Chosen Solution
Hello ! I’m struggling with my sister’s maccintosh, I’m an IT engineer with some small electrical knowledge… Failure symptoms are : (A) When turning on the computer, everything is normal for 0.5 seconds (all the peripherals are powered), then everything shut down -> The computer does not boot.When battery charger is plugged, the computer try to turn on and loop each ~ 3 seconds on symptom (A)Every ~ 40 hours, the computer does a successful boot.During a successful boot, everything works well, RAM / Disks / etc are OK, Syslog is OK, software is OKThe logic board have same issue without peripherals plugged in (Disks, RAM, trackpad, keyboard, WiFi etc.)Both RAM & optical drive have been replaced 1 month ago for 8 GB RAM & SSD (with compatible units)Reset SMC works but does not resolve issueThe logic board have no sign of grilled components If I send the computer to Apple (after cleaning my hardware changes), they will surely detect a logic board failure and charge me for ~400 USD to replace it. I want to repair the logic board, not buy a new one. I think this mess is coming from a capacitor that have some issue to full charge. IMO, that would explain the ~40 hours to wait for a successful boot. Could my conclusion be correct ? (Capacitor failure)How can I check which capacitor is failing ?Can I try to replace it ? (I love to repair ‘hard stuff’ like this)Did you have some nice gifts for Christmas ? Thanks for reading, sorry for bad english (not my primary language) and happy holidays (if you have some) Matthieu
While symptoms can often lead us to a problem. The length of time the symptom is present can make diagnosing much harder. I would recommend to get a set of schematics for the system and start by reviewing the power rails as I’m suspecting that is the issue here. But before you start tracing, how about making a detailed inspection to make sure you don’t see any burnt components or liquid spill damage.
All else failing, call Apple at 1-800- MYAPPLE and request a Flat Rate Depot Repair. In Texas the total cost with shipping and taxes is $357.00. Total time is four days and they overnight the shipping box. For this fee, they will fix any and ALL things that are not working as long as it hasn’t received a sever impact or been liquid damaged.
