Chosen Solution
Sorry for my English, come from Germany. I have a Macbook Air 13" 2014 Board 820-3437-B, no water damage or anything else. It booted permanently in the loop with the startup sound. I exchanged the EFI/SMC chip for a reprogrammed one. Now it takes about 1 minute until the start tone comes and after about 1 minute the Apple logo appears with the bar. The bar will load for about 45 minutes until the end and then stops. Nothing happens anymore. I can’t go into recovery mode. Everything is fine on the logic board, no corroded areas or the like. SMC reset, NVRam reset, I did everything. Apple diagnosis showed no errors. I also disconnected everything from the logic board and tried to start it blank, so only display. Without keyboard and trackpad. Can anyone help me? Translated with www.DeepL.com/Translator
An diesem Punkt ist klar, dass Ihre Logikplatine noch ein Problem hat. Jemand mit tieferen Fähigkeiten müsste herausfinden, warum der SMC-Chip ursprünglich durcheinander geraten ist und warum Ihr Ersatz so schlecht funktioniert. Angesichts des Aufwandes ist es möglicherweise billiger, einfach die Logikplatine zu ersetzen MacBook Air 13" (Mid 2013-Early 2014) 1.4 GHz Logic Board und wenn bei Ihnen nur ein 4-GB-Board vorhanden ist, ist ein 8-GB-Board ein gutes Upgrade. English: At this point its clear your logic board still has an issue. Someone with deeper skills would need to dig into figuring out why the SMC chip got messed up originally and why your replacement is acting so badly. Given the amount of effort it maybe cheaper to just replace the logic board MacBook Air 13" (Mid 2013-Early 2014) 1.4 GHz Logic Board and if yours is only a 4 GB board a 8 GB board will be a good upgrade.
