting the I/O board cable, replaced the I/O board itself (i.e. the USB-C/charging port), punching in every combination of “reset” keys I could find online, disconnecting/reconnecting the battery, etc. Nothing works. I initially thought the logic board was bad, but I don’t know how I got it to briefly work. Any thoughts?
This Macbook is a beautiful machine but it’s quite troublesome when it comes to repairs. There’s a small button on the logic board that has to be pressed until the led goes off, before anything else, to discharge residual power from the board..did you do that ? After reassembly the 2015 model cannot be simply plugged in with its Usb-C adapter, but first it needs to be charged for a while with a lower voltage adapter, such as an iPhone or iPad charger, otherwise the logic board might take some damage. Was that done ? If answer is no to either question, that might explain the problem you’re facing right now.
